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Hey guys, looking for advice on full suspension kits. I've had my 80 Vette for 16 years and have done everything (I do my own work), but have put off really addressing the suspension due to cost. I have restored and mildly upgraded the suspension front and rear (front: Steeroids, new springs, all poly bushings, Bilstein shocks... Rear: Is actually a full conversion to a 1978 rear end with VBP composite spring, offset TAs, adjustable strut rods, Bilstein shocks) All of this was done over a period of 5-10yrs ago, and while all of this improved the handling, it's nowhere near where I want it to be. I want to have more confidence when I get on the GO pedal around a corner, and more high speed stability!!
So, that brings me to now... I think I'm ready to invest in making my car more safe/comfortable to drive. I'm curious to get guys opinions on what they've used and how they liked it. I've done several hours of research, including on this forum through old threads. I think I've looked at most the brands out there, and I kind of have it narrowed down to the following:
Vansteel
SpeedDirect
I appreciate any advice!
On a side note, I've always been a fan of sticking with 15" wheels on classic cars because I felt the smaller wheel/bigger rubber was the right look. But I've been considering stepping up to 17's for a long time for the benefit of rubber with better handling characteristics. It's hard for me to pull the trigger on this one.... any input on whether it's the right move? I think I know the answer haha
Last edited by 80vette21; Mar 28, 2020 at 09:45 PM.
My 80 is not far from where yours is now. I also like the 15" wheel look, so I won't change the brakes. I'll always keep a set of N90 wheels and RWL tires to cruise around town in.
That said, the limiting factor right now, by far, is the tires. You know you need to, so change those first. When I finally get to track this car, I'll run 18" tires, likely on ET LT-III wheels. @cagotzmann has written extensively about these wheels, and there are better performance tire options in 18".
Tires first.
It is your only connection between you and the road. Every thing else is just supporting the tires.
Between the availability of better quality rubber for handling and the greatly reduced sidewall squirm from the drastically shortened sidewall height, you will feel drastically sharpened steering response. Mine went from normal "mushy" steering to go kart like reflexes. Steering wheel intital turn-in response reduced from 3-4" to like 0.5-0.75". Tires went from 255-60-15s BFGs to Yoko 008R autocross tires in 245-45-16 size. Wheels from 15x8 to 16x10. Sidewall from 6.5" to 4.25"
It did not even feel like the same car in an aggressive turn! It had razor sharp reflexes after.
Make sure you check out this video of C3 tire squirm on an autocross course: And these are probably 17" wheels.
Tires first.
It is your only connection between you and the road. Every thing else is just supporting the tires.
Between the availability of better quality rubber for handling and the greatly reduced sidewall squirm from the drastically shortened sidewall height, you will feel drastically sharpened steering response. Mine went from normal "mushy" steering to go kart like reflexes. Steering wheel intital turn-in response reduced from 3-4" to like 0.5-0.75". Tires went from 255-60-15s BFGs to Yoko 008R autocross tires in 245-45-16 size. Wheels from 15x8 to 16x10. Sidewall from 6.5" to 4.25"
It did not even feel like the same car in an aggressive turn! It had razor sharp reflexes after.
Differences in Tire Sidewall angle between 15" narrow width & 18" wide width wheels
Thanks for the replies so far guys.
That video is impressive!! I never would've thought of that, but that is a TON of flex!
Ideally I plan on doing wheels/tires and at minimum front a-arms and coilovers, if not the rear as well. So if anybody has any input on the different suspension options that would be great!
Another side note: I've been running the car without a front sway bar for 12yrs... Back when I first did the motor when I was 20, I loosened and moved the core support to paint the engine bay. When I put everything back something shifted and I couldn't get the radiator in without contacting the sway bar. The main problem is the core support has a couple broken bolts, the typically rotted lower ones, so it's not well supported. So, the easiest thing or me to get the car back on the road at the time was to just pull the sway bar lol. I'm working on actually fixing it now, which may come down to doing a new core support... But either way I need to get the nose supported right so I can get a sway bar back in, because I know that's hurting me. That and I plan on adding a spreader bar with what ever kit I get. I know my front end definitely needs to be stiffened up.
Yes it is a lot of tire flex, and that is why I mentioned it. Most people have not seen it or measured it. After I changed those wheels/tires I could feel & measured the flex in my rag joint, and switched to a solid joint. That was another 1/2 to 1" slop at the steering wheel.
Shocks are your next most important upgrade, after tires. Really good ones, especially adjustable ones. Don't go halfway, just get good ones.
Bilsteins seem to be the best and are set great for non-adjustables. There are HD and Sport versions. You need different ones depending on what springs you have, well documented here.
You can get good adjustable shocks without the coil-overs. Konis, QA-1s, others. Singles or doubles.
After that point, the main remaining advantage of the coil overs is a wider selection of spring rates, and extremely easy ride height adjustments, and the "wow" cool factor.
After that all the other hardware helps a little bit for each one. But it all adds up in the end.
Last edited by leigh1322; Mar 29, 2020 at 10:26 AM.
This C2 same chassis you have with stock style suspension won the Good Guys street machine Auto Cross championship this last year. That tells me you don't need any of that aftermarket stuff. But bigger tires would be good
Did not see caster mentioned in your work on the suspension over the years. Unless you are doing nothing but auto crossing the car all the time the old vettes have to little caster. The newer vettes are a bit longer in wheelbase but they have about 4 degrees more caster so when there trying to do that 170 to 200 mph along with better down force they have they are more stable. Cars with to little caster feel twitchy need correcting. Make sure whatever you do you have 7 degrees of caster. Motorcycles they do the same thing it's just called the rake on front forks on them.
I’m doing a restomod with my 73.
I purchased full coil over suspension through Van Steel.
Some will say it is un-necessary on a street driven car, but I like the idea that I can instantly change spring rates, stiffness and ride height to however I want it.
It was hard for me to go to a larger diameter wheel, because I also like the classic look of 15’s.
To get better rubber to the road I went up to 17” wheels and will stay with a tire that is in the 27” tall range, which still has the classic look over an 18” wheel and tire.
While I was at it, I went with Wilwoods all around with D8-6 calipers in the front and D8-4’s in the rear.
I won’t have it on the road with the upgrades for another year or so, but I’m excited to see the improvements.
Did not see caster mentioned in your work on the suspension over the years. Unless you are doing nothing but auto crossing the car all the time the old vettes have to little caster. The newer vettes are a bit longer in wheelbase but they have about 4 degrees more caster so when there trying to do that 170 to 200 mph along with better down force they have they are more stable. Cars with to little caster feel twitchy need correcting. Make sure whatever you do you have 7 degrees of caster. Motorcycles they do the same thing it's just called the rake on front forks on them.
Last time I aligned it I spent a lot of time dialing everything in ( I use the alignment rack at my shop on off hours ) I used Steeroids alignment specs and put as much positive caster into it as I could, I don't recall the total right now. However, the way I understand it is the stock C3 suspension is limited on how much caster it can provide. One of the benefits of the aftermarket arms is they relocate the BJs to allow for more positive caster. It aligned it a few years ago and am due, I plan on getting it in this spring. I'll update when I get it back in, but I want to say I only got like 3 or 4 degrees out of it.
Upper arms with an alignment for additional caster, an aggressive alignment (lots of caster, some neg camber, minimal toe in at front, more rear toe - depends on ride height) and some good sticky tyres on larger diameter wheels will transform your car. Oh and that front sway bar too. You need that! Do you know what springs and sway bars you have?
Upper arms with an alignment for additional caster, an aggressive alignment (lots of caster, some neg camber, minimal toe in at front, more rear toe - depends on ride height) and some good sticky tyres on larger diameter wheels will transform your car. Oh and that front sway bar too. You need that! Do you know what springs and sway bars you have?
Thanks! I think that's the way I'm leaning... front a-arms, new core support to correct the issue with the sway bar, and then a new sway bar and spreader bar. I did the springs about 15yrs ago (wow time flies!!!), from memory I want to say they were 550#. The sway bar I believe was the stock sway bar, I no longer have it.
I'm eyeing some 17" Weld S71's or S76's, but I can't find anybody running them on a C3 to see how I like them. Do you think it'd be worth doing just front coilovers and sticking with the composite spring in the back for now? Or if I do front coilovers should I just do the rear too?
As far as the core support, I need to figure out exactly where my issue is. I know the bottom bolts are rotted and there's play in the support due to that, to the point I can push the bottom of the support back and forth a little. But, it doesn't seem like I'd gain enough clearance by fixing that. I can only push the support forward a little bit before the holes are no longer aligned with the holes in the brace in the wheel well... it's definitely not enough to gain the needed clearance for the sway bar. It just seems way off...part of me wonders if the front clip has sagged. Here are some pics:
Driver side lower core support bolt. Weld nut is rotted and broken off the support.
Passenger side lower core support bolt. Bolt is snapped.
View of lower radiator neck from passenger wheel well. You can see the sway bar mount bolt holes just in front of it, and see how much lower the radiator neck is.
I read somewhere there's also supposed to be some sort of L bracket attached to these nuts on the bottom of the support to hold it forward. Clearly I have nothing.
On a side note, I've always been a fan of sticking with 15" wheels on classic cars because I felt the smaller wheel/bigger rubber was the right look. But I've been considering stepping up to 17's for a long time for the benefit of rubber with better handling characteristics. It's hard for me to pull the trigger on this one.... any input on whether it's the right move? I think I know the answer haha
I went through this on my '73. I ultimately made the decision to upgrade to 17" wheels for the better tire choices and I'm glad I did. Visually, I ended up liking the 17" wheel/tire combo better. I do think it might not look as good with the 17's if the tire height was too short but I chose tires in the 27" tall range and they fill out the wheel well just right.
your radiator is an aftermarket one. The stock one had a "dent" on the lower hose connection to make room for the sway bar.
Yeah, I put the radiator in 10yrs ago. It's a Dewitt Directfit which have been around for the C3s for a long time. Also, this issue with contacting the sway bar actually existed with the stock radiator. When I did the motor the first time I removed the stock radiator and had it rebuilt. While it was out was when I loosened the core support and moved it around to paint the engine bay. I put the stock radiator back in with the old "Taurus fan upgrade" and that's when I ran into the issue and ended up pulling the sway bar. A few years later I upgraded to the Dewitt radiator and dual SPAL fans for better cooling.
Dewitt radiator
OE radiator
No dents in either neck that I can see. If yours has a dent, that may be an actual dent haha.
Last edited by 80vette21; Mar 30, 2020 at 08:05 PM.
Here's my stock 2" 80 L48 radiator (AC removed), with the refreshed, but still stock, 1 1/8" front sway bar. The DeWitts radiator is a bit thicker, but I'd think you could make the swaybar work, even if you had to add spacers to drop it down from the frame stubs. This photo was taken when I was fixing a leak, so not the best photo.
Also, consider SPC adjustable upper A-Arms, and a SharkBite/SpeedDirect front brace (pictured, easy to fit with an electric fan). It's easy to dial in however much caster you want.
Last edited by Bikespace; Mar 30, 2020 at 08:35 PM.
Here's my stock 2" 80 L48 radiator (AC removed), with the refreshed, but still stock, 1 1/8" front sway bar. The DeWitts radiator is a bit thicker, but I'd think you could make the swaybar work, even if you had to add spacers to drop it down from the frame stubs. This photo was taken when I was fixing a leak, so not the best photo.
Also, consider SPC adjustable upper A-Arms, and a SharkBite/SpeedDirect front brace (pictured, easy to fit with an electric fan). It's easy to dial in however much caster you want.
Thanks for the pics!
I did consider doing spacers at one point, just some aluminum stock at whatever thickness I need to clear the neck, cut to the same shape as the sway bar mount. I may still go that route, but I feel like I should fix the actual problem (being the core support damage and possibly sagging front clip)…. If I could get myself to turn a blind eye the spacer might work.... I just have trouble letting things go lol
I purchased my spreader bar and new front sway bar from Van Steel.
They will help match you up with the proper front and rear combo for your driving needs.
I also saw that speed direct just release a new carbon fiber spreader bar.
It’s nice but a bit pricey.
Now you have me wondering what's going on with the radiator in my 1972 L48 with auto trans and no AC. Almost positive mine is OEM as well as the sway bar. Can you tell by all the surface rust? ha
Now you have me wondering what's going on with the radiator in my 1972 L48 with auto trans and no AC. Almost positive mine is OEM as well as the sway bar. Can you tell by all the surface rust? ha
Contact with the sway bar is a very common issue. My guess is someone "clearance" your radiator neck at some point during it's life. Personally I've decided I'm going to make some spacers for the sway bar mounts for the time being so I can finally get the sway bar back in, then next winter I will replace the core support and get it properly adjusted.
As far as the suspension, I think I'm leaning towards Vansteel. I've used both Vansteel and Speed Direct in the past for various things, but I like the options (and prices) that Vansteel offers for the coilover set up. Here's what I'm thinking:
Coilover suspension kits
