Engine Tuning for an '04 WRX

[LaszloT]

Decided to go with an Invidia catted divorced downpipe and Q300 cat-back exhaust. Now I need a tune to take advantage of it.

I like the self-sufficiency of the COBB AccessPort tuning tool, but all the advice I'm getting has been to get a Pro-tune instead.

Who do you suggest I contact for a 91 Octane general purpose tune for the street and occasional track days?

[STeveD]

My personal choice would be for Paul at Neetronics, or see if Frank at Fourstar has the Protuning software license now. Mike at Innovative Tuning is another excellent choice, but a bit further or a drive if CEL's or other issues that may or may not be tune related crop up.

Did you do a compression / Leakdown test and change sparkplugs before buying that Rex before you bought it? Would be a good idea on that higher mileage car before tuning to higher power.

[LaszloT]

FourStar is in Georgetown, but where are Neetronics and Innovative? Spark plugs were changed at 207,000 km, and I'm at 235,000 km now.

I haven't considered a leakdown or compression test, but I'll have it done if it makes sense.

I'm sure Caveman can do that as well. What am I looking for out of a compression or leakdown test?

[STeveD]

Neetronics is in Oakville, Innovative is in Buffalo a short ride from the Nagara crossings. Compression / Leakdown will tell you how healthy the rings / pistons are, and if there is a weak cylinder. You'll look to make sure that the compression numbers are within spec, and you'll hope for leakdown below 10%. Maybe 15% with an old motor. Ask the tuner what they are comfortable with. Change the spark plugs while doing the compression test (spark plugs are out anyway) and ask your tuner if they want colder plugs installed. By checking where the compression is lost (backflow through intake, exhaust, or oil fill cap) your mechanic can help diagnose where the problem is. More than 15% leakdown or uneven compression you might want to consider a rebuild instead of tuning.

Putting extra stress on a motor with higher boost and more aggressive timing when there's a weak cylinder can aggravate an existing problem and cause a big failure. Better to check the motor's health first.

[LaszloT]

Thanks SteveD. It makes sense about the leakdown testing, and I'll follow the tuner's advice on this.

I'm researching a rebuild at this time as well, because I want a plan when it's time. So far it looks like an 'almost stock' rebuild budget will be about 3 $k; with 1 $k labour to remove & replace the engine, 1 $k for machine shop work, and another 1 $k for parts.

[Robin]

is the uppipe the original also? seem to recall on early wrx that up-pipe was a good change also with turboback for stage2 tuning.

[LaszloT]

Robin,
I've got an Invidia turbo up-pipe already, as suggested by Caveman when I first got the WRX.