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Old 03-13-2017, 01:35 PM
Tydriver Tydriver is offline
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Default So I Autocrossed My Silverado This Weekend........

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 ...




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.



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:


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):


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:


Top of the Windshield:


The two runs with the SCCA Tech Guy:
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-16-2017 at 09:42 PM.
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Old 03-13-2017, 01:37 PM
Tydriver Tydriver is offline
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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:



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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-14-2017 at 11:03 AM.
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Old 03-13-2017, 01:40 PM
Tydriver Tydriver is offline
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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...
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-14-2017 at 02:27 PM.
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Old 03-13-2017, 01:41 PM
Tydriver Tydriver is offline
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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.....







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...
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride
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Old 03-13-2017, 01:45 PM
Tydriver Tydriver is offline
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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.




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
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-16-2017 at 09:42 PM.
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Old 03-13-2017, 01:47 PM
Tydriver Tydriver is offline
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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:
  1. every rubber hose under the hood that contained coolant including upper/lower rad hose, heater hoses and throttle body coolant hoses.
  2. 160* Lingenfelter Thermostat (nothing more than a re-boxed MOTORAD unit).
  3. New Coolant Recovery tank and Cap.
  4. New temp sensor for the driver's side cylinder head.
  5. 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.



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 !!




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:



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:



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



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




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:



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.
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-14-2017 at 10:50 AM.
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Old 03-13-2017, 01:48 PM
Tydriver Tydriver is offline
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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 ??




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.



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...
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride
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Old 03-13-2017, 01:49 PM
Tydriver Tydriver is offline
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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..


Servicing the Smurf Juice in the NP246.. Relatively drip free !
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-14-2017 at 10:51 AM.
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Old 03-13-2017, 01:50 PM
Tydriver Tydriver is offline
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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 !





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.
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2003 Chevy Silverado 4x4 - SCCA Autocrosser
2005 Chevy Corvette DSOM Z51 -- Daily Driver
2011 Subaru Outback - Wife's Ride

Last edited by Tydriver; 03-16-2017 at 09:45 PM.
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Old 03-13-2017, 03:34 PM
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gnx7 gnx7 is offline
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I love that you got this 2+ ton barge to handle!
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Project: 1969 Chevelle, alum 5.3, GTS76 turbo, Chiseled Perf A/W intercooler, Holley Dominator EFI, Davis TC, JRi coilovers, 14" brakes, T56 Magnum. CTS-V Recaro seats!
Coffey Fabrication Nashville, TN doing the fabwork! 800rwhp+/25mpg+/9's@150mph goal
https://lateral-g.net/forums/showthread.php4?t=52976

1993 Mazda FD RX-7, built LS7, T56 Magnum, Holley HP, Davis Tech TC, 8.8" 3.73 Cobra IRS diff, DSS axles, Ohlins coilovers, big brakes.
CCW 18x11 front 315/30/18's and 18x12.5 rear on 335/30/18 RA1's, 2850lbs
10.31@137mph 165mph Shift-Sector 1/2 mile speed
441ci AllPro headed motor and 200lb weigh reduction in the works....
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