Hi,
I just installed a Megan Racing 3" catback exhaust on my 04' WRX STi. Price was good, sounds deep and the build quality is pretty decent. However after about a day of driving with it on, I noticed that my oil temp gauge bounces from 90 degrees to 150 degrees when my foot is off the throttle, when my foot gets back on the gas it goes back to 90 degrees or so. Any ideas as to why this is happening from a catback? And if it is a problem, what should I do?

BTW, the only other mod I have is a K&N drop in air filter. I've searched this forum and others and couldn't find a answer. Any help you could provide would be greatly appreciated.

 

Hey Quick,

I am a bit confused...

1) How do you know what your intake temperature is? I know that there is no stock temp gauge on your intake system.

2) If you do have a aftermarket intake temp gauge, why? I can't think of a reason why you would need it with a drop in K&N and a cat back...

As far as a temp fluctuation between 90 and 150, there is no way that a cat-back could realistically cause it. Your exhaust install could have screwed something up but I doubt it. The only electronics you need to fiddle with is an 02 analyzer that you should have removed from the stock exhaust and screwed back into the new exhaust. The fact that your throttle causes the fluctuation most likely means that when you wired the intake temp gauge, you somehow managed to wire it into the electronic throttle - this is remotely possible because the STI is a electronic throttle vs a typically physical cable pull.

If this is a real problem, I wouldn't worry about your intake temperature being 150 degrees, unless you are in Death valley. I would remove the temperature gauge - you don't need it, sell it on e-bay and use the money for a cold or ram air intake.

Just my 20 cents

 

Woops...my bad, it's not Air Temp, I meant to say Oil Temp gauge...drrr.

 

what kind of gauge?

How did you mount it?

 

Its the stock gauge set...Turbo boost, oil temp, volts gauge dealer add on option...it came in the car when I bought it. It was working fine until today. I've had the car since June. But I did just put the catback on 2 days ago. I had the oil changed as well.

Looks like these...

http://www.subaruwrxparts.com/photos...perfgauges.jpg

 

hmm... my guess is that its a electronic problem, a cat-back shouldn't cause a rise or decrease in oil temperature. My guess is that the throttle correlation has more to do with a loose wire.

I would take it back to the dealer. A air filter and cat back shouldn't give you any warranty problems. If it is a oil temp problem they will fix it and if its the gauge problem, they will fix it.

 

Thats what I was thinking too, electrical prob.

Sorry for the confusion in the post. Nice way to introduce myself on my first post to the board...hi everyone, I'm retarded LOL.

Thanks for the help though!

 

fixed the title of the thread for ya

yeah I had a similar prob with MY EGT gauge that turned out to be a bad ground, so your probably on the right track!

 

No Worries Quick,

We have all asked some questions which in hindsight were a little off the mark. Fact is, you have a killer foundation of a car to build from. Do your research before each step to find the product that is truly worth the money - the board can help you do that. Also think about what your mod will do to the overall system.

For instance, next you may think of adding a down-pipe to eliminate your cat. Great mod but I had some downstream effects that I didn't anticipate which (to fix the problems) made me have to spend more dough that I wasn't quite ready to spend.

Welcome to i-club

 

Gotcha, that was actually my next step along with tuning. Thanks for the help.