So I Autocrossed My Silverado This Weekend........ [Archive]

Tydriver

03-13-2017, 11:35 AM

I have this thread posted on other sites, but I have some suspension specific questions so I am posting here to hopefully add some enthusiasm from the group to the questions I am going to be asking..

I gotta tell you.. It's been a long time since I have autocrossed or for that matter, competed in any SCCA event. The last time I did it was in a BMW e30 that was 50/50 weight distribution from the factory. Clearly a full size 4WD Silverado doesn't share this luxury. When I bought this silly truck with this crazy idea (take a full size 4x4 Silverado and autocross it competitively) in mind like 5 years ago and it's been on hold ever since.

Here's what the truck looked like when I bought it ...

https://cimg1.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/800x600/80-14079787_10209854707394052_4016905725386006243_n_3 60bb67a624e3fcf257db53d56a894f1e7bfee40.jpg

Well over the winter, I started by converting the front end to Atomic's coil over suspension (deleting the torsion bars) and installing McGaughy's drop spindles on the truck. A lot of work, but pretty straight forward. Richard (Atomic) was great, I ended up changing my mind a couple of times during the process and he was great to deal with, and quick to get the parts out.

After I completed that installation, I turned to the rear of the truck. Last winter I chose to deliver the truck to Jeff and Mike at JSM and asked that they build a bad-ass 4 Link that can withstand the rigors of an autocross and tolerate future HP mods in mind, specifically stand up to a forced induction LS motor. Jeff and Mike have been extremely helpful, communicative and very willing to offer advice as I try to dial the truck in further. They are also a Viking dealer so I get parts quick as I try to get shocks/springs working together to support this big gal. Couldn't be more happy with this kit!

This is what was installed, my truck was the prototype installation for this kit, but I am very happy with how things turned out.

https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x735/80-15288508_532358966973629_9016018769666530513_o_581 179d540ac2108546be6db6ad450173560ab86.jpg

About a month or so ago, I got the truck back from JSM and have been tweaking on it to get the ride dialed into my liking. Playing with the Viking coil overs on all 4 corners can be a bit overwhelming, but I am making progress as I understand how it all ties together and works.

Here is what the truck looks like after the front coil overs and rear 4 link is installed:
https://cimg0.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x810/80-2017_01_30_13_29_38_b5e4314515aa76700b21fc0107b04c d52a39bf3b.jpg

I still have some changes to make regarding spring rates and dialing it in, it will be lower than pictured above. While I still have a ways to go in that department, I can not tell you how delighted I was to autocross the truck. I started off in RWD only and ran a few laps. Then switched to Auto 4WD and the truck responded amazingly! Not more sideways drifting action, I have to tell you, it is very very neutral. Over-steer is available if you dial in a little more pedal in RWD mode, but I ran most of my runs in Auto 4WD. While even in Auto 4WD it is possible to overdrive the truck, for the most part it goes exactly where you point it and responds quickly to steering inputs. During these runs, was there never any time I was worried it was going to roll or I was going to run out of luck and end up in the weeds or wall.

Arguably this truck will never rival a Corvette or a Viper in terms of handling, but I guarantee you, as it sits right now it will get the attention of many performance cars. The 4 link really woke up the handling, ditching the torsion bars and leaf springs is the best mod I've ever done.

I still have a little work to do sorting out the spring rates and ultimately adding a rear sway bar (not equipped from GM on these 4x4 trucks). When I get this work completed, well lets just say I'm very excited to get it done and see what she has..

Here is how the truck looked during the SCCA event (Not too shabby for a 4WD):
https://cimg2.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-2017_02_13_05_23_49_a43d548e7944f6fab1e008891e08ed b3dc20e3c3.jpg

The last run I had the tech guy from our local SCCA chapter approach me asking for a ride. I let him ride the first round and then drive the next.. As a self proclaimed Miata/Volvo guy he walked away from the truck amazed. He just couldn't believe that he had rode and drove a Silverado that quick around the course. Commenting how well the truck drove and relatively neutral it was.

I still need to make some minor changes in spring rates front and rear, as well as add a rear sway bar, then most of the suspension work will be complete. (Spoiler Alert) Big CTS-V brakes are coming for the front..

Anyhow, I have a bunch of videos up from this weekend, but here's a few of the good ones:

Bumper Cam View:
YIyYuH8Vofw

Top of the Windshield:
MT-90yXAVJ0

The two runs with the SCCA Tech Guy:
vSSuQGVVt7U

Tydriver

03-13-2017, 11:37 AM

Very soon I plan on going with a budget front brake setup..

The 14" Summit rotors and CTS-V calipers/pads I already have.. In fact I had a machine shop make me brackets a few years ago to adapt them to the sprindles around the 14" summit rotors.. I think I will have $450-500 into rotors/calipers/pads + machine shop building the brackets.. I just need to figure out the stainless lines to the Brembo calipers.. Definitely not as cheap as you mentioned, but waaaaaaaaay cheaper than the big brake kit.

Here's some a pics:

https://cimg8.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/900x640/80-picture_php_pictureid_10271_3e03b1309229de3b71284f e15ab0df51a303a360.jpg

https://cimg2.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/900x640/80-picture_php_pictureid_10275_9e351c8d69b1008d0c2573 855a5da5fb3c281f0c.jpg

Tydriver

03-13-2017, 11:40 AM

Good news ! Just got the notification my personalized plate from TN has been approved, that will be going on when I get it, no handling improvement, but hey..

I am very familar with Hydroboost, it just hasn't been installed yet.. It eventually will, but the stock brake system wasn't going to deal well with repeated stops from high(er) speeds ..... brake fade..... the CTS-V caliper/rotor setup was actually intended for my Avalanche that was a heavy bitch.. I designed it for that, and actually had 2 sets of brackets made and never installed either set.. So one is going on this truck.

I was surprised at how flawless it was in Auto 4WD. The truck was very stable and it was seemless power with virtually no slipping other than off the line until the front axle engaged. No creaks, groans or complaints.. I have a Silverado SS TCase (NP149) to install but damn.. This will let me push that off a bit until it starts to complain.

In other news, today I ordered 2 sets of Eibach coils (one set each for the front and one set for the rear). The rear spring rate was waaaay high, like 150# too much, and the front springs are supposed to be around 1100-1300, I have 650# springs currently installed (my mistake ordering them). So I am righting my wrong on the coils and hopefully going to be able to dial this thing in a whole lot better and level it out.

I honestly can't believe that it drove so well at the autocross. With my luck, I probably hit on some stupid offbeat combo that worked well.. Putting the recommended springs in on all four corners will make it handle like ass.. :bash:

Apparently spring rate coils that high are a bit of a unicorn..Nobody had the 1200# rate springs in a pair. Most didnt even stock it, or they didnt have a pair.. Amazon says 1-3 month delivery, Summit was backordered until first week of March.. Jegs didn't even show they knew what a coil spring was Ugh.. I found a vendor in CA that actually picked up the phone and verified stock with Eibach, and at $64/ea it wasn't too awfully bad. Hopefully they should be here within a week as they are being drop shipped direct from Eibach. I'll be sure to update when I get them installed...

Tydriver

03-13-2017, 11:41 AM

So while parts are still trickling in.. I decided I'll post up some pics from last Sunday's autocross event. The local SCCA group has a gal that likes to come out and snap some photos for us. She posts 'em up for us to download... Anyhow I got some good 'action' shots of Diabla doing work.....

https://cimg5.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1280x818/80-diabla1_e2dc23fd3bda4a1921764c8c671ecdda17c0a7d4.j pg

https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1280x818/80-diabla5_d61f8b01b978c6c3a7fd1a9f83d7356664b778e8.j pg

https://cimg7.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1280x817/80-diabla6_0abd9620931db84a9ef459db93e9a0bb1b9457b3.j pg

I have parts coming to do the eFans conversion, that will probably get started this weekend and I received notification that the springs have been shipped from Eibach so it's probably going to be the following weekend for the spring swappero...

Tydriver

03-13-2017, 11:45 AM

It figures, the parts that I want to show up the fastest just got shipped Friday (my heavier rate springs).. Looks like I am going to tear into the cooling system this weekend and start replacing all the hoses, the thermostat and 34" radiator. Then it's eFan install and PCM reflash with the EFILive.. I started to think that my cooling system is 14 years old and I want to beat the piss out of this truck this year, better do some preventative maintenance.

LOL. I guess by dumb luck I managed to hit on a very balanced combo in terms of tire sizing.. I have 275/55/18s on an 18x9 wheel. I was playing with tire pressure a little when I was a the autocross.. I went down 6 psi in the front and 8 in the rear.. I was in fear of rolling the bead off the tires.. As you can see in this video, it gave the sidewalls a workout, but it never rolled over on to the sidewalls like I have had happen on my BMW.

-D5RJ2bmLDI

Sadly, I don't have enough power for a bigger course, I can get the fury that a 4.8L can dish out to the ground as it currently sits.. About 3 years ago I installed a TruTrac in the rear, in 2WD it can put enough throttle in to break the rear end loose, once I go 4WD, it all changes. To be honest, I was dumbfounded how much it changed the trucks characteristics, at least on this course. It added a huge amount of stability entering and exiting the corners and virtually all the tirespin was gone unless I drove it in waaaay too hard and thats just driver error that no vehicle can make up for.

As far as moving things around, in all honesty I don't plan to do much. This truck isn't going to go full race mode. I will probably borrow a page out of Steve-O-08's playbook and move the battery when the current one expires, and I'd like to borrow his idea about the half height rollbar that would let me install 4 point harnesses. I mean it's always going to be a fat lady at the track, you can move the weight around, but she'll never hang with a Miata or Mini on a tight course.

My goals for this truck are: street truck first, race truck second. I still want to use the truck as a truck so I can't fill the bed up with all the underhood bits. Unless I lose my mind, this truck will probably retain the full interior as GM delivered it.

However, with that said I do see mods coming for the engine and transmission. I'd like a built 6L with a turbo or LSA blower, and I eventually will switch over to the Silverado SS AWD (NP149) T-case I have in the shed.... Dammit.. gotta add researching an Accusump system to the list...:hmmm:

Hydroboost, CTS-V brakes up front and SUV brakes in the rear will come too, probably sooner than the engine/transmission .

And I already have a quick ratio steering box that I keep forgetting about... Damn need to get that in place.. LOL

All these things take money and patience.. Getting the truck setup as it currently is hasn't been cheap.. I'm not complaining, I just need to settle down a bit on the spending :-D

Tydriver

03-13-2017, 11:47 AM

Alright guys, I've been busy though I looked at all of the events I want to participate this year and I questioned whether or not the 14 year old cooling system was upto the task of keeping me on the road. So I started to research parts and I wanted to upgrade the radiator anyhow since I have had an e-fan harness and some chinese e-fans now for like 2+ years..

Anyhow, I ordered the following:

every rubber hose under the hood that contained coolant including upper/lower rad hose, heater hoses and throttle body coolant hoses.

160* Lingenfelter Thermostat (nothing more than a re-boxed MOTORAD unit).

New Coolant Recovery tank and Cap.

New temp sensor for the driver's side cylinder head.

34" AC Delco Radiator.

Anyhow, I started ripping parts off last weekend, and finished it up this weekend complete with an PCM reflash to set the efans settings so the PCM controls them.
https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170219_123243_b0bbe056ca589f11385537b6445d62de5a bac483.jpg

I finished up the coolant system yesterday, and turned my attention to the spring issue.. For those of you who have been paying attention, you probably remember I was rolling on 650# springs on the front, which are, ironically, about half of what they should be.. I ran the first event (above) with those springs but the ride was miserable and there was less than 2" of travel before the truck rolled onto the bump stops. I got under the truck and measured the clearance between the lowest point on the front end and the ground.. LOL WOW !! It was the front crossmember and it was less than 4" off the pavement, probably in part why it drove well around the track, but rode like ass !!
https://cimg0.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170219_131231_51aa71bfcd06b678728a07538131120593 80ca7d.jpg

https://cimg7.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170219_131105_58d9d4e7329e472d60401cdcc5446dfed5 7b0b94.jpg

As you can imagine this spells bad news for CV Shaft angles in the front, this is event with McGaughy's 2" drop spindles... :EEK:

https://cimg0.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170219_131534_e33bdbcaa22317dee8e7d13a2becf39e11 d1c327.jpg

So I started the hunt for the correct (better) spring rate springs.. As it turns out, not every vendor has +1000# or higher springs on the shelf. LOL I guess not everyone is racing a fat bitch 4WD Silverado, who knew ??

Anyhow I did find a place in Cali that could actually access Eibach's inventory and tell me for certain that they could get and drop ship 1200# springs, so I ordered them and some softer springs (225#) for the rear as well.. Purple Santa brought me these:

https://cimg3.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170226_131245_eb8db782bdf720c1b68d77d98d1c30600e 635ecd.jpg

So today, I got to switching the 650# springs over (left side) for the bigger stiffer beefier Eibach 1200# springs (right side):

https://cimg9.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170226_132615_68f2ddfb5dcb2a91419cd748f17df05d7a 98acdf.jpg

So with all those swapped in place, the truck is done and I am a lot happier with the spring situation:

https://cimg2.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170226_135139_35521287f7b1537653bb7e4fd4892ffaef 4bc16b.jpg

Here's the truck at the current ride height, I ~think~ the front is pretty well sorted in terms of ride height, we'll see.. I still need to put the softer springs in the rear and lower it to match the front and I'll be ready for the next event:
https://cimg9.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170226_151412_637f0d3b34146a598366c552d2af91b7ba f7b34c.jpg

Next weekend, I plan on a transmission flush/fill, replace the smurf juice in the transfer case and top off all the fluids.

Maybe a trip to the local scrapyard to hunt down a set of SUV brakes for the rear and maybe a hydroboost setup? Who knows.

The next autocross is set for the weekend of 3-11 / 3-12 and I plan on introducing the truck to the Misssissippi SCCA crew, I'm hopeful they will be as accepting as the Tennessee guys are, I'll follow it up with more video for sure.

Tydriver

03-13-2017, 11:48 AM

So I got the rear coils swapped out for the Eibachs.. Out went the 12" Hypercoil 350# springs, and in went the 10" Eibach 225# springs, dropped the truck right where I wanted it.. Pretty simple swap, 4 bolts, a couple of spanners and an hour or so time.. It sits level now front to rear and I think it looks pretty awesome.. The ride is improved immeasurably as well !

Not too shabby for a 4WD truck thats still 4WD eh ??

https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1488x1488/80-diabla1_df785d5a825ed0c2fa6e66c8815b315d9f59ea45.j pg

I also got a chance to tidy up a few things also, I bought this double din radio from Wal-Mart for like $100 3 years ago.. It's nothing special, but better than what was in it and it has more options to load music into it than the previous one. Just waiting on the mounting kit to come in, it's wired up and functional.

https://cimg3.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1152x1152/80-20170305_173136_b5b0f0d0e82dbf6bc2acb768e6d4b86027 87738f.jpeg

The next SCCA event is next weekend, I'll try to get some 'action shots' of it in action.. Also gonna charge up my GoPro...

Tydriver

03-13-2017, 11:49 AM

Another autocross this weekend, then the Brembo caliper mod gets moved up the list. I am still not sure my wheels will clear the calipers so I need to check that, if they do clear then I need custom brake lines and I'll be ready to bolt them up.. I'll update the thread when it gets to that point.

In other news, I wanted to share with the group a tool I made a bunch of years ago (for dirt cheap) and used again tonight. I can't take credit for the design of it, but I think its worth passing on in hopes that someone else finds value in it and makes one for their own use.

I use this tool for refilling fluids under the truck/car. It allows me to put gear oil, transfer case fluid back in nearly effortlessly. I fought and fought for years trying to figure out ways to get the fluid back into these components after draining out the fluid. With this tool, I was able to change the front diff fluid, rear end fluid, tcase fluid in <30 minutes.

Basically take a $25 bug/yard sprayer (I'd recommend a new one), and install a $4 rigid valve stem in the top. I cut off the very tip of the atomizing spray nozzle so it comes out in a stream vs. mist. Heavier fluids like gear oil take a little longer to push through the tubes, the ATF or Tcase fluid moves a lot faster.

Once you have the valve core installed you don't have to use the manual pump, I usually pressurize it up to where the relief valve starts to unseat and hiss.. (You can see it in the first picture where the YELLOW is starting to show)

Make/use at your own discretion.. Here's a couple of pics:

Bug sprayer modded to squirt go fast juices into the underside of my cars..
https://cimg1.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170310_181707_416a4c015c0cd91e7155c5e0adfe8814c6 fdafa9.jpg

Servicing the Smurf Juice in the NP246.. Relatively drip free !
https://cimg5.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1000x1000/80-20170310_175948_debb276222510490d99516f6a005dda7ab 46b503.jpg

Tydriver

03-13-2017, 11:50 AM

After I installed the softer rear coil springs it lowered the rear of the truck down about 2".. This changed the way the 4 link reacted, specifically under hard throttle.. So before today's SCCA autocross event I bumped the front of the lower bar up another notch on the 4 link and it's back to planting the rear end! I'm really impressed with how this all works, I know theres even more gains to be had once I learn all of the adjustments.

Anyhow, today started off cold, overnight we had about an inch of snow here in Western TN. I started the truck up and headed south to Grenada MS for the first points event of the calendar. The day turned out to be a sunny and warmer day when it was all said and done, a great day for autocrossing !

I accumulated a total of 6 runs, but forgot to reset the camera on 2 of these runs. The first two runs I DNF'd, it was a very large course and I'll admit that even though I walked it twice I still got lost. I managed to get it together on the 3rd thru 6th runs.. At the end of the day, I finished within 9 seconds of the fastest car, a well prepped Honda S2000 running on R-comps.. Not too shabby for a 4WD Silveardo on street tires..

At the beginning of this project I admitted to myself that I had a snowball's chance in hell of finishing 'on the podium' at one of these events in the class that I would be put in. Significant suspension mods immediately put you in a cut throat class with SCCA classing. Anyhow, today I was lumped in with the other CAM cars (I run CAM-C, they were in CAM-T and CAM-S). So I ran against 2 Factory Five Cobra replicas on race rubber (one a small block, the other a 610hp 427 car), a very well prepped 72 Buick GS that was running on 315 rubber all the way around, and a Pontiac Fiero with a supercharged 3800 swap making 300hp, and I still finished reasonably close to them with this setup. I'm literally running against cars that have twice the horsepower, half the weight and race rubber !

I'm convinced that the truck has more in it, it really needs a driver improvement, a bigger swaybar and better brakes.. All to come at a later date.

Here's is one video that was the best of my runs today, there's three other ones on the channel if you want to hear me wringing the 4.8L's neck out !

UPIF4tZoiNo

The stiffer front springs are exactly what it needed, the softer rears helped also, just need to get the stiffer swaybar to help it more now.. Still undecided on that. The first mod for the brakes will be the Brembo 1G CTS-V 4 piston calipers and the big 14" rotors.. I'll get to the hydroboost and SUV rears eventually but still need to allocate these parts from the scrapyard. All I need for the Brembo/CTS-V swap is the fluid lines, once I get those they will be going on and I already own the expensive bits.

gnx7

03-13-2017, 01:34 PM

I love that you got this 2+ ton barge to handle!

WSSix

03-13-2017, 01:55 PM

Nice work on the truck! Are you aware that many Tahoes and Suburbans came with factory hydroboost? I'm guessing yes, but I just wanted to make sure.

Good luck with it!

Tydriver

03-14-2017, 08:15 AM

I love that you got this 2+ ton barge to handle!

Thanks man, I appreciate it.. It is doing a lot better than I anticipated actually.. Especially when I hit the Auto 4WD button and hammer down into a corner !

Oh and its 4600# the last time it was weighed by the guys doing the 4 link... I need to hit the scales and get some accurate numbers with me in it and post 4-link..

Nice work on the truck! Are you aware that many Tahoes and Suburbans came with factory hydroboost? I'm guessing yes, but I just wanted to make sure.

Good luck with it!

Yes indeed, thank you ! I just need to hit one of the local yards here and see if I can't get the parts I need to convert it over ! I'm going to convert the rear brakes over to the newer SUV brakes which are larger diameter and better calipers.. Gotta love the bolt on options for cheap !

SSLance

03-14-2017, 08:23 AM

Tydriver

03-14-2017, 10:28 AM

Love this build!! Showing up in something completely out of the box and giving the regulars a run for their money is as cool as it gets.

When does the T56 get bolted in? That would be my next mod for sure!!

Please keep us updated on the build and runs...

Thanks man, I appreciate it.. I started off with a GMC Typhoon years ago so it is sort of the theme I am following on this build = Lowered AWD Truck with a few changes, a powerplant that is easier to build and a larger supply of aftermarket support.

As far as the T56 is concerned, it's not likely.. I'm not certain there was ever a 4WD version of that transmission made, its harder to swap in and retain AWD :G-Dub:

I do have a 4L80e in the shed, and the input drum for the Np246 transfer case is available all day long for like $75 since GM put them behind the 80e in the 2500's !!

I'll keep you guys/gals updated, I'm currently researching swaybars and planning more mods, while trying to keep the truck streetable so I can attend local SCCA events.

WSSix

03-14-2017, 03:55 PM

Earlier GMT800 2500s did have a 5 speed manual option that could be swapped in. I tried to buy one long ago. Not sure it would be worth it though. You can always run a stall converter in the auto.

ScotI

03-15-2017, 07:43 AM

Very cool build!

choffert1

03-15-2017, 09:56 AM

Nice build for sure! I just ordered a Watts 3 link for my Syclone from JSM. They build a nice product.

Tydriver

03-15-2017, 06:18 PM

Earlier GMT800 2500s did have a 5 speed manual option that could be swapped in. I tried to buy one long ago. Not sure it would be worth it though. You can always run a stall converter in the auto.

Ya know, I never really considered swapping to a manual, I know the ohh-ahh factor would be up there, but from everything I've read the NV4500 doesn't like to be power shifted, I dunno, not sure of any of that is true, it's just what I've read. I looked around briefly today, mostly on eBay, they aren't terribly expensive, but I'll be honest when I say I know I can build my 80e and forget about it once it's installed. It will take any abuse I plan to throw at it, and while the gear ratios aren't as favorable as the 60e, as you mentioned I can stall it up a bit..

Very cool build!

Thanks man, I've been holding off on this project now for something like 5 years.. I am soo thankful to finally be moving forward it.. I have had some good people helping me along the way, and I'm having fun with it.

Nice build for sure! I just ordered a Watts 3 link for my Syclone from JSM. They build a nice product.

Congrats man, I love the Syclone !! It's a neat ass color, I had an Aspen Blue Typhoon back in the day and thats where I met the JSM guys from. Good peeps for sure and excellent quality. I told them if they had plans on selling the 4 link to the Fullsize guys, they should plan for guys throwing 800+hp in a 6000# crewcab with stickies on the back.. LOL, I think they responded appropriately, this will definitely handle the power and it's turning out to be a great mod so far for SCCA autocrossing.. I'm sure you'll be happy with the 3 link for the Syclone, they've sold a bunch of them !

Tydriver

03-15-2017, 06:31 PM

Has anyone messed around with splined swaybars ?? I've been doing some reading but I can't really find a definitive source that makes a comparison between splined bars (similar to Nascar style) and mass produced pre-bent bars..

I'll be honest, she rolls over on her side like a wet noodle with the stock bar.. I crawled under the truck today to look at the rear, egads theres a lot going on there with the 4 link, coil overs, gas tank, spare tire etc.

The front end of my Silverado is exactly 32" from outside mount to outside mount of the existing swaybar. I'm thinking I'd need a 34" bar plus the arms and links to connect to the lower A-arms...

I'm curious if anyone has any input on what diameter bar I should go with?? Are splined bars any stiffer than a pre-bent bar ? I know Hellwig offers a good sized bar for my truck, and a few others offer smaller bars..

My truck currently has a bar that's 1 1/8th thick now, can a person 'over bar' a truck ? I see splined bars running upto 2" in diameter.. I think that may be a bit overkill but I don't know...

I'm all ears if anyone has suggestions throw 'em at me !

preston

03-16-2017, 09:52 AM

Go the suspension and chassis sub-forum and read every sticky post at the top by Ron Sutton.

Quick synopsis on sway bars - All sway bars are just a metal spring. Mass produced pre-bent swaybars are notoriously difficult to model ie determine their exact roll rate, so its experimentation or crap shoot or follow someone else's lead. The splined bars are easier to model and the manufacturers provide rate charts for various diameters and widths with the catch that each manufacturer has their own method of rating them. Speedway Mfg is the most prominent manufacturer of the splined swaybar so you can easily stick with them. Determine what width of bar will work including a 0-5" bend in the arms themselves (arm lenght also affects rate).

Now you have no idea what rate you want, but if you are going from nothign to something, you probably don't want to go to far, especially since more rear roll resistance can lead to too much oversteer. My ballpark recommendation is to determine as I mentioned above the width and attachment points that will work, then go to the speedway site and see what is available. I would recommend starting with a 1" diameter hollow bar and fairly thin wall. Thinner wall means less roll resistance. Try it for awhile, and then maybe experiment with something thicker (easy to swap in and out).

You can also drill multiple holes in the arms, and by shortening the arms (by moving to the shorter holes) you can get a sense of what a thicker wall roll bar will do and give yourself some finer adjustment. IOW build something, buy a fairly thin wall bar and start in the longest holes, adjust to the closer holes to see if it performs better. If it does, you might want to try moving up the wall thickness.

For a rear swaybar I cannot imagine you woul dwant to use anything larger in diameter than 1", but who knows I've never tuned a heavy AWD truck.

YAMATHUMP

03-16-2017, 10:10 AM

Very cool project, I have an 83c10 that I am starting on so it is cool to see someone else make a truck handle.

Tydriver

03-16-2017, 02:50 PM

Go the suspension and chassis sub-forum and read every sticky post at the top by Ron Sutton.

I think this is very good advice, I will do this ASAP. I also placed a call to Speedway Engineering this afternoon and I am awaiting a return call from their tech guru. I am hopeful that they have some sort of calculator similar to a coil spring rate calculator, we'll see what they say..

Quick synopsis on sway bars - All sway bars are just a metal spring. Mass produced pre-bent swaybars are notoriously difficult to model ie determine their exact roll rate, so its experimentation or crap shoot or follow someone else's lead. The splined bars are easier to model and the manufacturers provide rate charts for various diameters and widths with the catch that each manufacturer has their own method of rating them. Speedway Mfg is the most prominent manufacturer of the splined swaybar so you can easily stick with them. Determine what width of bar will work including a 0-5" bend in the arms themselves (arm lenght also affects rate).

I agree, Speedway Engineering appears to be a pretty cool company from their website. I also see that there is a bunch of stuff on eBay too so there may be some more 'economical' choices available depending on my needs.

Now you have no idea what rate you want, but if you are going from nothign to something, you probably don't want to go to far, especially since more rear roll resistance can lead to too much oversteer. My ballpark recommendation is to determine as I mentioned above the width and attachment points that will work, then go to the speedway site and see what is available. I would recommend starting with a 1" diameter hollow bar and fairly thin wall. Thinner wall means less roll resistance. Try it for awhile, and then maybe experiment with something thicker (easy to swap in and out).

You are spot on about this, I have no idea what to order.. I am totally shooting in the dark here. That's why I am seeking advice !

I do have a couple of clarifications to offer however.. I do currently have a stock swaybar on the front, it measures 1 1/8th in diameter.

The rear of the GMT 800 Silverado trucks ('99-07) didn't have a swaybar from the factory on the 4x4 models (my truck). I am unsure yet if I will need/want one in the rear just yet.. I've upgraded other trucks and added swaybars to trucks that didnt have a rear bar with remarkable results. I will say, it was one of the best mods I did on my GMC Typhoon back in the day, but I never drove that truck competitively like I am this truck.

You can also drill multiple holes in the arms, and by shortening the arms (by moving to the shorter holes) you can get a sense of what a thicker wall roll bar will do and give yourself some finer adjustment. IOW build something, buy a fairly thin wall bar and start in the longest holes, adjust to the closer holes to see if it performs better. If it does, you might want to try moving up the wall thickness.

This is interesting, I hadn't considered wall thickness as a tuning tool, but that totally makes sense. I think I have 4 options for tuning at this point. 1) Wall Thickness of the bar. 2) Arm Length (not really an option as I have other suspension components to clear, cant get too crazy here). 3) Swaybar Diameter. 4) Hole Location in the Arm

For a rear swaybar I cannot imagine you would want to use anything larger in diameter than 1", but who knows I've never tuned a heavy AWD truck.

Yeah the AWD changes a lot of things vs. a conventional RWD setup. As a test I've done this a few times: I've run the same course, on the same day, only minutes apart in RWD; then again in AWD. It is amazing how much more stable the truck is exiting AND entering the corner. It's much more composed in AWD..

Interesting, the pre-bent aftermarket bars are 1 1/2" of 1 5/8" in diameter (I can't remember which).. The stock bar is just over an inch, but I believe it to be a hollow bar so I know the spring rate is pretty weak in comparison to the aftermarket bars or the splined bar option. I'll read up on the suggestion you made and hopefully between that and the call back tomorrow, hopefully I am more informed to make a decent purchase.

Very cool project, I have an 83c10 that I am starting on so it is cool to see someone else make a truck handle.

Thanks man, it's fun to play with my toy project again.. I need a tire sponsor though.. This pig can eat some rubber !! Another autocross this Sunday !!

Tydriver

03-17-2017, 08:00 PM

The SCCA club here has a gal that goes to the events and takes professional pics of the event, pretty neat to get action shots of your ride in action.....

I have a couple pics from the last SCCA event I attended, the next event is Sunday I plan on attending it.

Punishing the RF tire:
https://cimg2.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x764/80-imgp8961_f04ceb2da44e3adf5346c40d0e5e2b1cd69f0ab9. jpg

Look at this lean, this is why I need bigger bars:

https://cimg9.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x762/80-imgp5635_8b4f9d292375ecbfa35b48d73263de91595c6f54. jpg

Sieg

03-17-2017, 08:57 PM

I'm guessing a splined bar setup on that truck with tuning insight would money well spent.

Call Ron Sutton and hopefully you'll get along and end up throwing some money his way. :thumbsup:

Tydriver

03-20-2017, 03:23 PM

Back in the day, I installed a rear swaybar on my Typhoon and considered it the best mod I ever did to that truck, so I am not opposed to adding a rear bar. My bigger concern is that with the 4 link in the rear it is very busy back there in terms of mounting a swaybar. Between the 4-Link, gas tank, spare tire, driveshaft and misc brake lines, there's a lot of 'confusion' back there. If I decide to add a rear bar, I'll need to make a concentrated effort to get something that fits well without hitting other components. Not impossible, but not just an order & install affair. I want to get a better setup in the front and resolve that first before I start on the rear.

I placed a few calls today, one to Speedway Engineering, they said they are the manufacturer, and have limited application data available (read NONE). They recommended that I contact a chassis shop because with all the angles, and dimensions they don't really have any idea what I'd need.. Fair enough, they have their market, and it's manufacturing, not spec'ing out rides. Very friendly and positive people to talk to, just not their bag.

I called another chassis shop here in Tennessee and basically got the brush off, not certain but it felt like it was because my truck is too new. :EmoteClueless: Must be nice to be able to pick and chose what customers you want to work with.

So I finally called Ron Sutton, he was heading back from a show in Vegas and was very accomodating on the phone. Even though he was trailering back a display trailer from his show he took the time out to talk to me and laid out my options. Damn.. I need to start plasma donation or something to support my hobby. :G-Dub: LOL I'll follow up with more details as they get finalized.

In other news, I did another SCCA points event autocross yesterday, overall everything went well (relatively speaking anyhow). While I was doing corner-worker duty the skies opened up and it started to rain, sort of sucks when its only 50* ambient air temp and the wind is blowing. I was hoping for a full on rain as it would level the playing field in my favor significantly.

At this event there was 2 other cars in my class this weekend (that's a first).. A 4th Gen WS6 Trans Am and 5th Gen Camaro. The Trans Am was a purpose built vehicle that was impressive to watch, the driver was very talented. The 5th Gen Camaro was a nice piece as well but leaned a little more towards the street than track/course built ride of the T/A. The Camaro had a nice lumpy cam in it and was rolling on ZL1 wheels. Both cars were running sticky rubber (opposed to my street tires).

Anyhow I had hoped for a full-on rain, SCCA runs in the rain, only stopping for storms involving lightning. With my truck in Auto 4WD and on street tires it would have levelled the playing field exponentially in my favor vs. the RWD race tire guys.. Sadly, this would NOT be the case, by the time it was my turn to run the track was at best, damp. By the 2nd run, I couldnt even tell it had rained. However, on my first run, while it was damp, I was able to pull a giant Petter Solberg style drift around one of the corners. The back end broke loose under braking and began to rotate around pointing the truck into the direction of the corner. I slammed the throttle WOT and the front end just pulled it straight forward and into the corner in a slingshot manner.. Pretty damn cool and by far my highlight of the day..

Sadly the rest of the day didn't end well for me, I need to learn to slow down and stop trying to hammer the F#_%* out of the course. I continually over drove the course.. I'm am attaching my 5th run of the day for your viewing pleasure/laughter. It was set to be the best run of my day until I over-baked the last corner (intended to slow people down, which I didn't), and I clipped the last cone and blasted through the finish gate cones, taking out at least 3-4 of them and causing the two guys behind me to get re-runs as they were setting up the cones I destroyed.. :mad: Fortunately I didn't hit any timing equipment.

PfxMkUNhnRU

One thing I did find myself doing was I was 'hugging' the center console in preparation for turns!! I didn't realize that I was doing this before, and I am certain it isn't helping my technique. So I believe I will be working towards a harness of some sort or at the very least, a competition lap belt to help hold my butt in place!!!! In the mean time, in an attempt to compensate, I moved my seat forward about 3-4 clicks to help wedge me in place, at 6'5" tall it's not uncommon for me to get wedged in a car/truck anyhow. This did wonders for my technique and I actually felt better on my last 3 runs.. I can't believe I didn't do this before, I used to back when I autocrossed my BMW back in 2008-2010. I believe a 4 point harness is in my future if I can figure out a way to mount it in place without losing too much recline room on the seat, being 6'5" tall I don't always want to feel 'wedged' in place. I do use the truck for other daily usages. Anyhow, more to come.

I'm guessing a splined bar setup on that truck with tuning insight would money well spent.

Call Ron Sutton and hopefully you'll get along and end up throwing some money his way. :thumbsup:

I concur 100%... I called Ron earlier today and I am in the early stages of getting a 3 piece splined bar in place.. Most likely it will be a weld in place 'bar in a tube' setup.. The bad news is, I think I just blew my harness money on a sway bar.. Great, more traction adding stuff to throw me around in the truck and less restraining devices in the truck !! Perfect !!:hitaxeonthehead:

glassman

03-20-2017, 06:24 PM

Tydriver

03-22-2017, 05:24 PM

Nice job!!!! just went through it and love it. I'm doing something similar to my '16 Chev 4x4 rcsb. I wont be autocrossing it but i'm in sales/estimates and spend hours in it everyday and WANT better handling. I've been intouch with McGaughy's and there doing a new spindle as these a arms are a little different than yours.

Watchin!

Did McGaughy's give you any idea on the time frame for this? I have a buddy that is lamenting about the lack of lowering parts for his truck (also a 4WD), I told him it will come, but the aftermarket is slow to respond it seems. I guess only those of us that are a bit offcenter lower a 4WD truck... LOL :flag2:

glassman

03-24-2017, 03:08 PM

Did McGaughy's give you any idea on the time frame for this? I have a buddy that is lamenting about the lack of lowering parts for his truck (also a 4WD), I told him it will come, but the aftermarket is slow to respond it seems. I guess only those of us that are a bit offcenter lower a 4WD truck... LOL :flag2:

I look at as "my 4500lb" Subaru with a bed. I use the 4x4 for snow and towing, almost never offroad.

They just said "some time this year". I might see if Ride Tech has anything up their sleeve, as i have their stuff on my Camaro...

minendrews68

03-24-2017, 03:37 PM

I was going to ask you where a autocross track was, but when watching one of the video's it says "Blytheville Aeroplex". Really! I didn't know they were doing that there!.. I live in Jonesboro, (used to live in Blytheville when the base was still there). I knew they did the autocross once a year, but do they do it more often?

Tydriver

03-24-2017, 06:13 PM

I look at as "my 4500lb" Subaru with a bed. I use the 4x4 for snow and towing, almost never offroad.

They just said "some time this year". I might see if Ride Tech has anything up their sleeve, as i have their stuff on my Camaro...

Thank you, I will pass it along to him.

I was going to ask you where a autocross track was, but when watching one of the video's it says "Blytheville Aeroplex". Really! I didn't know they were doing that there!.. I live in Jonesboro, (used to live in Blytheville when the base was still there). I knew they did the autocross once a year, but do they do it more often?

Honestly, that was the first time I have run there, I just moved to this area about 20 months ago. The Mid-South SCCA group lost their run area (TSA requirements), so there is going to be a lot of travelling for me if I want to continue to run in SCCA. The weekend prior to the weekend of the Blytheville event I was in Grenada MS running at the airport there. Anyhow, the next event is in Little Rock, but I believe they are going to have a few events at Blytheville Aeroplex. You can check out the schedule here: http://www.arscca.org/

Good Luck and say HI if you stop out for an event. I am on hold until I get the sway bar installed so it may be a month +/- before I continue running.. We'll see.

Tydriver

03-27-2017, 03:07 PM

+1 for a bolt on upgrade ! I have been playing around with the settings in EFILive, trying to lessen the effects of the fans turning on. With only one fan turning on at low speed it was enough to stress out my charging system, and almost kill the truck at idle.. As luck would have it, GM made 2 different options for alternators for the GMT800 trucks, a small frame and a large frame alternator (I wont get into specific model#s here)..

Of those two options, I had the weakest of the small frame option. My truck only had a 105amp alternator from the factory, and that was in 2003.. They also made a 145amp version for my year, but my truck was NOT equipped with it. They also made a larger frame alternator that is generally rated higher in amperages and an overall better alternator. I was going to get one of the larger framed alternators and upgrade the stator and internals to make it a higher amp unit, but I ended up stumbling on a HIGH AMP version For just a little bit more on Amazon than the parts themselves were going to cost me and there was no core charge !

Best of all, it was literally a plug and play setup. Unbolt old weaker unit, bolt in godzilla alternator and never look back. I also upgraded the charging wire from the small stocker to a 2 ga unit. Fortunately the unit I installed had an overdrive pulley installed that made up for the diameter difference, it left me just inside the 'acceptable' range on the tensioner, win win win !!

I found a test sticker on the unit saying it put out 100amp at idle and 253amps at full load. My volt gauge on the dash never drops below 14v and I can no longer tell when the fans cycle on/off. For $140/shipped from Amazon, I'd say it was a good mod.

https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x981/80-250amp_alternator_vs_stocker2_08d9094bb49aca6f2bc2 31246fa9f56a0c7e1c7e.jpg

Tydriver

04-04-2017, 06:41 PM

Regarding the front swaybar, ran out of luck on that today.. I finally got fed-up waiting on Ron Sutton Race Technologies to deliver on what they promised 3 weeks ago.. I felt I've been in communication and very patient. However in the end, it appears that their interest is in educating people on suspension designs vs. providing parts even though I pre-paid $750 towards the custom setup. It all ended well, they were most polite, it just seems too busy to fulfill the order.

Egads I about make myself sick when I think about spending that much $$ for a front swaybar, if it worked however it would be worth it. Back to the drawing board I suppose.. I already have a few leads from another place and the prices appear to be a little more reasonable, time to do more research and rely less on others I suppose.. More updates to follow ! :thumbsup:

preston

04-05-2017, 08:53 AM

Tydriver

04-05-2017, 03:05 PM

Patience is the watch word when working with Ron these days. If they actually promised you a date or implied it would be sent on a short time frame that's one thing but if the sway bar is a unique width then it has to be custom built. If you just needed a typical 1.25" hollow bar they should be available quickly in lots of widths. But as an example I ordered a custom width 1.75" swaybar direct from Speedway and it took 2+ months.

I'm not really going to get into the specifics here, it just isnt worth it. I am not trying to start a war against a vendor here. Last night when I posted I was upset about it, but whatever, I am over it. The guys at RSRT were polite and responsive when I contacted them. The refund has been issued, I am moving on..

The guys at JSM were a help again, when I contacted them inquiring about any leads for a splined bar they gave me a few leads I didn't know about previously and ones that my searching didn't find. I was hoping for a more calculated way of acquiring parts than just shooting in the dark and praying I got close, thats why I had deferred to the experts initially. No worries, I got this, just need to dig in a little harder and ask some more questions.

Anyhow, between the links I already collected and the ones JSM helped with, I am going to list them up here for someone that may be interested and for posterity.

Coleman Racing, I haven't actually called these guys so I don't yet know what to expect, but its another lead and hopefully will prove fruitful:
http://www.colemanracing.com/Sway-Bar-1-14-x-48-Spline-P3795.aspx

This was the golden nuggetI had been searching for, a sway bar rate calculator:
http://www.gtsparkplugs.com/Sway-Bar-Calculator.html

The Speedway Engineering website has a lot of good information:
http://1speedway.com/index.php?route=product/category&path=76

Detroit Speed Swaybar Setup via Summit Racing (not the best option IMO):
https://www.summitracing.com/parts/dsr-031404?seid=srese1&gclid=CKqprvHN7MECFcZcMgod8AUA9Q

Schroeder Torsion Bars (they go all the way upto Monster Trucks!):
http://schroedersteering.com/

Speedway Motors (Not Speedway Engineering) REAR SWAYBAR Universal Kit (may need this for the rear?? IDK yet):
http://www.speedwaymotors.com/Universal-Rear-Sway-Bar-Kit,4053.html

Anyhow I am sure there is more, but this is what I have at the moment. More to follow..

Tydriver

05-07-2017, 03:12 PM

I scored a Hydroboost and master cylinder off a wrecked '04 Tahoe at the wrecking yard for $40, it even came with one of the hydro lines. I'm going to hold off installing it until a later time, it will be soon, but not immediately. However, I did upgrade the rear disc brakes with a set of larger Tahoe rear brakes..

In my opinion, the difference between the two is impressive.. The rotors go from 12.8" to 13.0", but perhaps more impressive is the upgrade in the pad sizing. With the installation of the rear Tahoe calipers, the upgrade is from single piston to twin pistons calipers that allow for the larger pads...

The Tahoe rear calipers are twin piston, the stock Silverado are a single piston design.

Here's a picture of one painted up with silver caliper paint and black semi-gloss on the support frame.

https://cimg1.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x907/80-20170507_125025_82c73a173e9a5ffbd2fda9748aff94fb54 de5ad7.jpg

Here is a comparison of the stock (worn) pad and the new replacement '07 Tahoe pads (new).

https://cimg4.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x1110/80-20170507_125059_503c98ed796f9207dfcc60b4121cad73f7 8a77b8.jpg

Here's what it looks like all completed and installed, I just need to bleed the brakes and then it's driveable again:

https://cimg8.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x962/80-20170507_132504_14d7e1cfd3240ac735f21d69cc04ed644f 19fee9.jpg

https://cimg5.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x1200/80-20170507_132524_51e49d0aec26729726f69c5579c217a4e5 bfba20.jpg

I have about $225 into this upgrade, in all honesty, I needed new brakes anyhow. The rear rotors were SHOT, they were less than .750" thick, as a comparison, the Tahoe rotors are over 1.250" thick. The pads were cracked and tired, I could have gone totally cheap and just done rotors and pads, but this upgrade is a hard one to pass up for the money invested. The fron't will be up next, probably also going with Tahoe or Suburban rotors/calipers/pads on that. That will yield a larger rotors as well..

Here is a list of parts I had to complete this swap for the 100% bolt in.

These parts are from Advance Auto, but Advance merged with Carquest here and these parts were actually Carquest parts:

1ea 18B4764 twin piston left rear caliper)
1ea 18B4765 twin piston right rear caliper)

2ea YH145441P rear rotors 13.0" diameter
1set PXD834H rear SUV ('07 Tahoe) brake pads

Tydriver

07-28-2017, 04:47 PM

Hey Guys,

Just and update, its been kinda crazy here lately so I haven't been doing as much with the truck as I'd like to, well at least not FUN things.

We had a pool installed and I've been trying to get the yard back to some sort of normalcy since then so unfortunately, I've been doing truck things with my autocross toy..

https://cimg5.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x1200/80-20170715_121943_7e6ebadc0e756ae16c13d9658dd177a696 79828c.jpg

and

https://cimg4.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x1200/80-20170531_170042_deace68d4d8984c8d8e3cdbff8de3f7902 cec56f.jpg

The truck has taken it in stride. I just max out the airbags at around 110-120 psi and it just takes it. The brakes have been a welcomed upgrade for sure when doing this.. When I am done, just let the air out of the 'bags and I am back to a smooth riding truck. phump

It hasn't been all work and no play, last weekend we had a local SCCA event that I went to and competed. It was soo damn hot out, the heat index was north of 110*... That's a long time to be standing out in a parking lot ! So I was looking for some shade, anywhere to park the truck, overall it was still a good time.

https://cimg6.ibsrv.net/gimg/www.performancetrucks.net-vbulletin/1200x1200/80-20170722_093207_f1d8b4e201202208aa07d0da27edce61a3 16814a.jpg

I ordered some PAC1218 springs from eBay, they came in yesterday. I'll try to get them on the truck soon and order a Sloppy Cam and start working on re-tuning the truck.

Then it will be decision time, do I go turbo kit and risk annihilating the 4L60e or do I take the safe route and start on the 4L80e I have sitting in the shed ??? Haven't decided yet.. :bang:

WSSix

07-29-2017, 05:09 AM

Tydriver

07-29-2017, 05:03 PM

I personally wouldn't turbo charge the engine if you want to keep your throttle response for autocross. I'd look into a supercharger. You can do an LSA blower swap or spend the bigger bucks and get the newer blower. There's also a Magnacharger or Edlebrock kit which uses an Eaton blower. Those will all give you instant torque and throttle response. Good luck whatever you choose.

I hear ya man, to be honest, I've gone back and forth on this issue now for a little over a year.. I've weighed the supercharger vs. turbo debate for what I want to do with the truck.. I'll be honest, around here they run some pretty wide open courses. If I was still running in a region that ran mostly parking lots then I'd tend to agree with you. The reality is, most of the regions here run on old airport ramps with a LOOOT of area. Tuning is key with a turbo, and these days the technology incorporated in the turbo is lightyears ahead of what it used to be.. With a 4.8L and a properly sized turbo boost can be had at 2000-2500 rpm range, add a 2800 rpm stall and its all good. In all honesty the only place I probably wont see boost is off the line and I can foot brake that.. I've owned supercharged and turbocharged cars in the past and I feel the best balance is with the turbocharger.. Eventually I plan on going with a semi-built 6L to replace the 4.8, so light off will be even better..

Anyhow, I do appreciate the feedback, its been perhaps the biggest argument I've been wrestling with on this whole project.