Demonicbird00

iTrader: (17)

I know what gears Rob,Chris and Alex will say lol

Im torn between which gears to get either the 4.30s or the 4.56s

I recently went to the track and my setup right now is 12 bolt w/ 4.10s and 28" DR

spinning 1.67s and going 10.9s @ 128.8 going through the traps at 6300

my car peaks at 6k and holds power to 6800 when we stopped the dyno pull
on the mustang dyno it did 465/415

race weight is 3190 w/ me in the car

hooking and in good weather i feel the car will be trapping in the 131 range

thanks
brandon

studderin

iTrader: (28)

Something else to think about, sounds like a good time to sell the 12bolt. Then put money into it, if you want to race it alot and go sub 1.5s t56. Its like a 10bolt in a auto car, you will eat gears. At $300-500 and pop, $700-2500 if it tears up more. Think about what you can sell it for with the 4.10s now that makes it easier to sell street guys. I bet you can $1,200-1,500 with DS. Then put gears, maybe a new carrier ($400-1000) You could have $2,000-2,500 into the 12bolt. I don;t know your TA, DS, rear rim, setup, or if you have the moser with the 4 little TA bolt 12bolt. But just something to think about, I know 12bolts,t56s and wheelies don't play nice for getting alot of passes in. A new spooled S60 for about 2,200$ with any gear, or narrowed.


edit
on 28" 275DR and 4.56s Ive been 130s I didn't notice the shiftlight (under 7) so should be perfect. I'd guess its about 200 rpms more with no growth then 3055S ETdrags normally do

Demonicbird00

iTrader: (17)

midwest chassis short TA,PST 3.5" AL DS, 15x10 prostars

the 12 bolt has been very good to me multiple 1.49s and low 1.5s back when i had the old suspension, still trying to dial in new sus and get seat time w/ new engine setup as well

Heyfred

iTrader: (10)

What gears are you running now?

Can you post a picture of the dyno graph?

Stick or auto?

studderin

iTrader: (28)

he has 4.10s, running 28' Drs. t56 car

Heyfred

iTrader: (10)

What are the gear options for the 12 bolt?

Your peak is 6,000, how many rpm above peak are wanting to run?

On of my current mentors told me to run 200 to 300 rpm over peak.
http://dragracingonline.com/raceresu...irebird-5.html

A rule of thumb that was told to me was: For every 20 teeth added or subtracted, you gain or loose 250 to 300 rpm.

Demonicbird00

iTrader: (17)

thanks John!

Heyfred

iTrader: (10)

If the gears are available, 4.33 or 4.40 would be my choice. Spin the engine to 6300 to 6400.

I know they are available for a 9", because I am dialing in my car. Currently I have 4.22, 4.30, 4.33, 4.40, and 4.44

My peak is 5800 and I am wanting 6000 to 6100.

I see you are there.
4.22 would be my suggestion.

studderin

iTrader: (28)

Ive found with the t56 its more important getting the car to 60, and trade off what math, gears/RPM, anything really for down the track. Like working backwards for the best gear for crossing the finish. That dose matter, but less then other setups. Remember that the car is going 128, 130 MPH whatever, thats traveling some distance. You can let off at the top of 3rd and coast and a 10.8-127 full pass will still run mid/low 11, but 110 or whatever. You can let off 20-50feet before the end, and coast and only loose .0X ET. The gearing for having the rpms at 6800 or 6000 (4.56 vs 4.10 est.) is not that big of a deal, the cars just down/behind 10-20whp for that last 2sec. the motor pulls you alone (not 100% the way it works, LOTS more into then that, but the idea)
The improvement from 4.10s to 4.56s is getting the car moving, big help in the short times then down track. The cars only traveling what, 0-40mph is 1st gear. thats not getting down the track quickly with the timer counting away. tim tosto said a few years ago, how the t56 gearing is not great for drag racing, get the car out of 1st gear as fast as you can. I keep finding how true that is, the more I, and talk to others that race a t56. The far side of this would be run some crazy rear end gears so the car 60' better with the stock t56 gears, and buzz the motor more. A clutch/suspension tech guy will like that, but the valvetrain/engine guy will not.
Big example ALL the fast mustang NMRA/NMCA dont run a t56 (in t56 cars) and run a weaker t5. Not only because its a lot smaller and lighter, but the ratios. One of the reasons they run some much faster at the same weight and power as we do. single disc clutch, on 26' slicks 1.35 60 is bad.

Heyfred

iTrader: (10)

Johnny, you are spot on, it is going to be a trade off

exodus_gs1

iTrader: (3)

There is some good reading right there.

But sorry OP I don't have any info to help. Hope it gets all figured out, but a side note those are damn good numbers to a slow guy like me haha (12.9 @109)

93camaro_zzz

iTrader: (13)

I vote 4.30's.