traction is already going to be a big issue for you with a TT setup. I would stick with the stock gearing. I've even seen, perhaps not here but def with boosted 350z's, going to the A/T gears in a manual so they can stay in gear longer.

IMO, if you drag race, 4.08s are great if you stay N/A. Go FI and I think stock gearing is the best bet. As far as road courses go, it seems to be a 50/50 split on whether or not more aggressive gears are good.

I've had my 4.08 gears for just over a week and would never go back! I shorten the gearing of almost everything I have. IMO, makes the car feel much quicker. Second and third really pull nicely:-)

Will be going to Michelin PP shortly, and I'm expecting them to hook up better than the OEM crap that on there now. Car is sneaking up on 10k miles now and the rears are wasted...

Do you think a stickier tire compound would limit or remove all if not most of the traction issue along with OS Giken LSD when turbocharged?

/\ both of those things will help alot obviously but you are going to run out of gear so quickly with the 4.08s vs stock if you're TT. I know there's a more scientific way to say that so hopefully someone else will jump in here and elaborate on the point I'm trying to make.

Is anyone here using 3.9 or 4.08 FD in a 7AT?

im looking at changing my gears to 4.08 what are the exact parts i would need to buy i have a 7at

Contact Z1 as stated in the first post of this thread. If you do not buy their kit maybe you can at least get a parts list.

ok thanks for the info

No problem, if you go for it keep updates in this thread. I may still do this to our 7AT one day.

Hi,

I drive a 7AT but the kit listed in Z1 states that their 4:08 final drive is only for manual transmission. Can someone kindly point me to the right kit please?

Thanks in advance!

Best Regards,
Alvin

the best bet is to buy a manual rearend and throw 4.10s in that as if i remember correctly the automatic rear end is different might have just been the diff center itself though. you might be able to do it by buying a manual aftermarket lsd to mount the ring to.

The difference is the actual diff between the manual and Auto. The pumpkin and all parts associated are the same other then the diffs themself. I tested putting my 3.3 gears from an auto onto my original manual diff and it doesn't fit. I'm in the process of swapping 4.08 gears and quaife in BUT i purchased the pumpkin from an auto 350z. Shimming definitely is trickier as the use COMPLETELY different shims from each other. My shop had to order a full shim set to get it to work. Should be ready to be installed next week.

Sub'd

Here's a review I made from my install last week:
Review 4.08 Ring & Pinion Swap, she's alive! - MyG37

i have install 4.08 gears in my 7AT and its brilliant, i would never go back. what i had to do was buy the Z1 kit ( this is a must makes things easier) and then buy a pumpkin of a manual 370z and install it all into that and then swap over the pumpkins. not that hard to do and the difference is absurd.