Suspension setup info

[DominusEtDeusNatus]

Alright, I did some experimenting and found this out. We(V6 guys) DO NOT need stiff springs in the rear. Our power levels are lower then V8s and we don't need V8 springs in there. Keep your stock ones. The 95.4 lbs/in that came with 93-97 V6s are very good. Later years got the 114 lbs/in from V8s, at least they're not as stiff as 1LE. If you're getting springs, just get the front ones and save your money by not buying the rear ones. Unless you're lowering and going for apearance then obviously you want both. This is the first setup I had.

941LE shocks (very stiff Decarbons)
1LE springs front/rear
32mm 1LE front bar
21mm 1LE rear bar
Poly bushings

I took some corners faster then I should to see what will give first. Moderate oversteer. Rear end is more stiff then it needs to be.

Recently I went back to 96 rear springs. Car is still flat on corners, braking, and accelerating. That didn't change since I still have the stiff shocks. Shocks make or break your setup. I took this corner by my house way to fast to test the new setup. Tires made alot of screetching noise but the car never moved sideways. It just kept going through the corner. Very stable and much more balanced then with 1LE rear springs. Notice the 21mm bar in the rear. That is enough stiffness for the rear without the need for stiff springs. I hit a "better" combination. This is how you tune the suspension. Keep swapping out springs or sway bars till you hit the balance you want. Obviously not everyone is going to do this.

I now have less oversteer, but there is still some oversteer. This is good. You want oversteer rather then understeer. You want to be able to swing the rear end around the sharp corners with the gas pedal. I'm also hooking alot better on launches so I killed two birds with one stone. :D

My new setup that I like much better.


941LE shocks (very stiff Decarbons)
1LE springs front
V6 springs, 95.4 lbs/in, rear
32mm 1LE front bar
21mm 1LE rear bar
Poly bushings

I was going to get a panhard rod and LCAs this month, but the car feels very stable. I have to go REALLY too fast on corners to loose it. And when I do loose it, it's just alot of screetching. I haven't actually spun out or even had the rear slide out on me. And I really tried a few times. So if I do upgrade it I won't tell the difference on the streets since the limit is already so high up there.

Hopefully this helped some of you.

I'm going to have to edit that road race guide of mine soon. Remember it's all about balance. I'm concentrating on one piece of the suspension that makes the whole thing work "better" in "my" setup.

[V6Bob]

"there is still some oversteer. This is good. You want oversteer rather then understeer. You want to be able to swing the rear end around the sharp corners with the gas pedal"

Lots of people say this. I disagree, for two reasons.

In racing, if the rear end is sliding when you're coming out of a corner, you cannot be accelerating at maximum. Someone with less oversteer can get on the gas sooner, and they'll beat you.

Do not take my word for it (why should mine be any better than Dom's?). Look at the guys who consistently win autocross in competitive classes. They will not be slinging the rear around. Watch the Winston Cup guys around the 35mph hairpin at Sears Point or the slow turn one at Watkins Glen. Or the CART guys or F1 on sharp corners. If someone does slide the rear, the guy behind them will close up.

Second, on the street, if you have any oversteer at all on dry pavement, it will be worse if the pavement is wet, dirty, etc. This is unsafe. In an emergency, when you turn the wheel sharply, it is easier to maintain control if your car understeers a little. Oversteer can turn a near miss into an accident and a minor accident into a major one.

Two quotes from Carroll Smith - "Corner exit oversteeer thrills the spectators and makes the inexperienced (or ignorant) driver feel heroically fast. In some ways, it's a pity that it isn't the fast way around the race track." "Every fast car will have a certain amount of understeer."

That's for racing cars. On the street you want more understeer.

Edit - just saw this on another board -

"There was another Z there that ran 33's... he's a board member but I forget his screen name, he was hooking up a LOT better than I was, or maybe he was driving smoother , but he looked a lot less tail happy than I felt I was."

Bingo. I'll bet anything people would be surprised at the size (small) of that guy's rear antiroll bar.

[ July 22, 2002: Message edited by: V6Bob ]</p>

[carldev96]

The softer springs make sense with your setup. With no LCA and 1LE sway bars your car probably over steered pretty bad. With the weaker springs your essentially increasing the handling of the rear to allow the rear to keep up with the front. Once you install the 1LE LCAs/panhard I'd be quite interested to hear how balanced your car is.

To be totally honest, I'm a little disappointed with the 1LE springs. The rears are a little too soft (understandable/necessary for a powerful V8) and while autoXing the Z28 guys and myself still get too much nose dive under hard breaking. Maybe if the springs were 500lbs front/225lbs rear would offer better braking and blance. I'm a little anxious to see how the car handles with the sway bars at my next autox.

Well that’s just my opinion really. I agree how important it is to keep a good balance. [img]graemlins/thumbsup.gif[/img]

later
carldev

edit: I made a mistake :(

[ July 22, 2002: Message edited by: carldev96 ]

[ July 22, 2002: Message edited by: carldev96 ]</p>

[DominusEtDeusNatus]

<blockquote>quote:</font><hr>Originally posted by V6Bob:
Lots of people say this. I disagree, for two reasons.

In racing, if the rear end is sliding when you're coming out of a corner, you cannot be accelerating at maximum. Someone with less oversteer can get on the gas sooner, and they'll beat you.

Yes. I did mention I now have LESS oversteer.

Do not take my word for it (why should mine be any better than Dom's?).

Why so much hate?


Look at the guys who consistently win autocross in competitive classes. They will not be slinging the rear around. Watch the Winston Cup guys around the 35mph hairpin at Sears Point or the slow turn one at Watkins Glen. Or the CART guys or F1 on sharp corners. If someone does slide the rear, the guy behind them will close up.

Ok, more of the same.

Second, on the street, if you have any oversteer at all on dry pavement, it will be worse if the pavement is wet, dirty, etc. This is unsafe. In an emergency, when you turn the wheel sharply, it is easier to maintain control if your car understeers a little. Oversteer can turn a near miss into an accident and a minor accident into a major one.

We're not autoxing on the street. I'm not setting up my suspension to prevent accidents, just to go faster around corners. I would have to be going over 100mph to have a problem with slalom.

Two quotes from Carroll Smith - "Corner exit oversteeer thrills the spectators and makes the inexperienced (or ignorant) driver feel heroically fast. In some ways, it's a pity that it isn't the fast way around the race track." "Every fast car will have a certain amount of understeer."

I'm sorry I don't own any books. Member of my car club owns a track record with his camaro. He is close to a few others. I had a long talk with him recently. He told me my setup was very good. He told me that I want to be capable to induce oversteer with throttle. I simply decreased my oversteer, but still kept some. One of these days I'll have to get into a car with him with a video camera. That should provide some proof.

I'm sorry Bob, but he has credentials, records, and experience.

[ July 22, 2002: Message edited by: V6Bob ][/QB]<hr></blockquote>


I have some questions for you.

What suspension mods do you have in your car right now? How does the car feel?

What suspension mods did you own before?

Why did you change the mods?

If you kept the same mods, why?

Do you race yourself?

Where do you find out the stuff that you know?

And cheer up.

[Dominic]

Throttle induced oversteer is one thing, Natural oversteer is another all together.

My 1LE swaybar equipped camaro still naturally understeers, but with enough throttle I can force the tail out - allowing me more control over my car. Under racing conditions yes I normally stay on the virge of tail slide, and on the street its awfully fun to round a 90degree corner and sling the tail out burning both tires til I chirp 2nd - but thats not racing :D .

I like your suspension setup Dom - have you considered going with SLP Eibach progressive springs though? They're like 1LE's when pushed, but are V6 soft when cruising [img]smile.gif[/img] (See my spingrate post I made).

I personally love my 1LE rear bar, and only hope to make things better in the future with 1LE LCA's or Rod Ends (I can't decide). What improvements did you note by going to the 1LE LCAs, or are you not running those yet?

Have you considered a 35mm front bar?

[O0oSKAMo0O]

i have done much suspension work for auto crossing and road racing the biggest improvement was front sway bar and koni double adjutables check out my list it all is very effective i have specs for shocks that really work email me at o0oskamo0o@aol.com

[V6Bob]

I said - Do not take my word for it (why should mine be any better than Dom's?).

"Why so much hate?"

My sincere apologies. I honestly meant that to be humble and make the discussion about facts and not who's smarter or better. I see it was misunderstood and I take responsibility for that.

"We're not autoxing on the street. I'm not setting up my suspension to prevent accidents, just to go faster around corners. I would have to be going over 100mph to have a problem with slalom."

Once again, I see I'm crummy at being clear. :( One of my concerns is that people think a fast track setup is best for the street. On the track people with adjustable antiroll take antiroll out overall and move the roll couple balance forward when it rains. With our cars nobody can do this and the optimum dry track setup is unsafe in those conditions. It will bite you in an emergency situation.

"What suspension mods do you have in your car right now? How does the car feel?"

Mostly stiffening mods (sfcs, stb, Panhard). See below for bars. The stiffening crisped up the handling/steering response considerably. These are the best and safest mods.

"What suspension mods did you own before?"

I also tried the 32-21 bars since it seemed from these boards that that was the "hot setup". I rapidly decided that was _way_ too much oversteer with stock 2000 V6 springs and went to 35/19, keeping the balance more in line with the stock 28/15s. I'm not recommending changing to these bars (that's why they're not in my sig), that depends on many things. And it's really too much antiroll overall for rain or snow.

"Why did you change the mods?"

See above. On my future list are a tunnel brace for more stiffness and better shocks. A good roll bar/cage would be best for stiffness, but I can't deal with the cost/inconvenience. I see no handling reason to change springs.

"If you kept the same mods, why?" Above.

"Do you race yourself?"

A long time ago. I started autocross with a Fiat 124 Spider (so I'm an expert in understeer :cool: ). Then I raced SCCA for 10 years. Showroom Stock Scirocco. Titan Mk6 Formula Ford. Showroom Stock Fiat X1/9. I keep meaning to take the car to an autocross (where I'll have to run C Mod or something because of the sfcs) but haven't. I mess with computer simulations (GPL, NASCAR 2002, F12000) a lot. The good ones are very good these days.

"Where do you find out the stuff that you know?"

A combination of experience, books, and friends.

"And cheer up."

Darn. Once again I apologize for how I came across (and apologize in advance if I'm doing it again, sigh). I see endless people on this board putting on 32/21s. They are way oversold. GM realized that was too much rear bar for the car and only used them for one year. A late model V6s springs are biased more toward oversteer than a V8s(which is why the car comes stock with a 15mm rear) and 32/21s are definitely unsafe with those springs.

I'm not unhappy or offended or annoyed in any way. I'm genuinely concerned. I'm sorry if I came (come?) off otherwise.

:D And (a bit oversimplified) I still think being "able" to kick the rear out with the throttle means you cannot use the throttle optimally, to accelerate the car off the corner. At the risk of offending again, if the Winston Cup guys don't do it at the Sears Point hairpin, why not? :D

I want to be helpful. I'm going to write up my argument better and post it for people to take shots at. I hope I can make it worthy for consideration for inclusion in the modifications encyclopedia.

Bob [img]graemlins/burnout.gif[/img]

[DominusEtDeusNatus]

Don't worry Bob, it's all good. [img]graemlins/thumbsup.gif[/img]

We must have arguements in order to get to the bottom of how things work.

32/21s with stock V6 springs would have alot of oversteer. I see why you hated them. I would hate them too. The bars are good when matched to the right springs. I have 1LE springs in the front to lessen that oversteer with stock V6 springs in the rear. It was either putting on 19mm bar in the rear or replacing the 1LE rear springs with stock V6s. The whole point of the post was to say that I had too much oversteer with 21mm bar and 1LE springs in the rear. I might even have a neutral car now for all I know. I tried sharp and wide corners up to a point of tires screetching very loudly. The rear end never came out, neither did front end loose traction. I have to be very close to being neutral. That was with no throttle, just turning at high speed. So I imagine if I got on the throttle the rear end would come out. And on those instances I really tried to break the limit. Normal street driving will never come close to this limit. I feel it's a safe car. And the best thing is that it's still very comfortable for my tastes. But then again, I have a poly trans mount and I don't even know it's there.

Dominic, I don't want lowering springs at this moment as I don't have money to buy two different setups. Autox and drag. I'm at a point now where I have good cornering and good traction at the drag. Tires are really HUGE for autox. With Victorraces or some other similar tire the car would rule. I actually know someone selling them for $50 for all 4. They supposively have enough to last all season. I'll be thinking about them. It's tempting. My Kuhmos corner ok, but they are pretty crappy for competitive events. I got the "rolleyes" when I mentioned my tires to pros.

[DominusEtDeusNatus]

I just looked up the Victorraces and they are $150 each. I think I'm getting a deal for $50 for all 4. He quaranteed they last all season even if I go to EVERY SINGLE event.

[V6Bob]

Dom - Looking at the spring rates, I can see how 32/21s could work with 1LE fronts (360) and early V6 rears (95).

"This is how you tune the suspension. Keep swapping out springs or sway bars till you hit the balance you want. Obviously not everyone is going to do this."

I wish everyone understood this and that people didn't just slap on 32/21s because "some guy said" or "they're 1LEs so they're the best". I think 32/21s need the big spring difference front/rear that you have to work. I think we agree that on stock V6 springs (257/114 or 223/95) they have way too much oversteer for either speed or safety.

[FirebirdGT]

I think one thing needs to be clarified here. The 1LE springs were NOT part of the suspension setup with 32/21 mm sway bars. Only in 93 was the 21mm bar used, and the springs on those 1LE cars were the stock V8. Starting in 94 the cars used the "1LE" higher spring rate, but went back to the stock V8 19mm rear bar.

More information is in the Technical Database, 1LE section.