TWF

Advantage of the ride height adjustable shocks independent from spring preload is that you can choose better spring rate and than set ride height.

Sebring AP1

It compensates for the difference in rake. with a set coilover height, when you go from staggered to non staggered the rake of the car will change (the front will be higher with non staggered vs staggered)
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That would make sense if it actually was a matter of just evening out the ride height due to the differences in front tire heights, but that isn't the case. It sounds as if the car was specifically setup with higher rear ride height for the non-staggered setup, but maybe that's not the case. It's not like the car was setup for staggered tires and then 255s were thrown on all around, it was setup from the beginning for non-staggered.
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I always have rake on my cars. 3 turns is probably not even a quarter of an inch so it is more minimal than you're assuming it is. It's better to have that extra bit of rotation than not. Even heights or lowered rear would yield some high speed understeer which is a bad idea in a wingless car. Correcting an error almost certainly guarantees snap oversteer unless you're a left foot braking pro.

maxrev

The rear is about 4mm higher then the front at this point. I raised the rear by 3 turns and would raise it by 4 turns or more if I am running some type of wing. In regards to camber, this car was never built for lap times. I am running -4 degree to keep the tires from destroying the OEM fenders...

gptoyz

sorry to go off topic, but how much weight do you guys bias towards the front?

I'm just starting to understand how scary high speed understeer is when the car won't respond to steering input and dollar signs and insurance numbers fly across the windshield

gptoyz

I had the same argument as my friend and he was said that most of the high quality aftermarket suspension have such short springs that you rarely/if ever affect spring preload

Does this hold water?

andrewhake

It compensates for the difference in rake. with a set coilover height, when you go from staggered to non staggered the rake of the car will change (the front will be higher with non staggered vs staggered)
[/quote]

That would make sense if it actually was a matter of just evening out the ride height due to the differences in front tire heights, but that isn't the case. It sounds as if the car was specifically setup with higher rear ride height for the non-staggered setup, but maybe that's not the case. It's not like the car was setup for staggered tires and then 255s were thrown on all around, it was setup from the beginning for non-staggered.
[/quote]

I always have rake on my cars. 3 turns is probably not even a quarter of an inch so it is more minimal than you're assuming it is. It's better to have that extra bit of rotation than not. Even heights or lowered rear would yield some high speed understeer which is a bad idea in a wingless car. Correcting an error almost certainly guarantees snap oversteer unless you're a left foot braking pro.
[/quote]


The rear is about 4mm higher then the front at this point. I raised the rear by 3 turns and would raise it by 4 turns or more if I am running some type of wing. In regards to camber, this car was never built for lap times. I am running +4 degree to keep the tires from destroying the OEM fenders...
[/quote]

Ah this makes sense thanks for clarifying. High speed understeer to snap over steer is definitely not fun. I agree bias toward more rotation as it is much easier to control the rotation as it is more linear. Thanks.

TWF

Depends what rate springs are used. Stiff springs with shocks unloaded will have negative preload, reason helper springs are there. Once car weight is put on them there will be preload.
Lets say you use very stiff springs on the front and soft on the rear to deal with oversteer. If you want to raise rear you can do it without preloading soft springs, that way you not taking away from extension.

Sebring AP1

Good news is if you can see dollar signs flapping across the windshield you're not driving fast enough!

LickyMYwalker

Just wanted to post an update

I am currently on a set of EVS SRC now and have been for a little bit so this is long overdue. Did 2-3 track days since owning them and have been able to hit decent lap times. I didn't feel anything very dramatic except that the setup is more compliant over very bumpy surfaces. The car doesn't seem to catch me off guard so I think my set of EVS SRCs are as they intended them to be.

I was experimenting in the garage and I was able to create 2 scenarios.

1. the car at full raised ride height and have it sit on the bump stop.
2. used lower collar to lower the car to lowest setting but still maintain a 2 finger gap.

I was able to accomplish setup Scenario 1 by unloading the spring and by that it would lower the car and sit on the bumpstop no matter how "high" you try to make the car with the lower collar. This may have been the issue that Ivan was seeing in his car which ultimately lead to revalving. It may have been the bumpstops that Ivan was riding on but I'm out of town a lot and I'm no professional, just a friend who volunteered to help out. Ivan then decided to revalve to Guys spec which is same as OP. Tein has revalved Ivan's set of coilovers and he is happy with them. I am currently happy with my off the shelf EVS Spec SRCs as well.

I guess what I'm trying to say is that the shock can be valved correctly per manufacturer spec (whether it be good or bad is your choice) but if the setup of the actual suspension is wrong then that's a different story.

andrewhake

Could definitely have been the case. If the perches are setup with drastically different preload than recommended and the car was just always sitting on the bump stop that would make a lot more sense.