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Hi Guy's,

I'm about to undertake an Rb25/30 conversion on my Turbo. I have bought the head(Rb25det(R33)) and rebuilding my RB 30 Turbo Bottom End.

My questions !!!!!!

1. Who on here have done the conversion.

2. How many kilometres since the conversion or until you sold it

3. Have you had any problems

I spoke to a member of a performance shop at Morningside(not naming names) and they told me I will have nothing but problems and it's a waste of money.

Anyone wanna way in on the subject is welcome.

My plan is(No short cuts) ;

Full rebuild with the block full prepped, re bored 20thou oversized.

New Wiseco Forged RB25 Pistons, New RB30 Parr Rods balanced and shotpeened. All new gaskets etc etc. Garrett 35/40 Turbo, Custom high mount manifold and custom computer(Prob Microtech).

My mechanic said he had no problems with his conversion but only had it for three months before selling it. He has made me keen as, but after speaking to the guy from the shop I'm starting to have second thoughts.........cus I could buy a RB25 or Rb26 complete with some bolt ons for the same money...

Any assistance would be appreciated.

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I built an RB30/RB25DE hybrid over 5 years ago using all standard components, no aftermarket parts at all. It made 475 bhp on the engine dyno, it has done over 70,000 k's without one single problem using the standard ECU chipped. The secret is tuning, knowing the limits and sticking to them. Most problems come from poor tuning and wanting "just a little bit more".

You are going a few steps above that, but the same rules apply. Short comments on parts selction;

Wiseco pistons are OK, why are you going 20/100 over? If the block doesn't need it?

Never used Parr rods so can't comment, forged rods don't need aftermarket shotpeening, the shot just bounces off and does nothing.

Head gasket is important, do some research

Garret 35/40 is an OK choice as long as it meets your power and response targets. What are they?

Custom high mount exhaust manifold, some are good, some are crap, make sure you get a good one.

Personally I would NEVER use a Mictrotech on an RB, they are not suited. We use Microtechs on the RX7's, I wouldn't use anything else. But not on an RB, you will have all sorts of issues that will cost you time and money fixing. I would do some more research.

Hope that helps

;) cheers :)

PS, we have since built over 20 X RB30DET's, one is up to 950 bhp.

Yep,

Trying to get it done right. Parr Rods are being used by Hardcore Racing up here in Brisbane and have cars running 700rwhp without problems.

Looking for btw 300 - 450rwkw.

As far as manifold I will try to get something reputable and proven.

I hear so much about different computers. My mechanic said Haltech but the same guy from Morningside said they are crap and it will cost a fortune to dyno tune. Hardcore and them recommended Microtech. I was thinking the stock ecu with a chip but I'm still wondering what to do.

My mechanic said a 30/40 would be good responsive wise generally but he recommended a 35/40. He said it will lag a little(35/40) but in the event I want to boost it and get that bit more, I dont have to upgrade the turbo.

Good to hear the numbers you have built and the numbers they have been punching out.

By the way the car will be my drive car everyday so thats why I really need the reliability.

Cheers Imtorqing

The new microtech plug in is worth looking at.

They now have closed loop. Very attractive indeed.

If your looking for 300 to say 330rwkw then stick with prepped std rods providing the car is a streeter, if its anything more than a streeter I would not look past a set of decent rods. Run good bearings and u will be fine.

Edited by Cubes

Your motor is only as good as it's tune... The Gt35r turbo is the go with the .82 exhaust. I'd go with the power fc, they're designed for the rb and have been proven to better then most computers, and are on hundreds of cars on this forum.

ive got an rb25/30 combo

blueprinted/balanced, shot peened rods, aria's hpc coated pistons, just to name a few mods, got a whole list of them on the site

td07s turbo with to4r comp wheel and back cut t66 rear with 360 degree thrust bearing

autosalon dyno made 352rwkw@16psi

ben...

one last coment consider buildign an rb26 for the kind of power you are looking for 400-450 rwkw the development is there .

on last thing at that hosre power dont expect much more that 10 or 20,000 klms . and more than likely sub 10 000 klms. 300 rwkw will see a much longer servicable life with a good shot of nos when your on the track.

next before you build any thing I woud suggest going for a ride in a car with 350 rwkw + and make sure its what you want b4 spending all your money.

cheers

meggala

Exactly as Meggala states. :D

Our recent dyno day had a few cars up around the 300rwkw mark.

Their complaint was.. traction. One said, its quite dissapointing on the street, no traction until 4th gear. The car was setup with rather hard suspension and no pinneapples, and.. it was a rb30/25, torque kills traction. :rolleyes:

I thought the linear nature of the rb30 would help traction. I was wrong. :P

  Imtorqing said:
I spoke to a member of a performance shop at Morningside(not naming names) and they told me I will have nothing but problems and it's a waste of money.

I wouldnt be going there ever again for the simple fact of...

They obviously no idea about anything. Amatuers.

SK has hit it on the head with a lot of what he has said... but for a 300-450rwkw.. thats a massive span mate.

You need to be more specific. is it 300 or 450?

300 will be doable with a GT30, .82 or 1.06 and will be very responsive

350 will be a GT35 no worries with pretty decent response also

400 you can get from a GT35, you might have to fuel it up on something other than pulp though with bigger boost and more ignition gear over stock

Your also going to need some headwork in there for much over the 300 region, including cams, porting and all that jazz to get the flow going

As NIB said also, go with an ECU that your tuner knows.

You'll get the best results that way as opposed to giving them something they are unfimiliar with

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