I picked up from Bulletproof Automotive some Tracy Sports 3.909 gears. I arranged for Puddydad to install the cryoed 3.909s in my current '09 rearend and these are my first impressions.

I am running wide RA-1s in 275/40/17 and a light weight Comptech flywheel that makes driving with taller gears a little more difficult when starting. This is similar to the change I noted when going from 4.44s to 4.10s. Starting out on a hill requires a little more clutch slippage than I am used to.
With the 9500 redline first gear pulls to just shy of 50mph. It seems to accelerate just a quickly as before but with more authority. It holds to the ground slightly better and thus first seems to be more useable. This thing really gets going.

Second gear is a hoot and peaks out around 75mph. Third gear seems to pull just as quickly and yet ends up going 105mph third.

Fourth gear Rubber shorts time.

Fifth and sixth on the freeway are very civilized. I like cruising at 60mph turning 3050 rpm in 6th.

Overall impression is the car is more fun to drive with more speed in every gear.
Well worth the trade off with starting out difficulties.
For those that are curious, I don't check economy.
And yes, the differential has been polished.





Thanks to Puddydad for the timely and very talented install. The differential ended up quiet with no hint of whine.
Thanks to Ben at Bulletproof Automotive for sourcing the gears for me.
Thanks to Tony Fuchs for the quality install as always.
Thanks to Roger at CryoScience for cooling my parts.

 

nice, I might look into these for myself

 

what are the stat's on your car? I assume it is FI, but i the link to the dyno in your sig is bad.

 

I believe his car is Supercharged via Vortech and is putting down around 500hp+.

Sideways, are you currently using the AP1 or AP2 transmission?

 

I am currently running my four hundred horsepower tune. That is, 499.4 rwhp. I don't have a copy of the dyno.

This is a slightly different more agressive tune:


AP-1 tranny for the taller 1-4 gear ratios.

I'm considering running the 60 to 130 mph competition with the six speed guys in Texas.

 

Have you thought about doing the Texas Mile as well?

 

COOOOL!!! im glad you like these gears. im having these exact gears installed as well. Great review!! it must be nice to be able to use 1st gear lol

 

cost of gears?

 

http://www.bulletproofautomotive.com/catal...ail.php?ID=4241

 

^^^^^ theres no way i'd pay that much for gears. you've got to be kidding me