exhaust cut-out
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From: the woodzies
exhaust cut-out
does anyone have an exhaust cut out on a 5.4L SD. Would running with no muffler or cat be bad? i used to run no muffler but a mechanic told me it was actually bad for the truck although it seemed like i had more power and i definatly had better gas milage
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I've got a 5.4 2001 with no cat. It did improve power however I left the muffler on. I have the only pickup on my street in a neighbor hood that does not like loud stuff.. Plus I've had trucks with straight pipes before and it gets old after a while.
I don't know if all SD's are over 8600 gvw or not but depending on what state you live in you may not pass inspection with out it. In my state trucks over 8600 gvw only need saftey inspection no emitions.
I don't know if all SD's are over 8600 gvw or not but depending on what state you live in you may not pass inspection with out it. In my state trucks over 8600 gvw only need saftey inspection no emitions.
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From: Stephensville WI
There are a few ways that running without a muffler can be bad for an engine.
1: If there is no exhaust system the exhaust valves can be exposed to cold air, which will cause the valves to warp. This is why, even on airplane engines, you'll see at least a short exhaust stack.
2: Eliminating back pressure can cause an engine to run lean. Modern FI engines don't have this problem. The O2 sensor will adjust the air/fuel mixture. Old engines with carbs needed to be tuned after altering the exhaust system.
3: Eliminating back pressure can cause an engine to run rich. See #2
4: In certain situations, eliminating back pressure will cause the power band of the engine to shift up to a higher RPM range. You'll see more power at at WOT, but you may loose some power at the lower RPM range. A little back pressure isn't a bad thing. A lot is a bad thing.
1: If there is no exhaust system the exhaust valves can be exposed to cold air, which will cause the valves to warp. This is why, even on airplane engines, you'll see at least a short exhaust stack.
2: Eliminating back pressure can cause an engine to run lean. Modern FI engines don't have this problem. The O2 sensor will adjust the air/fuel mixture. Old engines with carbs needed to be tuned after altering the exhaust system.
3: Eliminating back pressure can cause an engine to run rich. See #2
4: In certain situations, eliminating back pressure will cause the power band of the engine to shift up to a higher RPM range. You'll see more power at at WOT, but you may loose some power at the lower RPM range. A little back pressure isn't a bad thing. A lot is a bad thing.
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From: the woodzies
well i am used to running with no muffler, but there are certian situations when it just cant be that loud. which is why it would be nice to have a cutout. so i can quiet it up when needed. i think after the cat is where i would put, that way the cab wont fill up with the exhaust.
