STI Type UK PPP problem..
 

Hi there!

I have a friend with an STI 8 type UK PPP. Yesterday she put it on the rollers & only manged 269 of the quoted 305bhp.

So today I hooked up a boost gauge & we went for a spin.

The boost peaks @ 20 psi (1.37 bar) but backs off to around 12-13psi (.9bar) @ 5500 rpm. I would've expected to see at least 1.1-1.2 @ 6500 to achieve the quoted 300 bhp, so no surprise that it didn't make what was expected. Currently resetting the ecu to see if that does any good, but can anyone suggest anything else I might try? Weak actuator? Can it be tightened?

Does anyone know what the boost should be on these?

Cheers!
Ren

Could be quite normal!....
 

All sti ppps are different, some i understand have well over 300 bhp, some not much more than a standard sti, however they are much more drivable1
Have a look here,
http://www.wrc-tech.co.uk/subaru-04sti-WRC350.htm
They had one on a rolling road here, didnt make anywhere near 300 bhp!

normal I expect...
 

I recently had my car upgraded by WRC-TECH (good guys)... they put my "standard" STI7 UK PPP on the rolling road before the upgrade and it came out at 289 bhp. Apparently this is quite good and expected. They said they VERY rarely get one making 300.

Mind you I now get 340 bhp / 350 lbs after the STI350 conversion I had done there ;) Awesome!

Thanks for the help chaps, showed her the wrc350 conversion & looked impressed.

Took the car for another run with an ECU reset & same boost behaviour was displayed.

Car peaks at 20psi & holds that until 5500rpm, boost then sharply drops to 15psi & holds that to 7000rpm.

Someone suggested it could be a PPP with no PPP ECU, and the power figures would seem to suggest that that was logical.

Can anyone confirm how the boost should behave?

Cheers!
Ren

Question. Was she happy with it before it went on the rollers ? I'm very happy with mine (STi8 ppp as well) never been on rollers, perhaps ignorance is bliss.

Exactly what's putting me off the 'generic' PPP. My money is heading towards the 333.

take it down your local subaru garage and get them to run diagnostic check on it,what petrol do you run it on?
martin

I have a MY05 STI PPP and mine peaks 20psi and drops back to about 16/17psi at high revs (6500rpm+). I'm running Tesco 99 fuel and find the performance better with that than Optimax (BP Ultimate makes it run ****e!) I believe mine is running as a good example and quite lively. I have time 0-60 sprints in circa 4.6 secs so not running slow. What fuel are you using ?

Car runs optimax only & has gone back into subaru for checks.

Thanks for your help chaps!

Cheers!
Ren