I know there are a few people with this setup currently just looking for a spring update on how the cars are running/bahaving now that road conitions are better and the time to run the cars harder is upon us.

Does the 3.9 limit you in anyway, does it allow the turbo to spool much quicker...

-Don

 

I wouldn't do it, when you shift, your rpms are going to be too high and you'll be way past your peak torque and I don't think the increased rpms would offset the huge mountain of peak tq that a turbo will give you at around 4000 rpms.

that and you'll be shifting more often which will cost you. the 3.3 gears will be the best setup with a single turbo - not to mention you'll have a harder time with traction

 

my problem is i "am" going FI but i already have the 3.9 FD and lsd setup from BJ... but i dont want to switch pumkins again, so i figured it would be helpful in spooling a bigger single turbo having shorter gears.

 

i'd try a lighter flywheel before the 3.9 gears - but if you have it already, give it a shot and see how you like it first. If anything you can probably get a NA guy to pay you some decent money for your pumkin and swap


but your KDW2 tires - and I don't even know what sizes you are running, won't be enough to get traction when the boost does kick in - which it does hard, then the torque being multiplied by an extra 10% = a tire spin fest unless you don't give the throttle some gas - which is lost power being wasted on not being used

 

im not a big fan of lightened flywheels, had one on my mr2 and ditched it for driveability.

 

Its not ideal but it would work.

In a perfect world I'd have the ST with a lightened flywheel and crank pulley, and 3.1-3.3fd gears.

 

I don't quite get what you are trying to say. He isn't changing the gear ratios inside the tranny. Why would this put him past his peak torque?

 

the taller gears make the rpm's higher while driving. say your going 65mph with 3.3 gears and your rpm's are 2500 but with 3.9's they will be 3300.

 

I would def go with the 3.3 out of the auto so u can hold onto boost longer. With the 3.9 ull be shifting too much at the track and probably traction would become more of an issue

 

good point, I suppose I was wrong on that

 

..

 

i would definitely NOT keep the 3.9. It's hard enough to get traction in 1st and 2nd with the 3.5....I can't imagine having to shift more than I am now, and I'm seriously considering doing the 3.3 swap.

 

I believe onyx350z has 3.9 with single turbo. He said it didn't bother him at all but he does have 20" momo's so that might help him out. My feeling is that Turbonetics + 3.9 gears + light weight wheels = Headaches.

 

you will add to your traction problems too.

 

its a mechanical advantage, plain and simple. shorter gearing = better acceleration up to a point when you shift too much loosing time uunder WOT. i would take the 3.9, and make sure to get some ***** tires, and i think you will love it. i know that just a gearing change n/a can net ~.3 alone in the 1/4, and im sure that will transfer over to ST as well with traction. throw some 300 series sticky tires on and hold on!

 

I do have the 3.9 and TN kit and love it. The exceleration is insane. If you want shoot me a PM and we can talk.

 

If your gonna be going to the drag strip or racing the car, then dont stay with the 3.9. You'll spend more time with your foot on the clutch than you will with it on the throttle!!

 

have you ever driven a FI Z with the 3.5?

3.9 is great for NA where you don't have traction issues. All the 3.9 is gonna do with boost is introduce an even more useless 1st and 2nd gear, plus more necessary shifting, and poorer highway mileage.

 

launch in 2nd - 5th during 1/4 mile...

before i get flamed to bad... i am not a track person, i just want an 11 sec timeslip once at 11x trap speed then im done beating up my car at the drag strip... my car is a daily driven Z that i want to have FI... more or less i just want the ability to keep up with some faster cars like my buddies 11sec supra (probably wont happen 132 trap) and 11 sec srt4(118 mph).

That why we all get FI right... bragging rights!

 

I hear ya MI 35th. I have spent a lot of money and effort on NA mods for my 35th AE and despite some pretty decent gains, the thought of going FI just keeps sticking with me. My original plan was to go the SC route but come to discover there is nothing on the market for the 300hp. Can't even do cams because of the motor but the turbo is still an available option. Of course the last mod I added was the 3.9FD gears which are nice even though they can be slightly noisy. It would be a pain in the butt to go back and pull the gears but my intentions were to stick NA hence why I got the gears.

BTW MI 35th, how do you like the gears since you have added them?