running longtubes through two cats and then two mufflers? is that too much back pressure or better to run the longtube with two cats and no mufflers or longtubes with no cats and two mufflers? This will become a future drag truck
thanks

 

I'm not sure where the backpressure idea came from, because eveyone talks about it, but its incorrect.

What you are actually referring to is, basically, air density. No exhaust system has actual back pressure to it. To small of pipes, or to much restriction, and you get to much air trying to be pushed out to small a space. This condenses the air, making it to dense to be pushed out efficiently. You open it up to much, and the air starts cooling before it gets far enough down the exhaust pipes. Colder air is denser than warm air, forcing the engine to push heavier air, losing power in the process.

To answer the spirit of your question: no, that will not be to much restriction. If you want it to be street legal, keep the cats (the muffler laws depend on your location). If you don't care about that, and possibly huge fines from the Feds, ditch the cats.

 

And too little restriction (referred to as backpressure) you lose low end torque....thats not an incorrect statment

 

it all has to do with reverbs.. if the pipes are to arge the exhaust gases expand and cool and slow down so when the split sec that the exhaust and intake valve are open at the same times it sucks the exhaust back in.. this is why the more expensive the header the better it works more time has gon into the research of it.... i have seen a guy spend well over 2 grand on a exhaust and come up with zero back preasure but the exhaust did its job on scavanging and all.

 

so what do most of you prefer for sound? duals with cats or with mufflers only?

 

2 grand on an exhaust????? WTF did he get

 

maybe its gold plated

 

unless you plan on competing in this thing, pick whatever exhaust sounds the best. The performance advantage on the street won't be enough to justify picking a gross sounding exhaust over a good sounding one. we're talking like under 10hp.

Something you CAN consider is exhaust tempurature. if you tow a lot, it might be wise to eliminate some exhaust restrictions just to reduce some under-hood temps.

 

lol, i just read that it will be a future drag truck. If that is the case than you will want to eliminate all muffs and cats and run some tuned lengths of tubing after the header collectors to optomize scavenging. The length of the tube will depend on the rpm and cubic inch you will be running.

If its just a friday night sort of drag truck, then i stick with my previous post.

 

stainless and all custom.... stepped header design into a x pipe from their