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Nonsense! Just replace it with a spare 1.6 TB or something. I'm sure our resident MacGyver could get it working!

Cutouts are stupid and pointless and provide no gains.

I saw some top end gains (maybe 4 hp) with the cut outs open (4" each) on my B5 S4 but those turbos were moving a lot more air than the average puny turbo on this site.

I kinda wish they'd catch on. I think one of the coolest builds you could have is keeping your OEM muffler, but also have a big ol' downpipe with a cutout. It'd be tough to do well enough, though the idea of keeping a completely stock sounding/looking system to avoid suspicion and attention is appealing

full 3 inch exhaust > cutout

How about a full 3" exhaust that makes little noise, to avoid suspicion, and always fully open so it spools better. cut outs are a gimmick joke rice mod.

but youre from FL so you couldn't understand rationality.

that's not difficult to engineer at all. just use a y (or two in my old car's case)

LOL you'z trippin.
My forester currently has a 5" exhaust system going into a 2.5" stock axleback very gradually (the taper is literally spread out through 5+ feet)


Makes 350/360 (verified last week) and curb stomps motherflossers while making next to no noise.

I have never enjoyed it more than I do now. And that's counting the previous setup of full 3" straight through all the way.

but with a stock downpipe and exhaust it should bring significant gains?

Well that kinda cutout is a little different.

I think it will work well and if it opens soon enough provide appreciable spool gains since it is so close to the turbine outlet.


hey hay heay 18psi do you still have stock suspension on fozzie? I put my Feal suspension on and it is frikken awesome. i am prolly making 70hp less than you but the suspension increased fun factor by 10x. AWD drift ftw!!!!

William, the problem with cutouts is you need two different computer tunes to run your car because the volumetric efficiency of the engine changes when you open the cutout.

Really? Was that necessary? How much "rationality" is even on the forums? How is that rice even?

Anyways, it was an idea. I absolutely agree that a full 3" and a nicely sized Magnaflow is the way to go, and that's what I'd do without a doubt, as with my other car. I'm just thinking of other ideas..as I said, I like the idea of keeping stock exhaust parts for street.

I personally think having a big oversized and obvious shiny exhaust tip or two is as bad or worse than having a loud car. Its a psychological thing really.
Yeah, I'd have a Y where the exhaust would continue straight into the cutout and Y also into the rest of the exhaust. The engineering fun would be keeping stockish diameter without killing too much power off. I think something like dual 2.25" exhaust would make it manageable

I saw 16rwhp going from capped to open on the stock WS6. I thought turbo engines benefit greatly from open exhaust?

*edit* Why am I arguing for the Florida group....

World, please just ignore this post.

All STi suspension including alum control arms and sway. Feels great, though probably not as cool as your coilovers.

Boost activated cutout. Meaning it only opens at say over 3psi or whatever and its always open at 3+ psi so conditions are always the same.

As far as the cutout being right after the turbo.... what are you planning on doing with the wideband then?

check out my thread about it.

I think its actually a fantastic idea.
I have yet to try it tho

Personally i think this is better in the exhaust. Remember the thread a month or two ago about the little flapper in the muffler?

Yeah, and I love that concept too, except it still requires you to get an exhaust.
The 2nd most appealing thing to me about a boost-cutout is not having to spend money, time, and effort fabricating a full exhaust

lol I R lazy

I just checked out that thread anyways and see why Brain is so much against it...you already pissed him off about it .

My idea is more of a passing thought, and I'm concerned about the long term aspects of having a big ol 3" downpipe merge into the godawful OEM setup with a Y. Honestly, just making a Y to adapt to the stock exhaust could be obnoxious enough. It should really be more gradual, about to the stock cat location, and by then, youve already replaced half the exhaust.

I have a different idea for what I'd actually do. Doing some research on it now, had the idea a while ago...dual 2.25" piping, because that's much easier to fit to a Miata than a 3". Plus I have a bunch of 2.25" exhaust bits

That definitely sounds like more work (and weight) than just doing a single 3" pipe.