RB25DET Buildup

[Tonba]

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Greetings All.

At the moment im planning out some future mods...

The focus of the engine is NOT max HP, but i want a very strong mid range and as little turbo lagg as possible...here is what i think...

• RB26 Crank
  
• RB26 Conrods
  
• 87mm Oversize Pistons
  
• CR 9.2:1
  
• GT-30R Running 1 Bar
  
• Adjustable Cam Gears
  
• Mild Cams (Unsure of manufacturer, Thoughts?)
  
• Intercooler
  
• Plumback or HKS SSQ BOV
  
• 3" Exhaust
  
• Oversize TB & Z32 AFM
  

What do you guys think?? Ideas?? What sort of things should i look out for?? Would it be possible to run a CR of 9.2:1 with 14.5 psi on PULP?

Cheers,

--Tonba

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[r33_racer]

i woudlnt see why not...arent rb25s 9:1 compression ratio standard? Correct me if im wrong.

[R31Nismoid]

depends what you class as little lag?

3000rpm 14psi?

4000rpm 14psi?

And what is a power goal?

[Tonba]

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Greetings All.

4000 RPM is too high, im looking for STRONG midrage torque so im looking for max power and torque between 3000 & 7000RPM...

Because im chasing midrange power/torque rather then max power id be happy with anywhere between 220RWKW and 280RWKW

I also want a turbo that wont run out of puff if i deside to pump up the boost and run race fuel for running times on circuit days...So at the moment im thinking of a GT30R or a GT28RS...

Cheers,

--Tonba

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[R31Nismoid]

you want a 450hp turbo then without a doubt, even then full power by 3000rpm is going to be a mission if anything over 200rwkw

you want 280rwkw, your gonna have to live with it being mid 3000rpm... but for the odd 280rwkw on fuel... you wont need a built motor by any means

You wont get 3000rpm out of a GT30 no matter what you do.

[Tonba]

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Greetings All.

Ok, first off...Im not aiming for MAX POWER...so im not really aiming for 280RWKW...but it would be nice...

do you think that by increasing displacment and increasing static compression slightly i can reduce the lagg by having better off boost responce??...Would that improve the powerband?

I want a car that can be good on the track, rather then a dyno hero...

Oh also, i dont mind about mid 3000RPM...as long as im not hitting max bosst over 4000RPM...

Cheers,

--Tonba

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[paulr33]

read the rb30 bottom end conversion pages and doco's, speak to your local workshop/tuner ask them how much to have it done and then die when u find the price. nah seriously read the rb30 thread and pdf and come to your own conclusions. theres a few guys running this config and they post frequently in the rb30 conversion thread and will have covered pretty much any questions you have. you could choose a smallish turbo on it and have it absolutely tear up the rear wheels when it comes on boost pretty early or get a bigger one and have it come on progressively, being u can control it and put the power down. sure fit a gt28rs an rb30 bottom end it will probably be a bitch on the road. youll have like 100rwkw floor it and youll goto like 240rwkw instantly so it will wheelspin its ass off. again im only going off the rb25 turbo upgrade threads. look at a few of them then pick one thats nice, then work out what rpm it comes on boost at, then consider the rb30 bottom end work and you can probably shift the lag point down 500odd rpm maybe?

[paulr33]

http://members.dodo.com.au/paul/pics/dyno/...bes-176rwkw.jpg

thats cube's rb30 graph. it makes 100rwkw at 2000rpm

http://members.dodo.com.au/paul/pics/dyno/172rwkw.jpg

that my previous rb25 graph with usual mods. it makes 100rwkw at 3400rpm

so you can see the difference in displacement

[paulr33]

both at 100km/h in 4th

rb30det 158rwkw ish

rb25det 118rwkw ish