does this sound right

WRXracer

New Member
Feb 28, 2003
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my heads on my 02 GT are going in to get ported new valves and a cam.. and im putting some headers on.. They told me my peak power will be at 6200.. so im thinking about putting some 430s on.. the calc says I should hit 111 MPH at 6200 in 4th.. does this sound like a good setup.. would this get me 12's..
 
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you should find yourself somewhere in the twelves but the gear ratio sounds a little high. depending on the speed you run the quarter in..it might cause you to have to make a shift into fifth which would probably kill your e.t.
 
WRXracer said:
my heads on my 02 GT are going in to get ported new valves and a cam.. and im putting some headers on.. They told me my peak power will be at 6200.. so im thinking about putting some 430s on.. the calc says I should hit 111 MPH at 6200 in 4th.. does this sound like a good setup.. would this get me 12's..

Whoa! Peak power at 6200 rpm? My redline is set at 6050 from the factory, have you changed yours? Just curious, is your bottom end forged?

Bo
 
02GT03SVT said:
Uh, gears do not affect where you will redline. They'll only change the speed at which you hit the redline.

You're right, but he's also doing headwork and cams. I believe the question is - will I make the 1/4 mile with a 4.30:1 with the motor work, etc. or should I stay with my 3.73's.

I'd say with your plans, I'd stick with the current gears. If you're going to be trapping that high anyway and you plan on doing more work, etc. you'll probably be swapping the shorter gears back in later anyway...

Just my .02.

Jay
 
asthmaticZeater said:
anyone who says 4.30s are too much needs to go look at what gear all the fastest n/a mod cars are running. 4.30s!

and people are now dipping into the 11s n/a. ;)


Curious, how high are they winding them up to get 11's N/A w/4.30's? What kind of trap speeds?

Thanks,

Jay
 
well, i think most of them trap right around 110, running low 12s. 4.30 puts them close to redline in 4th (not real sure what the redline is set at), but its no crazy rpm, alot are on stock bottom ends. bill having over 100k on his bottom end. but ask any of the top n/a mod guys and i bet they tell you go 4.30s if youre staying n/a. :nice:

http://forums.modulardepot.com/showthread.php?s=&threadid=185

theres the list of the fastest modular times. search around the site and see for yourself on everyones members page, 4.30s are the gear of choice for top n/a mod cars.
 
Zeater, I have no doubt. Bill Putnam is running them, and I think Starkie and AutomaticWeapon may run 4.30's as well. I'm just wondering as more and more aftermarket parts become available E/T's go down and speeds go up we'll either have to wind these motors out further (i.e. forged internals/head work) or drop the gearing to compensate.

Just an interesting topic - good thread and debate IMO.

Jay
 
it is a good debate.

i agree. sooner or later, there is gonna become a point when youll have to lower it to compensate for the higher traps. but, if youre staying n/a, until you make the car completely unstreetable, i dont think youre gonna run out of gear in the 1/4 in 4th with 4.30s.

bill has a fully drag suspensioned car, lots of weight removal, every bolton known to god, plus cams. his car is not very streetable in most peoples minds (he even would agree). he runs 12.2s i think now. most people wont go that far with suspension and weightloss. so even with headwork, and everything else you can do. i dont see a DD mod motor n/a hitting 11s soon. but hitting 11s is cause for a tranny swap anyways, no SFI bell housing for the t45. so that brings in totaly different ratios to work with.

and if all else fails. and the car is gonna see higher trap speeds, you can always pretty easily step up to a 27" or 28" tall tire to lower the ratio. :D
 
Just something to add to all of this with the stock limiter I was pretty much limited to 109 - 109.50 trap speeds in 4th. Which is fine for a car that is lightened up and has every bolt on under the sun. I moved my limiter up to 6600 RPM and put the cams in and now with 109K miles I rev it 6500 RPM in every gear and even launch the car at 6400 RPM. With a 26x10 tire and 4.30s I won't run out of gear till I trap 117 MPH. So really I need another 70RWHP before I have to step up to a 27" tall tire and that would add another 4 MPH on breathing room on the top end.

Bill
 
I say if youre going to stay n/a and plan on doing work to move the rev-limiter, go with 4.30 gears. You wont regret them. Im going with 4.30's in my bolt-on 01 auto GT. If I could do cylinder head and cam work, Ide probably go with 4.56's. :D