i am having several problems with my exhaust at the current time, and i have a few questions regarding the back pressure.

1: My exhaust from the cat to the muffler is just about completely rusted out, every time i fix one hole or crack, another one appears, about 40% of my exhaust system is now repair pipe, and it still has leaks from other spots. Is there enough back pressure from just the catalytic converter itself, or do i need the back pressure from the muffler as well?

2: if i do need the back pressure from the muffler, would an aftermarket high flow stillprovide enough backpressure?

 

I would replace the pipe with a new one. Any blockage in the system could build back-pressure.

I do not believe you want any back-pressure because the engine would have to work harder (less power, suffering gas mileage, etc...). On the other hand, for 2-wheelers they have "capped" tail pipe invented by SuperTrapp that is said to control torque. I would not SuperTrapp a 4-wheeler, though.


JPN

 

oh, really? i have always heard that you want a certain amount of back pressure in a non turbo car?

 

I could be wrong; see what others have to say.

EDIT: Did a bit of research, and a few sources noted that a small amount of back pressure does help combustion efficiency but many other sources did not mention much benefit.

I also went to SuperTrapp and here is their quote:

http://www.supertrapp.com/technology/index.asp

A signature feature of SuperTrapp exhaust systems is the diffuser disc technology, created and patented for the XDUSOR, the first motorcycle exhaust product sold by Moller in 1971. This technology allows the rider to adapt their bike, or ATV, to a specific riding environment. This is accomplished through a series of discs with a precisely aligned diameter that form the exhaust outlet. By adding or subtracting discs, the rider can tune the powerband and sound of their machine in just a few minutes with basic hand tools.

Removing discs decreases the exhaust opening and increases backpressure. This effectively decreases the powerband to create more low-end torque. It also decreases exhaust tone and enriches carburetion.

Adding discs increases the exhaust outlet and decreases back pressure. This widens the powerband at the top end. It also increases exhaust tone and leans out carburetion.

All SuperTrapp systems come with installation instructions that indicate the recommended number of discs for each application.

-END OF QUOTE-

Back pressure seems most suitable to increase torque at lower RPM.


JPN

 

I would replace the entire pipe. Exhaust leaks can be dangerous if too many fumes get into the cabin