2JZ in a Z4 Coupe - Custom Project

[dre99gsx]

Some images of the diff cooler. Exits out of some holes behind the original license plate area.

[Dan [Sac]]

Originally Posted by 3GFX

Redneck mathz:

If the stock drivetrain is built for 200,000kms at 325hp. Wouldn't that mean you should get half the life from twice the power?




NOW TURN UP THE BOOST

You did that like my wife does cooking...
"It says 30 minutes at 225F, so I'll just do 15 at 450F"

I go through more pans than ratchets

[Vanne]

Good job mate, that oughta help quite a bit. Extra fluild too.

[dre99gsx]

Just a quick recap on the GS6-37BZ transmission and how it's holding up, as well as the Z4 non-M 3.64 Diff (with a Quaife).

I have no idea how much longer these two will last, but:

- I'm on my 2nd transmission. 1st one lasted ~155 20 minute HPDE sessions before it blew. I am pointing the finger at heat. I've since installed two oil coolers and a pump, keeping it below 230F. Latest transmission is at ~70 20 minute sessions and going.
- I'm on my 4th? diff, this latest one is on ~49 20 minute sessions. Again, added larger oil cooler and pump.

I'm not sure if the cooler fluid will extend the life of these any further, but I'm at 630+whp for all of these events. I do not launch the car.

I think it's safe to say these two can handle 630whp with quite a bit of abuse. I went into this thinking the transmission would be a box of marbles but it's somehow holding the power. Perhaps don't spread this secret because I need spares to exist

The diff is smaller than the Z4M, and I may upgrade the entire rear end at some point. I'm itching to bump this to 700whp soon because why not.

I do wish there was someone else with evidence of power limit on this transmission. Doesn't seem to be much data out there...

[wdb]

Great data, thanks for sharing it.

I imagine that most of the race prepped cars are built for a particular class and don't have the kind of power you do.

[Dr. Minimus]

Long time follower of the build, happy to see it's still running strong.
I realize this was awhile ago, but what inputs besides the crankshaft position sensor did the BMW DME require before the EPS was enabled? I am planning an LS swap for the same model year.
Also, in case the rear differential is still giving you problems Seem legit garage sells a carrier for a Ford 8.8 diff. I assume you have seen this, but just in case.
https://www.seemslegitgarage.com/pro...frame-axle-kit

[dre99gsx]

RPM signal was all that was needed.

I'm saving up my coins for a Z4M rear frame/diff to replace this when ready. Parts alone will be a fraction of the cost of that cool subframe, but thanks for bringing it up. Didn't know there were other options

[dre99gsx]

[amcp]

That's real nice Clark.

[wdb]

What is that -- 3x the horsepower of the N52? Just wow.

[dre99gsx]

UPDATE:

Alright, transmission #2 blown. 4th gear. This time, was coasting through T5 on NJMP thunderbolt. RPMS shot up at part throttle, and box of marbles. Coasted to a stop, towed it in.

Transmission had ~4 years 79 20minutes sessions (let's assume 27 race hours on it). I think it's safe to assume these transmissions will last but the wear is what will tear it apart. The trans fluid never exceeded 240 degF, always on an oil cooler. I changed Motul fluid yearly. Never launched/drifted. I used 4th gear exclusively on most of the tracks.

I can source these for $600-$900. Have to debate if I keep replacing them or move up to T56 or CD009 (or even E46 M3 Getrag). The cost to swap to something more robust will most likely mean more weight, bigger upfront cost, unknown compatibility between 3.0si diff/driveshaft (would probably need to be custom), distance to shifter location, gear ratios... The fact that this Collins swap kit made the 2JZ swap into this Z4 effortlessly was the big attraction.

T56 and 2JZ adaptor kit: $3500+
Custom driveshaft: $1000?
New flywheel/clutch: $1000?
that's roughly 5 Z4 transmissions... lol.

I hear anecdotes that nothing else fits in the transmission tunnel, but I wish I could see evidence of why/where.