[20Bluezl1]

Ok guys so let me share the situation I have hopefully I get some track experts to chime in.

I have a Zl1 that I track mostly and bearly drive in the street. I have done the following mods. ZLE cradle bushing, rear suspension changed to SPL, Vorshlag camber plates, JRE125 package, ZLE front aero, APR rear wing. I run 305/325 SC3R on track cold 26 hot target this weekend was 32 - 34 psi

Ok so the issue I had over the weekend at Palmer was that I noticed alot of body roll and I wasn't getting the confidence on corners. Felt like if I pushed it a little harder my rear end would kick out, which it happened in a controlled manner.

I was reading that guys are using the following to help with body roll.
Hotchkis Front Sway Bar 22118F
BMR rear Sway Bar SB054 (hammertone finish)
SPL Sway Bar End Links for Front and Rear Sway Bars

Why aren't guys using the Hotchkis rear bar?

I have attached my alignment spec sheet.

Any suggestions would be appreciated

[cdb95z28]

Was this the first time you ran with those tires? And was the oversteer when you were on throttle (center of corner to exit)?

[20Bluezl1]

Originally Posted by cdb95z28

Was this the first time you ran with those tires? And was the oversteer when you were on throttle (center of corner to exit)?

No I have used SC3R snice I been tracking the ZL1. The oversteer was off throttle and yes about the center. Felt like if I would try and take the corner faster or apply throttle it would whip out.

[cdb95z28]

Any changes to the car since your previous track day?

[20Bluezl1]

Originally Posted by cdb95z28

Any changes to the car since your previous track day?

This was my frist event this year snice last event I have added the front 1le aero and the apr wing.

[SATINSTEEL1LE]

In your case, you SHOULD have gotten the 1LE. Unlike the 90% of other idiots that get the 1LE just to go to the store and the local car show.

[20Bluezl1]

Originally Posted by SATINSTEEL1LE

In your case, you SHOULD have gotten the 1LE. Unlike the 90% of other idiots that get the 1LE just to go to the store and the local car show.

Yes correct I should have but my ass loves to modify cars even if it's not required so I would have done all spl parts on the suspension and like some guys changed the DSSV. My next year plan is to get coilovers like Vorshlag or Detroit suspension.

[20Bluezl1]

Video I found of me at Palmer, minute 13:20 is when you'll see me.

https://youtu.be/CaindrSpec4

[cdb95z28]

Originally Posted by 20Bluezl1

This was my frist event this year snice last event I have added the front 1le aero and the apr wing.

Are the turns you are having problems with high or low speed, or are they all turns?

If it’s high speed only, I’d be questioning the aero balance. I would also confirm the alignment is as desired.

[cdb95z28]

Originally Posted by 20Bluezl1

No I have used SC3R snice I been tracking the ZL1. The oversteer was off throttle and yes about the center. Felt like if I would try and take the corner faster or apply throttle it would whip out.

Adding the aero to a car that has a suspension that is not setup for or adjustable to optimize said aero is going to be a tough deal. If someone likes to modify cars they better have a very good understanding of the dynamics involved. Modifying a car for the road course is a bigger challenge than modifying, for example, the drag strip.

Edit
I just saw you have a lot more power than stock. How old were the Goodyears? Could they be cycled out? What were the ambient temps?

[khcoaching]

Most of the issue can be attributed to driving technique. Missing apexes, late turn-ins, all exasperate body roll.

Ken

[synolimit]

to maybe answer your question about the rear bar and using rule of thumb, the rear needs to be pretty soft with the front as insane as you can get. in fact most racing teams will make their own front bars because nothing on the market is strong enough. Doran Racing that used 370z's would make their own sling blade style because the Hotchkis wasn't enough. as for the rear i think they and most others would use OEM or the thinner G37 bar. i understand these are different cars but all 3 are front engine RWD. why does hotchkis make a rear if no ones gonna use it? idk. money? but i wouldnt get anything aftermarket unless the BRM is thinner and weaker than OEM. im assuming you dont have the 1LE rear bar which is 3 way adjustable?

so my top 3...
1. less rear bar
2. looks like you're rear toe'd in already correct? just weird i dont see a neg anywhere since the front shows the arrow out and the rear shows inward but no neg sign.
3. more attack on that rear wing since you can adjust it. whats your angle of attack now? i use a straight edge and my phone as a level. are you over 6º?

EDIT, also, im almost betting the 1LE has stiffer springs which we can swap and replace with say Swifts since they are 2.5" ID. i know the OEM rates on mine but not sure what they are on yours. if body roll is your main issue vs the oversteer, you need stiffer springs since a ZL1 and 1LE should weigh the same.

[20Bluezl1]

Originally Posted by cdb95z28

Are the turns you are having problems with high or low speed, or are they all turns?

If it’s high speed only, I’d be questioning the aero balance. I would also confirm the alignment is as desired.

They are the tight low speed corners which where given me the feel that the rear end wanted to kick out.

[20Bluezl1]

Originally Posted by cdb95z28

Adding the aero to a car that has a suspension that is not setup for or adjustable to optimize said aero is going to be a tough deal. If someone likes to modify cars they better have a very good understanding of the dynamics involved. Modifying a car for the road course is a bigger challenge than modifying, for example, the drag strip.

Edit
I just saw you have a lot more power than stock. How old were the Goodyears? Could they be cycled out? What were the ambient temps?

I have 2 sets of wheels with SC3R this set that I used this weekend I purchased from a member here which said he had been on the track for a couple sessions. I would have ro look at the year on the tire snice I can't recall. I will also try to take a picture of the tires the best I can since the car is still on the trailer. The ambient temps where 89⁰ ro 92⁰

Front tires are the ones with marbles and from 2019
Rear are from 2017