Downpipe

Downpipe arrived for the Wagon.

 

 

 

 

 

http://i993.photobucket.com/albums/af56/cognoscentiX/IMG_20110726_114958.jpg

 

http://i993.photobucket.com/albums/af56/cognoscentiX/IMG_20110726_114904.jpg

http://i993.photobucket.com/albums/af56/cognoscentiX/IMG_20110726_114852.jpg

http://i993.photobucket.com/albums/af56/cognoscentiX/IMG_20110726_114841.jpg

Those are some blurry pics... what downpipe is that?

Its a custom fabricated pipe for JDM GT Legacies

Installed today, seems punchier and also the exhaust sounds different,raspier

so when you gettin tuned for it?

Not sure, not right now anyway.

Tuning shop said its not necessary right away unless you really want it done,plus it cost about USD$900 here to get basic tune.

Welp, here in the U.S. a tune is a must after a downpipe unless you feel like overboosting and running lean in higher boost.

wont overboost, and the vehicle's fuel system can compensate for the minor a/f ratio difference a dp causes. no damage will be done

wont overboost, and the vehicle's fuel system can compensate for the minor a/f ratio difference a dp causes. no damage will be done

 

 

let the flaming begin

I was biting my lip. I nearly bit it in half.

wont overboost, and the vehicle's fuel system can compensate for the minor a/f ratio difference a dp causes. no damage will be done

 

The Subaru specialist I spoke to who is an ex Subaru rally team mechanic said you can get overboost occasionally but the ECU will sort itself out over a week or so.

 

I'll get a tune once I can swallow the pain of blowing 1k on the car. It already goes like a cut cat.

The Subaru specialist I spoke to who is an ex Subaru rally team mechanic said you can get overboost occasionally but the ECU will sort itself out over a week or so.

 

I'll get a tune once I can swallow the pain of blowing 1k on the car. It already goes like a cut cat.

 

 

tell that to the guys with consistent over boosting problems...

 

thats why some cobb maps have LWDC and HWDC maps... to correct for over boost because the ecu can not.

Flame all you'd like, prove to me that just putting a downpipe on a vehicle will cause issues. Even catless, the only issue you will have will be a check engine light for catalyst efficiency. My car is tuned, and for long term you should get a tune, it just makes no sense for people to tell guys that they need to tune it the second they put an intake or a downpipe on their cars. And I'm not some uneducated forum mechanic, I'm a professional technician.

Do you have any sort of clue how a/f ratios work, and how subaru tunes it stock? Go put a downpipe on, drive it, and tell me what the AFR reads on boost There's a reason why nearly every open source subaru tuner says stay out of boost until you get a tune.

Yes as a matter of fact I do know how a/f ratios work, the o2 sensors will read the difference, and the short and long term fuel trims will adjust the injector pulse width accordingly. If you change major parts, like inj or turbo, then you should get it tuned soon thereafter, but the flow difference made with just a dp will not be so excessive that the stock ecu and fuel system cannot compensate. Do you know how a/f ratios work?

Just so you know, I'm not saying never get it tuned, I tuned my car, and for the long term you should def get it tuned. I'm saying that the extremely slight change in a/f is not going to damage anything. Is it the best for performance? Absolutely not. A stoichoometric mixture will always be best for performance. Im just saying you can still drive the vehicle without tuning with a downpipe without causing catastrophic failure. It won't lean the mixture out enough to burn rings or cause extreme combustion temperatures.

Yes as a matter of fact I do know how a/f ratios work, the o2 sensors will read the difference, and the short and long term fuel trims will adjust the injector pulse width accordingly. If you change major parts, like inj or turbo, then you should get it tuned soon thereafter, but the flow difference made with just a dp will not be so excessive that the stock ecu and fuel system cannot compensate. Do you know how a/f ratios work?

 

The 02 sensors don't do a thing in open loop.... My car backfired and hesitated like crazy with a downpipe and no tune...

I'm looking at getting the same DP, how is your fuel consumption looking? better? worse?

More power = less mpg.

If he hasn't tuned then isn't he getting more power using the same amount of fuel?

probably to a degree...certainly not optimal power since it's stock timing, but it is bad for the engine as it will run lean for the increased amount of airflow at higher boost levels. the stock subaru map has lean spots with detonation, so adding a better flowing dp will exacerbate these.

JDM, can you post up the dyno results for this downpipe (from the workshops website)? I thought it ran really rich and the DP made it somewhat better

He's getting road tuned