34 Gtr Gearbox Limitations

[j3rk]

Tried searching around but didn't come up with any R34 info, heaps of 32/33 but minimal solid details on the 34 gearbox.

So basically I'm trying to work out what sort of power these boxes can handle reliably.

Ideally people with first hand knowledge running x amount of power with no issues, versus accounts of people breaking them at x power.

I know that a lot of it can come down to treatment/servicing but looking to get the generally accepted 'she won't hold for long' levels.

k go!

[GTRNUR]

Its not power that breaks the getrag most of the time. Like all gearbox breakages it is mostly shock loading.

The R34 getrag is basically the same as a supra getrag box with the exception of the AWD transfer case. They run them at over 1000hp in the supra's. But if you've ever been in a supra, most don't get traction at all a well when they are over 500hp atw.

In the GTR however the AWD causes more load on the gearbox output, so the gearbox is more likely to sustain damage from launches. The generally accepted maximum would be around 600hp atw, but the quality of your tyres and the surface your driving on are the real deciding factors.

There are quite a few 1000hp R34's around that still use the standard getrag, however most won't have tried to put that power to the ground through a set of slicks on a drag strip surface. The yellow R34 (Nitto), the powertune white R34 (GTRB28) and the blue envy dyno (jetters edge) cars are 3 that are quite publicly know of as having serious power while retaining stock drivelines for at least part of their lives. The powertune car aparently has a sequential box now.

I do know of someone that has broken an R34 box through just excessive power, not shockloading. I can't remember the exact details, however it was either 5th or 6th that was broken, and it was at high RPM with an extremely healthy rb26 making around 850-900HP. The RIPS built R33 GTR called "BORG" (build on GTROC UK Forum), broke a PPG gearset equipped getrag the first time they drag raced the car as well. I believe that was on slicks with around 800-900 hp as well.

You can toughen up the getrag with billet intermediate housings around the gearsets to reduce the twisting effect that driveline torque is having on the box. This keeps the gears meshing properly and stops the housing breaking. I have also seen a getrag that used a chromoly thrust plate on the end of the intermediate housing, which helped reduce distortion of the gearbox where thrust was normally absorbed by the alloy housing of the box. A PPG gearset helps, but straight cut gearing sets also take away from the streetability of the car unless you like that sound. To go further you start to venture into no so well charted territory, and need a real transmission pro that is able to further improve the lubrication of the box which usually means custom gear modifications, oil squirters, external fluid pump and cooler. The costs to do this get pretty extreme and put you into hollinger territory which is where most of the insane power level cars seem to end up.

The only other option would be an auto transmission with an AWD transfer case fitted, as per that black R32 gtr with the RIPS engines owned by someone on the forum here. I can't remember their username though.

[j3rk]

You sir, deserve a gold star. Thanks for the information mate, exactly what I was after.

[Daz]

Bump 

 

Any other experiences. 

 

How much power can these boxes handle?

[Nismo 3.2ish]

My info is not worth much as I do not race or  drag but run it through the hills and have a bit of straight line fun with it. I would think if you are going hard all of the time and trying to go quicker , even with my 618AWHP and a lot of torque could cause some problems but as GTRNUR said, there are some real beasts running 800 to 1000HP

 Mine is 461KW , 1000Nm around 4000rpm. Getrag 6, twin coppermix C spec, quaif front diff, trannie has a few more plates, a Nismo2-way lsd and 265x35 AD08Rs. So it spreads the load to all wheels and puts a lot of twist on the box, only spins wheels a bit if it is a freezing morning. I stopped dropping the clutch but when I did I loaded it first.

Has handled it well, except I nearly fried the clutch being a DH the other day, but after the smoke drifted off, OK again,  lol

[Daz]

10 hours ago, Nismo 3.2ish said:

My info is not worth much as I do not race or  drag but run it through the hills and have a bit of straight line fun with it. I would think if you are going hard all of the time and trying to go quicker , even with my 618AWHP and a lot of torque could cause some problems but as GTRNUR said, there are some real beasts running 800 to 1000HP

 Mine is 461KW , 1000Nm around 4000rpm. Getrag 6, twin coppermix C spec, quaif front diff, trannie has a few more plates, a Nismo2-way lsd and 265x35 AD08Rs. So it spreads the load to all wheels and puts a lot of twist on the box, only spins wheels a bit if it is a freezing morning. I stopped dropping the clutch but when I did I loaded it first.

Has handled it well, except I nearly fried the clutch being a DH the other day, but after the smoke drifted off, OK again,  lol

Thanks for the reply.

I think we have similar set ups

I'm also running nismo 2way lsd's

Another thing that was appealing is I have a 33 GTR so running this box would make it ridiculously responsive with the 4:11 gears - it already is very responsive

i know the JEM 34 GTR was running this box with 1000hp for some time before upgrading to a ppg sequential. 

Ill keep researching. The OS seq was an option however I cbf pulling the box out every 6000kms to change dog rings

[Nismo 3.2ish]

Hi Daz

I change gears now when it was just starting to go before , lol

Great street setup

Piggaz put the OS seq in his 33 and said it is mad , wait until that one is finished, it will fly, if only I live that long, lol

[Daz]

Mines a street car I ain't pulling the box out every few months. I think if I go sequential I'll go ppg - they seem to last much more kms

[Hattori Hanzo 69]

no dramas with 740whp through a getrag with circuit, drag and 1000m racing.

 

 

[Nismo 3.2ish]

I am starting to feel a bit better about mine and might take it up a notch or 2.

Always wondering were the limit is with torque on the getrag

I guess stuff a change up at the wrong time and POP!

[Nismo 3.2ish]

I am starting to feel a bit better about mine and might take it up a notch or 2.

Always wondering were the limit is with torque on the getrag

I guess stuff a change up at the wrong time and POP!

[Tomak]

I think my r33 GTR gearbox is ending cuz i can hear grinding sometimes on gears 4 and 3 ;/

I have a chance to buy gearbox from r34 GTR and do the conversion. Is this worth the money to do this?

The complete swap with the gearbox will cost around 10k euro and the used gearbox from r33 gtr can buy for around 1.5k euro

I heard that this r34 gtr gearboxes are stronger from r33 and r32. Is this true or not worth the money?

[joshuaho96]

Major thread bump.

Rebuilding a Nissan 5 speed is not that expensive, you will save money vs a 6 speed conversion. Keep in mind if you want to have proper gear ratio spread you need to convert to a Nismo 3.9 final drive on the differentials, otherwise the gearing is excessively short for a street car.

If you have a lot of money to blow on making the perfect street car then sure, a 6 speed Getrag conversion with either 3.7 or 3.9 final drive on the front and rear diffs would make the best of the fairly laggy RB26. But if budget is a concern then I would just rebuild the 5 speed and try my best to widen the powerband of the RB first.