Only issue I've had with SRM since going to 4.08 was it's off by like 200 rpm. Still works fine though

Track guys have had it randomly turn off. Being off by 200 RPM also isn't ideal. Shouldn't hurt a street car however.

Did 4.08s on mine and SRM was totally off, very noticeable. and quite annoying. Blips were off by a fraction of a second and simply turned it off until Ecutek tune. Tune took care of it and it is fantastic. 4.08 makes it funner :) Maintaining the same driving style, my mileage dropped by 4/10s of a mile per gallon. Overall, a great mod for those staying N/A.

So you can fix the SRM issue with Ecutek?

Yes.

I don't have SRM, but after doing 4.08 install on my quaife I can honestly say, that's how these cars should come stock lol

Big thing to keep in mind with gears, especially 4.08's is your gearing for and against you. At speeds over 90mph, you'd be in the same gears for a shorter amount of time. There would be 10, 14, and 18mph per gear that you are sacrificing to the next higher gear. For At those periods, the 3.69 will be more beneficial. The only way to get around this is compensate by rpm. So 4.08's really make sense if you can rev the engine to 8000-8250rpm. That implies that you have more aggressive cams, oil pump gears, ad damper at a minimum. It would also be recommended to replace your rod bolts and look into running a slightly stiffer valve spring on the VVEL side to prevent spring attenuation. That would make for a pretty Nasty NA Z, but costly. Anything over 8500 would need a new rotating assembly too.

On the track, 4.08's can be great for pulling out of a corner, but a PITA on the straights or high speed turn where you find yourself between the right gears.

Coming from a 3.69 hands down I won't be coming back. I have a great street car and told Seb keep the old gear.

Any one know the top speed of each gear in the manual 3.69 final drive? Trying to see where gear shifts occur of going to a 4.10

Look in my thread. It was posted by Mr. Squeeze. He compared 3.69 to 3.3. It is around page 100.

Now that the MT Nismos come with 3.9 from the factory, has anyone had more experience with them? I'm on the 3.62 ratio with factory VSLD, and having a tough time deciding if it would benefit me.

Street car, 1/4 mile for the fun, and HPDE type of events
NA for the foreseeable future, N20 (nitrous) if I start chasing ETs at the strip
Daily now, but hopefully retired to weekend car by end of year
Wavetrac diff for planned upgrade
My driving makes MPG a somewhat moot point :)

Thoughts, everyone?

There is not enough difference to make a change IMO. If you want gain more then run an 18" wheel and tire combo.

Sent from my SM-G965U using Tapatalk

Huh. Didn’t think of that. Muchas gracias. :)

Are 4.08 gears avail through Nissan/Nismo or only avail aftermarket?

There are Nissan oem ring gears in 4.08. I'm still running mine and depending on what you plan on doing with them, they're a great option. I find more benefit a lot of the corners I find myself in. At times, I find where I need to shift up so I don't run into the rev limiter mid corner. If you ever do Road America, I think a 4.08 would work perfectly if your redline is at 8000.