Gears for Supercharged M6?

[frenchsquared]

Originally Posted by Dwright

I just finished my build and will tell you on forced induction 3:91 aren't the way to go. It's fun has hell but I don't think I will ever get it to hook. You would be spinning all the way down the track. At this point I don't even think drag radials will cure it. It would help but. After first hand experience I can't see 3:91 under fi working very well

Yep... My Vette destroys the tires. I doubt a Camaro is any different.

[2012LS3VERT]

A deep gear with a Centri blower or larger turbos could be just fine on a tall drag radial. My Maggie car with 3.73s will fairly easily destroy a set of 305/45R18 ET Street Rs. That's a 29" tall tire. Maybe with a 15" wheel it may be ok and really get the car going out of the hole, but I'm not a fan of 15" conversions on a car that sees a lot of street time, personal preference.

[fif_gen_powa]

Making high 600s My car was faster at the track with 3.91 gears than a 3.45 and traction was not an issue with an 18 inch drag radial. The 3.45 rear in forth gear can reach 160 mph around 6500 rpm it is not optimal for a sub 1000hp car which will not trap anywhere near that mph.

3.91 gears did make traction on the street pretty tough anything under 60mph would spin but at the track the car had zero issues with spinning. Any car 700 to maybe 750ish and under strictly a quarter mile car 3.91 would be perfect, 3.73 for 800+, I believe you need to make 1000+ to utilize the super long 3.45 forth gear

This is on a SS manual trans car IMO

[2012LS3VERT]

Many times it comes down to individual car setup. A large cam car with a centri or large turbo will tolerate a much lower gear than a TVS2300 car. Even a Whipple doesn't come on as hard as a TVS2300. A 6L80E car also will not tolerate as low of a gear as a manual especially with a high stall, as the 4.02 first gear is pretty deep compared to the 3.01 of a Manual SS, or the 2.66 in the ZL1. I have run the stock SS 3.45, the 1LE 3.91, then the ZL1 3.73s. I am eventually going to swap in the ZL1 3.27 gears, the 3.73s are way too deep on street, where my car is most of the time with a much shorter tire than my drag radials. I also have done many diff swaps and regears in customer cars, what I recommend depends on goals and car setup. All the power in the world won't do anyone any good if you can't put it to the ground effectively, so all variables need to be taken into account.

[fif_gen_powa]

Originally Posted by 2012LS3VERT

Many times it comes down to individual car setup. A large cam car with a centri or large turbo will tolerate a much lower gear than a TVS2300 car. Even a Whipple doesn't come on as hard as a TVS2300. A 6L80E car also will not tolerate as low of a gear as a manual especially with a high stall, as the 4.02 first gear is pretty deep compared to the 3.01 of a Manual SS, or the 2.66 in the ZL1. I have run the stock SS 3.45, the 1LE 3.91, then the ZL1 3.73s. I am eventually going to swap in the ZL1 3.27 gears, the 3.73s are way too deep on street, where my car is most of the time with a much shorter tire than my drag radials. I also have done many diff swaps and regears in customer cars, what I recommend depends on goals and car setup. All the power in the world won't do anyone any good if you can't put it to the ground effectively, so all variables need to be taken into account.

Well said, totally agree, I just see a lot of guys shy away from the 3.91 because of hearsay when in reality they will be optimal for quarter mile drag times

[dreksnot]

Originally Posted by 2012LS3VERT

Many times it comes down to individual car setup. A large cam car with a centri or large turbo will tolerate a much lower gear than a TVS2300 car. Even a Whipple doesn't come on as hard as a TVS2300. A 6L80E car also will not tolerate as low of a gear as a manual especially with a high stall, as the 4.02 first gear is pretty deep compared to the 3.01 of a Manual SS, or the 2.66 in the ZL1. I have run the stock SS 3.45, the 1LE 3.91, then the ZL1 3.73s. I am eventually going to swap in the ZL1 3.27 gears, the 3.73s are way too deep on street, where my car is most of the time with a much shorter tire than my drag radials. I also have done many diff swaps and regears in customer cars, what I recommend depends on goals and car setup. All the power in the world won't do anyone any good if you can't put it to the ground effectively, so all variables need to be taken into account.

I, too, have been there, done that with the 3.45, 3.73 and 3.23. Per some intense "bench racing" software apps, I was suppose to gain a whole tenth of a second going from the 3.73 to the 3.23 with my TT setup. Not sure how well that worked out as I change more than one parameter at a time, but I can tell you it didn't hurt. It was much easier to overpower the DRs off the line with the 3.73 than the 3.23 (but it can still be done pretty easy if I'm not paying attention). The usual statement goes into play - YMMV. I run with some built SC Camaros running 3.73 and they scream down the strip.

[fif_gen_powa]

Originally Posted by dreksnot

I, too, have been there, done that with the 3.45, 3.73 and 3.23. Per some intense "bench racing" software apps, I was suppose to gain a whole tenth of a second going from the 3.73 to the 3.23 with my TT setup. Not sure how well that worked out as I change more than one parameter at a time, but I can tell you it didn't hurt. It was much easier to overpower the DRs off the line with the 3.73 than the 3.23 (but it can still be done pretty easy if I'm not paying attention). The usual statement goes into play - YMMV. I run with some built SC Camaros running 3.73 and they scream down the strip.

Couldn't imagine running the 3.23 on the strip but can't argue with real world data. I actually lost one tenth and two mph going from 3.91 to 3.45

[fldrummer]

Originally Posted by fif_gen_powa

Well said, totally agree, I just see a lot of guys shy away from the 3.91 because of hearsay when in reality they will be optimal for quarter mile drag times

Yeah, 2012LS3VERT beat me to it. Even with my [sh*tty] current tune in the low-600s, I easily & accidentally broke my 325/40/18 M&H Racemasters loose from a stop, and that's running a 3.73 ZL1 diff. Even back when I was making 60 rwhp less, you can imagine how crazy it was running 4.10s with street tires, before they finally broke!

[dreksnot]

I finally stopped dumping the clutch and easing it out - makes for a much better 60 and no/less spinning. Clutch doesn't like it much though.