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Old 06-12-2017, 11:09 PM   #756
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Join Date: Jul 2005
Chapter/Region: South East
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Originally Posted by KillerBMotorsport View Post
I respectfully disagree. The engineering and development costs I estimate to rival what we put into our header, upwards of $100K. We spend the better parts of a few weeks going the 'throw a dart at the wall route' and it was fruitless. I think in total it was like 27 combinations of things we tried, plus a couple off-the-shelf products (Q300 & Cobb off the top of my head). In the end we went with a steel cat-back as it resolves 90% of cabin sound/drone when compared to stainless. It's cheap and starting to rust, but I can hear myself think and it had no problem making 597whp
I understand what you're saying but still don't agree it's pointless. Mine already sounded great with the 3" (ID) SRS midpipe and muffler, it would have sounded better with a longer resonator or even two. This exhaust was designed around a uel system which made it easy to defeat high tones leaving the exhaust. Even the 3" (OD) Invidia sounds good but is still a little loud. Both of these exhausts have relatively short resonators with very little volume to cancel high frequency noise. I understand how sound works, maybe not much about tuning of the engine, but there are common rules that govern sound waves.

Like already mentioned, these aftermarket Subaru exhaust systems are relatively easy for any company to pump out. Even the smaller can ones sound throaty, and this is because of the uel header. Throw that same system on an el header subie (doesn't matter which el header) and that same exhaust won't sound rumbly or deep and most likely will resonate to the higher frequencies the tiny center resonator can't defeat. It's not a complex problem, you can even see the aftermarket exhaust systems for our cars all have a smaller sized muffler, even on the Q300...and it's supposed to be "quiet"er than most aftermarkets. Sure that muffler is a tiny bit larger than the other aftermarkets, but still a good bit smaller than the oem mufflers. The oem resonator is even better designed to drop out high frequencies. Obviously having 3" diameter pipe plays a role as well in allowing more highs through, but using a puny resonator and smaller cans is the main reason they sound "raspy" on el header cars.

You can even compare the oem midpipe resonators of a 2006 normal impreza/2.5i to a 2006 wrx sti. There is an obvious size difference. Obviously they spent good money on research, but that doesn't mean a good sound couldn't be found without it. There are many resonators and universal mufflers one can buy and experiment with.

-The normal impreza/2.5i has an equal header:

--Larger midpipe resonator than the sti of same year, stops more high freq, I believe the muffler is even longer than sti

-The 06 sti has an uel header:

--Smaller midpipe resonator than the normal impreza, doesn't need as much high freq drop

The concept is relatively simple to me, and while you can say costs for development would be ridiculous, I've seen several people design and sell headers that were basically designed with primaries similar or a good bit larger than oem, then bolted on to see how they affected performance. There are a lot of important things that go into how those headers work, and yours are the most well thought out in my opinion, but you can't deny companies build them and sell on the marketing scheme alone. Get some bros excited over a new product with some dyno claims and they are ready to jump in and try, in the hopes of getting some unclaimed power.

Originally Posted by KillerBMotorsport View Post

That would put you in rotated kit category essentially. We've not gone in that direction, and having already spent development money on the kit we have, I don't see any benefit (from a performance standpoint), but more cost. Reverse rotation in that location would cause other conflicts as well with brake lines IIRC?
I understand that would make it more difficult for people who want to use the tmic design as well, just thought ordering a reverse outlet wouldn't be an issue since the GEN2 gtx turbo has to be special ordered anyway.

Another problem I realized today with having a right facing outlet, is that the turbo blade rotation would also have to be reversed. To do that, the turbine housing would also have to slope toward the passenger side instead of the driver side like your housing. That wouldn't work because it would move the centerline of the turbo to the right too far, and it would probably be facing directly into the manifold runner if not further over.
I gave up on that idea, wasn't thinking about the actual turbo shaft rotation being reversed as well.

On the subject of your spoolinator adapter, what type of gasket is that? I just noticed today you include a round fiber looking gasket in the kit. I was under the impression the vband adapter sealed by having an opposite shape vband surface on the bottom that mated to the turbine housing. How long to you project that gasket will last? What type of material is it, if you don't mind the question?

Thanks Chris
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