Gear ratio + differential ???'s

[Caveman]

I just picked up a new moser 9 inch from spohn with moser axles and all that...all still in the mail, ill throw some pix up as soon as i get them.

Im looking into building a third member shortly but not sure on parts.. I was thinking about an auburn posi/lsd for my diff..but as far as gears im not sure.. ive seens cars with similar engine/suspension setups run 4.57's with the stock t56 and its doing some major damage at the track so im kind of leaning towards the 4.57's... 6th gear with the t56 is pretty stout...should still be able to get some decent rpms on the highway, right?

Anyone have any ideas on diffs or gears?

Thanks!

[Boost Addict]

Are you going to have enough motor for that gear? By that I mean what RPM do you plan on shifting at? I wouldn't think you'd want to be going through the traps in 5th gear

[my95z28]

I would go with an Eaton Tru-trac if I were you, nice LSD. As far as the gear goes, what tire is going to be on the rear, and how high to plan on spinning the motor? IE, what will be the highest rpm that you feel safe crossing the traps at? Also, whats the HIGHEST you think this car will trap with this rear-end in it?

[kammi10]

i have a detroit tru-trac in mine and absolutely love it..

[Caveman]

I would go with an Eaton Tru-trac if I were you, nice LSD. As far as the gear goes, what tire is going to be on the rear, and how high to plan on spinning the motor? IE, what will be the highest rpm that you feel safe crossing the traps at? Also, whats the HIGHEST you think this car will trap with this rear-end in it?

im shooting for about 62-6300 MAX. as far as tires, im waiting to put it all together and see what size tire i can stuff in there...i have no idea what will fit width-wise.

eaton tru trac...ill look into that.. im not the most experienced with diff's... i dont want to buy something and find out its not what i think it is ya kno..

[DETROITMUSCLE]

I don't think you'll get a tire under there that is tall enough to justify those gears and those RPMs without going into 5th. 4.30s would be a much better choice if you want to go steeper than 4.10

[1BADAIR]

4.57=107 at 6300 with 26's
115 with 28's
4.30=113 with 26's
122 with 28's

will be pretty much impossible to get the car to leave hard and hook with either of those gears and any decent power
i would use a 4.10 with 26's*119) for NA and 28's (128)for a power adder

[Caveman]

im not saying i was for sure gonna buy 4.57's i was just wondering because ive seen several cars run them.. \/ \/ ill check out the 4.10's tho

http://www.youtube.com/watch?v=4tzm2pk9-nY

[1BADAIR]

it all depends on your HP, trap speed, tire size, weight.
my car crossed the line at about 66-6700 with 28's and 4.11's

[DETROITMUSCLE]

Mine traps under 5K stupid 3.23 gears

[Nocooler]

im not saying i was for sure gonna buy 4.57's i was just wondering because ive seen several cars run them.. \/ \/ ill check out the 4.10's tho

http://www.youtube.com/watch?v=4tzm2pk9-nY

This is a post from the guy that owns the car in the video

http://www.ls1tech.com/forums/12053266-post10.html

7000rpm shifts and 7200rpm thru the traps.

The next question is how much power does the car make and do you want to run 28" tires?

I'd run 4.11's w/26" and 4.30's w/28" tires

The nice thing about the 9" is - it's easy and cheap to change gears.