RB25 Swap

[GTS-James]

i have an 89 gtst that needs a new head, head costs as much as a new rb20 so i would buy an rb20 and just swap it out (1250$) should i just buy the rb25 for 2,000 instead? and would my intercooler, boost controller, turbo timer, intake and everything swap over? also what will i need other than the engine and trans?

[RHDskyline]

I think most people on here would say build up the rb20 because its a more steady platform.

if you went with 25 I don't know everything you would need, but you would need a rb25 ecu, which I happen to have for cheap

[cschepp]

ok if your dedicated to your car and are willing to trow some money at it go with the 25. Great engine more displacement with great response. Here are the things you would need to change over or i would suggest to change over:

- Because the rb20 transmission is weak you should change it to a rb25, in that case you will need a different driveshaft and depending on the situation might even need to change over the speed sensor.

-You will need a rb20/25 spliced harness to make everything work.

-Will need a new ecu

Anyways I pretty sure i missing a couple things.

My opinion take the plunge and do it man, well depending on your financial state at this time anyways. I have done it and I'm sure i will have boat loads of fun with it. The rb20 doesn't have as much potential which after putting all the money into it seem kinda depressing when seeing the final result in my opinion.

Best of luck with your decision.


Chris

[89Baysideblue]

I have the RB25DET in my R32 and LOVE it. hell with the 20 mang!! seriously!!
yea, the 20's have a better low-end, but the 25's have a better top-end - with that being said, imagine a 25 built! damn thing opens up like a can of worms and all i have done in my build so far is on stock internals, 3" Tubby-back exhaust, BOV, FMIC using a Graingervalve as my boost control at 12PSI. DaYuuuM! im hoping to get my ECU chipped if possible on a series II (ive heard all types of theories on this one?) or a Piggyback (yea...i know thay aint the best option but if i could just bump it to 15PSI it would hit approx 310 to the wheels. Not bad considering....

go for the plunge!!

[DRIFT4LIFE]

definatley go for the 25 dude get it balanced i got my engine completely balanced for 450 thats every moving part basically. i will be pushing 400 wheel hp on a engine that can handle 800. a person who just rebuilds a 25 even without forged rods or pistons can hit like 400 whp easy.it will be probably all you would want to push stock rods to. put studs everywhere con rods and crank and head combined of course with balancing with metal head gasket and vio la you have engine capable of 400-500 whp

[DRIFT4LIFE]

you can find a 25 and trany for um 900 at tiger japanese if it is still there i witnessed an imaculate 1JZ GTE for 1400 with mint trany from them and it was perfect no leaks anywhere very low k engine dont know if they are all that way and building a 25 like that would cost like 2-3k and thats having it done for you

[rak123]

.

-You will need a rb20/25 spliced harness to make everything work.

with a spliced harness don't u loose the valve timing? would it not be better just to use an rb25 ecu or a standalone to keep the valve timing?

[BigBlueR32]

with a spliced harness don't u loose the valve timing? would it not be better just to use an rb25 ecu or a standalone to keep the valve timing?

The point of the spliced harness is to be able to maintain the VCT while being able to plug into the r32 dash harness.

[cschepp]

tiger doesnt have any trust me i checked. I will check again tomorrow

[BrianV8]

definatley go for the 25 dude get it balanced i got my engine completely balanced for 450 thats every moving part basically. i will be pushing 400 wheel hp on a engine that can handle 800. a person who just rebuilds a 25 even without forged rods or pistons can hit like 400 whp easy.it will be probably all you would want to push stock rods to. put studs everywhere con rods and crank and head combined of course with balancing with metal head gasket and vio la you have engine capable of 400-500 whp

I can vouch for that. I did a tonne of supporting mods to make it happen but i hit 400whp with just head studs. Everything else in the motor is factory. I've read forums on skyline australia saying some people have pushed over 550whp on a factory engine. Thats definatly getting really high but i read time and time again on that forum 400whp is no sweat for the factory motor.

[cschepp]

yea factory engine should be able to hit 500hp easily. well with suporting mods anyways.