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your turbo wont overspool thats why you have a wastegate. Doesnt matter what rpms. And you dont absolutely need a tune. Wouldnt hurt but its not a must. I totally agree with ninefourteen on this. And he seems like he has some real world knowledge. And not all dp's have bellmouths. Alot of them dont.

Turbos don't work that way chief. There are physical barriers to prevent the car from damaging itself. The wastegate is on a spring and will open, and allow exhaust gasses to pass by with no issues. The turbo is NOT the issue. The issue is that the timing and AF's are going to go bonkers over more air without more fuel in the combustion chamber. This leads to detonation and can easily destroy a piston and ruin your month.

And gsr20, please for the love of god, don't tell him the only reason he should get tuned is if he does it himself. THAT is a very irresponsible statement, and will cause someone who has no idea what the hell they're doing to be dicking around with romraider and blow up their motor.




Get educated. Get Tuned. In that specific order.

^^^^^^^

Get rid of the AEM, no tune needed with your existing mods.
Get a CATTED downpipe (please, we have enough crap in the air here, and you won't notice the 3+ hp from losing the cat), then tune.
914er and 08whiterex got it straight.. There's a lot of misinformation in this thread.....

^^^^Yes there is.. just call cobb and talk to christian he will set you straight.

you can actually find catted downpipes with a 3" opening so you are fully legal and reduce emissions without losing the hp. some muffler shops can even get you a custom made one.

08whitewrx- ur right. not pushing the limits on the turbo, but on the piping and such. my bad. u run the risk of overboosting which is the jist of what i was saying, but i said it wrong lol.

^^^^Thisssssssssss.

Subaru ECU's will mix the air and fuel in different ratios and vary the timing depending on what is referred to as closed loop/open loop operation. Essentially one relys more on the sensors, and the other relys on the pre-loaded map. The thing is, the map can be tweaked, and if you are running it without a tune, it is still mixing air and fuel at those pre-loaded ratios when it should be mixing them according to your performance modifications. If you run an intake and full exhaust (I mean UP, DP, CBE, etc.), then you've got enough air moving through your system that you should probably get those ratios adjusted. That's all I'm trying to say.

You can run an OTS map that will help more if you get those mods, but at the end of the day the mod won't be that worth it unless your car gets tuned for having said mod. That way, the ECU knows EXACTLY how to respond with these new parameters and adjust accordingly.

yeah there is also that problem. i just got seriously noobified...

I wasn't saying to tune it himself. my bad for the miss communication

what i was asking though, is does exhaust modification really change your AFR's BECAUSE of the o2 sensor. when your pushing your car, i thought i would look at the fuel, and timing maps for what to do, not at the o2 sensor. the car would be in closed loop at that point

also on the notes of exhaust, can they really make your car run lean?! and if so, why?!?

^^^^turbo spools faster and causes problems.. also the o2 sensor has to be at a certain temp when it gets hot the ecu goes nuts and thinks the cats are bad and it is running bad and throws codes..

OH! THAT. JUST. HAPPENED.

I....JUST......WENT......THERE!!!!

oh!!! i get it! shouldn't the ecu know that its spooling faster / sooner though because the MAF sees the extra air comming in?

double post, my bad.