Right now I there are 2 LSD transmissions on car-part. One is P11 one is a B15. Driving distance is the only difference between the 2. So how bad is the b15 compared to P11.

I have read the threads and see the obvious gear ratios, and inputs in excel. But I will be honest with you that just doesnt sink in. I need some real world evaluations.

Reason I ask is I like to race at the local quartermile track. W/ T25 I was on the limiter in 4th through the traps. Now on the 28R I am on the limiter in 5th. But not the rev limiter its the speed limiter. So it comes in about 6K in 5th. This is on a stock B13 transmission (well was until I Blew 3rd gear out).

So I have heard and have been told B15 is N/A and P11 for turbo. Granted there are some variables that come into play. But could I get some examples of mph(x)gear(x)RPM to compare? If the b15 is even 10MPH longer in 5th then it is worth it to me. No need for me to go 140+ but 5th gear 6K 120 would be fine for what I need. Any inputs?

My B13 doesn't top out at 120 bro. I have a stock 1991 B13 tranny in my car, when the car was STOCK, it was doing 125mph. I've gotten it up to as high as 137mph, and the car isn't even boosted yet. It's got basic bolt-ons & cams. What car do you have now?

I hope you figure this out man. The car sounds fun as hell. Do you have any older turbo stuff you wanna sell?

http://www.sr20forum.com/driveline-transmission/104113-gear-ratios-b13%5C14-p10%5Cp11.html

My B13 doesn't top out at 120 bro. I have a stock 1991 B13 tranny in my car, when the car was STOCK, it was doing 125mph. I've gotten it up to as high as 137mph, and the car isn't even boosted yet. It's got basic bolt-ons & cams. What car do you have now?

I hope you figure this out man. The car sounds fun as hell. Do you have any older turbo stuff you wanna sell?

I feel you Stock I was well above that. And in the quarter it went 15.9 @ 87 at the top of 3rd gear. Then I got the t25 and in the quarter I was on the 4th gear limiter @ 102 then the 28 put me on the Speed limiter (this is ECU controlled) in 5th. Im not so worried about the speed limiter as that will be removed soon. But since its a u12 ecu it is shutting off at 109 or 112 and my rpms are around 5800-6000. I mean its frankly too much work to have to shift 4 times at the race track. So I am sure It would go 125 @ a screaming 7500 or around there. IDK hard to explain. I guess the P11 would just put me where I need to be and be done with it.

Looking at that graph tells me that the b15 would top out before the b13 would. I do not have anything laying around there is 1 guy local that keeps up w/ anything I take off :) I still have my 91 se-r nothing crazy just a fun street car. Stuff just keeps breaking before I get a chance to fix the original stuff. I got a few PMs out to some guys so hopefully I can get a solid answer by tomorrow!

theres a thread on here somewhere that has all the gear ratios broken down by

B13/B14, P10,and B15/P11 trannies....

Rev limit is the only thing that stops me from going faster. 120@6 is no problem. At 130 or so I was beginning to watch the tach a bit more. 1st gear is almost worthless unless you have a lot of weight or want to baby the clutch. 5th gear acceleration is nice, though for a DD lower RPM highway cruzin would be better with a P11. Can't get enough of that third gear pull though.

It seems to ME that your limiter is what is killing you man. 112mph is the limit on all JDM ECUs *** that is 180KM/H. you have a rev limiter also?? Is your ECU for an automatic U12, *** that is the only reason why there'd be a rev limiter on there also. I really think the ECU is limiting the performance of the car. i think you should buy another ECU and send it to Calum and have it remapped for all the mods you have/setup you are running, etc.

My car never hits the rev limit in 5th at ANY of the speeds I've posted.. maybe 6k at the most for 137mph, but I don't exactly recall. I just know the motor wasn't screaming at 7500 as you say. Rather than swap the trannys right now, since they aren't broken or anything, get the ECU mapped *** I think taht is what is REALLY restricting you. Not the trans. I have only seen people bring up the gearing when they have P10s & P11s with VEs *** if you don't rev them high, shifting keeps you out of the crossover point. But with a T25 or T28, I'd think that there is plenty of power to go around so that wouldn't be the case as much.

No doubt, the B15 tranny won't be a limiting factor unless you can't rev on the high end for the duration needed. I don't have any speed limit (that I've hit) and the B15 tranny has been great. A nice ECU would be a better mod.

No doubt, the B15 tranny won't be a limiting factor unless you can't rev on the high end for the duration needed. I don't have any speed limit (that I've hit) and the B15 tranny has been great. A nice ECU would be a better mod.

CALUM or JWT.

CALUM or JWT.

Stock B15 ECU for now, soon to be JWT when the VE goes in early next month.:biggthump