Hypothetically Speaking...

[beRwick_GTRage]

I was also thinking of doing the rb25 convesion in my gts4, im currently running an rb20 with 220kw.

Mods are: wolf v500 ecu, 32 gtr gearbox, excedy hd clutch, 2871r turbo and other supporting mods fuel pump etc.

with the wolf ecu, gtr gearbox and the 2871r .I know i have an awsome base for an rb25 coversion.

Ive got a few questions:

Do you think its worth doing an rb25 conversion?

How much would the engine cost? and How much would it cost me to do the conversion?

Is it an easy conversion?

And would the gtr gearbox fit the rb25 easily?

thanks

[Sydneykid]

After a little more reading of threads, I've seen mention of an adapter plate you guys have over there for making a non AWD block work with AWD. Any links for these? I realize it will make the motor sit up higher, but I am already running an RB26 ITB intake manifold with an adapter, so hight isn't a big issue with me. It also allows me to still use the plentiful cheap RB25's over here instead of relativly rare and expensive stagea motors. We are really pushing the limit of stock RB25's at the shop I go to. The guy is my good friend too so it's kind of an experiment he would be interested in and I get pretty good prices on work.

The shop owner currently has a stock RB25 bottom end pushing 650hp, and I'm mid to high 500's right now. We have a couple others making mid to high 500's also for a couple years. I know how crazy you guys think we are for pushing 25's that hard, but when they are $300 a pop and I have 2 good ones sitting here, it's a chance I'm willing to take. More info on the adapter plates please!

It's actually pretty simple, pull the RB20DET out of the GTS4 and remove the sump. Swap all the sensors over from the RB20DET to the RB25DET and your current ECU will run it just fine, no VVT of course. Buy a 4wd sump adaptor from ProEngines (they are the best design so far by far) and bolt it to the RB25DET block and then bolt the RB20DET sump to the adaptor, put the engine back in the GTS4. A one day job for 3 people if you know what you are doing.

Cheers

Gary

[Cjmartz2k]

That's the kinda info I was looking for. Thanks!! Isn't the GTR gear box the same exact thing as the GTS4? Strength and all?

[Adriano]

Or just use the rb25 out of a stagea, and save the $1000 on an adapter plate.

[R338OY]

I've seen a GTS4 on the road that kept the RB20. It sounded great, looked great (cream yellow) and the owner wouldn't have bothered with the conversion. If you make the RB20 work harder you'll have a very fun car.

I'd forget the conversion unless you are maniacally determined.

[funkymonkey]

That's the kinda info I was looking for. Thanks!! Isn't the GTR gear box the same exact thing as the GTS4? Strength and all?

the boxes are the same (i'm runnng a GTR one in my GTS4) but the ratios are different. A lot of GTR's in japan that are used for zeroyon swap to GTS4 gearboxes as a cheap first mod for this reason.

I'd look at getting a stagea or laurel AWD RB25 engine as well... esp in japan where you can just hook up an F-Con V and tune it. The availability of those engines in australia is pretty rare, but over there its not that hard to find em.

[Cjmartz2k]

Thanks for all the good info guys. Sounds like the adapter is the way I will be going. I'm avoiding the stegea motor if I can because I already have several 2wd RB25's sitting around that I know are good, and it makes replacing popped motors much cheaper. Stegea motors are EASIER to find over here, but still not easy. I've only found 2 in 2 months of searching here on Okinawa, but both of them are in vehicles that the junk yard wants to sell the car as a whole. Also, since I already have 2wd RB25's, all I need is around $700-$800 USD (?) for the adapter, instead of $500-$800 for a stegea motor which if I blow it up, I'll have to find another one, instead of using the ones I already have.

Is there a lot of other machine work or modifications to the block needed after the adapter install, or is it just a matter of dropping the pan and swapping the motors?

[funkymonkey]

ohh... you're in oki... haha no wonder. you need to be in the mountain regions of japan to have stags in abundance.

[Cjmartz2k]

Yeah, to bad for me I wonder how much power those adapters are good for? Also, I can't seem to find the adapter from pro engines. Any links?