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RB25DET into a GTS4

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i'm interested to know what needs to be done to get an RB25DET to fit into an R32 GTS4.

the engine of choice will be out of a R33 GTSt, so far i know i need a custom sump made up.

is there anything else? engine mounts/g'box bell housings. I'm guessing it will need a new dump pipe from the turbo?

Also just out of curiosity, what are the features on a R32 GTS4 ie p/steering, p/mirrors, AC etc etc???

any help would be great on either topic.



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It would be easier to transplant an RB26 into that car - or find an RB25 out of a 4wd model. The bottom of the block is wider to accomodate the larger sump/front diff assembly - I think RIPS is making sandwich plates to adapt a RWD block to the 4WD sump. Other than that Nizpro are making those uber girdles - they might be able to accomodate a 4WD sump as well.

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Exactly right. Another alternative is to rebuild your existing 4WD RB25DE block with the RB25DET pistons, or better still RB26 pistons, and add all the external bolt on turbo bits. There will be a cost saving, the motor will be fresh, and you get to keep the same engine number.

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Warpspeed, he's talking about a R32 GTS4 (with the RB20DET engine), not a wannabe-a-GTR R33 GTS4 (with the RB25DE engine).

Now, down to business. Firstly, I'm totally confused by this transplant, which I have considered myself. Some people say 'just get a 25DET', others say the sumps are different.

The engine mounts are the same. I believe the 25 uses a bigger clutch assembly and the bell housing is larger to accommodate it, but the bolt pattern is the same as the RB20DET. And many people appear to be using RB20 g/boxes behind the RB25. The dump pipes are the same.

Features on the GTS4 are basically the same as a GTSt (P/Steer, P/mirrors, HICAS, A/C), ABS appears to be standard (optional on the GTSt), and of course ATTESSA 4WD system (as on its big brother, Godzilla).

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I've been looking into this exact same mod and in my opinon you're better off doing up your original RB20DET if it's in decent condition, for the additional 10-20kw it is not worth an engine swap to an RB25DET. If your RB20DET is getting a bit long in the tooth go all the way, RB26DETT or bust.

Another alternative which is quite popular in Japan is to put an RB25DET Head on the RB20DET bottom end.

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hey people, thanks for that info :) it's what i was looking for.

As for why the engine transplant, basically i feel the extra torque would come out though the added capacity with later mods in the planning. making the car more drivable

the only problem doing the RB26 conversion is that the engine is VERY expensive! :( and i think the difference in price could be spent on mods



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You get a lot more than the quoted 10 to 20 Kw with a swap to the RB25DET. There is a huge difference in the low and midrange torque and therefor general drivability.

I have frequently swapped from Mick's R32 into my R33 and in situations where I just leave mine in 3rd or even 4th since adding the adjustable cam gear I have to go to 2nd in the R32 just to stop it bogging down

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Interesting topic. I've just recently bought an R32 GTST but it has an RB25DET conversion (done in Oz). It also came with:

- Stage 2 GCG 450hp turbo (Steel Wheel, Hi-Flowed) (I'm not sure what the equivalency of these are to the jap name brand turbo's (anyone know?), or their range efficiency, as i am unfamiliar with GCG's)

- aftermarket front mount intercooler

- 2litre surge tank

- Bosch 450hp fuel pump

- Malpassi fuel pressure regulator

- Three inch exhaust off the turbo, stainless muffler

- Apexi air fuel controller

The actuator is set at around 10/11 pounds. With these mods my tuner reckons in the vicinity of 210-220 rwkw @ around 5000- 5500 rpm.

Of course going with these mods the additional extra's for stability & handling which also came with the car.

DBA gold slotted and drilled brakes all round

Daiken Exedy Heavy Duty Organic clutch

Bilstein suspension

In the R32 the RB25DET is a monster! It is heaps stronger with low down torque and peakier at high revs. So far the turbo is very much on the leash and with a boost controller and advanced timing, I reckon it would hit the peak of its efficiency. Atm the unit is missing its kick once past full boost and getting up into the higher rpm's.

Go with the 25DET as the RB26 is heaps more expensive and unless you have the dosh (then go for it!) could be a real headache to fix if you end up with a poor unit. Its way risky.

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