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Old 04-10-2009, 09:04 PM   #1
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Default Did AFM delete, now car sounds like it's farting.

I installed my GM IAT sensor via the stock AFM harness, and removed the AFM.

There's the tight-bend tube that connects the AFM to the turbo.. I just ditched the AFM and connected the K&N filter directly to that tightly bent tube..

It's a little far down in to the engine bay, but the bigger issue is that it makes an annoying *** fart sound when coming off boost, even if it's just a little.
my car used to be darth vader where it would have a smooth sigh when the AFM was in place.

The upside is that the throttle response is instantaneous, much snappier than with the AFM.. The car also feels a little more powerful on the butt dyno, but that really is subjective at this point
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Old 04-10-2009, 09:08 PM   #2
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info about car and turbo system?

if you don't have a bov, my initial guess would be compressor surge......but then again, we know nothing about your set-up.
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Old 04-10-2009, 09:11 PM   #3
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Hey, sorry i've been posting a lot lately about my various prooblems, forgot to list my setup.

It's a 1991 1.6L with Begi-S. I have an MS from Braineack with an AEM WBo2 and now the no-afm, and GM-IAT. Still using stock injectors & begi FPR.

Budget racer - where in NNJ are you? I'm in bergen county, also on the mob.

-Tomaj
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Old 04-10-2009, 09:18 PM   #4
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The standard BEGI-S kit does not include a bypass valve, so I'm with budget racer here. What you are hearing is compressor surge which had previously been muffled by the flapper inside the AFM. Install a bypass valve (recirculated if you really want it quiet) and all will be well again.
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Old 04-10-2009, 09:18 PM   #5
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Quote:
Originally Posted by ctxspy View Post


it makes an annoying *** fart sound when coming off boost
what does?

does it sound more like a turkey?
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Old 04-10-2009, 10:25 PM   #6
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by "it" i meant the car, more specifically the engine bay. I think it's compressor surge as well, but my only question was that it's a toneless farting sound, not the turkey gobble i've seen on various youtube videos.

I'll take the sage advice from the posters above, and get a blowoff valve. Now the question becomes which one! I've been reading and there's so many choices, and it seems that each one of them has downsides.

Like Joe guessed, i'm looking for a quiet system, but as long as it's not obnoxious, i wouldn't be completely opposed to VTA..

Is this recommended?
BEGI Miata turbo Bypass Valve - 1 3/8" BEGi
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