Mark_1

As topic.. if you remove the restrictor on a later spec wrc engine and remap it, how much horsepower are you likely to see?

JonnyBravo

I'd imagine not a lot more as its totally designed around running a restrictor.

cjwood555

My understanding off the basic premise is that the turbo is spec'd so as to max out the restrictor very early on - effectively they have 300bhp from 4000-7000 rpm. So removing would probably result in massive surge problems...

Danny @ Enhanced Performance

iTrader: (3)

If you get a wrc engine and want to de restict it like just putting a t34.63 for example it will make around the 400 hp mark..
Done this a couple of times..
If you just remove the restictor on the turbo it will do circa 340-350 hp


cheers danny

J1mbo

iTrader: (1)

thats about right danny

we done a grp a engine for a guy who wanted the car for sprints too,

the t34 non restrictor made exactly 400bhp

but you have to remember, a wrc engine being at 10. something :1 cr any looked at every 1000 stage miles may not be so good long term as a properly specced road engine

Mark_1

the engine in question has an ihi turbo and 10.4:1 comp.
And if it makes 400bhp compared to the 300-330bhp with a restrictor, it is a significant gain if you ask me.

So anyone had any experience with a non restrictor ihi turbo?

Danny @ Enhanced Performance

iTrader: (3)

Yeah but like jimbo says as its 10.4 cr it will need to be mapped very closely and wont last as long,but still possible..


cheers danny

rs-tuner

iTrader: (1)

Is the high cr there to give big torque

ian sibbert

Mark,

I'd sell the IHI and buy a turbo more suited to your application, the IHI has a very low trim on the compressor wheel and dependant on which back housing is fitted could be restrictive above the design parameters. The IHI has a fairly small envelope in which maximum efficency is exhibited and as such trying to (get more out of it) would be pointless in my opinion...

The whole WRC engine package is a little unique and to be fair you could acheive 400 BHP cheaper and probably more reliably by going a different route..

By removing the restrictor you are going to see a decrease in air speed and as such ports, cams, exhaust etc would potentially need re-working...

The wrc engine is mapped to achieve maximum efficency against choke point (PRP) post restrictor pressure and as such eliminating the choke point (restrictor), still run a high C/R not re-work the motor and not run race fuel would dramatically reduce the life expectancy of the engine...

Mark_1

Thanks Ian, the answer i was looking for.
So very litle gains by removing the restrictor then.

Mark_1

also, future plans involves replacing turbo and running e85, any thoughts about that?
I recon the high cr is an advantage when running e85, and as there is 8 injectors, changing them to support the increased fuel needed is no problem.

Guess the head would need rework, but the cams should be good to achieve low end torque.