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Discussion Starter #1
I recently bought my MR2. Its a 91 with a rebuilt 92T motor in it. Mods include a Greddy 2.75" exhaust and APEXi intake. When I shift or let off the gas in boost I hear a strange sound. The best way I can describe it is a "whomp". Its a very deep bassy sound, very strange. My friend who has a turbo S14 couldnt figure out WTF it is either (Im new to turbos). I will try to get a recordning of the sound, but for now I can tell you that it mostly happens when I let off the gas more slowly rather then quickly lifting my foot off of it, regardless if I shift or not. The ammount of boost I lift at, and how slowly I lift throttle seems to effect how loud the sound is as well. Anyone want to throw anything out here?

-joe
 

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Discussion Starter #3
lol, like air passing through something. when I say it sounds like a "whomp" thats the "noise" it makes... that is to say this is what it sounds like... sort of like if I were describing the sound a BOV makes as "PSHHHHHHHHHHHHHHHHHT".
 

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Discussion Starter #7
well this isnt any "normal" turbo sound. Ive been in supras WRXs RX7s and a few SR20DET 240s (and a KA turbo 240), none of which made said noise. So unless the MR2 has something going on that said cars dont, Im assuming there is something amiss. I suppose I will have to get my friend to sit inside and video tape for me in order to get a clearer picture of the sound (so to speak).
 

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Discussion Starter #8
crackaonrice said:

hmmm, well that fellow said that his "fwoop" noise happens under load when boost is building. Mine happens as I let off the gas between shifts or just when I let off the gas at all while in boost. Of course the more boost, the louder the sound. It almost sounds like someone ripped a low toned fart on a leather seat or something.

I wish that guy would have made a video so I could say for sure though.
 

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mine makes that same sound i think its just a turbo sound. it rarely does it and its only under certain circumstances. you can only hear it though, not feel.
 

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Discussion Starter #10
true, you dont "feel" anything, but mine seems to do it quite often. As I said, usually when I let off the gas more slowly rather then lifting my foot off the gas as fast as I can (e.g. like between fast shifts when racing, etc... although its done it even then too, just not as much)
 

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i hear the same exact thing. i think its just a air sound, i read that on a thread here once. its kinda a weird sound that always catches me off gaurd like if i just let of the gas a bit going up a hill or entering a turn. nothing seems to of come of it in one year so im not worried.
 

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ive been meaning to ask about this sound as well. i have the same problem with mine. It happens to me when im boosting and when it reaches a point..it makes this "oomphh" sound like when you get hit in the stomach and the air is knocked outta ya. my friends discribe it as my car farting. (shrug). Sometimes when i let off the gas, it does it too. ive noticed that when it does make the noise, the gauge is showing the needle coming off boost. weird. oh yeah, the car is completely stock.

any insights?
 

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Hey Joe, i know exactly what sound you are describing. Its the intercooler pipings. When i swapped out my HKS bov and went back to stock it started making that noise. Try removing all the intercooler piping (turbo to intercooler piping, intercooler to intake mani piping) and make sure all the pipes and rubber connectors are on straight and all the clamps are tight. This sound get rid of that "whomp" noise. Let me know how it goes Joe and feel free to contact me if you have any other questions. Thanks
 

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Discussion Starter #17
hey, thanks man. I have some spec time alloted with the specialists at Group5 motorsports here in San Diego on monday. Ill have them check that out. BTW, I want to replace all this crap (pipes, hoses, lines, clamps)... the problem is that I dont know what sizes to buy and what lengths to get! Plus I plan on upgrading the intercooler and turbo in the near future so Im not sure if this is going to change what I need (right now its pretty much all stock 92 turbo parts).

-Joe
 

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Hey Joe, check your PM i replied to your message. If you plan on getting an aftermarket intercooler kit, all the necessary pipes, hoses, clamps, etc. should be included to replace all the stock components.
 

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Is it safe to say that this problem is abnormal? Because I hear the same noise under those conditions in my '91T. I would like to know if this is abnormal and can be fixed.

- T.J.
 

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I have the exact same sound..its normal. Its the air recirculating from the bpv back into the elbow pipe to the turbo as the valve closes. The more you boost the louder the sound will be.
 
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