DIY Exhaust Mod – Gain of 10+ HP!!!

[valiantechoes]

Another happy camper! Thanks crios!!

I did the drill mod on my 2003 Boxster and ended up using a 7/8" drill bit as final hole size. I did not have a 1/2" for my heavy drill. Worked as desired with a nice low growl at low RPM"s but no noticeable droning or noise increase at cruise RPM with the top up. I did have to use a cold chisel to start the hole for the drilling and had to step up drill size to make the final hole.

Changed exhaust tips to the two round S type to go with the new sound.

Great Mod!!

[CrashTest]

I know this is an older thread, but I just picked up a 98 2.5L and immediately removed the snorkel and put two ovalized 9/16" holes in the internal muffler pipes as described here. So glad I did. The muffler modification is subtle, mainly deeper and louder right off idle. The snorkel removal is a must. 5000rpm and up is spine tingling now.

I will probably be doing the Pedro's/PSE partial muffler bypass in the near future to give a little more exhaust noise.

[nquintans]

Another Happy User!! Thanks Crios!

It just took me 5 min to make the holes in a '99 2.5 Boxster, and the change is great! I made two holes of 1/2 and the sound is great at idle, a lot better than stock! Did have a chance to try it on the road but it doesn't seem to be any ressonance.

I'm glad i did it!

[JAAY]

I did 1" holes.

[CrashTest]

Originally Posted by JAAY

I did 1" holes.

Also very interested. There is a hint of raspy or hiss with mine when cold, with smaller holes. You have to lean down by the exhaust pipe to hear it. Any nasty sounds with the 1" holes?

[chipmunk]

I took my Toyo Sports exhaust off and put the std exhaust back on - resonance took the pleasure out of driving the car. It's a tiptronic and the box generally keeps the revs in the 2000rpm range until you are over 60mph, or you keep it in manual mode. Pity really as there was a noticeable increase in performance with the sports exhaust and it sounded good, when it wasn't resonating!

I've now drilled 2 x 10mm Crios holes in the pipes (thought I would start small). Definite increase in sound when idling but nothing really at higher revs - as you would expect. Think I'll take it up to 1/2 inch (13mm) and see how that changes things. I'll also record the sound and post it in case anyone wants to see the difference - unfortunately don't have a recording of how it was originally.

[Slate 01]

Originally Posted by chipmunk

I took my Toyo Sports exhaust off and put the std exhaust back on - resonance took the pleasure out of driving the car. It's a tiptronic and the box generally keeps the revs in the 2000rpm range until you are over 60mph, or you keep it in manual mode. Pity really as there was a noticeable increase in performance with the sports exhaust and it sounded good, when it wasn't resonating!

I've now drilled 2 x 10mm Crios holes in the pipes (thought I would start small). Definite increase in sound when idling but nothing really at higher revs - as you would expect. Think I'll take it up to 1/2 inch (13mm) and see how that changes things. I'll also record the sound and post it in case anyone wants to see the difference - unfortunately don't have a recording of how it was originally.

I have a 2001 base and have been apprehensive about just drilling holes in the stock exhaust. Concerned with resonance and such. Would love to hear your impression of not only the sound but the general resonance issues or any positives and/or negatives. I am looking for a little meaner sound but really don't want to make the car an annoyance to drive at particular rpms. Yeah I guess I am wanting to have it all.