>DynoMax cat-back (2 3/4in pipe), hi-flo catalytic and new O2 sensor. All
>upgrades done within the last month or so. Everything up to the exhaust
>work gained very significant torque and throttle response and 3-5mpg
>city/highway. The gas mileage increase with the performance gains was
>just what I wanted. When the exhaust work was done I lost the mpg gains
>and then some. I went from getting 16.5 combined city/highway down to as
>low as 14.2. On strictly highway mileage I went from 20.1(best) to 15mpg
>at best now. I gained some nice breathability with the
>exhaust albeit at a high expense of economy. Has anyone else ever run
>into similar mpg problems with a combination like mine? Am wanting to
>add an MSD ignition control box and coil soon but would like to get mpg
>problems identified first. Any ideas why the exhaust work caused the
>mileage to go down?
>
Is that 2 3/4in DUAL exhuast? Which muffler in that, the Super Turbo, or the
Ultra Flo? What brand/model/size of cat? what brand of O2 sensor?
If that's dual exhuast of that size, I think you went too big... that' more
like big-block sized pipe!
and the Ultra Flo is rated way high CFM levels, so it could contribute....
but we need more info... I would lean towards the new O2 sensor is not
working right if you have 2 3/4 single exhaust/ super turbo muffler
Gary Shook
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:13:00 EDT