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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 02-27-2012, 03:55 PM   #141
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why not instead of using a throttle link to the cut out, use a boost actuated cut out, spring set to 3\4 psi.
That way you can go under marginal boost and not make it go loud until you hot step it.
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Old 02-27-2012, 04:59 PM   #142
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Quote:
Originally Posted by RyanRaduechel View Post
... AEM units a couldn't find anything for electric cut out control,
The AEM has a bunch of gen purpose outputs which can be configured to switch based on TPS, MAP, RPM, IAT, ... etc.
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Old 02-27-2012, 05:00 PM   #143
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Has anyone here actually measured backpressure and can show a better result than my 5 psi at 280 whp?
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Old 02-27-2012, 05:46 PM   #144
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Quote:
Originally Posted by JasonC SBB View Post
The AEM has a bunch of gen purpose outputs which can be configured to switch based on TPS, MAP, RPM, IAT, ... etc.
Cool, then I must have read someone doing it on a forum at one point or another.
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Old 02-27-2012, 06:37 PM   #145
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Quote:
Originally Posted by Braineack View Post
But those aren't dumping to VTA. or did you change your mind on that?
Decision is pretty much in the air at this point.
I'd LIKE to avoid making a whole effin 3" exhaust if I can (for obvious financial reasons), but if not then it will be that + a valve or spring flap to keep noise down.
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Old 02-28-2012, 01:39 PM   #146
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I wouldnt think it would be to hard to make something like the motorcycles use. You just need a really long cable. Some sort of cable and pulley system and you'd be set. And to be honest, I think it would be pretty badass. Plus you could always design adjusters in it, so that you if you wanted it to open at 1/2 throttle instead of 3/4 or whatever the percentage may be, all you have to do it loosen a few jam nuts and your good to go. I say go for it. If my car was here I would be more inclined to come up with something. Its at the paint shop...
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Old 02-29-2012, 02:13 AM   #147
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Quote:
Originally Posted by JasonC SBB View Post
Has anyone here actually measured backpressure and can show a better result than my 5 psi at 280 whp?
Jason, you are the only person I have seen on the interwebs baus enough to actually have measured this stuff on a miata.

edit: not saying someone hasn't, but I have not seen it.
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Old 02-29-2012, 02:41 AM   #148
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Originally Posted by Savington View Post
I use the same big-*** Magnaflow that y8s and Braineack use, there is no discernible power difference between that and my 3" straight-pipe, and it is extremely quiet (84dB) even at WOT.
Do you ever use your straight pipe now that you've noticed no difference with the bigass muffler? I'm considering the bigass muffler as my ears still hurt with a smaller straight-thru and ear plugs.
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Old 02-29-2012, 02:44 AM   #149
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Why not use a spring loaded flapper for your bypass set to like 2-3 psi?

Last edited by JasonC SBB; 02-29-2012 at 03:23 AM.
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Old 02-29-2012, 02:49 PM   #150
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Wanted to keep my exhaust setup muffled but still flowing good.

Went 4" turboback with most importantly, wastegate routed back in way further downstream to cut down on noise. 4" in/out aeroturbine muffler.

Still loud, but reasonable. Can't stand excessively loud exhausts, especially wastegates dumping to atmosphere.
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Old 02-29-2012, 02:56 PM   #151
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Ever dyno GT42R? How were the results? Also how much boost? thanks
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Old 02-29-2012, 03:01 PM   #152
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Haven't dyno'd the new setup. Old setup (was very different) made 520whp @ 26psi. That was a 3" turbo back exhaust that ended with a turn-down below the drivers floor, and an externally dumped wastegate as well.

Looking to make similar numbers (~600whp) with more response and less boost with the new setup this year.
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Old 03-01-2012, 04:46 PM   #153
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It looks like I wont need the fancy flapper as it is quite enough for me as is.
http://www.youtube.com/watch?list=UU...&v=JfoCtrC7ICQ


Quote:
Originally Posted by sturovo View Post
I was thinking of doing something like this to deaden the sound at lower rpms. Probably a 4 inch flapper in the 4.5 inch section after the back box. The flapper would be opened with a vacuum / boost actuator.

Would it be any good?
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Old 05-27-2012, 11:53 PM   #154
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Well I have something like this on my subaru right now. Actually even more restrictive. Basically the "quiet" part, without the "cutout" part, yet retaining most of its power.

5" downpipe very gradually tapering to 4" at the end, then to 3" midway and to 2.5" at the axleback.

The axleback is stock/OEM (extremely restrictive), yet the car only gave up about 20hp up top and like 300rpm worth of spool.

I'm guessing that the enormous exhaust piping past turbo pre-axleback gives it enough room to expand/contract or cool or whatever, cause I was seriously expecting much more of a power loss than there is.

Still VERY fast ( mid to upper 300's ) but pretty much silent.
All you hear is the 20g. Sounds like a semi-truck.

LOVING IT
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