98 turbo not responding to mods?
 

I have recently got hold of a 98 turbo wagon, and it seems to have reduced performance.

Basically the vacuum pipe snapped on the recirc and it started loosing boost through that. So the pipe is blocked until aftermarket one arrives.
But did feel a loss of power since that.
After that it has had a powertec filter and wrapped 3" downpipe, and just doesnt seem to have improved in power. I know from experiencing with other scoobys that they do respond well to downpipes/decats.
It also has waterspray for the intercooler, now it is highly unlikely that i will "feel" a gain from this. But the car is definitely lacking in performance since i first got the car a few weeks ago. You feel/hear the turbo spool, but it has lost thrust. It still pulls evenly without any surging.

After searching on here i have cleaned out the boost solenoid and reset the ECU, to no avail.

Any ideas?

check the hoses going to the turbo, the one that goes under the intake manifold is prone to warping and leaking. is there a boost guage fitted? should be boosting at .9bar as standard. check for boost leaks. any whistles around 3krpm? if so id suspect a leak...

good luck, mines 98 turbo wagon too and it responded very well to a few simple mods.

You mean the inlet pipe that feeds the turbo (vacuum side).

Cheers for the help, am yet to get a boost gauge in there, but can hear plenty of spool and chatter.

if you have left the vacuum pipe off the dump valve it will open under boost!

when the pipe is in place the pressure from the turbo prevents the dumpvalve from opening, without this pressure the boost will over power the valve and it will leak causing a drop in performance.

vac pipe and the boost pipe to the recirc are blocked, definitely 100% sealed.

if you have blocked dump valve off back pressure from inlet will slow turbo (spits air back out air intake) this is not good long term will kill turbo and or maf sensor!! remember wagons only have tdo4 turbos as standard with blocked/leaking pipes ect will only make performance worse!!

This is actualy the other way round on a standard dv the vacuum pipe opens the dv if vacuum is disconnected the dv will stay closed although a standard one may leak!!

its boost AND the pressure of the spring that holds the valve shut, the spring alone isn't up to the job by its self so it will blow open under boost conditions.

I know that long-term it can cause turbo damage, but i have an aftermarket recirc on route.

I am having no luck finding any air leaks at the minute....

Anymore ideas?