hi guys,
i need some help. i just had my tranny rebuilt and at the same time i got a new converter to match the engine a little better. i was playing with it on the street and it has way less hook.
i run on hoosier quick time pro's, i always run 22-26 psi and never spin in the least. but now i am thinking those days may be gone. i usually launch from either 750 or 1000rpm depending on the weather.
i was wondering if anyone had any tips that could help put me closer to the right launch rpm and air pressure? i have to compete for points and the weather has kept me from doing any testing, so anything that will head me in the right direction would be a great help.


thanks
tim

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91 Camaro RS-LO3,Auto.
14.209@95.46mph
Best 60' 1.917
Check Out The East Coast F-Body Nationals Home Page
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Until you can do some testing just launch from an idle and let the converter flash. It'll be less shock on the driveline but your ET won't be as good.

 

The only problem I have with flashing the converter from idle is that my reaction time becomes unpredictable. With my mild TCI Break-A-Way converter (~1800 foot stall), I cut my best 60's (1.89-1.95) holding it at 1200 rpm against the brakes and then briskly rolling on the throttle, but not just standing ont it. This is with a basically stock L98.

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87 Formula 350 13.94@96.67
98 Z28 1LE 13.15@107.59
1LE Owners Association

 

I usually flash the converter from idle. The only time I have a problem is if I don't heat the tires enough, or the ambient temp is way down. If I load it to 1200, I bust loose every time.

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91 Firebird Formula. Converted to carb. Holley 750. Forged Flat top pistons. 10.5 to 1 compression. ZZ-9 Cam. Ported L98 Heads.
175 shot NOS, 700r4 w/ 3000 rpm converter and 3.73s in the back. Headers w/ full dual exhaust. 27.5 inch McCrearys.
12.98 @ 106 Natural,
11.83 @ 113 NOS.

 

I am just the opposite, I stall mine up to 2500, then stand on it. Last year I had consistant 1.9-1.95 60 fts. I ahven't had the new motor to the track to see what it will do.
John

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82 Firebird,408,Dart Iron Eagle 215's,Cam 229/239, .498/.520,TH350 Tranny, 750 Speed Demon carb, Hooker Headers(I.E. POS) Manual steering, Also a cowl for the big hole in the hood.
Shooting for low 12's.
Check out my birds new home.

 

If you're foot braking the launch, then you should probably tune the car to leave from idle so the coverter will flash. If you bring the rpm's up with your foot on the brake, you are preloading the chassis/suspension. The idea is to shock the chassis to dynamically increase the load on the back tires during the launch. If you have a transbrake or clutch setup it doesn't preload the chassis when you bring the rev's up.

I pull low 1.7x 60' times leaving from idle, but can only pull low 1.8x leaving at a higher rpm.

If you read any good chassis book, it will tell you the same thing.

Miles



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88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

 

thanks for the tips guys. i will be hitting the track for the A.M. test session to try getting practice before points at night. i am gonna try the old launch first and prolly adjust the rpm from there. i used to come off just above idle, i am gonna try idle then 1000, 1200, and 1400 to see what the car likes.
i'll let ya knwo the results.

thanks
tim

------------------
91 Camaro RS-LO3,Auto.
14.209@95.46mph
Best 60' 1.917
Check Out The East Coast F-Body Nationals Home Page
www.geocities.com/njspeeder

My MAFB.ORG Home Page
www.mycar.net/mafb/registry/detail.cfm?id=299

DSI Racing Home Page
www.geocities.com/foff667