maybe a stupid question but i am new to all this but after i had my magnaflow 4 inch installed my gas milege has been horrible to what is ws prior to getting exhaust,..is that right?

I'm not sure what kind of mileage gains you were expecting - from what I understand, main benefit to going to a 4" exhaust is for the lower EGT's and better looks/sound.





Is it possible your foot is to the floor more often because of the better sound?

yeah i didnt get it for any gains in that department but i didnt expect it to kill my gas mileage like that i thought i might have been alittle heavy footed at first but then i took it on a trip and with it on cruise at 70 i averaged 14 mpg. and i used to get around 19 i dont understand

When I replaced my muffler with a flowmaster my city mpg went up by about .25MPG and my highway mileage stayed pretty much the same. I did airbox mods at the same time.


Given the same driving habits the exhaust should have negligible effect on MPG.........

chasely27 do you have an LB7 or LLY?

2004 lb7 intake and exhaust

DID YOU GO TURBO BACK OR FLANGE BACK WITH THAT EXHAUST?

manifold i think like i said i dont know much about this yet i know it had a gasket and 4 bolts

That's a cat back system.

its only cat back?,..so does that mean it doesnt even really lower my egt's?,..i have the magnaflow 4 inch. but the more expensive one.