Seriously, driving VERY conservatively in D not S mode around town - gas mileage went from 15.6 pre Whipple to 11.2 post Whipple. Totally babying the car. I'm only getting 180 miles out of a tank - 2016 GTCS

Could the tune be wrong or MAS be wrong?

 

My roush blower running their 670hp tune averages 17 and that includes typical city driving, normal highway driving, and a lot of backroad gettin' on it driving.

 

My ProCharger also did not have any serious impact on mileage.

 

Your guys results sound normal. I'm only getting 11.8 city and 20 freeway going 75 for extended time.

 

When I KB'd my '03 2v, I lost almost exactly 1 mile to the gallon. If you are truly staying out of it, your drop surprises me.
The only thing I can think of is with blown engines, the AFR's will be around 12-13 or lower, and stock, the AFR's are around 14+...a lean FI engine will not last, so they richen it up for safety.

 

Interesting. Thank you for the reply!

 

I'd think a good tune would not go rich until under boost. No need to be rich with negative manifold pressures.

 

It does take power to spin the blower. Try driving hard and or at least normal and see what the mpg does then.

 

Any suggestion to drive hard is all I need! 😁. Will do. And will report back.

 

What tune did you get for the car? Is it Whipple's tune, or a custom tune?

 

Whipple tune

 

If I were you, I would contact Whipple immediately. They are great to work with. They will work with you to get it right.

 

Just called them. Will call me tomorrow with answer.....

 

Sounds about right, my mileage took a good hit when I installed my 2.9 with a 3.00 pulley and mods for 700 RWHP.

 

Any update?

 

^^THIS!

 

I have a buddy with the 2.9 on his 2015, Performance Package, and Whipple's tune. He's averaging about 11mpg also. It seems it's their tune. Did you pay extra for the Whipple warranty? If not, I'd have it dyno tuned by someone else.

 

Wow that's crazy mpg average compared to other blown systems.

 

Whipple said that the supercharger is always running and therefore sucks more gas in stop/go traffic. So 11.5 is what to expect... Drove 530 miles round trip to Vegas this weekend. I got 20.1 mpg going 80-85 with a couple full throttle passing of slower cars

Therefore, I just ordered whipple's Crusher 132mm throttle body. Will be installed with new tune next weekend.. Then new dyno run and pics 👍🏻

 

Awesome. That is going to be killer.
Stay with Whipple's tune. I hear that is the best for the system, with Lund being a close second. Good luck and keep us posted Allen!