Thanks for the replies.

Bob, it is more of a surge than an agressive power off/power on and is reasonably smooth in transition. I'm not that technical, but it does seem to me to be consistent with what I would imagine fluctuations in boost would feel like. Only happens when I can't be arsed changing down!

With hindsight, its more noticable under higher load, ie going up hill.

Definately not as bad as Lee describes!

Car is running well aside from that.

Cheers

D.

 

Actually, not that bad but at least the heading got more attention than my post in Misc.

Not a real problem as such, and definately not an overboost cut out, but I'm experiencing an uneven power delivery in 4th/5th at 2,500 revs to about 4,000 revs when coming on to presumably high boost.

No problems 1st,2nd,3rd and no cut out problems at all.

It may just be a trait of the car (UK MY99 car, no mods, 97 ron petrol), but before it goes in for a service next Monday any info /similar experience would be helpful.

(I never trust main dealer garages)

Cheers

D.

 

Does the engine feel as though it is surging ? If you have a boost guage check that the boost is holding steady, if not be a good idea to get a temporary one fitted and then see if the boost is oscillating up and down at the time you feel this happening. If ecu is having trouble controlling boost due to 97 ron (better grade = more aggressive boost ramp) then it could just be over and undershooting its target values leading to the result you are getting.

Bob

 

At Donington when the engine got *really* hot I had a problem which sounds exactly like yours..for whatever reason the boost was flying upto 20+psi, then immediately down to 10, back upto20 etc etc..made for very alarming, come-n-go performance.
I let the car cool and it was ok then.

but even though I was hitting loadsa boost, because it was so short it didnt cause the overboost cut to come in.

whatever problem you have it will always be worse in 5th cos it generates more load hence more boost.

suggest a boost gauge and QUICK !

 

.......and a 3 port boost solenoid maybe the cure. A lot of people on here know that for some inexplicable reason Subaru went from a 3 port to a 2 port with the 99MY. In Australia they were all recalled to have the 3 port retrofitted.

 

Definately not as bad as Lee describes!
Yes but Lee is running from 20lbs+ to 10lbs
your jump would be 13-14lbs to 10 lbs. Not so big a differance.

Bob

 

Bob,

If it is the ECU is having trouble controlling the boost due to more agressive boost ramp on 97 Ron, is there any cure (leaving ecu alone) other than change to 95 Ron?

It may be subjective but didn't seem so bad on 98.

Cheers

D.

 

I have noticed this too. The wierd thing is I dindt notice it untill the weekend after I fitted my turbo back exhaust....

Any ideas here guys?

Nige