with all the mods we are all doing, you'd think the only gas related thing that would truly matter to us enthusiasts (DD or not) would be that our fuel level was accurate. maybe that's just me tho since i can use a calculator to find true MPG wenever i actually care :iono:

I daily drive my BRZ and there is no reason the addition of a turbo kit, injectors, and fuel pump should result in a large loss in MPG, so I do calculate it sometimes. If your tuner has scaled the injectors properly and your idle and cruise AFRs are where they should be, then you should be getting close to the MPG you got prior to your turbo kit. You definitely won't pick up MPGs though.

I installed the FBM with the gtx28 and had it running for the last 3 days and filled up twice already with E85. getting about 11. mpg only due to excessive force on the peddle. Enjoying the power for a little and expect not to get good mileage for the next few weeks. running 8psi. cant wait for 15psi

Anyone running 7-8 psi on a turbo (I think that'd be around 320-350 hp? Sorry, been looking deeply into the SC, not so much the turbo) and still seeing pretty decent mpg on 91 pump? (Sorry, I need to read up more on the turbo threads)


Welcome to the... DANGER ZONE (Sent from tapatalk mobile.)

Interestingly enough, the 2010 BMW X5 (recently sold, thank God!!) only calculated MPG when the vehicle was moving. I only noticed a few weeks before getting rid of it because we were looking at GL350 Bluetecs and the mileage was listed close to 25 MPG highway and that's great for a 7 passenger SUV. My wife said "the X5 is WAY BETTER!! It gets 31 MPG!!" I hopped in and looked at the average MPG and she was right..or so it would seem. The car didn't average in idling apparently and must've been off big time because EPA rates it at 14/19. I could let it run forever and it never dropped at all.

My BRZ does take this into account, as it should. Its the E85/93 octane averages that get me. I average 28-30 on 93 and average a solid 17.5 on E85. I know I'm spraying roughly 30% more fuel on E85 and I'm guessing the added power makes my foot a little heavy too. My range on a tank is decreased by 40%!! I'm anxious to see how low I can get it to go with E85 on FI.

It would be interesting for sure! I'm not a good candidate to go E85 because I don't daily drive the car. Maybe in some distant future I'll do flex fuel kit. It's tempting for sure.

I'm running 9lbs on pump gas (92-93) and got 31.8 mpg. Can't complain here

You know its not hard to see actual mpg. just fill, drive, fill and calculate.
I doubt the bmw did that good on a complete tank. You could look at Fuelly and see what most those cars average. Anyway, using 30% more e85 should not be an issue if the cost is discounted that much per gallon. So, look at cost paying for 93, and cost for e85 in your area. What is the real ... cost per mile with each? I have not seen e85 discounted 30% to 93 mostly about 20%. So, seems your paying 10% more for the power boost ? seems like that should be reasonable for a power upgrade, what is your hp boost realistic number?

I believe this is incorrect.

A turbo doesn't increase the efficiency of the motor.. it simply adds more air so that you can add more fuel to make more power with each combustion. This adds power per liter, but doesn't make it use less fuel.

In fact, a turbo system is a slight drain on fuel milage. The exhaust gasses travel through the compressor wheel which slows them down a bit. .(with the exception being at full boost when the wastegate opens). That little bit of drag will make it slightly less efficient. Plus, the added weight of the turbo kit has a slight negative affect of overall gas milage.



To my knowledge I think Hyundai has been using some electronically controled wastegates that actually remain open during startup and low-throttle situations to help reduce the load impact of the compressor wheel on the exhaust.

http://www.edmunds.com/hyundai/sonat...oad-test2.html
"ne bit of turbo trickery deployed in the 2011 Hyundai Sonata 2.0T is a fully electronic wastegate actuator (conventional pneumatic actuators are so last week). It allows a greater degree of control over boost than traditional actuators, but Hyundai has also found other benefits. For instance, the electronics can open the turbocharger's wastegate during cold starts to enable rapid light-off of the catalytic converter. In turn, this functionality allows the catalyst itself to be positioned under the floor, far away from the turbo, where it induces less exhaust backpressure than would a close-coupled catalyst. And backpressure is the enemy of power and response, especially when you're trying to make a lot of power on low-octane fuel. The e-gate (we just made up the term) also permits some trick tuning during part-throttle conditions. By opening the drive-by-wire throttle and manipulating boost, part-load pumping losses are reduced, improving fuel economy."