How much horsepower would a new intake and exhaust add to my 2011 subaru legacy?


Asked by Jan 27, 2013 at 12:48 AM about the 2011 Subaru Legacy 2.5i Limited

Question type: Car Customization

14 Answers


10-20 hp.

3 of 3 people found this helpful.

Cool thanks are there any other ways I can improve performance w/o spending a lot of money?

2 of 2 people found this helpful. they sell all sorts of performance parts. But I do not recommend the supercharger kit, and a 2011? Wait until your warranty, the drivetrain factory warranty runs out or it will be voided

2 of 2 people found this helpful.

I can't afford to do anything to it yet just getting advice for what I should do in the future thanks though

Right on. Good luck and the reason I suggest not buying a supercharger kit even if you could afford it, your engine life will be reduced greatly. It taxes everything up to and past the limits of what the engine can tolerate

1 of 1 people found this helpful.

I no thanks ill probabli just put new exhaust and intake and Maby put a turbo on it


Best things to do are cold air intake and a more free flowing exhaust system. Turbocharging it can be done by simply transplanting an engine from a turbo Impreza (preferably a WRX STi model), but it's not cheap. Don't try to simply put a turbo on your engine as the ECU and fuel system aren't designed for the extra air forced into the engine. You can try and set up your own fuel maps by getting a standalone fuel and ignition controller but that requires access to a dynamometer for proper tuning. All in all I'd stick to minor modifications unless you really know what you're doing and have access to the required equipment and facilities. By the way, if you do serious power upgrades you also need to do serious suspension and brake upgrades or it will handle and stop like a school bus...

5 of 5 people found this helpful.

You won't get 10-20 HP from an intake and exhaust. Not on this car. The intake already flows pretty well, and also already draws in cold air. Not only that, an aftermarket intake can throw off fueling tables on Subarus. This can adversely affect fuel mileage, among other things. Again, the factory exhaust flows more than enough for an otherwise stock car.

5 of 5 people found this helpful.

The intake on Subaru's are already free flowing, hell with my Turbo 2.5GT and a Cobb Tune with the Cobb Cold Air Intake I doubt its more than 3hp. Your 2.5i will likely see 1hp 2 if you're lucky from an intake. Exhaust might free up another 5hp. Aftermarket intakes can mess up the reading the Mass Air Flow sensor understands and therefor can negatively effect power and mileage on Subaru's do your homework on which intakes are safe. If I remember correctly SPT and Cobb are your safe choices with a stock ECU tune. If you really want power and easy mods the answer you don't want to hear is: trade your car in for a Turbo Subaru. You can add 35hp with a tune on an otherwise stock Legacy GT and exhaust with a matching tune will give you another 25-30hp....(all with the stock intake again showing how free they flow already). On a 2.5i the only noticeable difference with an intake and an exhaust will be sound.

7 of 7 people found this helpful.

Get a rear sway bar to kill the under-steer Legacys are known for and a kartboy shifter, and if you really want to treat yourself the bushing kit too....then thank me for the bestest advice haha. Good luck :-)

3 of 3 people found this helpful.

It's actually been dyno proven that intakes don't show any real power gains.

1 of 1 people found this helpful.

my subaru had problem with my engine throlttle?the RPM meter when i press the brake pedal my rpm go down then released go up n normal.wat the problem?


Why do you think you need more horsepower and what will that do for you? You're not going to Indy? Bad call, the person who mentioned your warranty is correct.


Honestly the best power up grade I have ever done is the GrimmSpeed SCREAMING PHOENIX TRIPLE SEQUENTIAL UP- PIPE. I'm running this with stock tune and its incredible!!!! My buddies and I are guessing i make about 500whp now in my 09 LEG GT. Do a google search you won't be sorry...

1 of 1 people found this helpful.

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