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having a problem when leaving the line...

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Old Jul 20, 2009 | 10:58 AM
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Default having a problem when leaving the line...

ok the car is full suspension with a slightly street bias (lowered) with G2 springs rears are 180-220 progressive and have koni adjustables for shocks and yes i have relo brackets and they are set to the bottom hole.

now my problem is i ran 11.6 on drag radials with no problems and now i have hoosier QTPs 27" tall and out of the hole it feels as though im slamming down on something and the 1-2 shift feels just the same and hard! i wish i had video so i could analyze what may be happening but my friend did say it looked like my car was bouncing? he doesnt know much athow to describe tings and i didnt feel bouncing in the car just a hard slam off the line and the same during my 1-2 shift. he did say tho my car looked slow out of the hole and it was with my best 60 being 1.8 but then after that i would fly with my best ET being 11.8 (which is worse than expected and worse than when i was on drag radials).

im thinking maybe my car is just too low for this much tire and maybe im slamming down onthe actual tire with the body of my car? on the street with these big *** tires ive never had any problems like this at all. just it seems at the track maybe theyre hooking so good and im bottoming out my rear? should i throw in some stock rear springs for the track?
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Old Jul 20, 2009 | 11:12 AM
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How much air pressure are you running in the tires? A bias ply tire will wrinkle and compress alot more than a radial.
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Old Jul 20, 2009 | 11:37 AM
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maybe your car out the hole is boggin down due to the slick grabbing better....even though you got a better 60ft...as for slamming down out the hole and 1-2 shifts...what does that mean????
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Old Jul 20, 2009 | 12:02 PM
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Originally Posted by 5.3LJimmy
How much air pressure are you running in the tires? A bias ply tire will wrinkle and compress alot more than a radial.

+1.

Depending on your air pressure you might be bottoming out the tire. Meaning the rim is hitting the pavement causing it to bounce back up. Then on your shift it just doesn't do it as much since you're rolling.

-Mark
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Old Jul 20, 2009 | 02:54 PM
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Car is too low.
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Old Jul 20, 2009 | 03:29 PM
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Tire pressure was at or around 14 psi (I had to drop it this low cause I had insane wheel hop).

By dropping down I mean squatting hard

and I just don't get how my ride height can really be doing this? I've got bumpstops and these tires have plenty of inner fender room from what I can see...?
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Old Jul 20, 2009 | 04:49 PM
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Oh yea I'm running tube less and have confirmed the tire would spin a half inch on the rim but that's nothing enought to cause such unimproved times. Also the car didn't bog at all just seemed to squat hard killing my 60'
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Old Jul 21, 2009 | 08:09 AM
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If it's squatting it's not moving. If you hit the bumpstops it unloads the tires and could cause false knock.
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Old Jul 21, 2009 | 08:14 AM
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My car is stock height and with 26" tall M/T ET Drags, I am slamming on the bump stops. Got some QA1's to help control that. Get that car stock springs see if that helps (which I wager it should).
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Old Jul 21, 2009 | 10:00 AM
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Originally Posted by tektrans
If it's squatting it's not moving. If you hit the bumpstops it unloads the tires and could cause false knock.
how do i want the rear suspension? stiff or soft? konis only adjust rebound i believe so i dont think i can really "stiffen" the rear with these shocks.

just wondering why am i having this problem? ive seen a ton of other camaros/TAs with what looks to be less tire-quarter panel gap or theyre about same yet these people arent having any issues? i find it hard to believe that i am actually slowing down because of possible tire rubbing up in the inner wheel wells....ivelooked up in there and cant see signs of rubbing.

maybe i am getting false knock and dont even realize it?

man i need someone to video tape me so i can see for myself what the car looks like leaving the line
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Old Jul 21, 2009 | 10:25 AM
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oh and the other thing i just remembered... back with my drag radials the car would violently hook like throw my head and body back in the seat all with the same suspension set up. i know the "violent" feel is due to the drag radials construction and not absorbing shock of the launch but that would make me think hey im hooking harder with the drag radials and not having any problems at all? so this should rule out the false knock and possibly bring back the tire rubbing somewhere, maybe my rolled lip of the quarters? but again no sign really of that happening...

man this is annoying. ive considered air bags to stiffen up my rear suspension. would that cause any other problems such as wheel hop from the bags being so stiff/bouncy?
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Old Jul 21, 2009 | 11:00 AM
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If you were rubbing you'd see signs of it on the tire.
If I were you I would lose the lowering springs. Get the car back to stock height and I would get Hal adjustables up front at least, on the rear as well would be ideal.
I would also put the control arm in the middle hole and go from there.
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Old Jul 21, 2009 | 01:39 PM
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As Madman says "Girls squat, drag cars don't"

You want the rear stiff. By squatting you're unloading pressure on the tires and that'll lead to wheel spin. I wonder if the lowering springs are making the shocks retract farther and basically you're bottoming out the shock.

-Mark
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Old Jul 21, 2009 | 06:11 PM
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Ok so at least I know one thing going wrong, squatting. I'd like to try and avoid raising my car as it is more street than drag and I'd have to do so
e suspension adjustment everytime I raised the rear for the track.

Would air bags help solve the squatting?
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Old Jul 22, 2009 | 06:49 AM
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the airbags will pretty much eliminate the squat depending on how much air you use in them. I use 30psi and that works for me. The airbags may also raise your rear a bit whe inflated and that may itself solve your ride height issue. They won't help your weight transfer though so like I said I would suggest the Hals up front, also remove the front swaybar at the track if you're not doing so already.
If you do install the airbags make sure you run the lines separatley (don't tee them together, use 2 separate valves) so they don't share air between them under load.
A cool place to mount the valves is the 2 bottom holes on your liscence plate, just drill them out enough and through the bumper to mount them.
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Old Jul 22, 2009 | 10:37 AM
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^^^ok thanks for the tip. yea weight transfer will be my next problem i guess. i havent yet removed my front sway bar but i have planned to do so. hals up front will be the only thing i prob wont be doing cause i already have konis and like i said im more street set up anyways. sometimes i wish i were all out drag that way itd be simple to set up my car. just want to get the best possible times on a more street set up car.

thanks for the help. air bags here i come!
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Old Jul 22, 2009 | 11:18 PM
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With 180-220 lb. progressive springs I doubt his car is "squatting". Those are some stiff springs that just get even stiffer with weight transfer.

Maybe the rear is unloading?
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Old Jul 22, 2009 | 11:46 PM
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Sound like a good hook then bogging try more psi not much may 1 psi warm and slip it a little more
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Old Jul 23, 2009 | 08:48 AM
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Originally Posted by joblo1978
With 180-220 lb. progressive springs I doubt his car is "squatting". Those are some stiff springs that just get even stiffer with weight transfer.

Maybe the rear is unloading?
If it is unloading its either due to the rear springs are too soft or the nose is too tight. From a cost perspective I'd try the airbags first. Then if the nose it too tight invent in some struts.

-Mark
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Old Jul 23, 2009 | 09:20 AM
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You want the shocks set stiff on compression in the rear. You need a double adjustable on the rear, extension medium, compression stiff.
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