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TrakCar
post May 5 2014, 12:56 PM
Post #1


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Posts: 37
Joined: 13-May 05
From: Louisville, Ky
Member No.: 743



Over the weekend I took the Camaro out to the Midwest Musclecar Challenge (www.midwestmusclecarchallenge.com/).

I had a blast, however I now am much more humble about my driving ability.

I have the power, I have the brakes, now I am ready to begin improving the suspension on the Z.

This, is where you guys come in.

Usage
Street - 1-2 times a month to work or cruises
Track - 3 or 4 track day events per year
Autocross - occasionally

Details about the car:
1991 Z28 hardtop

LS1/T56 Stock rear with 3.42 posi
C5 corvette front brakes, factory 91 z rear disks (HP+ pads and ATE superblue fluid)
weld in subframe connectors
Spohn tubular K-member

Suspension
boxed rear control arms
solid panhard bar
Factory 91 Z28 front and rear swaybars (not sure of size)
Eibach sportline springs (fronts cut 1 coil to level ride height after LS1 transplant)
no name shocks and struts from prior to 2003 when I bought the car.

Wheels/ tires
18X8 (245/40/18) front 18X9.5 (285/35/18) rear street tires. 200 treadwear

Be aware, I am not a rich man. changes only come slowly when I can scrape together extra cash. I need a priority list to tackle for best bang for the buck.

Questions:
1) I know I should replace the shocks/struts. should I jump straight to double adjustable or is there a less expensive option that will help?
2) Have I totally screwed myself up by cutting the coils on the Sportlines? What rates should I target?
3) Should I skip coils and struts and convert to coil overs?
4) Can I have a good setup for both track day and autocross without changes?
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TrakCar
post May 22 2014, 04:20 PM
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Group: Advanced Members
Posts: 37
Joined: 13-May 05
From: Louisville, Ky
Member No.: 743



I took the car to the F-body event last weekend. notes from the event:

car weight with 90% full tank and 185lbs driver

3420 with 57/43 front rear bias. I didn't get side to side.

1) 18" 285/ 245 rear/ front street tires suck on my setup. Loose as hell, no ability to pedal the throttle to control through a long corner. (sorry, best way I can describe it. I enter the corner as fast as possible, then use the throttle for weight transfer to get the car to "slide out" to the outside apex)
2) switched to 555r2 in 275/40/17 all around. no tread left so basically 100 treadwear slicks. The difference was amazing. balance was there, could use the throttle to control the car much better. I believe I went from 1m 24s to 1m 19.1s with no other changes.
3) second day it rained, so I switched back to the street tires. I switched front to rear though to see what the difference was. Much better balance on auto-x. not as much grip as slicks (go figure) best time w/slicks 57.56, best time on damp with street tires 58.51. I think both times could have been better.
4) I need better brake proportion. C5 z06 front. stock 91 discs rear are good, but too much front bias.

Plan for improvement:

1) Koni yellow shocks struts.
2) adjustable prop valve
3) 18x10 all around (285/35 front, 295/40 rear) I hate the way the 285/35 doesn't fill the rear wheel opening.

4) swaybars/ springs
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Posts in this topic
TrakCar   Suspension Improvements   May 5 2014, 12:56 PM
RacingZ-44   QUOTE (TrakCar @ May 5 2014, 07:56 AM) Ov...   May 5 2014, 01:51 PM
TrakCar   QUOTE (RacingZ-44 @ May 5 2014, 07:5...   May 5 2014, 02:51 PM
gscherer78ta   QUOTE (RacingZ-44 @ May 5 2014, 01:5...   Jun 4 2014, 12:52 PM
Blainefab   QUOTE (gscherer78ta @ Jun 4 2014, 05:52 A...   Jun 4 2014, 09:07 PM
trackbird   Hey James! Good to see you around. That car is...   May 5 2014, 02:45 PM
TrakCar   QUOTE (trackbird @ May 5 2014, 08:45 AM) ...   May 5 2014, 02:53 PM
CrashTestDummy   Keep a close eye on that K-member. Few ever survi...   May 5 2014, 04:31 PM
TrakCar   QUOTE (CrashTestDummy @ May 5 2014, 10:31...   May 5 2014, 05:20 PM
BumpaD_Z28   Pics of the car ??? Just for reference I'm ru...   May 6 2014, 03:12 AM
TrakCar   QUOTE (BumpaD_Z28 @ May 5 2014, 09:12 PM)...   May 14 2014, 02:53 PM
nape   If you want to get serious about the street tire e...   May 6 2014, 05:41 AM
TrakCar   I thought I would update the group. I have the Me...   May 14 2014, 01:32 PM
Pablo   QUOTE (TrakCar @ May 14 2014, 05:32 AM) 2...   Jun 1 2014, 08:19 AM
slowTA   That's the same power steering cap I used on m...   Jun 1 2014, 01:26 PM
dailydriver   QUOTE (Pablo @ Jun 1 2014, 04:19 AM) QUOT...   Jun 1 2014, 08:23 PM
Pablo   QUOTE (dailydriver @ Jun 1 2014, 12:23 PM...   Jun 2 2014, 07:32 AM
Smitty2919   That's my buddies brown C2 that you have a pic...   May 15 2014, 12:45 PM
TrakCar   I took the car to the F-body event last weekend. n...   May 22 2014, 04:20 PM
trackbird   I'd run the same size tires on both ends. As y...   May 22 2014, 04:22 PM
slowTA   The cap will fit but the dipstick part is too long...   Jun 2 2014, 04:07 PM
CrashTestDummy   We got a 80's/90's Saganaw pump cap off a ...   Jun 4 2014, 06:16 PM

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