Due to an oil pump failure, as of last week I have been
looking into a forging my 2.0 WRX….. since I’m rebuilding the engine anyway.


The plan is to push the 400bhp mark with the rebuild using either
a SC40 or AFP TD05 20G turbo> However I would like to retain the current
exhaust setup, which is a 2.5” prodrive exhaust system (sports cat and backbox).

Is this even possible with the restrictive backpressure and
would the spool be effected. There is the option to convert to a twin scroll
also

Any ideas?

 

I don't think your gearbox will handle 400bhp?

 

Have a 6 speed box sitting waiting. This has been on the cards for a while!

 

Sports cat would restrict it, also are you running standard injectors?
PM simon (Jolly green monster) he will advise you.

 

650cc injectors will be put on the car. As for the sports cat, i realise this would restrict the power but not as much as the exhaust diameter.

I am just after the ultimate stealth wrx - Max power, no noise.

Also which turbo is best SC40 or AFP TD 05?.. not sure if Andy's one is billet'd?

 

650cc is wise and good upgrade,i'm running same with FPR...
Sport ca will be restrictive,in some point,but i've seen some car run 400BHP on sport cat.
2.5" is restrictive again in some point,i've seen again some car run 2.5" with 450bhp,but not on standard exhaust.

SC40 is good,but best from these SC range is SC46,Andy Forrest billet not sure,but best is ask Andy via PM or email.

But i will advise fit FMIC,much better temps and TMIC will be at some point restrictive.



Jura

 

Was thinking i might put a PWR charge cooler on instead or a STI 8 intercooler with matching tray as i already have the scoop.

Its not the sports cat that my main issue, switching front pipes for the MOT pretty straight forward but i am wanting the car to be quiet (ish) for daily driving, hence the 2.5"


There is the option of a 3" straight through decat with the a resonated centre section and prodrive backbox as the baffles/ pipe diameter reduction from the backbox should minimise noise ( just not enough)

 

Probably best bet will be run FMIC.

For best exhaust,which is not quiet i would recommend Miltek or Cobra Track Day exhaust,nice sound and will be still pass any noise limits or will be almost as standard exhaust,just have look on youtube.


Jura

 

The Milltek is one of the quietest of the aftermarket exhausts and very subtle!

 

From our experience of charge coolers, I wouldn't go there.
This is how we see it.
A charge cooler is vulnerable to damage or system faults. A pump failure or water leak can be disastrous for charge temp.
An intercooler just goes on working, with even a large leak just resulting in a loss of boost and possibly a rich mixture.
We experimented with a PWR system and found it wanting, even compared with a top mount.
A front mount set up has its downsides, but even a cheap one will do the job.
Yes, it is possible to make a charge cooler work, but I'd only look at a sophisticated one for a seriously high powered drag car, rather than every day use.
The Milltek resonated system will easily flow enough for 400 bhp, we've proven that one.
We'll offer a discount on either Milltek or Cobra systems.