Quote:
Originally Posted by brythefly
well thanks for the help so far, i took the truck out for a drive this morning, it seems to rune fine. The noise was coming from up front towards the fan, either a bearing or a belt, but i sprayed it down and it stopped for now, ill keep an eye on it.
as far as the exhaust goes, truck is sluggish on bottom end but i can deal with it, it runs better than before im just wondering if it was a mistake to up the size of the pipe. It seems to have destroyed my gas mileage though, which sucks because it wasnt that good to begin with.
just one last question, will placing a cat back in instead of having a straight pipe help boost my mileage a little bit?? something like a flowmaster aftermarket cat or something
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I still think 2 1/2" is too big for this engine, but in the meantime put your cat back in. Cat's heat up as they cook/burn off excess unburned fuel from your engine. This will keep your exhaust products nice and hot and may help them flow better, as remember exhaust gasses are under pressure and the hotter they are, the more pressure they have, as the gases seek to expand to areas of lower pressure i.e. out your tailpipe where there is atompsheric pressure. If they lose their heat, they don't expand as well, cool down, and slow the flow of exhaust until you rev the engine more which gets more exhaust pulses moving. If the cat still doesn't help, I would consider downsizing your pipes to 2 1/4" max. In fact Thorley has their 2 1/4" Mandrel bent system with the Jardine muffler which is a good overall bet for this engine. You know I honestly think that if somoene made a 2 1/8" full mandrel bent exhaust system from exhaust manifold, to cat, from cat to muffler and from muffler out, it would be absolutely perfect for this engine. But 2 1/8" is more of an exotic size and good luck finding an exhaust shop that has the dies to bend that size. I have the Borla catback on my truck and it's 2" and lots of guys have praise for the 2 1/4" jardine system. My Borla system is aimed more at torque and the torque improvement is awesome and it revs a bit better up high. If I had another 1/8" I think that would help a bit for the overall power band.