L99s with 3:91s come in

[Chevrolade]

How do u guys like them ? And did u notice a nice gain from the stock 3:27? Also in the 1/4 mile are u still finishing in 4th gear? I would hate to hit 5th in the 1/4
I'm so close to doing the 3:91 swap just need a lil more info from the experienced.
Thanks in advance

[amerimuscle]

Sorry i have no input but im in the same boat, very interested in 3.91s

[woodside783]

Me 2

[VADER SS L99]

Originally Posted by Chevrolade

How do u guys like them ? And did u notice a nice gain from the stock 3:27? Also in the 1/4 mile are u still finishing in 4th gear? I would hate to hit 5th in the 1/4
I'm so close to doing the 3:91 swap just need a lil more info from the experienced.
Thanks in advance

This would depend on your current mods and future goals. If you have LT headers, tune and CAI then 3.91's might cause a shift to 5th just before the traps because the RPM limit for a L99 should not be more than about 6200. A L99 car with a 6200RPM limit and 3.91's will only be able to go about 111mph in 4th. Since there are many bolt on L99's doing 112mph 3.91's may cause a shift to 5th. If you had a triple disk torque converter that could be locked up at WOT at the end of 4th gear you could for sure run 3.91's and not worry about it because you will not run out of gear until about 117mph. If you never plan to go above 500RWHP and stay NA then I say get 3.91's. On a cammed car with a 6600RPM limit you could run to 118mph in 4th with a standard converter or 125mph in 4th with the triple disk converter. All of these figures are assuming the stock diameter tire height of 28.8" and 6% converter slip for unlocked figures.

Bottom line is if you plan to stay NA I think 3.91's are a great gear for the L99.

[Pro Stock John]

Well if Terry is going 117mph in 4th (I'm assuming he's not shifting into 5th), that would seem to validate that 4th is good for 119 @ 5900 RPMS based on what is in the PCM for the commanded 4-5 shift.

Terry goes 117mph here:
http://www.camaro5.com/forums/showthread.php?t=287509

[Jimmy Superfly]

Subscribed!

I am really interested in what other L99 owners have to say about 3.91's. When I track my car its on a roadcourse and not the strip so the MPH and gear that I would finish the 1/4 in don't matter.

I only have a ported TB and a CAI W/scoop on my car right now. I do plan on getting Long Tubes this summer but since my car is my DD I don't really want any more power then that. Would 3.91's be too much gear for me? I keep hearing that 3.70's are ideal for the L99/A6 but they are so much more expensive then the 1LE gears.

[Pro Stock John]

Jimmy, seems to me that it would depend. I'd do longtubes and cats or !cats first, I picked up a lot in my car at the strip and on the dyno, 315 -> 368rwhp and with the mods in my sig went 6 mph fast at the track, sounds about right.

But if you are doing autocross or road course stuff, you'd have to look at your rpms and see if you need more gear to put your car in a different part of the power band, know what I mean?

I'd try a set of 3.91's if the labor price is not ridiculous.

[Juice2SS]

My gears shipped after being on back order forever. I'll have them in asap!

[sasquash1984]

Let me know how they feel and work on the track

[Jimmy Superfly]

Originally Posted by Pro Stock John

Jimmy, seems to me that it would depend. I'd do longtubes and cats or !cats first, I picked up a lot in my car at the strip and on the dyno, 315 -> 368rwhp and with the mods in my sig went 6 mph fast at the track, sounds about right.

But if you are doing autocross or road course stuff, you'd have to look at your rpms and see if you need more gear to put your car in a different part of the power band, know what I mean?

I'd try a set of 3.91's if the labor price is not ridiculous.

Thanks for the advice John. Cheers!