jcmbird

Curious, why or why not does a coil over suspension [rate of spring the same] " out perform " a transverse leaf setup[c5 vette]? would a stiffer leaf and shocks setup be cheaper for road racing application? thanks

TLGunman

Adjustability would be the biggest advantage. You can change spring rates easier with a coilover vs. swapping the leaf.

davidfarmer

I agree. Leaf springs can perform very very well once your rate is dialed it......experimenting gets expensive and time consuming with leafs.

rfn026

The leaf springs work just fine. The only advantage of coil overs is that you can adjust the ride height quickly. The other advantage (maybe) is you can swap spring around quickly. Remember though a spring change can make your Corvette slower just as easily as it can make it faster.

The more things you can adjust the more things you can screw up.

Richard Newton
Intervention Motorsports

fatbillybob

The fixture of the transverse leaf attempts to isolate one side from the other so that each side is independant spring like a coilover. The reality is that a leaf has charactoristics of a swaybar too and there is crosstalk to the otherside. It is very difficult to figure out what is happening when dealing just with CO's and with sways and with shocks and even more difficult when the leaf is a spring and a partial swaybar and having sways and shocks. That said the guys running out of the box GM engineered T1 leaf suspensions have some pretty darn good laptimes and many a CO car is having handling problems because owners have no clue how to collect meaningful data in order to make good changes. Add that to messed up alignment settings, chassis rake problems, power adders, wheel tire choice, aftermarket shocks and sways and you have just as good a chance to go slower as faster.

Mojave

Coil springs are cheap. I recently picked up a pair of used Eibach's for $50 shipped, hard to match that with leaf springs.

redtopz

I agree, I bought some used coilovers for my car when I was just starting hpde because they were a good deal and I thought they would be a good mod. However, I think they hindered my driving more than helped because it took me about 6 track days to finally get them configured how I like them. And since I don't ever adjust my ride height or shocks settings or spring rates throughout the year I might as well be using leaf springs with my stock 04 shocks. On the other hand, I am very comfortable with my setup right now which is why I don't want to change it. BTW anyone know the actual wheel rate difference between a pfatd spring F/R versus the stock C5Z springs?

0RAAMaudio

The leafs also provide a lower CG and less unsprung weight

Nothing wrong for serious drivers to run the leafs, much better to deal with sways and shocks, setup well, great results Easier to get to a sweet spot and just drive!

For those more serious about tweaking, all out performance of the car, etc(often times at the detriment to actually driving the car instead of chasing ones tail trying to figure it out) coilovers are great fun to play with and altimately the best way to go.

My all out race car, coilovers, my street/show/demo/HPDE car, leafs, upgraded shocks and sways If I only had one vette it would have coilovers though

Rick

Note: inverted shocks have less unsprung weight than regular shocks but add a bit to the CG. In general when figuring out unsprung weight you only count the weight on the out end of the shocks, control arms, etc, the end connected to the chassis is not counted. This info is not that important for most of us though, not unless you are very very serious about calculating spring rates to the infinite degree or building to the extreme limits of your particular racing requirements, class rules that allow changes in these areas, etc.......

flycastinguy

OK, so now I'm confused. In the couple of years I've been tracking the car, most of what I've heard (especially from vendors) is ya gotta eventually go to coilovers ... "the difference is unbelievable!" they say. God knows they're all marketing them. But now I think what I'm hearing from you guys, is a good set of shocks, '04 Z stockers for instance and the right set of leaf springs is more than adequate for HPDE, time trial, etc. Obviously it's adequate for T1 since that's the spec suspension setup. My question now is one of balance between shocks and springs. GM obviously did a good job of suspension balance with the C5Z in stock form. If one wants to upgrade for the track, should you stay with a proven combination such as T1 shocks and springs, or is there anything to be gained (or lost) by staying with stock shocks and going with T1 springs, etc?

David, can you weigh in on this one? Right now I'm still running a stock C5Z suspension with a Pfadt bar. Maybe there can be life without coilovers!!!

mousecatcher

I would argue not. OEM shocks are generally chosen for cost reasons. Upgrading your shocks is pretty much universally a great cost effective improvement.

gonzalezfj

What he said!!!

Frank Gonzalez

geerookie

T1 springs with adjustable shocks would be a great set up and probably as fast as a coilover setup.

But coilovers do make a big difference in the feel of the car and that can inspire confidence which will help you be faster if not over time get faster. The car just feels more connected with the track.

drivinhard

bob if you still want to run in TTA, shocks and springs will eat up a bunch of points. you'll be stuck with a skinnier tire and/or something not near +10

BrianCunningham

So, no one's mentioned that there's less crosstalk with coilovers yet?

95jersey

Of course vendors are going to tell you to buy their product. There's not to much value in selling leaf springs, but with coil-overs you have the wow factor and each vendor individual designs and metals and brand names.

I decided to go coil overs a couple years ago and YES they mad a HUGE difference, but I am sure if I bought a set of VBP 1250lbs leafs and got the right shocks, it would work just as well.

I personally bought coil-over's simply out of cost and value. A T1 kit (if you can find one), goes for $4-5k (not installed), and the spring rates are not much stiffer than stock C6Z leafs, so I could not see spending all that cash for a nominal change. I also did not want to buy some custom leaf spring rate and try to match shocks, as I knew I would probably make the car worse, so go with tried and tested product that provides the $$$$ bang for the buck.

I think anyone that has been around will tell you T1 works and may someday prove to be better than coil-over (who knows), but I'd personally save the $$$$, buy as set of WELL proven LG coil-overs and use the rest of the money for other mods.

On Hoosiers, I found my C6Z with OEM leafs to bounce arounds, dive hard under braking and bottom out on high G turns (I wore 1" off the left front of my air dam at the GLEN with OEM leafs). Also, I got some fender rub. The car was still fast, but it was a LOT more to handle. With my LG's, I feel WAY more confident, the car is stable and I am not nose diving under hard braking. While I give significant credit to the LG's, they have probably have a bigger mental affect giving me more confidence to push the car harder.

Also, seems everyone that puts on coil-overs slams the car, when at Phoenix we agreed we would run the car pretty high with only a minimal reduction in ride height. This put more "pre-load" on the springs, and while a rougher ride, the car works REALLY well at the track. I am not the absolute fastest, but I ALWAYS get compliment on good my car looks in the corners and under braking. Best money I ever spent on a mod.

L98Terror

Post #5


Anyways, I would stick with leaf springs for HPDE for TT you really can't do coilovers in a C5Z and stay in TTA but if your looking to run TTS than by all means

flycastinguy

I agree Mark. Judging from some replies, I may not have been clear on my comments or intent. I was not saying that stock shocks can't be improved upon. Obviously they can. I was just saying that for street purposes and for beginning HPDE for that matter a C5 Z06 is balanced very nicely from GM with its combination of shocks and springs. My question is one of maintaining good suspension balance when moving forward through advanced HPDE to Time Trials and the like. Moving forward in the progression of mods, does it make sense to change only shocks, only leaf springs, go to T1 shocks and springs, or just go ahead with coilovers? ... (depending on what TT class you want to end up in of course. ) It's part of the learning curve for me. I'm not so concerned about TT class right now as I am about understanding bang-for-the-buck when it comes to an improved suspension.

BrianCunningham

variable rate is another advantage.

You can do it with leaf springs, but it gets real complicated.

With coil overs it's real easy.

L98Terror

Bang for the buck is focus on the driver and leave you C5Z06 suspension stock, maybe just change shocks but I wouldn't do anymore. Once you start changing things the next question is are you improving your driving or just your car. The best of us only get about 90% out of a stock C5Z, get every thing out of the stock car first.

The biggest mistake you can make is to go out of the box and build up a car that you haven't mastered it will increase your learning curve dramatically.

I wouldn't change anything (except for brakes) until you are at least TTing, you never know what you are changing and what it is doing to your car until you are a very consistantly fast driver. Don't be one of these people that spends tons of money and ends up going slower than a stock car.

rfn026

Shocks that are good for the track are terrible on the street. My Bilsteins are incredible at the track. They have so much rebound that they're really bad on the street. To make matters worse (or better) Bilstien just gave me 30 per cent more rebound for the track.

If you're running HPDEs what's the point of turning a nice street car into a really bad street car. You don't go ot HPDEs to beat anyone. It's all about fun. Drive what you have an learn to drive it better. Save your money for entry fees and motels.

Now that we're all spending about $1,000 a day to run HPDEs why spend a bunch of money on parts? Get a driving coach. That's a much better return on investment.

Now if you really want to have fun go Crap Car Racing.

Richard Newton
Intervention Motorsports