open pipe vs glasspacks = mpg

ive got a stock 350 with center dump manifolds with dual exhaust thats 2in pipe leading into 26in gl*** packs and dumps out of the packs but my question is how much millage will i lose if i cut the gl*** packs off and leave it open???

 

I've read that the most significant decrease in mpg of an open system occurs in newer ECU-controlled cars as the computer makes adjustments for the lowering of back pressure. In non-computer cars, its supposed to be about the loss of torque due to lower back pressure and the resulting increase in the weight of your accelerator foot, as you come down harder to get the car moving as you're used or need to. It follows that city/stop and go driving takes the big hit without a muffler. Again, what I've read, not what I know. And the figures I've seen are in the neighborhood of 1-2 mpg and around 5 horsepower, but of course that has to be subject to a gadzillion variables.

 

I'm not trying to be smart here but why don't you just try it and find out? If it doesn't help, then put the gl***packs back on.

 

That would depend on how far you drove before the "SOUND POLICE" got you.

Just being a smart ***.

Your mileage for around town driving wouldn't change very much at all. You would notice a small decrease on longer highway type cruises.

 

nuthin to excting about an uncapped stock 350 leave the gl*** packs on

 

Do baffles split the difference then? I have 14" homemade baffles on my 283.

 

I guess I dont understand why anyone would run a stock 350 open piped, it sounds horrible, if you are looking to make it louder just put onsome smaller gl***packs, find a couple 12 inchers and put them on, or (a bit dangerous) you could burn yours out

 

Every street driven ngine needs some degree of back pressure in order to run well. I don't know where I either read or heard that;...I've subscribed to that theory for years. you need a little back pressure to keep an engine functioning in balance.



....still shootin' for that elusive 800th post!

 

i second that, you need a some back pressure for the motor to behave on the street. on the strip it really doesn't matter. but on my race cars i would play with the length of the tubing on the end of my headers to increase the ET.

 

Depends on how long the pipe is.

I experienced a significant loss in torque and mileage
on my 283 when the y-pipe broke.

The longer the pipe,the less difference it will make.