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What Do You Guys Reckon?

czy18e

By czy18e,
in Engines & Forced Induction

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czy18e Community Regular

czy18e

Posted
Posted

I have a fully built rb25det with 700hp t66 turbo.

tuned and built by the same company.

Why would they only want to run 20psi?

I am always reading about stock 25's running 20psi and built 25's running 22plus.

The car made 315rwkw on stock cams with that 20psi but i was just wondering why they dont want to lean on it any harder.

Also the car is a tad laggy with full boost hitting at 4900 it builds from 3500 though.(stock cams and gears though)

The rear housing is a .86 t04r flange housing.

Any input would be great cheers.

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I have a fully built rb25det with 700hp t66 turbo.

Also the car is a tad laggy with full boost hitting at 4900 it builds from 3500 though.(stock cams and gears though)

well, you kinda answered your own question...

Your using a 700hp turbo, its not going to make boost/power early in the RPM range. :)

My GT30 (stock head) was making 17psi by 4200rpm, your turbo is bigger again.

Cams might improve it a few hundred RPM, some tuning might aswell.

But as for why the workshop wont push it, have you thought of actually asking them this question?

I think they would be the best people to address the questions you ask here.

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

boost is enemy number 1.

they may be running your engine at a high compression ratio and have not put an agressive tune.

Say your running low ignition - this could be tuned later to have better timing advance which will give you lots more power at the same boost levels but at the same time you have think about how long the engine is going to last and the posibility of it detonating.

Seems to me the engine builder has put a safe tune in it and wants your engine to last because at the end of the day its there reputation on the line if something lets go.

If you ask them why and they wont give you a good enough reason then take it into your own hands and take it to another tuner and tell them to push the shit out of it.. just dont go running back to the builder and asking him to fix it.

BHDave Grand Master

BHDave

Posted
Posted

You have stock cams which likely means stock springs and lifters.

Around 20psi is where you start to see the factory gear start to valve float.

float = bad. If you want to run more boost get cams and springs and probably lifters in there.

Wheezy Mentor

Wheezy

Posted
Posted

what youve got to ask yourself becides building the engine to run more boost...

...is, why do you want to run more boost? to make more power? or is it a boost figure you just wanna run (magic numbers are kinda pointless IMO)...

T04GTR Grand Master

T04GTR

Posted
Posted

mainly reliability. fuels etc etc.

if i rana workshop i wouldnt build up a motor, hand over the keys and go hey, pump 2 bar thru it . sik mate sik.

is it a bush bearing turbo? mayby therre woried it might shag the trust bearing. with more boost.

czy18e Community Regular

czy18e

Posted
  • Author
Posted

Nothing like that at all i was just wondering why there are guys running 20psi through stock 25's and i spent alot on getting a strong motor built and it still only runs 20 psi.

I'm happy with how it goes 315rwkw is nothing to sneeze at even if it is a tad laggy but it should pull an 11 at over 120mph so im stoked.

i was just wondering what you guys thought.

Ill keep yas posted on what changes the cams and gears make,thanks.

Wheezy Mentor

Wheezy

Posted
Posted

maybe the workshop doesnt know you well enough...and therefore doesnt know your driving abilities, therefore are letting you take it easy...

although most people do fiddle with their boost controller from time to time, there is nothing stopping you from playing with settings if you wanted to.

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