R34 Gt Auto Tuning

[bullet300]

My son has an R34 gt auto. I'm looking at methods on how to tune it with the view to be able to further tune it down the track when he is off his P,a and can go turbo. The issue is the 98 gt auto has a seperate TCM and is not compatible with swapping out a gtt auto nistuned pcm ( from what I have read so far ) Please if anyone has info on what to do here I would much appreciate. Realise that some options include manual swap, manualised valve body. Just hoping there is a more direct running option I haven't been able to find. Thanks in advance. 

[GTSBoy]

Just put a Haltech in it.

Be aware that there is little extra speed available, so almost any money spent on NA "tuning" is wasted. Far better to spend on brakes, suspension, etc.

Be also aware that the auto will die behind a turbo, so a manual swap is not a bad idea.

Be aware that parts for these tasks are becoming very difficult to find.

[Murray_Calavera]

Does the car have to stay auto? If so, you might be looking at a ZF swap in future. 

[Kinkstaah]

If you want to do the wiring, the GTT engine ecu has the same pinouts extra that the seperate TCM in the NA car has.

You can literally grab the wires/pins that lead into the Seperate TCM and wire them into the corresponding pins in the GTT Engine ECU.

You could then in theory Nistune it.

I realised this when everyone put it in the too hard basket and I actually looked at the f**kin R34 manual. This is after I had previously had a seperate aftermarket TCM controller in my original N/A chassis car and a very built gearbox from a GTT, running a seperate Haltech engine ECU.

I ran into this issue when I re-shelled the car into a GTT shell, so my aftermarket TCM was no longer plug and play, because the loom/modules were not present. I was pretty livid when realizing just how simple the original fix actually was. It sat for 3+ years at various workshops trying to find a solution.

In practice none of this is a worthwhile idea for a lot of reasons, generally surrounding the shitness of the NA auto, the autos in general that come with skylines, and the NA engine and lack of gains. The gearbox is specced for the 2.5L N/A and barely at that level.

If you have to pay anyone any money to do any of this, that is money spent on manualizing the car and it's not even close in terms of a comparison. Learning to drive manual is simpler than going through the pain of dealing with the N/A gearbox and he'll have fun to boot.

[dbm7]

Yeah, R34 with RB25DE likely has a 4AX01 box in it, which is a medium duty auto ~ with the RB25DET mill, it would've been fitted with 4AX00 (4AX13) heavy duty build (same case, different internals). An RB25DET will lunch on a medium duty 4R01 auto in pretty short order ...to give you some visual idea of differences between the 'medium' and 'heavy duty' boxes, you only have to look at the 2/4 band for comparison...it's chalk and cheese...(plus bigger high clutch, extra pinion in the planetary sets, higher oil pump output, different bearings, higher TC stall speed )...

You can control them with just about any aftermarket TCU for electric-over 4-speed with TC lockup clutch (ie; the GM 4L60E and others)...I have a custom standalone TCU that includes MAP sensor (for turbo applications) along with TPS, RPM, and line pressure monitoring...in other words, I don't use any ECU signals...no real need to.