My Mpg's plummeted...help?
 

So I installed my stack racing 62mm throttle body and spacer, along with an updated tune from Bama. At best it provided decent power gains, but my average mpg plummeted. I have a 2010 GT/5-speed manual and my average mpg at 70mph was 28.7, now it's 21.1. Is this average, or should I look further into the matter?

Is that based on 1 tank of gas or multiple data points? I wouldn't freak yet until you have at least 3-5 tanks under your belt. And, of course, be sure that you're hitting the reset at each fill-up.

Also, aftermarket TB's do little to nothing for power gains on a non-FI S197 engine and tend to be trouble from the get-go. On another note, why in someone's deranged mind would you not only buy but install a TB spacer?:icon_really:

what's a stacks racing throttle body? Hopefully it's a gt500 tb with adapter plate. A larger throttle body isn't going to kill your mpg

If you are really getting 28mpg, then you need more gear or more power or both.

28 mph.....huh.........I'm lucky to see 15 mpg.

X2 on the TB and spacer mod.....does nothing.

I have a larger TB and commute daily and see about 23 MPG. Would be higher, around 25-26 but traffic sucks.

Call Bama and see if the tune is proper. After that, throw away the TB spacer. It's pointless.

The mods you've done shouldn't negatively affect your gas mileage. If anything with more air getting into the motor you should be seeing better gas mileage!

A really common occurrence is how the car is driven after modifications are added. Is there a chance that you've been a little harder on the throttle then when you got 28MPG? Either way we can definitely look into this for you. Shoot me a PM with your order number included and I'll have our head tuning specialist contact you directly. He'll be able to trouble shoot any issues you may have!

I hope this helps! Our Bama Performance tuning specialists are here in the building Monday-Friday from 9AM-5:30PM EST and Saturday 9AM-5:30PM EST. You can also hit them up directly at 888.226.9764 and they'll get you squared away!

-Dan

I don't know about the mods/tune.

But I know in my 07 I average around 18 mpg, I drive the car 1300 miles and only average 25.5 for an all highway trip.