I'm upgrading the exhaust this winter to open up the airways for future upgrades and maybe even gain some power on the 1.8.
I'm not upgrading the rear muffler as I believe it is superior in doing exactly that, muffling the sound. I have other plans of dealing with the back pressure and flow of this part of the exhaust.
What I want:
- Non catted 4-1 header with generous OD and equal length primaries with OEM 2.5 connector
- Higflow catted 2.5 midpipe with resonator that fits stock muffler.
- Compatible with future 2.5l swap (both for power and fitment)
- Drone friendly
There are quite a few options out there and all of them fixes the shortcomings of the OEM restricted header. Here are some of the brands I considered
- Tomei Expreme : Very light and looks to be good quality. Comes bundeled with a non resonated mid pipe. New and small user base as far as I know.
- Racing Beat : Known good quality parts. Nice flange and good OD primaries. This is what FM uses and sells. No catted midpipe but can be mixed with other brands.
- IL Motorsport : Looks very raceland'ish (china) but are cheap and seems to have decent OD. The midpipe they sells need to be hacked to fit stock CAT.
- GW Roadstersport : Good quality and large user base. Right size OD, 1st O2 sensor moved to midpipe. Midpipe has the largest resonator of the pack.
- PPE longtube : Probably best performance, needs its own midpipe which looks to have modest sound dampening. Racy.
- Enthuza 3" catted midpipe : Best flowing but probably most noisy midpipe. Well suited for FI
I believe the GW Roadstersport header + midpipe will fit my needs best. I was tempted to try the 3" Enthuza midpipe since I have a C38-61 needing a home but I'm afraid the sound would be over the top when there is no turbo to muffle the sound. That combo is also known to be less likely to throw a CEL.
OEM header for comparison. Notice the strangeled collector before the pre-cat:
As for the rear muffler my plan is to use a cutout. I found a brand, Sound Performance, that is properly engineered without the stupid restrictive flanges or electric activation that takes 5 second to open.
There is enough space in front of the rear muffler to create a y-pipe. My plan is to fit a small resonator there as well and let the pipe blend into the left rear exhaust tip if possible.
Here is an example where they just dumps it out under the car:
Stock muffler for transport, no backpressure when WOT.
I will make a cable operated override one the actuator to be able to open non boosted.