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Forum namePerformance/Engine
Topic subjectStrange Engine Noise
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=57125
57125, Strange Engine Noise
Posted by TalonSpeed, Aug-13-03 04:17 PM
My car makes this strange engine noise between 7000rpm and 7300rpm. The noise is coming from my intake. It sounds like a machine gun shooting extremely fast. It really cant be heard in first since that gear blows by so fast. I can hear it in 2nd, and in 3rd oh god it is loud. I took off my HP racing filter and put on my old AEM filter and the sound got louder. It sounds good and I like, but what is it?
57129, RE: Strange Engine Noise
Posted by 1TuffRS, Aug-13-03 04:24 PM
Mine makes the same noise, I really dont know what it is though. I just always assumed it was simply the sound of the explosions in the combustion chamber, but I dunno. Anybody got any ideas.
57142, RE: Strange Engine Noise
Posted by Matt_95tgs, Aug-13-03 06:15 PM
it's fuel cut.
57145, RE: Strange Engine Noise
Posted by hawaiidiverx, Aug-13-03 06:27 PM
the rev limiter on the engine is set for 7K, that is probably why you are hearing that sound
57156, RE: Strange Engine Noise
Posted by TalonSpeed, Aug-13-03 07:55 PM
The revlimited aka fuel cut is documented as being at 7200rpm. But judging by my eye it is 7300 although the needle maynot be accurate at that high of rmp.

Any explain how u can hear fuel cut and hot it last at least 3 seconds long in 3rd gear.
57161, RE: Strange Engine Noise
Posted by Matt_95tgs, Aug-14-03 02:26 AM
First off, the stock tach is far from accurate, so you really can't rely that your rpms are exactly what it tells you. You hit fuel cut right around 7200 (some cars very slightly for some reason), but you do not hit ignition cut until later (around 8k i believe). What may be happening is that you are getting fuel cut and for a few seconds, you are leaning out and backfiring out of the intake... Otherwise, maybe you are floating your valves really bad at that high of rpm. How many miles do you have on your valve springs? Whatever it is, I would stray from doing it for fun because I doubt its healthy for your motor. And besides, you dont make any power at that high of rpm anyway.
57175, RE: Strange Engine Noise
Posted by 1TuffRS, Aug-14-03 07:42 AM
man, there isnt anything wrong with my car, lol. I have about 80,000 miles on my head and about 30,000 on the bottom end, but my car has always made that noise even when everything only had 30,000 miles on it. Ive also hit fuel cut before and this sound isnt that either and it cant be the valves floating because, atleast on my car, the sound starts around 4000 rpm and only intensifies as the rpms and power increase. Plus Cordells (aka Talonspeed) car and mine are factory freaks, Cordells is more of a freak than mine though, with just a cai, UDP, and muffler my car barely pulls on his on the highway (i mean just crawling away) and my car has run a best of 15.46 NA. We've noticed that hondas make the same sound once they switch over to Vtec so we arent alone in this.

Edit: I also have an A/F gauge and I know the car isnt leaning out, in fact my car runs really rich up top and at times will shoot flames out the exhaust on the 1-2 shift.
57221, RE: Strange Engine Noise
Posted by eclipse_99rs, Aug-15-03 03:18 PM
My car makes the same noise right b4 fuel cut it kind of sounds cool.