Should the exhaust suck in at all?

[horizontalkev]

Should it always suck, or blow? (that's what she said?) I placed cardboard over the exhaust and had someone rev the motor, and for a split second after letting off the gas the exhaust sucks in the cardboard, then goes back to normal.

I knew a guy a long time ago who said the 'sucking' exhaust on his mustang GT meant something was wrong with his motor, then again he was a moron and his only sucked at idle.

 

[Nuzzi]

do you have big cams? sounds like overlap to me.

 

[Pipnorcali]

What.wait, why are you doing this again? Is your car running ok ? I dont get why you where doing this checking for exhaust leaks...slaps forehead

 

[RamenPride]

I placed cardboard over the exhaust and had someone rev the motor

And you did that because???

 

[Pipnorcali]

Stick a banana in your tailpipe if it sucks it back into the motor you have something wrong...hahahah

 

[RamenPride]

Stick a banana in your tailpipe if it sucks it back into the motor you have something wrong...hahahah

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Posting this knowing that 97% of the people either aren't old enough to remember this scene and/or never heard of the movie....

 

[Pipnorcali]

Axel foley bwhahha

 

[DJ Raydiate]

Should it always suck, or blow? (that's what she said?) I placed cardboard over the exhaust and had someone rev the motor, and for a split second after letting off the gas the exhaust sucks in the cardboard, then goes back to normal.

I knew a guy a long time ago who said the 'sucking' exhaust on his mustang GT meant something was wrong with his motor, then again he was a moron and his only sucked at idle.

An "old" way to tell if something was wrong with the valvetrain in STOCK form was to stick a dollar at the tail pipe. Hold it there with the car at IDLE and if it got sucked to the pipe, valvetrain work of some sort was needed.

Another example to think about is on MUD Trucks, they don't put snorkels on the tailpipes because the exhaust should always be blowing out. They do however put the snorkel on the air intake so that way it does not suck water into the motor.

 

[Black95TSIawd]

Exhaust reversion. Normal to an extent.

 

[horizontalkev]

I did what I did because my car was spitting out black soot everywhere, and wanted to get it on the cardboard so I can get a better look. Just water, from condensation probably. And to the guy who asked if I was looking for exhaust leaks. No that's crazy I use seafoams 007 smoke screen for that :thumbup:

 

[horizontalkev]

Exhaust reversion. Normal to an extent.

"To an extent" I should be fine though right? My brothers GST doesn't do it. Then again he has stock cams, and I have 272s

 

[motomattx]

Its normal and fine.

 

[NHerron]

Not sure how good a link this is but...boat headers,marine exhaust,lightning headers,boat exhaust

Yeah, something about boats. But hey they'd know all about it since exhaust reversion severe enough can really damage a boats engine. (Reversion introduces water to engine internals)

 

[motomattx]

Its also known as scavenging effect, normal on any engine even your lawn mower.