DIY Exhaust Mod – Gain of 10+ HP!!!

[TimAustinW]

Are you running OEM Headers and Midpipes with all cats intact? Just curious.

I just got a new OEM S muffler on Ebay so I may try this with my current muffler to see how it sounds with my performance headers and secondary bypass pipes. Might get too loud.

[MN 986]

I did the crios mod on my 02 2.7 about 2 weeks ago, and am loving the additional sound at idle, and cruising at 2500 to 3000 RPM. That is where I notice it the most, but I am sure it adds a little sound all the way to redline (de-snorkled intake noise drowns it out).
I'd love to drill another hole in each side but with the welded on tip, 1 hole/side was hard enough. Maybe I can find a bigger bit and make them larger.

Thanks for the idea, crios!

[GT_YellowJacket]

First off, a bump for this awesome mod!

And in almost every exhaust/intake mod discussion, I hear at least one person say "I wish I could hear them side-by-side!" Well, today I got my chance! A fellow identical 2003 Boxster S owner brought hers to my office and we parked them side by side for a little comparison.

I've got mine drilled with one hole per side with only a 3/8" bit and little bit of extra filing to ovalize the hole. Hers is completely stock. Definite improvement in low RPM sound in mine. Even with the relatively small drilled holes, it has a much lower, aggressive growl. Improved sound continues until the de-snorkeled intake sound takes over on mine.

I didn't realize how much of an improvement this minor mod actually made until I could hear them side-by-side! It doesn't take a lot of drilling to make an impact either. Well worth the 10 minutes!

And for grins, a picture of our test lab...
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