Hey everyone...

I've had the grounding kit and intake mods (K&N, removed silencer) for about 1500 miles now. The ECU is definitely back up to speed. I've been doing some testing on the car, and here's what I've found:

At wide open throttle, I get a *serious* surging from the turbo starting at about 3K rpms on up to redline. It gets bad at about 4K-4500, and I've noticed it in 3rd, 4th, and 5th gear. It feels like the turbo is spooling and dropping off in a pulsing pattern that cycles about twice a second. I was actually having issues passing a car in an uphill passing lane at 70 mph in 4th gear because the car was pulsing so badly. I do not have any traces of this at all at half throttle in any gear. It was also doing this before the grounding and intake mods too.

Any thoughts? This can't be normal. My thought is a malfunctioning wastegate, but I really have no clue. Has anyone experienced this at all, or have knowledge of what I'm facing?

Thanks again in advance. I appreciate it.

 

Definitely take this to a dealer. You have no reason to expect denial of warranty coverage.

 

Well, one reason would be that I bought it used and it has 63K on it. =) (Sorry...shoulda specified that...)

It's an '02 that totally checks out otherwise mechanically and throws no CELs. Any thoughts?

 

What other mods do you have?
Are you hitting fuel cut???
What boost are you running?

 

I'm not running nany mods at all other than the airbox mod and the grounding kit...no boost controllers or electronics at all. It's basically bone stock. Stock boost, and I'm not coming anywhere near fuel cutoff.

 

The car is already past warranty, unfortunately. In any case, it's at the local dealer now. I wnd for a ride with a tech, and his thought was a bad coil. He seemed to think the wastegate wouldn't be the issue at all, as it would throw a CEL if anything malfunctioned with it. We'll see what they say after they get a chance to go over it.

He said some interesting things...he agreed that aftermarket BOVs on stock turbos do nothing but hurt performance (atmospheric venting models), and also was impressed with the grounding mods, saying that it helps the WRX big time. He also said that a stock WRX will throw out 19.5psi on a hard pull to redline.

 

That's news to me unless he's referring to a boost spike, which is generally undesirable anyway.

I hope they get to the bottom of your turbo problems.

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0==WW==0
"…axles of evil…" - george w. bush

 

Yes...basically, we're talking about a boost spike. He was telling me they were testing the cars as part of the Subaru mechanics course, and that was a result of a baseline pull. Crazy.

Anyway, the verdict is in. The number 1 coil is cracked. I'll have the car back on Thursday, so I'll keep you all posted.

Incidentally, he also advised me to remove the K&N drop-in, since the oil in the filter very easily clogs and confuses the MAF. I know I've seen this somewhere else too...has anyone else had experience in this?

 

I was at a Dyno Day at Vishnu Performance this past March. Shiv told us that one of his customers encountered an elusive problem with his WRX and traced it to an overoiled K&N drop-in filter element. A film of K&N filter oil had coated the MAF, causing mis-readings. He carefully cleaned the MAF and the car then ran as it should.

I only use OEM pleated paper elements myself, although I change it out once a year rather than at the recommended 30,000 miles.

--
0==WW==0
"…axles of evil…" - george w. bush

 

Yeah...that's pretty much what the tech said as well. He said a mist of carb cleaner into the intake inlet in the air box would clear it too, given proper time to air dry. But it runs the risk of reoccuring. I may look to the OEM filter now after all...

 

I like K&N filters but just not for my WRX. I've used them in the past on other cars but none had a sensor in the intake path that would have a problem with a light oil film buildup. It might be possible to use a K&N without getting the buildup but I'll be darned if I know how much K&N filter oil to spray onto the filter so that it's just the right amount - I could never tell if I applied too much.

--
0==WW==0
"…axles of evil…" - george w. bush