Our Community is 940,000 Strong. Join Us.


exhaust/gas mileage 94 gmc


slredstorm62
03-24-2008, 01:29 PM
on my 94 sierra with 5.7 litre TBI i have dual exhaust(dynomal ultraflow welded muffler, y-pipe, tails with no tips) it doesnt sound that loud and i have a flange gasket lead(passenger side) i can hear the leak over the exhaust all the time:shakehead . is it possible that i makes the truck sound like crap?

i also was wondering how i could get better gas mileage(running middle or high grade gas help?) i have a cheap advance auto aftermarket air filter. any other suggestions for good mileage? i also was wondering if the bosch platinum 4 plugs would be good for my truck

Z15
03-24-2008, 05:13 PM
You are not going to be able to increase mileage by any significant amount with a 4x4 truck. You are moving 2-1/2 ton of metal and thats where all the fuel goes.

Some things that don't help, wide oversize tires, they are heavier, cause more resistance and alter your speeometer. Go with a Load Range C tire which can handle high air pressure over the stock 35 psi, wide is bad, go narrow, more aerodynamic. Don't carry any more that you need to carry to reduce rolling weight.

I would stay with AC Delco or NKG iridium plugs, keep the stock air filter, all the claims about mileage increases with K&N like filters are mostly BS. Been there and done that, nothing gained.

On some of these trucks, dual exhaust can often be a negative because the way the ECM is programmed. The back pressure is reduced and the ECM compensates for that in a bad way. Also, with duals you often will drive in a manner just to hear the noise and that will likely loose you mileage.

slredstorm62
03-25-2008, 07:47 PM
i barely ever drive it to hear the exhaust. i have stock tires for it

Add your comment to this topic!