Single or Double adjustable shocks

[Jeremy]

I am running a VBP transverse leaf spring set up on my TA and am real pleased with it except for shocks. I started off with Edelbrocks and they were no where near correct. I am running Hotchkiss bilsteins and they are real close.

Here are the choices I am considering:

Have Bilstein or Hotchkiss revalve my current shocks as I think we can get close if they will work with me.

Buy new shocks, QA1 or Varishocks. I like the idea of adjustable shocks so that I can dial in the ride I am looking for. The system rides very well with the Hotchkiss shocks but under certain circumstances they are slightly under damped. How much will I give up going with the single adjustable shocks versus the doubles? My budget would prefer the singles as it leaves more money for a new dash. The VBP setup is pretty adjustable as to ride height and spring rate and I want to take full advantage of this with adjustable shocks. Am I going to be happy with the singles or will the doubles offer that much more?

This is a street car and I doubt it will ever see road course or autox. Once I get the shocks dialed in, I plan to leave them and enjoy driving the cars.

[1971novaSS]

Go double adjustable, I have 3-way adjustables on mine. Just helps with the launch and handleing of the car. Stiffer is more for handleing and cornering, Softer helps to disperse the weight for launching.

Its always better to have another adjustment rather then having them set to a certain ride.

But thats IMHO. :cheers:

[darren@ridetech]

In this case double adjustable refers to having two adjustment knobs. One for compression and one for rebound. With single adjustable you are mostly just adjusting compression. With the Varishock you will have 16 positions per knob. That's a total of 256 available combonations. Very helpful for drag and road race cars.

[Jeremy]

It looks like I will be going with the varishocks as SC&C is having a good sale on them. If the SA only adjust the compression or mostly so then I will probably be better off with the DA. The hotchkiss bilsteins I am running feel pretty good on the compression side but are too soft on rebound hence the need to go to something adjustable.

[ProdigyCustoms]

I ran one of the first transverse leafs way back in the stone ages. Car handled OK, but rode horrible no matter what I did. I think partly because there is very limited travel to the spring, due to how far out the supports are. Also the spring seemed to be VERY progressive, which meant the deeper the bump, the more the arm moved, the more agressivily it rebounded making the car almost hop. I had many a teeth chattering moment in that car as it was a daily driver. I will be curious to see if 14 years corrects the problem.

[Jeremy]

Some things I found that I think contributed to the poor ride characteristics were that 2nd gen shocks are too long and bottom out. Since I switched to shorter shocks the rides is actually better than the ws6 springs and edelbrock shocks. I also changed the poly bushings for greasable solid and the arms rotate much freer by hand compared to the poly.

I am very pleased with the ride 90% of the time and I am hoping that adustable shocks will help me control the last 10%. I know what you are talking about on the hop. For me it occurrs when both wheels hit a bump or big dip. My theory is that since the sides are tied together and transfer energy from side to side due to the pivoting mounts, when both wheels compress the center of the spring has twice the energy and thus the hop.

I am very pleased with handling and the reduced unsprung weight the system offers. The lack of road noise compared to a coil spring has been very noticeable as well. The highway ride is as good as any factory car I have driven and better than our old 03 mustang and the 96 ws6 TA I drove.

The problem is I need to keep the low speed control similar to the hotchkiss shocks and stiffen up the rebound control on larger inputs.

I also have an aquantance with a c6 Vette and he has offered to let me drive it. I am going to have to take him up on it to see if they have any of the hop feel as they use the same style suspension. I would be curious of they have it all removed. My theory is that if Chevy can do there should be no reason I can't get close. Lofty goals, but I enjoy tuning my suspension the way some tune their motors.

If I never got it any better, I could be very happy with it if I stay on reasonable roads or slow down on the rougher roads.

I really think the Hotchkiss bilsteins are close. The control is much better as the temp gets warmer above 65. I can't figure that 15 degrees would stiffen the shocks that much.

[ProdigyCustoms]

I ran shorten Carrea shocks from the get go. I determined the ride problem was two fold, The supports are farther outbound then on a Corvette. I also think the spring is stronger and more progressive then the Corvette spring. The hop is down right wicked over speed bumps. The front of the car literly jumps in the air. It was a bad beotch on the autocross though.

I dug up the first page of the install story I did. 1992, WOW I can't believe I talk about things 15 years ago. It was Pro Touring before Pro Touring was cool!

Also incuded a picture of the car when I was 50LBS lighter

[Jeremy]

Frank,

I appreciate your input. As for the "hop" we are definitely talking about the same thing, although I don't think it is no where near as bad for me.

I notice it most at low speeds, especially when its cold. Above 30 mph it gets a little better, better again at 50, and I can't say I've ever noticed above 75 or so.

I re read all the posts and if I under stand now, you are refering to the inboard supports under the motor being farther outboard compared to a vette. It would be interesting to see if VBP tested the spring rate in compression and rebound. It definitely sounds and feels like it is stiffer in rebound than compression.

I am guessing you would recommend double adjustables giving me the most tuning options.

I drive mine daily during good weather and had some teeth rattling moments with the edelbrock shocks, but haven't had any with the bilsteins. This seems a little odd to me as the Edelbrocks don't control the suspension no where near as good as the bilsteins.

[Tony@AirRideTech]

frank.... I am calling you out here big time man...... 50lbs????:rolleyes:

[Jeremy]

I talked to quite a few shock companies today and I ended up ordering some vari shock double adjustables.

I was suprised to find out that the Bilsteins were valved 82 % stiffer in rebound than compression. The Bilsteins are digressively valved and it is possible that the sharp bumps exceed the point on the curve where the rebound does not increase anymore. I am hoping that I can find a curve on the adjustables that is nearly the same. Since the vari shocks are linear, if I match the rate, then it should have more damping force at the upper extremes to control the rebound and still ride well.

I'll post the results after getting them installed. Hopefully they will be here by the end of the week.

[ProdigyCustoms]

frank.... I am calling you out here big time man...... 50lbs????:rolleyes:

LOL, I grew into my nose!

[Jeremy]

The Hotchkiss Bilsteins worked well for most driving but I wanted more. I just got my varishock double adjustables today. I can't wait to get them in and see how they work. I may even have to knock them out tonight after the little one goes to sleep.

I'll keep you updated on how they work, but they looked great in the spun aluminum. The instructions were well written with great diagrams. All of the hardware and associated pieces are definitely beefy.

[Jeremy]

First impression is that these shocks are awesome.

It took about 1.5 hours to get the swapped out and the worst was figuring out how I was going to mount the bottom. SC&C recommended on top of the arm but due to the construction of the VBP arm, I would have had to do a lot of fitting to the front side of the cross bar.

Since the lower mount is three piece, I disassembled it and slid the eye through the arm and re assembled. This proved the ticket and it mounted up perfectly.

While I was at it I checked total wheel travel and I have 5 1/4 inches.

I checked with Bilstein and the Hotchkiss shocks were 1.81 times stiffer in rebound than compression. Varishock recommended starting on 3 and working from there. I put the compression on 3 and since I needed more rebound than the Bilsteins set the rebound to 6.

On my normal "test" circuit it road like a new car. Bumps were soaked up and no "bouncing."

Two bumps in 10 miles felt a little soft on rebound but the ride was so soft, yet controlled I am leary of going stiffer. The nice thing is I can try and go back. One on ramp at speed used to feel real jittery and it was so smooth now.

Turn in is amazingly quick now even though I backed of the tension on the sway bar endlinks. The front end does not roll at all, or at least it does not feel like it. The car is a little tail happy now but not unnerving.

If anyone considers the VBP setup, go with this shocks as they let you dial in the unique properties of the suspension. I am so happy with it that I was others were closer so I could let them ride in it. It is so much better than the factory setup.

[Steve1968LS2]

First impression is that these shocks are awesome.

It took about 1.5 hours to get the swapped out and the worst was figuring out how I was going to mount the bottom. SC&C recommended on top of the arm but due to the construction of the VBP arm, I would have had to do a lot of fitting to the front side of the cross bar.

Since the lower mount is three piece, I disassembled it and slid the eye through the arm and re assembled. This proved the ticket and it mounted up perfectly.

While I was at it I checked total wheel travel and I have 5 1/4 inches.

I checked with Bilstein and the Hotchkiss shocks were 1.81 times stiffer in rebound than compression. Varishock recommended starting on 3 and working from there. I put the compression on 3 and since I needed more rebound than the Bilsteins set the rebound to 6.

On my normal "test" circuit it road like a new car. Bumps were soaked up and no "bouncing."

Two bumps in 10 miles felt a little soft on rebound but the ride was so soft, yet controlled I am leary of going stiffer. The nice thing is I can try and go back. One on ramp at speed used to feel real jittery and it was so smooth now.

Turn in is amazingly quick now even though I backed of the tension on the sway bar endlinks. The front end does not roll at all, or at least it does not feel like it. The car is a little tail happy now but not unnerving.

If anyone considers the VBP setup, go with this shocks as they let you dial in the unique properties of the suspension. I am so happy with it that I was others were closer so I could let them ride in it. It is so much better than the factory setup.

The normal spread between rebound and compression is 3 settings. I'm starting with 6 and 9 on my Varishocks then I will tune them from there. Very happy with the Varishock quality.

[Jeremy]

Here are some of my findings with the VBP set up. I have experienced the ride harshness, bouncy feeling, and vaulting off the back side of bumps that others have reported.

After driving over the same bumps many times in my TA and several factory Fords, I noticed that going into dips that the front end drops going into the dip on my TA, but the front stays fairly flat over the same dip on the other two cars. Hitting the back side of the dip was down right painful and the car seemed to vault out the back of the dip.

I tried going super soft on compression to try to soften the jolt with no effect. I tried going super stiff on rebound to control the bounce with no effect. By this time I was getting frustrated as I had spent around 1k on a new suspension and high end shocks.

I went back to the basics of a fiberglass spring and remembered that they are generally bad for drag racing on the front as they don't store energy. This keeps the front end from rising on heavy acceleration. This got me thinking that maybe the fiberglass spring doesn't rebound with as much energy as a coil spring and actually needs less rebound control. I felt that I may be on the right path as the suspension did not feel like it was dropping fast enough into dips.

Believing this hypothesis, I surmised that the suspension was bottoming out on the back side of the dip and was hitting hard as the weight of the front end was all doing down into the dip. To test the theory I backed the rebound down to 8 from 10, leaving the compression still at 8 and the ride got better. This seemed to work but it seemed like I was getting bounced all over on rough roads.

I backed it down to 6 R leaving compression alone and the ride got amazing. The nose stays nearly level over dips now. You can actually feel one wheel drop now to accomodate the road. I figured if some was good, more was better, and dropped to 5 R. The ride is amazing. I can visualize all four wheels now dropping to accomodate the road. Impact harshness is as good as my 05 Taurus and Crown Vic. The bouncy feeling is gone. It feels as good as a new car. Bumps are soaked up so much better that most of the rattles are gone (I still have a problem with my windows occassionally, but that is an issue with them).

I think the problem with off the shelf shocks is that they are valved backwards. They are soft on compression and let bumps input way too much into the suspension. The shocks can't keep up the car bounces. People expect some ride harshness from a stiffer spring and figure the problem is on the rebound side and try to go firmer. It doesn't work and the system gets a bad rap.

From my experience and research, I think that a composite spring, at least in the VBP system, is stiffer on compression than rebound and needs a shock to match. Most of the shelf shocks for coil springs are soft on compression and stiff on rebound. This lets to much input in on bumps and doesn't allow enough drop on dips causing a rough ride on almost all occassions.

I'll post more as I keep tuning, but the where I am at now I am stoked. The system is giving me what I hoped for. It is a smooth, highly adjustable, quick responding suspension. Once I get the ride dialed in I can start pushing the handling capabilities.

[Jeremy]

Well I continued to play with the setup and found the biggest problem with it--the jounce bumpers. I removed them and the difference was utterly amazing. I have had to start all over on finding the sweet spot of the shocks.

To put things into perspective at the incredible potential of this system, let me give you some numbers. The advertised spring rates for the VBP system are 390, 450, and 530. While I was under the car I realized that the linkage ratios for the leaf were drastically different than the coil springs. To compare apples to apples, the VBP rates (if running a comparable coil) would be in the ballpark of 625, 750, and 850.

Since removing the jounce bumpers, I have been able to back way down on the shock valving, even though I stepped back up to the middle spring setting. I am currently at 5 C and 8 R. The car rides amazingly soft, so much so that it is really unbelieveable. I never thought a 2nd gen could ride this smooth, especially with 17 inch wheels and tires, big sway bars, and very high spring rates.

The system doesn't give up handling for the good ride. When I throw it into a corner, it turns in quickly and flat sticks. It does understeer a bit, but a little throttle balances it out nicely. You can feel the transverse spring do its thing in the corners. The other thing that I have found with the lower shock settings is that the weight transfers quicker and more evenly from tire to tire on the front. Bumps mid corner don't phase it. The ride is so soft that any rattles I had are now all but gone, even over the roughest roads.

I figured I could get the good ride with the lighter weight components on the front but it is now exceeding my wildest expectations. I know this sounds like a big claim, but if you are in the Rolla area I would back it up by taking you for a ride so you can see for yourself. Better yet, bring your 2nd gen and we will drive the same roads back to back so you can see how much of difference there is.

My best theory on why the jounce bumpers make such a difference. First, I have cut a lot of weight on the front suspension components both with this swap and other things. There is a lot less weight now. The fiberglass leaf spring reacts so much faster than a coil spring. From all my reading, it is generally accepted that jounce bumpers don't add rebound rate to coil spring setups and act like a variable rate spring at the far ends of compression. Given the lighter weight and the quicker reaction of the composite, they apparently do add a lot of rebound rate. Every other review I have read on this setup reported the need for a lot of rebound control. I think this explains why.

For those looking for something very tuneable and adjustable with great ride and handling potential, give it a look.

I wish I still had my Edelbrock and Bilstein shocks as it would be interesting to see how they do now that I have discovered this. I really believe an off the shelf shock may be able to effectively control this setup without the jounce bumpers.

[PTAddict]

Just a note, the jounce bumpers also serve a function in preventing metal to metal contact (e.g., potential for bent suspension arms) over severe bumps. Cutting down the bumpers rather than removing them entirely may be a safer choice.

[rocketman]

I love Koni's on the street,ride is awesome I but them on my 94 Z and wife's 68 camaro.very nice

[itlbtu]

I dug up the first page of the install story I did. 1992, WOW I can't believe I talk about things 15 years ago. It was Pro Touring before Pro Touring was cool!



Frank,
I think I have you beat. I think I attached a pic of my current re-do-correctly pro-touring '69 Camaro. I hade the largest 50 series Pirelli tires that they made back in '84 when I fixed up my Camaro the first time.I think they were p235-50zr15's. I didn't have as much to use as today as far as the suspension went. I was limited to a larger front sway bar and I installed a rear sway bar too, around '90.

http://www.itlbtu.com/images/camaro2.jpg