danc

Hi all,

I have had an annoying misfire on my ’96 WRX,(70K,km) which I think was due to cracked coilpack. I’ve replaced this and the misfire appears to have gone.

I think I have an unrelated problem with the turbo boosting time. The car seems to have lost a lot of its’ sharpness off boost, and seem very slow building up to max pressure.
I’ve timed the car in 4th gear, level ground, mild weather. Boost level rises slowly, almost as gradual as rpm rise. Boost pressure peaks at 1 bar, then backs off to 0.9 and stays there ok.
Starting in 4th gear, approx 50kmph @2000rpm,started timing when throttle is floored. Boost rises slowly, hitting max boost around 4500rpm just over 100kmph takes around 9seconds.
Car is fairly standard, only mods are large bore exhaust from cat back. Apexi induction kit. I have swapped the following items from another WRX (’95) and fitted my parts on the ’95, the ’95 still runs better.

MAF, coilpacks, plugs, dump valve, oxygen sensor, boost solenoid, ECU (original ECU refitted after) I also fitted a standard air box and filter, in order that any air leaks could be heard easier, none found. Have done ECU reset after each swap etc.. there are no obvious leaks in the exhaust system. I’ve never had a CEL come on at any stage.
Anyone help with this one, its wrecking my head.. Turbo knackered, wastegate passing ??

Thanks,
danc

stevem2k

Leaky dump valve ? is it the plastic one as they are known to leak ....

Steve

ChrisSTI

Sounds like a problem waistegate to me.

The_Judge

Have you tested the tention in the wastegate actuator arm? Might just need tightening a bit.

Or a leak in the exhaust somewhere between the manifold and turbo maybe...?

danc

Thought about a leaky DV and I've swapped DV, and fault remains, I'll remove the heat shield and check the waste gate actuation rod. Shouldn't the boost build up a lot quicker that what I'm seeing.

thanks again,
danc

danc

Have shortened the rod,3 full turns on end section which connects to the lever arm.....took for a spin...... not much change, at lower end, but now getting 1.1 bar max boost instead of 1 bar.... what else could it be ??

The_Judge

When you swapped stuff over, and you did the wastegate solenoid, did you also swap the associated hoses? I'm thinking about the restrictor just before the T-piece. Although (assuming there is one in there!) this normally creates overboost problems rather than delayed boost. Might be worth a look though.

I would have thought the boost should build quicker as well. Although I can only compare to a MY00 with a TD04, which has max boost just before 3000rpm in 4th gear. What turbo is on yours...?

danc

Judge--I'm not sure which type I have, I'll have closer look now I've got the heat shield off.Will the id be stamped on the exhaust section, or the intake section of the turbo? I'll check out those hoses too, no I didn't change them during all the swapping... I'll try anything thats easier than swapping turbos....I'm not looking forward to snapping bolts etc etc

The_Judge

Should be on the compressor housing...



Wouldn't have thought you'd need to swap turbos, I just wondered whether or not your turbo was the same as mine, to determine if I was comparing like for like with my own experiences.

danc

It doesn’t resemble the td04 turbo in the pic above, there are some numbers cast into the compressor side but I can’t read them clear with all the pipes and intake manifold. The comp entry is downward and back, and exits to the right through the intercooler… is this a TD05?
The other car has a similar turbo….
Gave the actuator arm another turn,(shortened it further ) max boost is being reached earlier.. around 3750rpm, sometimes 4000rpm… max boost is 1.1bar, stablizes and holds 1bar. I'm in a rural area with crap roads, so it hard to watch all the instruments and watch for bends.!!

I swapped actuators between cars, and still seeing similar results (however the boost was back to 1bar max, holding 0.9, probably due to arm tension)
I can’t see where this restrictor is in the pipework.

danc

ticky

The restrictor is fitted in between the rubber pipe that comes off the turbo. This rubber pipe leads to the boost solenoid. The rubber pipe turbo end is slightly bigger in diameter. The restrictor fits into the end of this pipe. Then a smaller diameter pipe is fitted to the restrictor which then leads to the boost solenoid.

danc

..........the pipe that goes from turbo nipple to boost solenoid. Several inches from the turbo nipple there's a plastic fitting which looks more like a reducer. I can see through this..full inside bore... but can't see a fixed orifice type restrictor here anywhere, on either car... should there be something here....

Is it possible that there is carbon/soot built up where the wastegate should seal?

The_Judge

This is a MY99, so don't know how similar to yours. On this MY, the restrictor is in the hose in between the two red arrows, just before the T-piece. There should be a slight bulge...



If there isn't a restrictor, this could well be your problem.

danc

Thanks for the nice pics!

I’m afraid the ’96 WRX pipework is slightly different, there is no T, except where the boost gauge is plumbed in, this T has a restrictor (the restrictor goes toward the boost gauge). So from manifold to boost gauge via restrictor then to the brown pressure thingy above the boost solenoid.

The pipe from the turbo nipple to boost solenoid, has an in-line plastic fitting, but on both cars there’s no restrictor within this fitting.

So I played around a bit, and fitted a makeshift restrictor in this pipe (turbo nipple to boost solenoid). I used the T mentioned above from the other car as my restrictor (blocked 1 outlet off).
Definitely boost pressure building faster, and higher, 1.3bar I think, got my face close to steering wheel at one stage!!, bit too much maybe ??…didn't want to do too much messing with this 'til I find out more, so I've removed this restrictor again,to be safe.

Can someone check this pipe (turbo nipple to boost solenoid) on a ’95,’96WRX, and check if anything is inside this black plastic fiting.

I spent today fitting everything back on the ’95 car, took for a spin, it still seems a lot less laggy, and much sharper, despite having 100000km more on the clock!

danc

ticky

The black plastic fitting is the restrictor.Looks more like a reducer to me but thats what they call it.
Its just a small black plastic pipe which starts with a larger diameter pipe which reduces to a smaller pipe. There is nothing inside it.

I have also tried various sized restrictors (home made). Boost comes in slightly earlier (not that much) but the mid range torque felt a lot stronger. Only problem was the overboost, getting 17-18psi where as standard I would get 15.5psi

My car is a 95wrx saloon running a TD05 (Swan neck entry type)