Effects of running no exhaust

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MidnightThunder said:
You would harm and eventually kill your engine.

I don't think this is true. Not going to get into a pissing match about it, but I ran a Chevy 350 w/ shorty headers like that for a year many years ago, heard the same argument from a few people. Never hurt a thing.

The header is still hot, the heads are still hot, they aren't going to be sucking in this freezing cold metal warping air that will bend valves. It's about 3 feet long. By the time the air hit's the valves from the intake side or exhaust side, it's warmed up. For instance, hot engine in the winter, freezing cold air hit's the intake valve, then goes into the cylinder, compressed against the exhaust valve, somehow everything survives. :D

I drove my LX some years ago about 25 miles to get an exhaust system for the car after I installed the Pacesetter Header - WHOA! WAS THAT LOUD! TREMENDOUSLY LOUD! COULDN'T HEAR YOURSELF THINK! It's not really a bass thunder rumble you'd hope for, it's a stocatto tinny metal POWPOWPOWPOWPOW.
 
The way I've heard it, the valves burn not bend. And it's not cause the air's cold (since it isn't). I've never heard a good explanation of why, but I'm trying to figure out a way for it to happen. Perhaps when there is valve overlap the piston can draw in extra air heating up the burn. But I gues as long as you have an O2 sensor the computer will richen it up? Does the 2.3 even have any overlap?
 
nomuffler said:
The way I've heard it, the valves burn not bend. And it's not cause the air's cold (since it isn't). I've never heard a good explanation of why, but I'm trying to figure out a way for it to happen. Perhaps when there is valve overlap the piston can draw in extra air heating up the burn. But I gues as long as you have an O2 sensor the computer will richen it up? Does the 2.3 even have any overlap?
Yup, they get brunt, not bent.
The velocity of the exhaust passing past the valves is much higher with just an open header. This causes more heat transfer to the valves, and in extreme cases can burn a slot in them, which causes them not to seal any more. If you are running a low performance NA engine, I wouldn't worry to much about burning a valve. The velocties stay slow, and the EGT's low.
 
bhuff30 said:
Yup, they get brunt, not bent.
The velocity of the exhaust passing past the valves is much higher with just an open header. This causes more heat transfer to the valves, and in extreme cases can burn a slot in them, which causes them not to seal any more. If you are running a low performance NA engine, I wouldn't worry to much about burning a valve. The velocties stay slow, and the EGT's low.
But wouldn't the O2 sensor richen the mixture when it saw higher EGT?
 
nomuffler said:
But wouldn't the O2 sensor richen the mixture when it saw higher EGT?
The O2 sensor looks at the A/F ratio, and it only does that in closed loop (cruise speeds).
The problem isn't higher exhaust temps per say... it is higher exhaust velocities at the valve which causes more heat transfer to the valves. (just trust me on that, it has to do with renolds number, and I don't want to teach you heat transfer and fluid mechanics).
 
bhuff30 said:
The O2 sensor looks at the A/F ratio, and it only does that in closed loop (cruise speeds).
The problem isn't higher exhaust temps per say... it is higher exhaust velocities at the valve which causes more heat transfer to the valves. (just trust me on that, it has to do with renolds number, and I don't want to teach you heat transfer and fluid mechanics).
Yeah, I get how it burns the valves. But wouldn't that heat the outgoing exhaust to? The O2 sensor determine the A/F ratio based on the temerature of the Exhaust gas, so it seems to me it'd richen the mixture whic DUH! damnit I just realized would't do **** to stop the burning valves. But, there's another downside, baad gas mileage de to the computer richening up what it thinks is a lean mix. Maybe? The computer only runs in closed loop at cruise? I thought they only did one or the other.
 
Last year I was working on my exhaust and unhooked it at the flange right after the 2nd cat. I had to drive home like that and I hated it. Sure it was bassey but the whole car shook like crazy and Icouldnt even hear my stereo which is no cheap stereo. So without the cats I think that it would just be horribly loud. I had the 2 cats to a glasspack and a 3" tip and my parents could hear me coming about 2 1/2 miles away.
 
nomuffler said:
Yeah, I get how it burns the valves. But wouldn't that heat the outgoing exhaust to? The O2 sensor determine the A/F ratio based on the temerature of the Exhaust gas, so it seems to me it'd richen the mixture whic DUH! damnit I just realized would't do **** to stop the burning valves. But, there's another downside, baad gas mileage de to the computer richening up what it thinks is a lean mix. Maybe? The computer only runs in closed loop at cruise? I thought they only did one or the other.


The O2 sensor doesn't measure HEAT...It's called an O2 sensor because it measures the amount of carbon dioxide in the exhaust (I think. Unless it just directly measures the amount of oxygen). At any rate that is how it regulates fuel.
 
I ran my 2.3N/A motor with a longtube headman header (two piece) and 2.5 exhaust w/ cat & high flow muffler. It was a decent sound. Then my header came apart at the collector, the tubes still lined up, so it wasnt completely open, but just that was enough to make it sound like a V8, and make a rather nice sounding explosion on in-gear decel. yummy! :D

It was very loud though, and i was lucky i was not pulled over for it. I got a lot of looks from people while i was driving, that included a few cops that were going the other direction at a stoplight. It also leaked exhaust gas into the cabin, and made me lightheaded after city driving for about 30 mins.

Overall, it was a nice experience, but not what i would want all the time! too much!

-Ryan
 
93GreenLX said:
Yeah and definitely not what I want to sound like

Man if my 93' LX sounded like that I would...Umm wait it does sound like that :rlaugh: Ya I didn't mean for my to turn out like that either, I just told the guy put a cheap muffler on that had more flow than a stocker. I also left off that pre-cat deal next to the mainifold and used a high flow cat.