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Thread: Breaking P11 trans

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2010-04-26 03:49:45
Breaking P11 trans
Well, my friend broke another trans. This time it was a LSD P11 trans. Yes, the stronger one.

He was playing on the freeway and had a few really good pulls with the car loaded, then 4th let go.

I think he is going to go with a spec v swap later down the road, but this makes me nervous. Being that I have a p11 and already broke it and rebuilt it with QG18 stacks.

Is there no real hope for me? In the future, I won't be able to do a spec V swap. the change of flywheel will trigger my CEL for the crank sensor and render my car useless. Can't register the car if it won't pass emissions.

I can continue to rebuild the p11 transmissions every time they fail? But why would 420whp and 340wtq break a p11 so effortlessly? It seems I am on borrowed time with 400lb ft of torque. The sentra is lighter than the p11, so this may give me a couple hundred more miles of abuse. Maybe not.

There has to be some way to get these gears to hold up over the long run. We need billet gear replacements like the honda guys or something.
2010-04-26 03:52:23
I figure we can rebuild the trans and see if we can get it to hold up for just a few runs down the 1/4. But this P10 of his hasn't even gotten off spring pressure on the 60-1 (13psi) and he cant get a transmission to hold up.

I really don't know what we can do. Why did Nissan curse us with such great engines, but crappy transmissions?
2010-04-26 03:58:25
I am in the same boat..

I believe the only hope we have is the Spec V swap. The question is how much can it hold?
2010-04-26 04:13:05
I am sure I will be there soon as well ....mine is cryo treeted and shotpeened , so I hope it holds up for a minute...or it will be spec V box here I come
2010-04-26 04:15:04
I had pretty good luck with the heavy shockproof, even though i shattered 2nd. Perhaps I will continue using it as there seems to be no hope for me.

If I keep breaking transmissions I don't know what I will do. Prob just keep it on low low boost 10psi and less. Too much power. With the next build I will be close to 350whp on ~10psi, maybe 12psi. Last time I broke 2nd I was only making about 380whp.
2010-04-26 04:15:54
ya you guys are lucky you don't have this obd2 crap and strict emissions standards. The spec v swap looks great. Too bad it will cause a CEL on Obd2 cars.
2010-04-26 04:17:51
whoa whoa whoa,
SO Coheed, you're saying that your friend has a P10 w/ a garrett 60-1 and broke his P11 trans on 13psi?
how much was he making to the wheels?

I am about about to rebuild my bottom end and put on a 60-1 that i picked up from Jerry(Scrildo)

How did he drive, I heard that the tranny life can be extended by not slamming into gears, especially 3rd, but this is 4th he lost?
2010-04-26 05:17:29
I also stripped my fourth gear in my b15 box. I just swapped in the 1.8 stacks and B13 final drive and was good to go. Now after a little while it started popping out of second gear so i took it back out and put back in a spare B13 box that i had until i fix it. I just don't enjoy fixing these trannies. To much little pieces compared to the B13 boxes.
2010-04-26 06:18:35
Coheed, you dont have to change the flywheel when doing the specV trans swap. Just use the p12 bell housing and keep your same flywheel and clutch and get a custom disk made to fit the input shaft splines. Im using my same twin disk setup with the 6 speed swap and just using the s15 disks for the twin and all is good to go. Just need to make sure i can get a throwout bearing to work with it.

If you can save up the money Coheed i would do the swap if i were you. I believe the p12 housing has a spot for the crank angle sensor as well if im not mistaken. So custom disk and bam, no check engine light.
2010-04-26 06:34:40
^^yeah you can get the p12 bellhousing from infiniti parts usa (everythingg20.com)
the 6-speed swap would be golden if i could find a spec-v tranny
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