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andybyrd 06-05-2009 07:42 AM

Rear Gears $64.000 ?
I know this as been ask a 10.000 Times and I've read every post on it and I still can't Understand it. I'm not stupid just ignorant. my car runs 140 mph @ 7800 rpm in the 1/4 with a 9.70 et. with a 5.14 gear its a 2670 # 85 camaro with me in it. it has MT 32 x 14'' tires now and a 665 HP 434 I've ran all the calculaters and I don't understand them completely. now I'm only running 1/8 mile tracks and I would like to get the best et's in the 1/8 I can get. now I'm running 6.20 what gear would get me a quicker 1/8 mile et if any at all. I've ask this before but cambird was the only one that answered and he didn't have any Ideas on it.
Thanks Andy

curtisreed 06-05-2009 09:28 AM

Andy, let me turn this around to you first. How much would you like to pick up with a gear change?


andybyrd 06-05-2009 09:46 AM

Well all I want to do is get all I can out of it in the 1/8 mile being that is all I'm gonna run. now 6.20 is great but out of all the calculaters I've been checking on it says that I should be doing 6.20 with 580 flywheel HP with my weight and present gears and mine dynoed 667 at the flywheel with 575 ft# tq. [434 ci] I'm not being greedy I just want it to do the best it can do and if 6.20 is the best it can do then I will be Happy with that. But if a gear change can take me down to 6.00 or 5.90 then I need a gear change.
Thank you Doorracer for your reply. and your help.

curtisreed 06-05-2009 10:15 AM

Your not being greedy, that is not why I asked. Some people have unreal expectations sometimes and there is no way to help them. I will do some checking and see what I can come up with.

I think we all want all we can get out of what we have.


P.S. I forgot to ask, what does it 60'?

andybyrd 06-05-2009 10:46 AM

The 60' times are 1.43. and I thought they were a little slow. it has a pro brake but I'm foot braking now at about 3500 and it is very consistent 1.43 60' and 6.20 with a 3 or a 5 always in the 1/8 and even foot braking it brings the front tires up 3 to 4 ft every time. I'm running a 1.76 Glide with a 6000 coan stall. I bought the car like this so I don't really know much about it other than all the reciepts the man gave me.
Thanks for your Help.

curtisreed 06-05-2009 11:51 AM

Andy I think as far as gearing is concerned you might pick up a couple of hundredths if you went lower, if that. I believe you might pick up more with some chassis tuning. I did some tweaking in my drag program and it didn't really pick up much with a gearing change.

We have a 66 nova @2700 pounds, SBC that made 702hp at 7200 at the flywheel. This car typically runs 6.teens to 6.0s at around 112-114mph, 1.27-29 60' times. This is leaving at 3500 off of the tranny break, 5500 chance converter, 4.88 gears, 14x32 tire.

Looks to me you might be leaving some on the table early in the run. Just my .02 cents for what it is worth.


andybyrd 06-05-2009 12:22 PM

Thank you very much Dooracer you know a lot of people have said that my 60' should be better than 1.42 or 43 they say if I us the brake and come out around 4000 to 4500 it should pick up. but me not knowing that much I was in the mind set that being it was already launching hard with the tires off the ground 4' it couldn't come any harder only higher so I guess I should put the wheelybars back on and try that first. Thank you Very much for your Time and Help.
Andy Byrd

CamBirdRacing 06-05-2009 12:24 PM

Andy, my Firebird goes 1.45 in 60' but only runs 6.70's footbraking it. I usually leave about 1500, drum brakes won't hold much higher than that. Sounds like suspension tuning is in need.

itsabird 06-05-2009 01:32 PM

andy, doorracer hit the nail on the head, your short time,s are hurting you, what 330 times are you getting, and how much air pressure are you running, any video?

oldandtired 06-05-2009 02:01 PM


Doorracer has a very valid point that is very obvious and that's the chassis tuning. Your car is wasting energy going up instead of going foward.

You know the old golf saying, you drive for show and putt for dough? The wheelstands look great, but are costing you 60' time.

I sure you will receive several more thoughts to test.

Good luck with your ride!!


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