Transplanting an R34 GTR engine into R34 GTT

[rovingboy]

Has anyone got experience of swapping the GTT's stock engine for the GTR - both R34? I am considering the upgrade at the moment and wondering if it is worth the cost. Actually the problem I am trying to solve is the gearbox performance on the GTT - a stock auto. After some tuning to around 280 hp I am getting trouble from the gearbox.

• A/T light comes on after spirited driving. Clears when engine stopped and restarted,
• stuck in third when trying to push past 140kph,
• revs dropping to tick over speed despite car doing 100kph when releasing throttle in D,
• revs soaring when accelerating hard in 2nd (say) but car remains at steady speed.
• slow, delayed changes up when accelerating hard, causing engine to red-line and complain loudly
• etc etc.

Not pretty.

Maybe the gearbox needs an overhaul, but I would prefer to swap it for a manual, of course. But the manual I have sourced is currently attached to the back of an RB26DETT and the suggestion was made to take the engine too and "drop it in". I want to tune the GTT further, so need to plan for more hp.

Option 1. - overhaul the autobox (once fixed, is it capable of handling 300+ hp?)
Option 2. - find a GTT manual gearbox (but can't trace at the moment)
Option 3. - Put in the GTR gearbox I have at the moment (any known problems, issues?)
Option 4. - Put in GTR gearbox and engine, get more power, better tuning platform, 6-speed gearbox, etc

Option 4 seems to be it :-) Seriously, though, this is going to cost $$$. What should engine + box from a half-cut cost?

Anybody see the obvious solution hiding in there as it isn't clear to me!

Thanks

 

[chimaera1855]

i swaped an RB26 in my cefiro with over 5**hp++ with rb25 gearbox no problem at all.dont bother keeping ur auto trans u ll get too much problems with it.

 

[V-Spec]

Hi rovingboy.

Wrt your slush box issue, have you change the ATF and ATF filter since you bought the car? Might help to check the solenoids as well.

I guess the sensible option is to convert to a manual tranny and keep the RB25DET. Yes you might be able to plonk in the RB26DETT (costs a bomb!) but the Getrag 6 speeder (costs a bomb too!) will not be able to fit the ER34. So you'll still have to run on a 5 speeder.

 

[heterodyne]

sounds like a clutch plate worn causing clutch slippage, nothing serious and nothing to do with gearbox.

 

[rovingboy]

sounds like a clutch plate worn causing clutch slippage, nothing serious and nothing to do with gearbox.

I am revealing my ignorance here, but does an auto box have a clutch plate ..?

Does anyone have experience installing and using a shift kit (sold by MV automatics in Adelaide, Australia) They get rave reviews there for reducing the shift time, and the ozzies seem to think their auto boxes with this kit are faster than manuals (cos the boost doesn't drop between gears)

The kit upgrades the valves thus making the changes faster, but sometimes clunkier

 

[huakenny]

I am revealing my ignorance here, but does an auto box have a clutch plate ..?

Does anyone have experience installing and using a shift kit (sold by MV automatics in Adelaide, Australia) They get rave reviews there for reducing the shift time, and the ozzies seem to think their auto boxes with this kit are faster than manuals (cos the boost doesn't drop between gears)

The kit upgrades the valves thus making the changes faster, but sometimes clunkier

auto still got plates inside.....try do a proper maintenance job to the auto trans 1st....the issues u mentioned mostly is slippage.....

 

[rovingboy]

ok that's the plan. gear box being serviced now. thanks

 

[kaminari]

ok that's the plan. gear box being serviced now. thanks

Good to hear that, but i`m not sure they will change the wet clutch maybe perhaps a common
overhaul....cleaning, change gasket/seal and kasi air spray skit....then the bill comes~ Berapa?RM800???wahlau....hehe

 

[shark79]

Basically it boils down to what you want,if you prefer manual then go for the swap but its auto that you prefer then there are many options. The MV shift kit helps you to shift fast and hard (not much rpm drop)You must remember this is not enough cause you need to strenghtened your tranny/ install high stall converter..your stock 34gtt a/t tranny should be able to handle about 300bhp without any problems

 

[rovingboy]

ok. i am going to continue with auto and see. On the Australian forums they debate a lot whether auto is faster than manual or not, and even use auto boxes for drag racing, so mine should get me to Bukit Bintang :-)
The car is back from the workshop, but I haven't experimented yet. I am still <300bhp so alright there - thanks for tip on high speed stall torque converter... will investigate.

MV from Adelaide, Oz, quoted me A$535 for a Valve Body to "improve shift speed and the strength of the trans". Also they do high performance servo for A$285 to "improve the shift quality and strength further". Well I think I'll order one, and report back here on the outcome. thanks

 

[heterodyne]

trust me, auto gearboxes are faster. I know of one street car that ran a B&M auto shifter that ran 9 sec in an official 400m drag race. People that still insist that manuals are faster on the drag really have no clue what they're missing(until they try the real thing)

 

[[PIMPIN]]

ok. i am going to continue with auto and see. On the Australian forums they debate a lot whether auto is faster than manual or not, and even use auto boxes for drag racing, so mine should get me to Bukit Bintang :-)
The car is back from the workshop, but I haven't experimented yet. I am still <300bhp so alright there - thanks for tip on high speed stall torque converter... will investigate.

MV from Adelaide, Oz, quoted me A$535 for a Valve Body to "improve shift speed and the strength of the trans". Also they do high performance servo for A$285 to "improve the shift quality and strength further". Well I think I'll order one, and report back here on the outcome. thanks

If you have close to stock power there really is no point in investing in a high stall torque converter. Especially if its a daily driven car. In layman's terms, its the same as you 'launching' the car at a certain RPM each and every time you move from standstill so the higher the stall, the more torque is needed before it actually engages.

trust me, auto gearboxes are faster. I know of one street car that ran a B&M auto shifter that ran 9 sec in an official 400m drag race. People that still insist that manuals are faster on the drag really have no clue what they're missing(until they try the real thing)

Granted they may be faster down the drag strip but for us everyday commuters, changing gears are the highlight of our daily traffic jams.

 

[shark79]

Hi, u can choose to have engine braking option for street driving VS transbrake which is more suited for bg hp and drag. Make sure you fit the kit properly(MV)

 

[rovingboy]

This problem has gone full circle. I bought the shift kit, but the outcome of the auto-box service was that the torque converter gone and recommend replace with recon unit. As there are don't seem to be any ones around we go back to the post at the start of the thread and plan to replace with a manual box :hmmmm: !

I'm sorry I won't get to try the shift kit in action.

Not going the RB25DETT engine/box route as I really want the car back on the road soon.

Thanks for observations guys it has been a learning experience for a total non-mechanic.

PS anyone want to buy a shift kit for a auto-tranny ?

 

[atermizi]

just convert to manual bro..sooner or later ur greed for HP WILL make u change to M/T anyways..

 

[rovingboy]

well i wanted a manual all along but i have to think of wifey taking the kids to school.... anyway got my excuse now cos there ain't any auto-boxes around.