K8 Ideal exhaust size

[Daninski]

Remember bigger means richer. Your engine will run richer with a larger exhaust, not an issue till you hit 2.5". E Test could be effected. Just go 2.25 and your gold.

[Nd4SpdSe]

All good advice on pipe size. Don't forget the resonator. You can just use a second straight thru muffler (same thing). Your ears will thank you later. Personally on a KLDE w/ headers and 2.25" pipe I used magnaflow 4" round x 20" straight thru muffler in place of a resonator. I've got essentially an OEM muffler on the end. Yeah it's old man style, but that's what I am. This setup isn't quiet, but at least my ears don't ring after driving the car.

You don't need a resonator, I never had one and never had any problems, but I largely suspect it's because of the dual-tip mufflers, cause I never had problems with my 4" single tip and anyone with a dual-tip that plugged one tip (say with a tennis ball) greatly reduced the resonance/noise in the cabin. But most want the dual-tip for the OEM look or don't want the single tip for the not-ricer look.

[mikeinaus]

All good advice on pipe size. Don't forget the resonator. You can just use a second straight thru muffler (same thing). Your ears will thank you later. Personally on a KLDE w/ headers and 2.25" pipe I used magnaflow 4" round x 20" straight thru muffler in place of a resonator. I've got essentially an OEM muffler on the end. Yeah it's old man style, but that's what I am. This setup isn't quiet, but at least my ears don't ring after driving the car.

You don't need a resonator, I never had one and never had any problems, but I largely suspect it's because of the dual-tip mufflers, cause I never had problems with my 4" single tip and anyone with a dual-tip that plugged one tip (say with a tennis ball) greatly reduced the resonance/noise in the cabin. But most want the dual-tip for the OEM look or don't want the single tip for the not-ricer look.

wouldnt the tennis ball melt from the heat? i wouldnt mind giving this a try but i dont want to get melted tennis ball in my muffler...

[93GSDude]

Another option is getting a greddy sp1/sp2 and modding that to fit the k8. Especially if youre going to swap in a KL soon. I have a SP2 on my probe with a vibrant hi-flow cat and that car just sounds damn sexy! Im in the process of getting a pacesetter or another sp1 and modding it to fit my 3

[Nd4SpdSe]

wouldnt the tennis ball melt from the heat? i wouldnt mind giving this a try but i dont want to get melted tennis ball in my muffler...

They do eventually, so you just put in another one, lol.

[mikeinaus]

but when it melts would it not get all over your muffler tips and possibly inside the muffler? making a horrible burning rubber smell every time you drive your car

[projectzemx3]

1" all the way

[93GSDude]

^^^ what he said ...but honestly 2.5 isnt bad, If you plan on swapping to DE/ZE, I have 2.5 on my probe and it moves out nicely!

[RX8SE3P]

2.5 is huge. I'd say 2.25 is smart because an upgrade to 2.5L engine will suit it also.

When I got my 2.25' exhaust on the K8 I did not see any gain in performance lol.