Thread: P11 Transmission Article

Hey guys, just got done writing this article and figured it'd be useful to you guys. While not a mega-powered setup, road racing is certainly hard on transmissions, and I think all of these mods would help keep it alive.



Project Infiniti G20 Racecar: Transmission Upgrades

Nice!

I haz questions for you about your P10.

You guys with Moto IQ write good articles but when I read a lot of them it seems you guys are far behind the times with parts choices and so on. You had it on point about the 6 speed but you were wrong about it not being a bolt in affair. At this stage in the game, its a pretty much bolt in affair with readily available parts. No custom mounts needed, no custom axle bracket, DSS now resplines the b13/b14 hubs for the axles so there is no need to swap to b15 hubs and so on. Though for a race car like yours you could benefit from the b15 brembos and so on.

Also Id have to disagree with some things about the p11 transmission. While the shift actuation is more supported by the new design to help prevent wear on the hubs and syncros that cause things like 5th gear popout on the b13/b14/p10 transmissions. I disagree about it being smoother. Every B15/P11 trans Ive driven it did not take well to fast shifting, felt really notchy and a lot of times like to get "Lock Out" of 2nd and 3rd gear. This is due to the new design. The b13/b14/p10 trans feel soo much smoother when it comes to shifting and especially during spirited driving and shifts.

You guys do a lot of racing and Ill bet you after even a first go about with the p11 trans you'll probably notice the same thing.

Even with the p11 trans I highly recommend you guys use a heavy weight gear oil such as the Valvoline 85w140. I know, I know its not GL4 compatible but for a race car who cares. Its not going to eat through the syncros any time in this centrury. I think 85w140 would have saved your old trans from breaking 3rd gear as well, especially at that power level. Its a night and day difference guys. Im telling you, everyone thats used it has notice a dramatic difference. Not only better shifting but the trans actually holds up well. My last b13 trans proved that after going through 3 gearstacks in 3 months on 3 different gearoils, then all of a sudden the 4th set lasted 9 months and 4X the miles and abuse of the other 3 combined? How else do you explain it other than the gear oil switch to the Valvoline 85w140. You cant. Its proven.

Anyways figured I would throw that out there. Please read through my new 6 speed How To/Ultimate Guide and it should answer any questions you have or misinformation you have on the swap.

http://www.sr20-forum.com/howtos/64081-ultimate-6-speed-swap-thread-parts-instructions-results.html#post865495

what was the cost of the 3 treatment processes

@ashtonsser They have already been in a few races with the new P11 transmission. I just wanted to clarify that. it seems like you did not know this.

I missed that last page. lol. I think all the treatment and having it soo fresh is what makes it feel smooth as it does. Again my own personal experience with swapping to b15 and p11 transmissions and driving other p11's is that the shift feel while more solid, was a bit notchy and it definitely didnt take to spirited shifts as well as the b13/b14/p10 transmissions do.

Again, this could be accounted for in wear so who knows. Im sure all the new parts and wpc treatment on all the internals helped that feel greatly.

I am fully aware of what is needed to throw an RS6F51H into a P10, and it's not bolt on. It's close, but you still have clutch pedal things to figure out and you've got to notch the crossmember to clear the diff. I literally read through your thread the week before I wrote this article. Unless you call cutting and welding of a crossmember, pounding a clearance dent in the shock tower, and drilling/grinding for the pedal bolt-on?

Semantics aside, it's an order of magnitude more involved to install a RS6F51H into a P10 than the RS5F70A. That, and I think gear-type diffs suck for road racing. Time will tell, but I think the 51H would've been overkill and added 50+ lbs of unwanted weight to the nose of our car.

And, I suppose you could BUY everything needed (maybe even a P12 crossmember will bolt in?), but really, would you burn thousands of dollars on a 51H setup to hold up to 230lb-ft of torque?



From a stock B15 I drove daily for years, to this racecar, I felt the opposite. Much more positive shift feel, and definitely smoother. Like a Honda.

Either way, it's ironic to complain about shift feel for the 70A while recommending the 51H. The 51H shifts like pure shit on a stick.



The 32V ran Redline Ultra Heavy Shockproof. It lasted 3 laps. Road racing is not drag racing. One lap of LVMS has 4 shifts into 3rd gear, curb hopping in 3rd gear (which is far more abusive than a clutch drop, as you're catching the intertia of the entire drivetrain), and crazy fluid-thinning temperatures (we saw over 300*F on the CASE). Valvoline would not have saved that transmission, nor did we want to burn another weekend of 8+hour hauls, $400 entry fees, hotels, etc on that cursed transmission.

Even PAR-equipped 32Vs don't last road racing. The case flex and heat kill them fast.

We are running Ultra Heavy Shockproof in this trans, to good results so far.

With such a detailed reply, why was my post ignored?

The economic scale of this process is very important to know.

Because I'm a jerk?

Sorry, your post must've come up while I was writing a response to ashton.

Shotpeening is usually less than $100. Cryo is $250, according to Cryoscience's webpage (we had a whole pile of parts to cryo and got a bulk discount). WPC, I'm not sure of, as they don't list their prices and I had a bunch of other stuff done there as well. Give them a call.