What makes the exhaust pop and gargle?
07-09-2006, 05:21 PM
#11
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Join Date: Feb 2005
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Posts: 524
RE: What makes the exhaust pop and gargle?
ORIGINAL: eternal981
no no no, don't order one. make one. if you have tin snips, a drill, drill bits, and a few pieces of wood laying around, you can do it yourself just fine. a dremel tool could help too. i made my first out of very thin aluminum sheet metal. i could cut it with scissors, and used a hole punch (not a paper hole punch, but they might work too) to make the holes. its easy. i made 2 of them in 5 minutes, and stacked them both to compensate for how thin the sheet metal was.
and as far as the IAC causing it... i completely understand why they'd cause it. but why, after removing them and resetting the computer twice, does it still keep happening? never did that before the IAC install, and i haven't modded my car in a LONG time.
EDIT: i forgot to explain why you need wood. it'll take some playing around, if you've never done it before. but sandwich the sheet metal between two pieces of wood before you drill the hole. otherwise your drill bit will do more tearing than drilling. might even help to drill the bypass hole in two sheets, and then cut the rest of the shape around that, to make sure its perfect. it really isn't very hard to do at all...
no no no, don't order one. make one. if you have tin snips, a drill, drill bits, and a few pieces of wood laying around, you can do it yourself just fine. a dremel tool could help too. i made my first out of very thin aluminum sheet metal. i could cut it with scissors, and used a hole punch (not a paper hole punch, but they might work too) to make the holes. its easy. i made 2 of them in 5 minutes, and stacked them both to compensate for how thin the sheet metal was.
and as far as the IAC causing it... i completely understand why they'd cause it. but why, after removing them and resetting the computer twice, does it still keep happening? never did that before the IAC install, and i haven't modded my car in a LONG time.
EDIT: i forgot to explain why you need wood. it'll take some playing around, if you've never done it before. but sandwich the sheet metal between two pieces of wood before you drill the hole. otherwise your drill bit will do more tearing than drilling. might even help to drill the bypass hole in two sheets, and then cut the rest of the shape around that, to make sure its perfect. it really isn't very hard to do at all...
07-09-2006, 06:00 PM
#12
2nd Gear Member
Join Date: May 2006
Posts: 180
RE: What makes the exhaust pop and gargle?
hmmmm.. i dont recall the size. this was just aluminum flashing, you can get at home depot. if you know anybody who's done work on their house recently, you'd be surprised who has got pieces left over. if you're using scissors, it's gotta be pretty thin. i think when i measured the stuff i used, it was 0.010" thick, which is less than 1/64th. thats why i doubled it up. if you go with anything thicker, scissors probably won't work too good. trust me though, as long as you double it up and make sure your holes line up perfectly, there's nothing wrong with it. if you're real precise, make your bolt holes pretty tight (the tighter you drill them, the more perfect they need to be). again......not hard to do by hand, it just takes patience.
depending on whether your car is a stick or an auto, the bypass hole size changes. you wont hurt anything by experimenting. 9/32" worked good for me. some have gone as low as 1/4", others as high as 5/16" and maybe even a touch bigger. depends on how your throttle body is set. the only reason autos go bigger is because they'll stall when a load is initially put on the engine at idle (i.e. turning on your A/C). they either make it bigger, or compensate by giving it gas THEN turning on the A/C. i guess it all depends on where your priorities lie.
you can use a LOT of materials to make one of these out of. anything flat and smooth is fine. it doesnt have to be thin either. you could make it 3/8" thick if you wanted. the bolts used on the IAC are ridiculously long. the outside size/shape doesnt really matter, its just the 3 holes that to. the size of the bolt holes doesnt matter at all, just the size of the bypass hole. just make sure when you're done, you file off the edges so nothing sticks out. anything will work. file, sandpaper, whatever.
worst case, it doesnt work and you need to take it out. so i wouldnt worry too much. just give it a shot, and if it works, you saved yourself $15. if you have any other questions, feel free to ask. that $15 would give you half a tank of gas, so i'd be glad to help you save.
depending on whether your car is a stick or an auto, the bypass hole size changes. you wont hurt anything by experimenting. 9/32" worked good for me. some have gone as low as 1/4", others as high as 5/16" and maybe even a touch bigger. depends on how your throttle body is set. the only reason autos go bigger is because they'll stall when a load is initially put on the engine at idle (i.e. turning on your A/C). they either make it bigger, or compensate by giving it gas THEN turning on the A/C. i guess it all depends on where your priorities lie.
you can use a LOT of materials to make one of these out of. anything flat and smooth is fine. it doesnt have to be thin either. you could make it 3/8" thick if you wanted. the bolts used on the IAC are ridiculously long. the outside size/shape doesnt really matter, its just the 3 holes that to. the size of the bolt holes doesnt matter at all, just the size of the bypass hole. just make sure when you're done, you file off the edges so nothing sticks out. anything will work. file, sandpaper, whatever.
worst case, it doesnt work and you need to take it out. so i wouldnt worry too much. just give it a shot, and if it works, you saved yourself $15. if you have any other questions, feel free to ask. that $15 would give you half a tank of gas, so i'd be glad to help you save.
07-09-2006, 07:04 PM
#14
2nd Gear Member
Join Date: May 2006
Posts: 180
RE: What makes the exhaust pop and gargle?
i'd go with 9/32". on mine (5 speed also), that size hole stopped it from idling above 1100-1200. and since you're not looking to limit your idle, a touch on the big side shouldn't hurt. my problem was that the car liked to idle at over 2000 rpms, and the IAC was what i was using to stop that. if you go too small with the hole, (so small that the car can't idle at the setpoint in the computer), i think it'll throw a code.
also, a bit of advice: when you reinstall your IAC, make sure you start those bolts by hand. i.e. - if you used a ratchet to take them off, take the ratchet off and just spin the socket & extension with your fingers until you're sure the bolt is started. you're putting a steel bolt into an aluminum plenum. if you're careless, you can strip the hole (which isn't the end of the world either, but would still suck). so just dont get carried away. its pretty hard to strip a thread out as long as you're careful.
also, a bit of advice: when you reinstall your IAC, make sure you start those bolts by hand. i.e. - if you used a ratchet to take them off, take the ratchet off and just spin the socket & extension with your fingers until you're sure the bolt is started. you're putting a steel bolt into an aluminum plenum. if you're careless, you can strip the hole (which isn't the end of the world either, but would still suck). so just dont get carried away. its pretty hard to strip a thread out as long as you're careful.
07-10-2006, 02:48 PM
#16
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Join Date: May 2006
Posts: 180
RE: What makes the exhaust pop and gargle?
nooooo. MY idle was higher, until i used the plate.
the IAC is a valve. the computer tells it to open/close in order to let more or less air in, depending on what it feels that it needs. my problem was that something was telling the computer to hold it all the way open, running at 2200rpm at IDLE. insane. the restrictor plate went in as an "upper limit", so to speak. only so much air can flow through that little hole. MY idle would hang as high as 1600 afterwards, which was a 600rpm improvement. but the high idle wasn't higher because of the plate, it was higher because of my screwed up car.
i just didnt go as far with the plate as i could've.
so no your idle shouldnt ever be higher because of one of these. it should idle the same. and it will come down a LOT faster than stock.
trust me..... you'll be very happy with a restrictor plate.
the IAC is a valve. the computer tells it to open/close in order to let more or less air in, depending on what it feels that it needs. my problem was that something was telling the computer to hold it all the way open, running at 2200rpm at IDLE. insane. the restrictor plate went in as an "upper limit", so to speak. only so much air can flow through that little hole. MY idle would hang as high as 1600 afterwards, which was a 600rpm improvement. but the high idle wasn't higher because of the plate, it was higher because of my screwed up car.
i just didnt go as far with the plate as i could've.so no your idle shouldnt ever be higher because of one of these. it should idle the same. and it will come down a LOT faster than stock.
trust me..... you'll be very happy with a restrictor plate.
07-10-2006, 09:12 PM
#17
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Join Date: Jul 2005
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Posts: 351
RE: What makes the exhaust pop and gargle?
I made my restrictor into the rubber hose. I just found one size smaller that barely fit into it and stuff about a three inch piece into it. Cost about 10 cents and works great.
07-10-2006, 09:37 PM
#18
2nd Gear Member
Join Date: May 2006
Posts: 180
RE: What makes the exhaust pop and gargle?
yeah thats actually not a bad idea. i wouldn't try it on mine because of the pressure it builds when my supercharger really starts pushing air....but on a N/A engine that'd probably work awesome. and be a LOT less work.
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