Effects of running no exhaust

93GreenLX · May 17, 2004

Oh, it'll pass emissions

Yeah I'll take a look under the car and start simple and see how I like it

MidnightThunder · May 17, 2004

93GreenLX said:
What would happen if I ran no exhaust, just a Pacesetter longtube header.

You would harm and eventually kill your engine.

Not to mention tons if tickets,possible loss of liscense,car impoundment,and maybe federal prison time.

140cilx · May 17, 2004

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.

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.

nomuffler · May 17, 2004

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?

bhuff30 · May 17, 2004

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.

Pro-Hawk · May 17, 2004

bhuff30 said:
loss of hearing
multitude of tickets
pissed off neighbors
no girlfriend or friends
burnt exhaust valves

the biggest problem is cold air traveling up the header after you stop, and harming the exhaust valve.

This about sums it up right here

nomuffler · May 17, 2004

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?

bhuff30 · May 17, 2004

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).

nomuffler · May 17, 2004

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.

slow88stang · May 17, 2004

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.

Red_LX · May 17, 2004

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.

nomuffler · May 17, 2004

unless I have been misinformed greatly (which is quite possible). [edit] I have been, it uses a certain material that measure "the partial pressure of oxygen in the mixture"
Link

I stand corrected and apologise for any misinformation I may have spread.

ib_steed · May 17, 2004

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!

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

kiddiccarus · May 17, 2004

header vs ported e6 anyone?????? This is not going to turn into one of those threads is it?

Hey listen to the men who have no muffler hence nomuffler and corvax

Bearded Forever · May 18, 2004

C-R-O-V-A-X

93GreenLX · May 21, 2004

http://www.exhaustsoundclips.com/sound/ford_mustang_2.3_1991_openexhuast.mp3 I hope it didn't sound anything like this 91 2.3 that is just labeled as open exhaust

i4power · May 21, 2004

Yup, that's exactly what it sounds like. Of course, it sounds better when you actually get on it.

Pro-Hawk · May 21, 2004

93GreenLX said:
http://www.exhaustsoundclips.com/sound/ford_mustang_2.3_1991_openexhuast.mp3 I hope it didn't sound anything like this 91 2.3 that is just labeled as open exhaust

It sounds fair from being American to me

93GreenLX · May 21, 2004

Yeah and definitely not what I want to sound like

Pro-Hawk · May 21, 2004

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 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.

Effects of running no exhaust

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