thats some very interesting info... I shall save. thanks!

 

WHOA.....

Silver & Red, you dont play any games when you post...do you!

I'm glad this topic came back up again. I recently discovered some equally useful information. I talked with my uncle last night David Lindsay (former PRODUCTION ENGINEER for the Bowling Green plant). His reply was this: Corvette's goal in ZR1 (275/315 tires) suspension engineering was to create a completely neutral feel for the car, not "a little oversteer" or "a little understeer". He said that the setup closest to neutral is found by using a 26mm tubular bar for the front suspension, and a 26mm solid for the rear (this is for 275/315 tire setup of course). After reading the posts again, almost all of your posts agree with the 26/26 setup whether you know it or not. Silver & Red is right, the 26mm SOLID in the rear is a stiffer bar than the front 26mm TUBULAR bar. This counters the understeer that derives from having a 275/315 setup, giving the car GM's best attempt at a neutral handling C4. GM apparently spent an ungodly amount designing the Zr1 suspension. Ive decided to order the factory 95' Zr1's swaybars from GM and go with poly bushings. After I install them (first weekend of December) I'll do a right up on what I think. I'm going to order a GM Conv. X-brace as well. Hopefully that will stiffen up the suspension quite a bit. Thanks for the posts. :chevy

 

Just a note...not sure if ZR1 is the one to mimic as it has extra 200-300 pounds over front axles...but I'm sure it will help.

:)

 

365ZUM, you're correct in a way...pretty much any C4 suspension setup from the factory is pretty neutral handling, once you get the proper alignment of course. The factory does their homework.

Just going to nit-pick a bit here. :) You can't compare the stiffness of the front and rear C4 bars because they have totally different geometry. If you place the bars next to each other, you'll notice the rear bar is longer, and has arms that are nearly twice as long as the front bar. The bar diameter, as silver&red posted, is just one of the many factors that determines roll bar stiffness.

There isn't much reason to compare the actual bar stiffness anyways, unless you are going through some geometrical exercises such as trying to calculate front and rear roll stiffness, etc.

 

According the table cited by 92TripleBlack, the ZR1 setup -- 26 solid in the rear, 26 tubular up front -- is also the same setup as the GS has in all suspension configurations, which is relevant because all GSs have the 275/315 front/rear tire combination.

[Modified by Charles Klein, 7:26 PM 11/26/2001]


[Modified by Charles Klein, 8:57 PM 11/26/2001]

 

Just a couple thoughts to stir up the pot...

If you have never ridden or driven in a car with 4-point full coil over suspension, be careful making any assumptions. Handling is (can be) awesome but the ride will definitely be choppy over uneven surfaces compared to a stock, even Z51, suspension. I'd still have one if someone were to give it to me, though. :)

Not all GS's come with the 275/315 tire combo... the convertibles got the relatively skimpy 255/285 tires. Yeh, I know you knew that. :)

And lastly, you could just do what I did... remove the front sway bar altogether! I can't tell the difference on the street and on the drag strip it helps (a little) for weight transfer on launch. If I was into autox and road racing like youse guys that would be a different story, of course. :D

 

Ok, educate me. I have a '95 bone stock. I previously owned an '84 and have a friend with an '89 and both of them hug a turn like the stripe. My car has a lot of body roll. Are the sway bars the issue? What is different and can I change to the 84 sway bars without causing some other problem down the road. I don't give a "rat's butt"about comfort. I wanna stick like glue. :confused:

 

check this site, and I think you will see what happened in the years between 1984 and 1996...

GM softened the springs... I would install coil overs, myself...
http://www.vettenet.org/susp_chart.html

 

I keep reading about suspensions and looking at the damned coil over prices....

My problem is I also live above the snow line and get to enjoy some poopiety roads about 65% of the time... problem is when I hit these little bumps during a straightaway no biggy I can handle that I'll live... but when I'm coming through a turn at like oh 30 and I hit the slightest bump and suddenly realize oh poopie my backend (power tires) aren't on the ground and can't get traction that's a really really bad thing....

I want to solve that, I really don't want to drop $2k to solve that though ;P
Any cheaper ideas to help this out? I mean yeah coil-overs sound pretty sweet.... also sound kind of ridiculous in cost ;)

I'll agree the vette rides like rails on smooth roads... problem is how many of us really live in florida where the roads are smooth as hell? I've hit 4in+ deep potholes in the middle of the expressway before at 110mph in my other car... this town isn't safe for them speeds thanks to those things ;P

 

DRM sells the coil over kit for 995.00...

 

OK, Blow torch "ON" ;)

Bogus, I really like the guys at Rippie a lot. BUT, my guess is that even THEY would tell you that coilovers are NOT a panacea! You have opined about DRM C/O's in so many other threads and posts, I just had to respond. If you want them, get them. Coilover's will not make up for bad driving. (not suggesting you :) ) There ARE trade off's with C/O's. First and foremost, if you don't have the car corner weighted after installation, you probably will have done youself more harm than good. All of the gushiness I've read bout from others on the CF about adjusting ride height is simply overrated at least, and at the worst, ill informed. When you adjust ANY of the spring perches, you also change the corner weight. If you have ever heard of the Nascar boys making a pit stop to remove a "spring rubber", it had nothing to do with car sex, but it allowed them to shift weight to the opposite corner....Blow torch: "OFF"....

There is a lot of good info offered above, but unfortunately it's intermixed with a lot of well intended but inaccurate information. So the original poster, 365ZUM, has got to be totally cornfused. So...ZUM, if you are basically going to use your car as a driver, and not as a competition car, IMHO, you may want to consider simply running the 275/315 tire setup with the 26T /26 solid bar combination. This will keep the car balanced, without adding any additional understeer. If you are going to run a more aggressive competition alignment, then I would "steer" you towards some other options. You car floats over bumps and rolls a lot in the corners, it's mainly due to the fact that spring and shock valving was set up so that the General could make the car to appeal toward the more mature set that would appreciate a more compliant ride. (like they were going to intoduce in the C5) The anti-sway bars are a big help in reducing roll in the corners, without appreciably negatively altering the ride chacteristics. If you really want to make a difference in the "floatiness" of the ride, I would direct you to the Bilstein guys in Calif. Tell them what you are trying to acheive with YOUR car. Tell them how YOU are going to use it, and the spring rates etc.etc. They can re-valve your shocks in two weeks over the winter. (or almost any other time of the year) My guess is that they will recommend a lot more rebound control in the rears, a little more in the fronts, and a little more bump (compression) valving all around. Too much of that (bump) would "over power" your soft springs. But let them guide you. They are super to work with.

Again, I was getting a headache reading this thread, and could only imagine what 365ZUM had to be thinking. So I'm sorry if I tramped on anyone.

 

ok. you are absolutely correct about corner weights... but my comments about coil overs are more related to the concept, versus application.

I am not a fan of the transverse leaf spring. done. hate the idea. fine in 1915 when Ford put it on the Model T, but geez, this is 2001. Name another world class car that uses transverse leaf springs? you can't. because they don't exist.

Now, lets look at "coil overs". The idea is that the shock and spring are one unit. Not off set, not seperated. The aftermarket has added the excitement of adjustablity. This is both good and bad. the reasons are obvious...

I want the coil overs (and will get them as soon as I have a job!), and the reason is not for adjustability. That adds a facet I don't want to deal with. If I set the ride height the same, and align accordingly, I should be close enough to ok. I don't plan on adjusting them daily.

What I want from the coil overs is improved ride. The transverse springs set up little quivers and funky oscolations... the real weakness in this chassis setup.

you didn't trample on me! I enjoy the free exchange of info, thats what this forum is all about. I admit my bar recommendations were off... sorry about that... but the concepts were sound.

 

WOW, what a discussion. Just a little info. The ZO7, which is closer related to our non ZR-1 cars (weight???) had , in my 93 year, 30 S front, and 24S rear. It of course has 275's all the way around. My base Vette FE1 (93 Coupe), had 26t front and 24s rear. I just put the 275's up front (from 255's) and 315's in the rear (from 285) and I put the 30S up front, and 26s in the rear. I think it handles much better. I had the tires on for a while before putting the sway bars on, and it did make a differenmce. Is there really much difference in 2mm here, solid vs tubular here. As I dont go to the track, just street, I think my combo, based on forum members recommendations, is fine, and I like it. Beats a stang any day!!

 

The Grand Sport Coupe has 26 tubular up front and 26solid in the rear. This is with the 275 and 315 combo. Steve

 

H Rocks,

Thanks for the post. I was wondering if you were going to "chime in". I'm taking your advice and going the 26/26 route. Heard that your the one to talk to about suspension setups. Ive got some more questions for you, but I'll just IM you. Thanks to everyone for the posts. This one's definately going in the notebook :chevy

 

H Rocks, what kind of info would you recommend for shock revalving.
I have the FE1 suspension, with the 30/26s set up with the 275 G Force and 315 GForce tires on my 93 Coupe.?


[Modified by steve40th, 8:22 PM 11/30/2001]

 

This is all great info. but regardless of what or who is right or wrong I have 30 and 26 solids going in tomorrow because that is my plan and the money is spent and appointment with Vettewrench is made. My base 96 has 24 and 24 with a 255 front tire and 285 rear tires. I plan on at least increasing the front tire width to equal the rear and maybe maybe 315's in the rear but I will report back tomorrow with what the sway bars accomplish by themselves.

For what its worth, H Rocks really seems to know his stuff!

Stay tuned.