Central 20 makes a 3.9 now. The 3.7 and 4.0 are OEM nissan parts.

Check out www.z1auto.com

 

I would check into some of BoostedPerformance's dynos. I know that he is running some lower boost making 400whp and his setup would be perfect for some short gears.

 

My 8psi dyno:





I am having a heck of a time getting traction in second right now. As soon as I hit about 4500rpm the car gos sideways. It is still cool out here though, and our max temperatures are in the high 40's, with frost overnight. I have the PS2's on right now that are a bit worn.

This is with a 3.3FD VLSD. I will have to get some new tires right away
(295/30/19 RE08's) to really make a fair comment on the 3.3FD. The roads have to warm up a bit too.

I also have a 3.5FD from a base, and if I find the 3.3 to be too long I will get the Quaife and call it a day.

 

I'm running APS TT with low boost on stock DE motor for road racing with 4.08's and Cusco 1.5 LSD...Just don't use 1st or 2nd much!!!!

 

I'm running a Central 20 3.90 final drive on my G35 with an HKS GTRS twin turbo at ~6 psi of boost. It's not bad. It will spin when the boost hits in 2nd, but I am also on stock size tires (FK452s). First gear is pretty much useless, I start in 2nd a lot. 3rd gear is amazing. I can't compare it to the stock gearing though, since I did the FD before the turbo.

 

I would say that in a race car with slicks or really sticky tires it could be worth running boost and 4.08's. Otherwise, on a street car it won't be much fun until the middle of third gear.

 

i have to hit 5th right before the line now though with my trap, just made a thread to get some input...
https://my350z.com/forum/drag/481042...questions.html

 

depends on how you look at fun

 

All you guys pining for shorter gears might be forgetting that shifting wastes time (you're not accelerating during the shift). The amount of acceleration you gain from increased torque multiplication through shorter gears is often negated by the increased frequency of shifts (i.e. time spent not actually accelerating). Not to mention shifts often induce wheelspin, and shorter gears themselves induce wheelspin.

Z gears are short as **** already, there's no way I'd want shorter ones, personally.

 

Unless you are 5AT.

I still don't see how you guys are running such short gearing with forced induction when traction as it is should be a huge problem.

 

maybe not everyone runs that retarded dumped and flush with stretched tires.

proper camber and decent tires nets decent traction. I only had problems in WOT 1st gear.

But ya, I wouldnt consider shorter gears either. Hell I really want a regeared tranny with a 0.6 6th gear, or a 3.0 FD.

 

For us supercharged guys the power is so linear I think we can get away with doing 3.9 gear. Turbo is a different type of power delivery.