alright, I put my car away for the winter over uhhh thanksgiving break... and I got it back out and now when its warmed up good and I foot it, it makes a sound like a turbo... only if its in gear and only above 3500 rpm. its a nice pressurized air hiss/sound coming from the engine. and no, my family wasnt so nice as to put a turbo in for me while the car was in the garage. I havent noticed any loss of power or hesitation, and I've been driving it like this for a few thousand miles now... I've checked the engine over quite thoroughly, but since its something that only happens when its moving and above certain rpm, I cant really find it with the hood open. should I really worry about it if its not causing trouble? I mean, it does sound cool and all, makes me think there is a turbo in there. any help or ideas on this mystery sound will be greatly appreciated

JR

 

oh, and its a 91, KA24DE, if anyone was wondering. manual transmission, 119000 miles.

 

could it be the belts ?? maybe some how there was rust in your exhaust system and ate a hole big enough for there to be a whistle??? it happend to me.. cuz the pressure finaly broke thrugh a weld *long story* and now after 3500 - 4550 i have a "turbo" sound... more like a supercharger but anyways...

 

that was what I thought too (exhaust) but when I had my new muffler put on, I had the piping checked. its stainless steel from the headers back, and its all clean... and the belts are old, but that'd be more of a squeal I believe, and this is a hissing kind of noise.

I just put over 600 some more highway miles on the car, all at 85+mph and its still fine, so I guess I'll just ignore it for now... I'm rebuilding the engine this summer so I'll check it more then.

 

you have an electronically controalled egr valve that doesn't open untill you get going (at least that's how it worked when i tested mine, but my car doesn't pass emissions...), so if you had a leak in the vacume hose you wouldn't hear it untill you revved it up. That's my first guess.

 

mine whistled and a few people thought it was turbo also, on my old 91 auto. Turned out to be a bad weld at the cat. I reccomend checking the exhaust again.

 

it only does it when its in gear and there is a load on the engine... weird, I know, but thats how it is. free revving it there is no noise