C63 Guy

So... yeah. Since picking up my car this past Friday, I've put around 500 miles on it and this keeps happening when I drive to work:



Averaging 61mph door to door on my commute I get this insane (relatively speaking) mileage. I've never seen better than 22.6mpg over the same route in the past. When I filled up I double checked that the computer was reading right by dividing the distance travelled/gallons added, and it actually is.

Mike at Weistec partially attributes it to the lower duty cycle of the larger injectors in the Stage II kit.

Don't get me wrong, she drinks gas like an Irish alcoholic on St. Patty's day when I'm driving hard (and I have NO problem with that), but this just blew my mind. With the improved mileage I only have to drive another 153,000 highway miles for the kit to pay for itself! How awesome is that?

More of the REAL review to follow...

Josh

M3EvoBR

Just double check if the injector rescaling was performed, this is very common, as the duty cycle is lower in bigger injectors, so it will fool the computer, ''thinking'' the gas mileage is better as it doesn't pulse as much.

AWOL

What M3EvoBR said

blackbenzz

Yup I get like 30+ mpg after I upgraded injectors loll v8 hybrid. Its not true mpg

C63 Guy

Yeah, that's what I thought at first, too. But I reset the mileage and did the math myself after putting gas in (twice). It really went up 90% of what the computer thought it did.

Josh

_AMG_

Great stuff Josh!! How I love the wonders of forced induction.

Kreuzfeuer

With savings like that, we should all buy a Weistec. It would pay for itself eventually, the way gas is at the moment

M3EvoBR

there is no miracle.... never saw anything better than 18mpg on my car.
Either he's running on 17:1 AFR (not possible in a regular injected car) or the scalling is wrong, which is obvious.

jacob502

I dont think its the larger injectors. I also noticed better gas mileage on my car after it was supercharged when driving normal.

BTW, How did you get the stage 2 injectors? I thought they are still in R&D

PTE

Within the ecu Is a Fuel Mileage / consumption Table , which most tuners do not look at. Why would they.It is calculated by by MB e-lab Based on their dyno runs . Actual test track & Road driving .,The injector flow tables , engine & drive train data & Gas tank level senders. That table doesn't know went an injector / injectors have been installed with smaller or larger flow values , that are different that the OEM injectors . There is no fuel flow device, Reed or paddle wheel in the fuel delivery system. Like what is used in some stationary engine platforms. Best Is to pull out the calculator , Keep track on a weekly chart. Cheers _PTEngineering

BAD430BENZ

c32AMG-DTM

+1 to these.

99.9% sure it's a scaling error.

Do you guys honestly think, with all the regulatory and consumer pressures to improve fuel economy, that MB/AMG would've left a ton of MPG on the table that could've been easily captured by swapping to some different injectors? And that after adding the drag of spinning a blower at part-throttle closed-loop cruising, you'd somehow improve fuel economy? (Those're rhetorical. )

Harold1898

But he used a calculator to validate his figures. Hard to argue with that.

Fung63

subscribed.

I've seen this debate happen across many boards. Would definitely like to see OPs followup review as well as possibly some more opinions from the tuning community

GeorgeSmooth

With the major shift of power to the left of the rpm band the OP is simply utilising far less rpm in his daily commute than he used to. Less rpm equal less inection cycles hence the saving in fuel economy. He said he measured the fuel physically so I do not see why there is a debate about it.

M3EvoBR

scaling. No miracle.

c32AMG-DTM

This theory could work, if the built transmission has gearing ratios different than OEM. If not, cruising at 70 mph would be the same rpm before and after (for example).

Here's an easy solution - if Weistec can chime in and definitively answer: do they alter the fuel consumption tables in the ECU tune to match their aftermarket injector specs?

If yes, it can be considered accurate and we can debate the reasons. If no, it's obviously not accurate due to the scaling being incorrect.

GeorgeSmooth

I think you misunderstood what I said or I didn't explain properly. More power equals lighter foot hence lower consumption. If you get to cruising speed easier or quicker makes a big difference too.

b16

However more power is coming from more air being forced into the engine which would require more fuel. Still doesn't add up.

Pickles

Easy way to check would be to simply fill up, take mileage, do say 100/150 miles whatever, fill up again & take the mileage, & simply calculate MPG?
Cheers, Pickles.

Keithb

It's plausible - have seen it before on other supercharged vehicles when you're not constantly mashing the gas to get the big sh@%-eating grin

My Mustang got better mileage when I put a Vortech V1 on it and so does a friend's M3. The disclaimer is that this is ONLY ture when running the car nice n easy or doing hiway cruising. As soon as the right foot gets a little heavier, the mileage swirls down the bowl