4:30's M6

[gregrob]

Couple questions:

Who runs 4:30's, how do you like them on the street and at the track?

Car is not a DD but does take fairly long trips sometimes, for which I can slow down a couple MPH compared to the 4:10's I have now.

Who makes 4:30's for the stock 10 bolt? I'm not seeing them?

Will they be too much gear for my mods and the stock short?

I plan on trapping 115ish on the bottle this coming spring with the current jets. Then upping the jets to 200 and maybe knock on the door of a 120 trap?

What rpm would that put me through the traps. Have the limiter set at 6400 right now and dont really want to go any higher.

I am on 26 x 11.50 . 16 ET streets. I plan on upgrading to drag wheels though and will have to move to a 15" tire for that. I can go up to 27" or 28" if need be but then not sure if I'll gain anything by moving to 4:30s

We just make a lot less power up here and I'm looking for that little "edge" if you guys are running 4:10's at SL the 4:30's up here will still put down less tq in every situation at this altitude.

I just dont want to make it a joke to drive on the street. Traction in 1st and 2nd on shitty street tires is already hard enough to come by.

Thanks for any input!

[Jperran]

I friend of mine runs 4.30's in his LS1 M6, I probably would too if I had an LS1 but it might be too short for an LT1. Also on a 26" tire you wont be able to trap 120, he runs 28" slicks and crosses the line bouncing off the limiter (which I believe he has at about 6700) at like 124. There are calculators online you can google search for to get an exact answer.

[96LT1355Z28]

I'm not a rear end expert but I would think 4:30's would be to weak for a 10 bolt. I know some people have had issues with 4:11's strength. It has to do with the amount of teeth required to make the ratio, the small ring gear is weak enough, then when you add teeth to get 4:11 each tooth gets smaller. I don't know if anyone even makes a 4:30 for the 10 bolt and I would guess that is why. You'll probably need to step up to a 12 bolt or 9" to get that low of a rear end ratio. I know it sucks our cars came with these rears! :doh:

P.S. If you gonna be on NO2 and are wanting 120+ trap speeds definitely step up to a 28" tire.

[gregrob]

I cant find a 4.30 but they make a 4.56 so I dont think it's a strength issue, although I dont understand what you're saying about less engagement depth of the gears.

I've been doing some math and figuring and it wouldn't work for me anyway, I would need at least a 29.5 tire to trap what I want to with 4.30's so I'm just gonna leave it as is.

[Pro-jection Eng]

figure what rpm you want to be turning through the traps, then figure in an inch of tire growth on the top end, then pick a gear to meet that. I would try to run a 28" tire if possible.

[mrbadlt1]

a guy on ls1lt1.com is running 4.30's in his lt4 t/a and he say's they feel good.

[taylor]

I ran a 4.10 gear this summer with a 27x10.5 ET street.....going threw the traps at over 120mph (6-SPEED)
a week ago I launched the car at the track at 5200rpm ....broke the diff on the 10 bolt finally(had been doing it all year, lol) the gears did not break, but the spider gears and the carrrier broke into 4 big pieces!!
just launch easyier and the rear should be fine for a wile, with a 4.56 I would step up to a 28" tire