View Full Version : De-cat and Downpipe questions

12th October 2000, 15:30
Afternoon all!

After being told on iwoc that my MY94 WRX Wagon won't be on the emissions database, thus meaning that it don't need a cat at all. which is nice. I think I've got the original downpipe on the car though, so it's got at least one cat.

Anyway, I've got to thinking that one should really think about decatting the whole thing. I would therefore assume that all I need would be a nice shiny new downpipe (and equal length manifold might be nice as well http://bbs.22b.com/ubb/wink.gif) Would I be correct about this? I'm sure that the channel tunnel extension that is pretending to be my center section has no cat it in, and I'm doubting the Hiper back box has one. Is this correct. (this is one of the reasons for my post about peeps at brands giving the beasty a quick once over)

Anyway, what downpipe would be best, seeing as the center section seems to be 3 inch wide, I think! also what benefits/pitfalls can one expect, apart from having to declare this to the insurance company?

thanks for any help

13th October 2000, 09:01
Hiper centre has no cat... the bump you see is a resonator.

Only downfall with a downpipe is noise me thinks.

Have heard the Scoobysport pipe is a better downpipe than HKS because it provides a bit more back pressure for those off boost moments.

Anyone know how much noisier (can it get noisier?) the HKS Hiper system is with a Scoobysport D/P?


13th October 2000, 09:48
The "hump" on the front end of the Hiper centre section is ther primarily to ensure flexibility of the joint to the downpipe and not to resonate.

I would say SS downpipe is the one to go for and it works wonderfully with the Hiper mid and back section.

HKS downpipe generates different levels of noise in different applications. Compared to the ScoobySport one it is (to my old ears at least) not much louder, but other reasons for perhaps not having it are more important.


23rd October 2000, 21:01

Falkland do a good stainless front decat.
Fits pretty good on an Apex mid / rear section. May have to move the mounting bracket though. Hey no doubt some1 will correct me but I thought the HKS was mild steel ? Noise does go up a bit but who cares ? The only thing u need do is find a place to put the exhaust temp sensor (normally in front cat pipe). Some of my m8s keep these on and just roll them up. I had no probs jus removing it from the connector block.