NJ_phil

Can't get the car to leave straight. Goes straight as an arrow when the tires are cold but gets goofy when tires are hot and it starts to dig it's way out of the hole. Getting used to it now and just drive around it but wondering what I need to get it straight. Obviously something is out of square when it loads up and don't want to just throw money at it by adding a drag bar, poly bushings, coil overs, solid mounts, etc... unless I have to. The pic below shows a straight cold launch (green line) which went straight but I had to steer away from the curb (red x). The Yellow line shows a typical leave with hot tires. Back end just wants to slide right. Took a video of the front end and driver's side seems to get a lot more lift that the passenger side.

Yes, this is the street but does the same think at the track, prepped or not

PatsLs1vette

Measure your wheel spacing front and back of the rear tires to your quarter panel.See if one wheel is farther forward then the other.Just something to look for.

NJ_phil

Might get it a little more accurate by setting up the 4 corners on jack stands under the lower ball joints. Then remove the tires and drape 4 plumb bobs down the rotor hubs. essentially comparing the wheelbases first, then diagonally to check squareness. Not sure what the tolerances should be though but a simple alignment should get it close if needed.

Still think the problem is deflection when the chassis or drivetrain loads up. Probably some rubber part not handling the load. Would have this figured out in 3 passe with my old 4 link setup

subfloor@centurytrans

When you say it does the same thing at the track, is that also with street tires or drag radials?

NJ_phil

Always use drag radials. Funny thing is I get the best 60ft when the back slides out and I can really feel the car digging in. Less power on launch leaves straight but bogs, more power on launch leaves straight but excessive spin.

subfloor@centurytrans

What brand and size of drag radials?
Tire pressure?
How old are they?
How long of a burnout?
Launch RPM?
Stock or aftermarket converter?
If aftermarket, what stall speed?

NJ_phil

It's an M6, Depending on conditions, launch at 4000rpm, 6-8 psi, on a 2 step.
Nitto NT05R 305x19s on 11" CCWs.
Usually run 20psi /20psi but tried dropping driver's side 4-6 psi and didn't help.
Still like new, maybe 10 passes

EDIT: Have line loc but they overheat real quick if I just sit there so I usually do a rolling burnout out of the box, maybe 30 feet past the tree. Seems to work the best

subfloor@centurytrans

I think your burnout is the issue because based on my understanding of what Nitto drag radials are like they need to get really hot to work properly.

NJ_phil

Thanks man. Easy enough to try that or maybe try MT SS DRs on the next set. Want to keep the street sleeper appearance and avoid the 15" step up, coil overs, etc.. which just turns into a cash drain. Low/Mid 10s in street trim is my target which I've hit already with a good launch. Crooked, but good

junk c5

I wonder if the tire rollout is the same. Swap the rear tires and see if the car shoots the other way. I’ve seen slicks that are sized the exact same but for some reason in the manufacturing process, 1 tire ends up a hair taller causing sudden issues with cars going straight. Just another suggestion....

383vett

Then check the alignment. If the thrust angle is off, you will head toward one direction when you launch.