Is our suspension setup correctly by aftermarket strut MFR's? Is the bias correct?

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Originally Posted by J. Fast

According to the wind tunnel testing that was conducted by the Russians there's a hundred twenty pounds of lift on each corner in the front and approximately 150 pounds down force at each corner at the rear when Active Aero is engaged.
I'm seeing corner weighed setups with 950 lbs at the fronts and 700 lbs at the rears. When you add aerodynamics into the equation the wheel rates for all the corners are equal therefore it would appear that all the aftermarket suspension options available for VR4's are set up incorrectly unless the spring rates in the front and rear are equal. It's looking like 10k front and rear its a good starting point. If you have a GTC 300 wing or bigger add a couple hundred pounds to the rear Springs. That's just my. 02

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Does anyone know about the other wings, including stealth? I remember reading the 1g active aero wing had the most down force of all the stock variables, curious about the stealth, with it's flow directing sail panels and stupid looking banana wing lol.

What are stock spring rates? Curious what the engineers equated as perfection. Thinking about all of this information now, it's weird to think why anyone would go lighter in the rear, with the added aero forces. At best, equal does seem to make the most sense, although, at what speeds, I don't know...but heavier rear seems logical

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Originally Posted by Nihil

Does anyone know about the other wings, including stealth? I remember reading the 1g active aero wing had the most down force of all the stock variables, curious about the stealth, with it's flow directing sail panels and stupid looking banana wing lol.

What are stock spring rates? Curious what the engineers equated as perfection. Thinking about all of this information now, it's weird to think why anyone would go lighter in the rear, with the added aero forces. At best, equal does seem to make the most sense, although, at what speeds, I don't know...but heavier rear seems logical

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Understeer is safer for the average driver. Most car manufacturers purposely set cars up to be understeering pigs from the factory because it's safer.

I think in fairness this thread will be limited to setups capable of sustaining a lateral g or lower. Street/strip combo type vehicles or HPDE's that maybe have an occasional track visit. It's really a different animal when you have a setup that sticks so well you flex the chassis and need a suspension that's picked up and reinforced by the cage. I'm talking all four corners tied to the cage and structural rigidity work. I don't really want to get into the complexity of why dual rate springs vs. single springs vs utilizing helpers with either setup and etc... Dual adjustable strut vs. triple and four way adjustable struts and etc. What I will say is there's a light year difference between an off the shelf Megan, KSport, KW, BC, and Tein vs an AST 4100+, JRZ , Ohlin and etc.

What I think is fair to discuss is good modeling, measuring, and good principle function/operational limitations and constraints regarding what we have off the showroom floor (this is what we have... and these are the limitations to stock chassis setup whether it be caster or camber due to McStrut, valving limitations, avail grip, bump steer behavior based on adjusted ride height and suspension travel, geometry behavior and so forth).

What we need before anything is a good model built from actual measurements that account for a majority of the elements such as suspension travel, aero, tire selection, environment, road surface and etc. Once the model is built and realized on the vehicle we employ data acquisition and test test and test to dial it in.

I think 99% of owners should know that for many many years the spring rates and valving for what's avail can be improved. Additionally there's good setups avail that bolt on with Adapters.

I might circle back and correct my spring rate and wheel rates based on my recent findings from actual measurements, but not atm... Im wrapped up in a few things and don't have time.

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Originally Posted by B-Man

Understeer is safer for the average driver. Most car manufacturers purposely set cars up to be understeering pigs from the factory because it's safer.

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This is correct. With the suspension biased to understeer we're pointed to the outside shoulder or guardrail which usually has a buffer built in. If our suspensions were oversteer*biased... if the rear end broke lose you would be pointed at oncoming traffic on turn exit. I would suspect there's a NHTSB understeer requirement intentionally in place which likely reduces head on collisions on two way roads with hair-pin turns.

If you can drive the understeer condition can be removed and improved :)

Even if you don't go back and edit the table or anything, people should take the time to read this whole thread as it is completely in conflict with most current available coil overs that folks run. Not sure how interchangeable the springs are on most of those models to change the performance. The principle thing to take away from this for folks would seem to be that the front and rear should at least at the same rate or close to it, potentially slightly stronger rates for the rear (without AA or combat wing) and drive front (due to weight distribution)

Also, the dampeners should be valved matched to the setup.

There was a study done that showed that for a typical driver, understeer is actually more dangerous than a car with consistent oversteer. I'll be damned if I can't find it, but the way it was explained to be makes total sense. The way most AWD cars handle is actually the most dangerous, with understeer transitioning to snap oversteer under braking.

Keep in mind, that 150 lbs of downforce was at like 150/170 MPH? For the typical track day guy....setting your suspension up for that isn't going to be helpful in 99% of corners at tracks in America. Or ANY autocross.

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Originally Posted by anyonebutme

There was a study done that showed that for a typical driver, understeer is actually more dangerous than a car with consistent oversteer. I'll be damned if I can't find it, but the way it was explained to be makes total sense. The way most AWD cars handle is actually the most dangerous, with understeer transitioning to snap oversteer under braking.

Keep in mind, that 150 lbs of downforce was at like 150/170 MPH? For the typical track day guy....setting your suspension up for that isn't going to be helpful in 99% of corners at tracks in America. Or ANY autocross.

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That's kinda what I was thinking about the understeer thing...understeer and you end up across the way in oncoming traffic, real quick...regardless, though, it'd sure be nice to have a car that oversteers in a nice controllable manner.

Looks like an even biased spring rate between front and rear is what is desired, I wouldn't think the wing comes into play until fairly high speeds, at which, I don't see utilizing through cornering, where our problem is.

That aside, as mentioned, looks like the ksport RR series are the only aftermarket, off the shelf coilover that is setup correctly, which means it's valving should match the spring rates as well...I believe all others, you can request different spring rates, but does that mean the valving is corrected for the requested rates? Doubt it...I wonder what 14k would be like for a DD though and I wonder what it'd be like to get whatever stock fronts are, then match the rears to them to balance it out.

...in for good reading material, even if nothing comes of it :D

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Originally Posted by J. Fast

This is correct. With the suspension biased to understeer we're pointed to the outside shoulder or guardrail which usually has a buffer built in. If our suspensions were oversteer*biased... if the rear end broke lose you would be pointed at oncoming traffic on turn exit. I would suspect there's a NHTSB understeer requirement intentionally in place which likely reduces head on collisions on two way roads with hair-pin turns.

If you can drive the understeer condition can be removed and improved :)

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Originally Posted by Nihil

That's kinda what I was thinking about the understeer thing...understeer and you end up across the way in oncoming traffic, real quick...regardless, though, it'd sure be nice to have a car that oversteers in a nice controllable manner.

Looks like an even biased spring rate between front and rear is what is desired, I wouldn't think the wing comes into play until fairly high speeds, at which, I don't see utilizing through cornering, where our problem is.

That aside, as mentioned, looks like the ksport RR series are the only aftermarket, off the shelf coilover that is setup correctly, which means it's valving should match the spring rates as well...I believe all others, you can request different spring rates, but does that mean the valving is corrected for the requested rates? Doubt it...I wonder what 14k would be like for a DD though and I wonder what it'd be like to get whatever stock fronts are, then match the rears to them to balance it out.

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maybe I'm not following correctly but wouldn't that depend on what direction you are turning. Example turning left would be safer to have understeer, while turning right would be safer to oversteer, when considering on comming traffic. (Assuming we're driving on the right side of the road. [driving on the left side of the road would be the opposite.])

maybe we're talking about NASCAR and I didn't catch the hint.