slight situation

[disturbdgt]

ok so i think i have a slight problem. After installing my lt headers my gas mileage has gone down, way down. Before i installed the lts i was getting like 18 mpg with all mods listed in sig except for lts. And with everything else besides 4:10s and lts i was averaging 20-21 mpg. All this is averaged between city and highway driving mixed. ex: miles per tank divided by gallons of gas put in tank. So do i need to get a tune for the lts or what. because right now i am getting like 15-16 mpg per tank.

 

[Winters98GT]

Yep, I would get the car tuned. I'm not up to date on the sct software, but after longtubes, I would recommend a dyno tune, or at least a good shop with a wideband. Something is not right if you are loosing that much on your milage.

 

[myponyrocks]

LTs and some brands of shorties require a tune, Modular Powerhouse did mine and it was dead on through the mail

 

[bhuff30]

The O2 sensor is located much further away from the engine with long tubes. It may not be getting hot fast enough or staying hot enough to stay in closed loop. A dyno tune should give you an idea what's going on, but you may need to replace the O2 sensors.

 

[disturbdgt]

so i guess a dyno tune will be my next step then.

 

[LaserSVT]

so i guess a dyno tune will be my next step then.

Yes.

 

[Gearbanger 101]

so i guess a dyno tune will be my next step then.

I would say yes....and if you've got any other minor bolt ons planned in the near future, I would go ahead and install them before taking it to the dyno. You might as well get tuned with all of the parts in place, rather than tune it the way it is and start throwing parts into the mix again to add to the inaccuracy a second time.

 

[disturbdgt]

well as far as engine mods the only thing i may do now is just steeda udp's thats about it.

 

[disturbdgt]

well im def gonna get a tune. and i do think that my right foot is part of the problem too. but well see, cause i think i may know what it may be also. About a month ago, end of march i went and got new tires put up front. and while checking my tire pressure today i noticed that my rears are at what i normally put them at. 36psi. but my fronts were put way up at 43psi, so could this of been my problem too.

 

[Gearbanger 101]

About a month ago, end of march i went and got new tires put up front. and while checking my tire pressure today i noticed that my rears are at what i normally put them at. 36psi. but my fronts were put way up at 43psi, so could this of been my problem too.

If anything, increased tire pressure will help your fuel economy by decreaseing rolling resistance.