No Muffler?
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
What ya all are affecting is the acoustic and wave tuning of the exhaust system for lengths and diameters.
No muffler, short pipes etc., are not always the the best for performance unless you talking about 5000 + rpm then it may help to have a more open and shorter exhaust.
The large OEM muffler is there for a reason as a best factory compromise for noise and pulling power for the average owner.
What you want ideally for low rpm efficiency is a system that tunes the wave action to produce a near vacuum or lower pressure at the exhust port in the rpm range you most use.
This helps the next intake charge have less contamination with exhaust that did not get fully evacuated on the power stroke after the exhaust valve opens for blow-down.
The longer the exhaust length the more it helps low rpm wave tuning.
As the rpm gets higher the long length helps less because the timing of the return vacuum producing wave front arrives at the wrong time to be of as much help.
Actually the averge rpm band for a tuned exhaust is less than 500 rpm before the help deminishes before and after the approximate tuned point.
So far I have not saw any attempt by any vendor to maximize low down power in a truck application and supply any data to support it or we would know about it by now.
Down low in rpm you are essentially talking about maximizing torque.
This means the cylinder has to draw as much air, and fuel in the correct ratio as possible without left over exhaust contamination.
Forced induction largly does this plus packing more air and fuel into the combustion chamber before the intake valve closes.
As most know, the results of this is a great increase in torque from the much higher cylinder pressures after combustion.
No muffler, short pipes etc., are not always the the best for performance unless you talking about 5000 + rpm then it may help to have a more open and shorter exhaust.
The large OEM muffler is there for a reason as a best factory compromise for noise and pulling power for the average owner.
What you want ideally for low rpm efficiency is a system that tunes the wave action to produce a near vacuum or lower pressure at the exhust port in the rpm range you most use.
This helps the next intake charge have less contamination with exhaust that did not get fully evacuated on the power stroke after the exhaust valve opens for blow-down.
The longer the exhaust length the more it helps low rpm wave tuning.
As the rpm gets higher the long length helps less because the timing of the return vacuum producing wave front arrives at the wrong time to be of as much help.
Actually the averge rpm band for a tuned exhaust is less than 500 rpm before the help deminishes before and after the approximate tuned point.
So far I have not saw any attempt by any vendor to maximize low down power in a truck application and supply any data to support it or we would know about it by now.
Down low in rpm you are essentially talking about maximizing torque.
This means the cylinder has to draw as much air, and fuel in the correct ratio as possible without left over exhaust contamination.
Forced induction largly does this plus packing more air and fuel into the combustion chamber before the intake valve closes.
As most know, the results of this is a great increase in torque from the much higher cylinder pressures after combustion.
Senior Member
Joined: Jun 2010
Posts: 739
Likes: 0
Skimmed through all of this. I run a single exit straight on my lowered truck. Never noticed a change in mpgs, or how it drove (butt dyno cant prove this though). I have it side exited like the L's do.
Heres a video of it idling, and a few small revs. (nothing to see really)
Heres a video of it idling, and a few small revs. (nothing to see really)
