Thread: Best tranny setup for FI..

So I've been reading into the whole tranny setup for FI threads again.

If you have a B15 5spd tranny, remove the 4.4FD and replace with the 4.176FD from a B13/B14. Does this make sense? Obviously all gears will be longer, most noticeable would be 4th and 5th gears.

I need longer gearing all around because I don't like sitting at 4KRPM on the highway at 80~81mph.

First thru third in the B15 are shorter than in a B13/B14 gearstack, but I think replacing the FD with a 4.1 will make the difference not very noticeable from the 1-3 B13/B14 and B15 with a 4.4 FD.

Plan is getting a B15 LSD tranny for the SE-R.

Interesting , I might look out for a B15 transmission and do this...

Now what RPM's are you going to rev at at 70-80mph?

for me its a toss up, although a longer gears would be nice and rev at a lower rpm at higher mph...with me on my setup personally, having a 70mph 3500rpm sit, my boost in instanteous no lag whatsoever since i am seeing 14lbs full around the later 3000's it almost makes for a optimal setup. thats sjut my opinion.

I agree with you, I love having instantaneous boost if you need to pass a car, but for gas mileage reasons it sucks

If you need the Output Shaft to convert the B15 to 4.16 FD I have one BNIB form the P11 gear stack all you need is the Ring Rear from a B13/B14 transmission let me know if you want it ...

V - I just finished creating a new spreadsheet from SCRATCH.

I'll be posting it up later for all to download. We can then sticky it somewhere as a downloadable file (hopefully) so that other members can adjust the formulas as they wish.

From what I've calculated - at 3000rpm in 5th gear with a B15 tranny and B14 FD, I'd sit right at 72mph. with stock wheel/tire combo. That would make 60mph at 2500rpm PERFECT.

or you could take the 1.8 trans from the qr18 b15 and swap the gearstacks into your p11 and put the b13/14 final drive in with it and you would have the best gearing all around.

I think this is what im gonna end up doing as its practically impossible to find a p11 trans for a decent price. Couldnt fine one in mexico either but i did find the b15 trans with a broken rear case. So price breakdown would go something like this for a complete p11 setup.

B15 trans in mexico with broken rear case: $100
B15 QR18 manual trans: $150
Brand new OEM Nissan B15 trans rear case: $300

So i would have basicly a P11 trans for about $550 About half the cost of what it would cost me for one shipped to my house.

Think about it tekkie.

If you want the longer 5th for low rpm freeway driving, you will want to keep a SR B15 5th gear and put the gears onto the QG or P11 stacks. The QG and P11 stacks mate up with all 4.176 FD gears AFAIK. B15 SR 5th gear on P11 FD will give a nice 5th gear for the highway. Should max out around 185mph at 7500rpm or so.

T - Let me know when you have it, I can upload it to your first post then

You guys are misssing this thing

A B15 and P11 gear box share the same gears 1-4. The 5th gear being longer in the B15 ( 0.733 ) vs the P11 ( 0.756 )

The B15 comes with the 4.444 FD
The P11 comes with the 4.176 FD

It would be cheaper just to buy the B15 5th gears and put them in the P11.

Or

Just buy a P11 gear box from the get go.