anyone know anything about these. would they do harm to a truck if left open all the time and are there and hp or mpg increase with these

 

It would be loud as hell if you left it open all the time...and you'd more than likely get pulled over for a noise ordanance violation (or having too loud a vehicle...which is easy to notice)...and then cited for using off-road only equipment (ie not street legal) on the street. That's if you could still hear

As far as gains, probably somewhere around around 7-9hp. Couldn't say on mpg increase. I don't think anyone has run one open long enough to find something like that out.

 

Loose alot of your low end tq, which is your basic source of mileage. So I would assume your HP may go up, especially in the upper RPM ranges, and your mielage will go down. EFI needs certain amount of backpressure/flow resistance to work efficently.

 

i should get that, not tell my friend, and whilst mudding open em and say i hit something

 

I had the manual ones where you gotta get get under your truck and take off the 3 wing nuts and pull the plate off. Used them off road and off road only. Made the truck sound LOUD.

I cant see you going long enough to find out the increases (if any) with them on the street before getting ticketed

 

i had no cats on my '84 corvette, and i cut the exhaust off halfway under the vehicle, so there were no mufflers or obstructions at all. very, very loud. i drove like that for over 2 years and only got one ticket because of a police checkpoint crap setup in the road once.

 

My friend has a 98 ram 5.2 and he has no cat with dual mufflers after that..I think. I know he doesnt have a cat tho and it is loud.