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GRT85c
07-27-2011, 11:03 AM
I am looking for some help trying to get my older GRT to work.
Its an '02 with some updates and put the newer (1/2") 4 link brackets on this year.
We are on a smaller track ( they call it a 1/3 mile, maybe around the outside!) with tighter corners that typically gets pretty slick come feature time. We run D55 tires (WRS2) with a WISSOTA engine (358 steel block with Brodix SPCH heads). We must weigh 2300 lbs after. I have run this car for a few years and have had good luck in the past at this track, but haven't run there in a couple years and took all of last year off. I can keep up on the straights, but lose some through the corners. The car is somewhat tight on entry and need to use the brakes to loosen up entry, then get a small mid-corner push of the gas that makes me wait a bit to get back in it hard (typical GRT). I don't attack the corners hard, but prefer to be on it hard before the apex. When it really gets black I struggle with forward drive on exit, but if there is moisture in the track we are pretty good.
The front end is standard GRT with '96 and up Black spindles, left lower 16 5/8, upper 10 1/2, right upper 7 3/4 mounted outside, lower 17 5/8.
The 4 link bars are in the standard location and 19 1/4" J-bar mounted in standard location.
The 5th coil has a 325 spring all the way back with good travel, 400 on the 6th.
We scale as GRT recommends with 20 gallons of fuel (alcohol) and about 50 lbs of lead in the seat to make up the difference between my weight and their fictional 200 lb driver.
Stagger is 1" at the front and 6" at the rear.
The corner weights from scaling are:
LF 523 RF 464
LR 654 RR 579
The shocks are Integra double adjustable and the springs are:
LF 500 RF 375
LR 250 RR 225
I have gone basically back to basics after trying a bunch of stuff we didn't have to do a couple years back. The competition has gotten much faster and I'm trying to catch up!
Sorry for the garbled info but I'm beating my head against the wall trying to figure this out.
Any feedback would be greatly appreciated.
Thanks in advance,
Tim

Bcollins82
07-27-2011, 12:18 PM
By hearing how you like to drive the car, it sounds like that's where you need to start. You are getting in too easy, and back in the throttle too soon. When you do this you use up your available sidebite traction by trying to drive forward when you should be turning. Results in a loose off car in the slick no matter what you do to it. Good luck!

racin29
07-27-2011, 01:36 PM
also i would try scaling with you in the car once i think you will find your percentages to be pretty extreme at least on the rear just a thought

sj valley dave
07-27-2011, 03:34 PM
Our older GRT is set up just about like yours, except we are running a 19" lower RF arm. To help get the car to turn in and get through the center we went down 25 lbs on the LF spring and will sometimes go up 25 on the RF. It seems to let the car rotate through the middle with out the dreaded "push".

GRT85c
07-27-2011, 05:38 PM
As an update and suggested above, I hopped in the car to see what the impact is and came up with the following numbers:

LF 593 RF 458
LR 730 RR 628

I am looking for any and all suggestions.
Thanks,
Tim

dirtdiggerracing
07-27-2011, 10:04 PM
try more lr bite and soften the rr spring !!!!

tomuchbite
07-28-2011, 09:11 AM
Put the car on 3 wheel brakes when track is wet/hooked up if tight getting in corners, also more bite will free car up getting in. When track gets slick you can increase left side % to help drive from center out down straights. Have you tried indexing to help forward drive ?
If your are tight with a throttle push, raise the upper right 4bar for more rear steer. All these adjustments will only work if your car maintenance program is top notch - remove and check spindles,ball-joints, pull rear end and check for bent bells or tube. Next check all 4bar joints for binding, shocks (dyno). Next use brake caliber gauges to see if a brake caliber is sticking which if the right front is can cause a push getting in.
Before leaving for the track know that every part of the car is straight, free in movement and race ready. Start with a basic setup and adjust as needed.

GRT racer for 12 years (hope this helps)

racin29
07-28-2011, 10:42 AM
one thing i noticed back when running grt was with they way they have you setup the car you do all your ride heights and scaling with you out then you get in and throw it all off, try setting ride heights with you in the car too i would go down on rear percentage a little too, i am courious as to what your bar angles are at ride height and what they change to when you get in might need to go up on left to get a better split