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Rb27det Versus Rb26det?

PRO-L20

By PRO-L20,
in General Automotive Discussion

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PRO-L20 Proficient

PRO-L20

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Hey guys,

I've been thinking(never a good thing for the wallet) and I've come up with an idea of a nice torquey animal of an R32 GTS-t. I don't want monster power. 320-400rwhp would be nice. I think a GT3071R would be suffice for the power output i'm after?

Now I'm sure an RB27DET(name for capacity change) can be build using an RB26 crank & 40thou pistons in an RB25DET engine. Is this correct?

I was all set that'd be a good idea, but then I remembered the RB26 has itb's, solid lifters, better head design and oh oh that sound.

Problem is it will be built cheap, so an RB26 would lift costs markedely.. Although how much difference is there between tired 25s/26s? I'd have to go a 25 gearbox also, so no need to fork out for a 26 cut (i realise the boxes are the same)

Is the RB26 really that much better than a 25? I read somewhere back in the day Keir Wilson was producing 500nm or so in the space of 1500-2000rpm on the 1/4 mile due to the the 6 throttle bodies? that sounds FUN!

Any suggestions/advice/experience welcome!

Thanks

edit: forgot to mention - car will be driven as a daily too, not that it really matters that much. hardcore cars are meant to be driven

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

A 3017 isn't going to be at its limits end with 400rwhp... so you don't need to worry much about building anything IMO.

A 3071 will be within the limits of a STOCK RB25 bottom end no problem.

So cost vs result just put the RB25 in with the 3071. Bolts up to the stock manifold too from memory, stock motor head and so on = no problems and cheap for the result.

Going RB26 is added expense for no beneficially major result for that kind of setup IMO. Id only go a RB26 if you were chasing OVER 400rwhp with a bigger turbo than that...

I mean in the world where cost isnt a problem you'd go a 30k 2.9ltr lol, but you want to keep costs down

B0oStEr Mentor

B0oStEr

Posted
Posted
Hey guys,

I've been thinking(never a good thing for the wallet) and I've come up with an idea of a nice torquey animal of an R32 GTS-t. I don't want monster power. 320-400rwhp would be nice. I think a GT3071R would be suffice for the power output i'm after?

Now I'm sure an RB27DET(name for capacity change) can be build using an RB26 crank & 40thou pistons in an RB25DET engine. Is this correct?

I was all set that'd be a good idea, but then I remembered the RB26 has itb's, solid lifters, better head design and oh oh that sound.

Problem is it will be built cheap, so an RB26 would lift costs markedely.. Although how much difference is there between tired 25s/26s? I'd have to go a 25 gearbox also, so no need to fork out for a 26 cut (i realise the boxes are the same)

Is the RB26 really that much better than a 25? I read somewhere back in the day Keir Wilson was producing 500nm or so in the space of 1500-2000rpm on the 1/4 mile due to the the 6 throttle bodies? that sounds FUN!

Any suggestions/advice/experience welcome!

Thanks

edit: forgot to mention - car will be driven as a daily too, not that it really matters that much. hardcore cars are meant to be driven

I don't think you could call that motor an rb27 as the capacity only calculates out to 2628cc.

PRO-L20 Proficient

PRO-L20

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A 3017 isn't going to be at its limits end with 400rwhp... so you don't need to worry much about building anything IMO.

A 3071 will be within the limits of a STOCK RB25 bottom end no problem.

So cost vs result just put the RB25 in with the 3071. Bolts up to the stock manifold too from memory, stock motor head and so on = no problems and cheap for the result.

Going RB26 is added expense for no beneficially major result for that kind of setup IMO. Id only go a RB26 if you were chasing OVER 400rwhp with a bigger turbo than that...

I mean in the world where cost isnt a problem you'd go a 30k 2.9ltr lol, but you want to keep costs down

Yeah I know it can be done on a stock motor, but when it's going to be at the track every weekend and spend more time on limiter than it spends idling - it's gotta be tough.

I want the extra torque and midrange offered by extra capacity - something different too.

I mean, one day I'd probably have it over 400rwhp, but when the car has nothing inside it and stiff suspension, big power is not needed for fun

Imtorqing Community Regular

Imtorqing

Posted
Posted
+++1 for the RB25/30...This combination has been tried and tested many times...Extra torque all over the rpm range...Best bang for your buck by a mile...

Had both 25/30 400rwhp with 35/40 .82rear & 26/30(Currently 524rwhp 42R). Personally if that is the power u r chasing I wouldnt bother going with the hybrid. A decent rebuild on a 26 would be better (Excellent motor, already forward facing plenum and excellent throttle and responsive as hell with a high redline. Hybrids are generally 7500rpm and torquey as a mofo) and dont be scared to get a big Huffer. With head work the 42R is an awesome turbo for track work and has a lot more to go.

You need machining of the crank for the 25 and 30 to allow 360 degree oiling of your big ends(Good Insurance) which the RB26 has as standard as it was built with that extra power in mind.

In the end the price for either hybrid will be around the same if u shop around and stay smart.

Hope you have big pockets. Good Luck :(

Personally if u have the money get a 2J :) (As I duck for cover)

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