When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I was looking at coil overs for my 93 and the kits say direct fit for 88-96. Sounds like you had a fair amount of fabrication. Is that because the kit doesn't direct fit the 84-87 or is the maker of kit full of BS when they say direct fit? I don't track my car so definitely not be interested in a bunch of fabrication
So I was looking at coil overs for my 93 and the kits say direct fit for 88-96. Sounds like you had a fair amount of fabrication. Is that because the kit doesn't direct fit the 84-87 or is the maker of kit full of BS when they say direct fit? I don't track my car so definitely not be interested in a bunch of fabrication
in relation to the later model cars,
Front - the towers are wider in the later 88+ cars, this makes it easier to get the coilover in. which kit are you looking at ? some kits use narrower body shocks and springs to get the clearance, but beware that narrow body shocks use narrow shafts - 1/2" instead of 5/8" and the narrow springs are harder to come by. Some kits hang the coilover assembly upside down to get the clearance also.
Most kits use low rate springs because its easier to get a skinny spring inside the tower. Lower spring rates arent such a problem on the street.
Rear - most kits use the alloy adapter blocks to fit the coilover unit in. the adapter blocks have an offset and higher installed height so you start to lose compression stroke on the shock - not a big deal on the street if you dont lower your car too much. They also use low rate springs and again the skinny springs give clearance from the axle.
I was forced to fab my rear brackets 1- to keep the shock at its correct height to ensure as much compression travel as possible. 2 - to be able to move the shock forward to keep the fat higher rate springs away from the axle (I have been using 450 lb in the rear).
below is a pic of the rear adapter bracket, you can see how it lifts the shock up a bit.
Kit on Corvette central and other vendors. Shocks are QA-1. Springs are hyperco. Bottom mounting bracket looks a lot like the one you fabricated.
that looks like the Vansteel kit - same as the pic I posted above (that pic isnt my car - its off another thread)
the QA1 shocks are good - for street I would probably get the single adjustable.
they use Hyperco springs which are good quality.
the brackets are well made, I havent heard anyone who has bought one of these kits complain about the setup.
also when doing rear coilovers use 8" springs - no longer or you will have clearance issues if using a strengthening / support bracket.
Lol
You know you are going to get our American cousins head scratching using metric and imperial together
Like the bracket small and simple
I went back to the standard transverse rear spring due to our poorly maintained roads, used the koni coilovers without springs.....
Turned out the shock absorbers were way to hard even at minimum adjustments, was barely any different in harshness (somewhat comparable to being kicked in the *** by a donkey)... .
Put standard bilsteins on the rear and so much better, now even the little woman will go for a drive with me Not quite like a Volvo but nicer than before. Happy wife = happy life
Could not believe how the shock absorbers made the ride so hard, the old coilover springs have 300lb or 330 on them cant quite make it out.
I never had any understeer with my 85 she always wanted to go off backwards even when standard, I didn't use the Z51 front bar went for the standard ones going to coilovers.
To do with the front spring rate and coilover valving I recall, was an ex racer that recommended a stiff front spring soft rear to control the oversteer.
and make the car behave on uneven surfaces, think maybe the rear were valved incorrectly.
She is even more well behaved now, very neutral handling slight power or detroit locker oversteer.
We all remember the famous saying "loose is fast but on the edge of out of control"
Like my ex racer mate said ,,,,, do you want to see what you are going to crash into our let it be a surprise?
Interesting to see how stiffer rear springs change your C4s balance and let the rear step out a little to give you more excitement?
You have no body roll or twitchy rear end from what I see in your video, looks really well setup.
My track days are numbered, now at 56 my body prefers softer suspension and cruising highways to the track drug.
In a perfect world I would have two C4s one track setup one highway cruiser, well they are so cheap now so maybe that wont be too long if I can keep from getting motion sickness after several hot laps that is lol
Keep up the good work, making C4s look good and fast
You know you are going to get our American cousins head scratching using metric and imperial together
Like the bracket small and simple
I went back to the standard transverse rear spring due to our poorly maintained roads, used the koni coilovers without springs.....
Turned out the shock absorbers were way to hard even at minimum adjustments, was barely any different in harshness (somewhat comparable to being kicked in the *** by a donkey)... .
Put standard bilsteins on the rear and so much better, now even the little woman will go for a drive with me Not quite like a Volvo but nicer than before. Happy wife = happy life
Could not believe how the shock absorbers made the ride so hard, the old coilover springs have 300lb or 330 on them cant quite make it out.
I never had any understeer with my 85 she always wanted to go off backwards even when standard, I didn't use the Z51 front bar went for the standard ones going to coilovers.
To do with the front spring rate and coilover valving I recall, was an ex racer that recommended a stiff front spring soft rear to control the oversteer.
and make the car behave on uneven surfaces, think maybe the rear were valved incorrectly.
She is even more well behaved now, very neutral handling slight power or detroit locker oversteer.
We all remember the famous saying "loose is fast but on the edge of out of control"
Like my ex racer mate said ,,,,, do you want to see what you are going to crash into our let it be a surprise?
Interesting to see how stiffer rear springs change your C4s balance and let the rear step out a little to give you more excitement?
You have no body roll or twitchy rear end from what I see in your video, looks really well setup.
My track days are numbered, now at 56 my body prefers softer suspension and cruising highways to the track drug.
In a perfect world I would have two C4s one track setup one highway cruiser, well they are so cheap now so maybe that wont be too long if I can keep from getting motion sickness after several hot laps that is lol
Keep up the good work, making C4s look good and fast
G'day Gerard,
I reckon if I have to put up with metric and imperial all the time on this car then so can everyone else !
I think you need different shocks (at least on the rear), its a bit like old money and new money, there are old shocks and new shocks. you would probably get the ride you want by getting some of the new single adjustable shocks on the market.
I ran the last meeting with 450 lbs coilover springs in the rear, car only went 1 tenth quicker than last meet with the leaf in the back. But to be fair it was bloody cold - zero degrees when we arrived at the track so no-one was setting any real fast times. Also the rear tyres are past their best and need replacing. Im getting a big front bar made and that should make a difference when the weather warms up.
Hello I am in the process of changing to coil overs front and rear You said you used 401's in the rear with 350lbs springs? what did you use for the front? I am running a LS3 engine with a T56 6 speed trans. It was suggested to me to run 550's up front and 300 for the rear. I still don't know what shock to buy for the front I hope you can steer me in right direction .. Love the post and the pixs TY regards Mark
Hello I am in the process of changing to coil overs front and rear You said you used 401's in the rear with 350lbs springs? what did you use for the front? I am running a LS3 engine with a T56 6 speed trans. It was suggested to me to run 550's up front and 300 for the rear. I still don't know what shock to buy for the front I hope you can steer me in right direction .. Love the post and the pixs TY regards Mark
Hi Mark,
I used the Viking double adjustable coil over shocks on the front. The ones I bought have Flaming River decals on (but they are Viking) sold thru Summit Racing, part no. FR70028. I dont know what the equivalent Viking part no. is.
These shocks are threaded body, double adjustable (Viking dont make single adjustable) with the stud top and tie-bar bottom to suit the C4 front.
They also have 14.4" extended and 9.4" compressed lengths which suit the C4 front (especially if you lower the front end).
They dont have the spring caps so you need to buy them extra.
I wouldnt go any lower than 350 lb in the rear, that would be ideal for street use. If your going to track the car or use it on rough roads I would go higher.
550 lbs would be fine for street use on the front.
Dont go any longer than an 8" spring.
I just pulled the trigger an ordered the flaming river FR70028 front shocks with 550 springs and QA 1 DD401 rears with 5/8 brg. (lower) 350lb springs.. also the speedway lower pin mods Thank you so much for your time and advice..
Originally Posted by blackozvet
Hi Mark,
I used the Viking double adjustable coil over shocks on the front. The ones I bought have Flaming River decals on (but they are Viking) sold thru Summit Racing, part no. FR70028. I dont know what the equivalent Viking part no. is.
These shocks are threaded body, double adjustable (Viking dont make single adjustable) with the stud top and tie-bar bottom to suit the C4 front.
They also have 14.4" extended and 9.4" compressed lengths which suit the C4 front (especially if you lower the front end).
They dont have the spring caps so you need to buy them extra.
I wouldnt go any lower than 350 lb in the rear, that would be ideal for street use. If your going to track the car or use it on rough roads I would go higher.
550 lbs would be fine for street use on the front.
Dont go any longer than an 8" spring.
I just pulled the trigger an ordered the flaming river FR70028 front shocks with 550 springs and QA 1 DD401 rears with 5/8 brg. (lower) 350lb springs.. also the speedway lower pin mods Thank you so much for your time and advice..
I forgot to ask what year your car is ??
the other important thing is the spring cap for the front - you need to get the angled one so that it gives more clearance inside the shock housing. and it needs a washer to go in the top, I made mine but you could probably get something at the Fastener store. For some reason they dont come with the shocker.
Test fitting the coilover - let the problems begin !
I started by fitting the coilover onto the stud to see where the clearance issues actually are, the people who have been there before will tell you its the axle and the lower trailing arm link that cause the problems.
First problem is the stud that the shock mounts to - it is a 16mm where it goes thru the hub ear, but is a 5/8" where it mounts the shock (it is .4mm difference). you will remember that the QA1 shocks have 1/2" bearing mounts. After pondering what to do, I found out that QA1 sell a 5/8" bearing for this shock, so ordered a pair of those.
The original stud is not long enough - due to the fact the shock bearings have an extra spacing length in the them, and having to space out the shock away from the lower trailing arm. I have put a 5/8" grade 8 bolt in to overcome these issues.
I have jacked the suspension from full droop to full compression and guess what - it actually misses the axle , something is going right !
The top uses a 1/2" bolt and spacer to move it forward enough to ensure that axle clearance.
Here is the test fit on the right side with the Banski arms in place.
I did consider the Vansteel bracket, but I dont like the way it starts extending the coilover assembly upwards and forward the amount it does - looking at too much leverage and going upwards you start to lose compression stroke on the shocker.
This goes to the subject that Gerard just raised, leverage and force at the hub ear. This point is designed for a shocker only, not a spring. The experts say that the shock actually exerts more force on a point than a spring does, but the addition of the spring will add something. There have been people who have snapped the ear off with a coilover assembley.
Also take into account that every inch you space the assembly out (towards the middle of the car) it creates something like 4 x extra force.
After a discussion with my suspension guy he suggested taking the inside conical bush out of the lower banski arm - this will allow the coilover assemble to move in on the bolt as close as possible to the hub and reduce the force acting on it.
I will show some pics later of how I made some strengthening arms to support it all.
I have just recently made the switch from Exptic muscle coilovers to a QA1 set up and i have my rear coilover spaced out pretty far in my 86 Vette and i was wondering what stud you switched it to for the bottom rear shock mount because i cant find an inexpensive method of switching it.
I have just recently made the switch from Exptic muscle coilovers to a QA1 set up and i have my rear coilover spaced out pretty far in my 86 Vette and i was wondering what stud you switched it to for the bottom rear shock mount because i cant find an inexpensive method of switching it.
I knocked out the original 16mm stud and replaced it with a 5/8" high tensile bolt.
First you need to knock out the 1/2" bearings on the bottom of the QA1 shocks and replace them with the 5/8" bearings (sets available from Summit)
The 5/8" bolt is necessary to fit the 5/8" bearings - if you use a 16 mm stud there is a fraction of looseness there.
I knocked out the original 16mm stud and replaced it with a 5/8" high tensile bolt.
First you need to knock out the 1/2" bearings on the bottom of the QA1 shocks and replace them with the 5/8" bearings (sets available from Summit)
The 5/8" bolt is necessary to fit the 5/8" bearings - if you use a 16 mm stud there is a fraction of looseness there.
Yes correct i found that out the hard way, now i also saw that the original has a cone spacer welded onto the original bolt what cone space did you use for your car or will any 5/8 spacer work?
Yes correct i found that out the hard way, now i also saw that the original has a cone spacer welded onto the original bolt what cone space did you use for your car or will any 5/8 spacer work?
You can use anything really, I used metal tube with a 5/8" hole cut to size. You space it out just enough to miss the trailing arms.
The 5/8" bolt is 2" long.
07-18-2018, 03:20 PM
.
Not quite like a Volvo but nicer than before. Happy wife = happy life 
