[Repman]

Guys has anyone changed or researched a softer spring for the rear of the ZLE . I think that it is sprung a bit hard in the rear and with a softer rear spring might not pogo over rough tracks. I also think it might improve traction out of corners with a little more squat to the rear. Thoughts ? I do not want to upset the balance of the car but it seems just sprung heavier than needed in the rear the front feels about perfect to me .

[Harpinc]

The softer rear spring will more than likely induce more understeer. It's surprising to me that you're lacking rear grip. I run with all the nannies turned off and I am blown away by how this car puts the power down.

[BlueinTN]

I think hes talking when the car hits a single big bump the rear seams to pogo stick like he said.


It can be an eye opener on a normal highway. The exit ramp to my work has one big undualtion that even at 70 my head hits the ceiling with my seatbelt on. I dont think I would want to hit it at 100.

[Harpinc]

Originally Posted by BlueinTN

I think hes talking when the car hits a single big bump the rear seams to pogo stick like he said.


It can be an eye opener on a normal highway. The exit ramp to my work has one big undualtion that even at 70 my head hits the ceiling with my seatbelt on. I dont think I would want to hit it at 100.

He states "over rough tracks".. I know what you mean on the highway stuff. But my home track has some pretty big bumps in certain places and the car is actually much better at full speed than not.

[TRZ06]

Originally Posted by Harpinc

He states "over rough tracks".. I know what you mean on the highway stuff. But my home track has some pretty big bumps in certain places and the car is actually much better at full speed than not.

From what I have read, that is supposed to be the beauty of the DSSV shocks. Randy P. has even commented on how settled the chassis stays when going over the curbing on tracks.

The faster you go, the better they should be, that is the whole purpose of a racing derived shock.

My previous M3 on Ohlin R/T coilovers was similar. Rather harsh on big bumps on the freeway, but anytime I pushed it hard into triple digit speeds it felt even more composed. It's the whole reason for their existence, to excel at track speeds and keep the car stable.

[Repman]

Originally Posted by BlueinTN

I think hes talking when the car hits a single big bump the rear seams to pogo stick like he said.


It can be an eye opener on a normal highway. The exit ramp to my work has one big undualtion that even at 70 my head hits the ceiling with my seatbelt on. I dont think I would want to hit it at 100.

At Road Atlanta for example there are parts of the track that are a bit rough for example the back strait coming off turn 7 depending on where you are positioned on the track the rear can get twitchy bouncy as you are accelerating up thru the gears . Some of the roughness upsets the car a bit and you have to be careful with the torque of our cars to not break it loose in lower gears .

I think the back can skate and perhaps a softer rear might be helpful and also allow a bit more weight transfer to help off corner traction.

Thanks for the input guys

[Norm Peterson]

A softer rear won't increase "weight transfer" . . . if anything it'll reduce it a little because allowing the rear to drop further under acceleration works to lower the car's (sprung mass) CG relative to where it ends up with stiffer rear springs. Nose rise remains about the same, so you're not getting any compensating effect there.

What you're best off hoping for is that having more rear compliance eases the shock of hitting sharp little bumps and losing traction that way. Think in terms of "controlled give" and "losing less traction" here.


Norm

[gotroost]

Just a thought from a novice - have you tried to adjust the sway bar?

Never felt an issue with my ZL1 1LE. The rebound damping is phenomenal. Car just sticks to the road.

[Repman]

Originally Posted by TRZ06

From what I have read, that is supposed to be the beauty of the DSSV shocks. Randy P. has even commented on how settled the chassis stays when going over the curbing on tracks.

The faster you go, the better they should be, that is the whole purpose of a racing derived shock.

My previous M3 on Ohlin R/T coilovers was similar. Rather harsh on big bumps on the freeway, but anytime I pushed it hard into triple digit speeds it felt even more composed. It's the whole reason for their existence, to excel at track speeds and keep the car stable.

I am actually more than happy with the way it handles curbing ect and when the track is perfectly smooth it keeps the tires well planted and controls body roll extremely well it’s the sharp bumps that tend to make it skitter
Maybe it’s at the best compromise now ?

[Zee_Ohh]

You ever try changing anything? I would be interested to see what a rear swaybar adjustment would do since it basically has a direct affect on spring rates under compression.

[Vtor_ZL1]

There is very little travel in back - that's what hurts. No distance to soak up the bumps.


If possible, try softer tire. Ps4S for daily = awesome!