Help... Only 10 mpg

[Redd]

I get 11-12mpg consistently, primarily city driving. 10mpg sounds normal.

[SilverSlug]

Originally Posted by akkando

sadly I won't be installing new o2 sensor today to check to see if this helps my gas milage because FCP euro sent me one correct sensor and one for a Volvo.

Somehow I’ve always been reluctant of FCP Euro... Do they sell strictly genuine products? Nothing counterfeit??

[SilverSlug]

Originally Posted by tlrid3r

Depending the mileage there is a few items to do. This is what I did @ 120k miles.
All 4 o2 sensor (bosch)
Injector refresh @ : https://injectorrepair.com/contact-us/
New plugs (ngk)

Was unable to replace coils due to national back order.

I was averaging 14mpg on the dash and it jumped to 20mpg.

Car also felt smoother.

I mostly track my car so mpg is not my concern but, as mentioned here it's a good indicator of something needing attention.
mostly noticed the improvements driving to and from track, plus city miles. So a lot of freeway miles.

Thanks. This is great info.

How much did the injector refresh cost you? Did you have to send yours in? What was the turnaround time?

Were you getting any CEL codes when you replaced the O2 sensors?

[SilverSlug]

Originally Posted by PYE46M3

Go live in San Francisco where 91 octane is $4-$5. We will see if you care about fuel consumption when you pay $300-$400 a month in gasoline!

Exactly. I think the trolls who chime in with childish comments about not caring about engine health and efficiency, don’t even have M-cars.

[akkando]

Originally Posted by SilverSlug

Somehow I’ve always been reluctant of FCP Euro... Do they sell strictly genuine products? Nothing counterfeit??

I'm not aware they sell anything counterfeit. Their customer service has been good.

[tlrid3r]

Originally Posted by SilverSlug

Thanks. This is great info.

How much did the injector refresh cost you? Did you have to send yours in? What was the turnaround time?

Were you getting any CEL codes when you replaced the O2 sensors?

The injector service came out to $181 with expedited shipping. Yes. I removed my oem ones and sent it to them and a week later was back.

No CEL before or after O2 replacement. O2 sensor are very delicate with the wire side. I did not twist any wire installing them and did not add any additional anit-seize or lube to any threads on the O2, it was installed the way bosch sent. There is already a small amount on the thread added by bosch.

[PYE46M3]

Originally Posted by SilverSlug

Exactly. I think the trolls who chime in with childish comments about not caring about engine health and efficiency, don’t even have M-cars.

Lol yes! on this forum you shouldn’t expect to get the maximum efficiency out of your car. You should just let it run poorly and guzzle a lot of gas because BMW M power bro. People act like these cars are some exotic high performance car like a veyron or something

[Davisca455]

10mpg seems low to me, but I've only owned my car for about 2 years, and I've never actually done the actual math.
My two year average has settled in around 19.6mpg.
Take it to Thunderhill and it drops to 19.2mpg.
Drive to my folks (700 miles each way mostly at 80-85mph) and it bumps up to 19.9mpg.

[SilverSlug]

Originally Posted by PYE46M3

Lol yes! on this forum you shouldn’t expect to get the maximum efficiency out of your car. You should just let it run poorly and guzzle a lot of gas because BMW M power bro. People act like these cars are some exotic high performance car like a veyron or something

Exactly. Rather shameful if you think about it.

[SilverSlug]

Originally Posted by Davisca455

10mpg seems low to me, but I've only owned my car for about 2 years, and I've never actually done the actual math.
My two year average has settled in around 19.6mpg.
Take it to Thunderhill and it drops to 19.2mpg.
Drive to my folks (700 miles each way mostly at 80-85mph) and it bumps up to 19.9mpg.

WOW! See, that’s what I’m talking about!!

Do you do mostly freeway driving though? Or city driving?

[SilverSlug]

@Davisca455 you should download Mileage Keeper from the AppStore, it’s free, and the best one I’ve found to track mpg.

Sometimes when I’m in a hurry, just take a phone of the gas pump showing how much you fueled up and paid, the price of gas, and your odometer, and input the data when you get home.

(although usually I just do it right there at the gas station though, takes 1 minute).

[Davisca455]

Originally Posted by SilverSlug

WOW! See, that’s what I’m talking about!!

Do you do mostly freeway driving though? Or city driving?

Well, my "commute" to work is 5 minutes max, but I'm in the driveway at least that long warming it up, always drive in M mode and I like to take my car when we travel, so I think my driving is a fairly even blend of city/highway?
But I'm an idiot and forgot to mention that the car has a G-Power super charger kit and an Akropovic exhaust, so not an apples to apples comparison. Sorry about that.
I was thinking "Oh so I have a blower, so that means it would even better MPGs if I didn't, so I'll chime in."
But maybe that's not correct?
The DME was sent to Germany to get tweaked, so who knows if that had a beneficial effect on mpg?
Bigger injectors and some kooky looking spark plugs as well.

[SilverSlug]

Hmmmm interesting. I would have thought that the SC would have lowered the MPG significantly.

Why did you go with G-Power and not ESS (like seemingly everyone else).

Why did the DME get tweaked? Was it part of the install??

What type of spark plugs are those? Do you replace them every 10k miles like required with the ESS SC kits?

[Davisca455]

Originally Posted by SilverSlug

Hmmmm interesting. I would have thought that the SC would have lowered the MPG significantly.

Why did you go with G-Power and not ESS (like seemingly everyone else).

Why did the DME get tweaked? Was it part of the install??

What type of spark plugs are those? Do you replace them every 10k miles like required with the ESS SC kits?

I assumed the SC would hurt mpg as well, seems like it would have to, at least at full throttle?

I bought the car from a friend, so he's the one that chose G-Power. He purchased the car new in '08 and had the blower installed soon after. The car had maybe 6000miles when the kit went on.

Sending the DME to Germany is Assy Step #1 when installing the G-Power kit. They definitely turn off some stuff, like the downstream O2 sensor check and the spark plug ion field (?) sensing.
And they must do some tuning as well, because after the kit was on for a few months, G-Power called my friend and told him they found another 20hp, so they sent him a smaller pulley and the DME needed to go back to Germany for an update.

The spark plugs are NGK R2556B-9.
I have never replaced them, and they now have 54,000 miles on them.

The car is an absolute brute, it will spin the rear tires (305/30/19) at some fairly decent mph and point you towards some things you don't want to be pointed at.
Throttle control is at a premium!

Chris

[SAMM3Y]

It's a short stroke high revving v8.. it's gonna get shit mileage, especially if you live in an area with oxygenated gasoline. Drive it like a little girl will help, less rev's less gas.

[SilverSlug]

Wow interesting... So the DME needed a re-tune when an underdrive pulley was added to the mix?

It seems that the general consensus on here that anyone with an ESS SC should be changing out their spark plugs every 10k miles.

How often do you do oil changes? What brand/weight oil do you run?

Thanks for all the info!

[Davisca455]

Yes, the DME was tuned twice, once for the initial blower install, and then again after they did some further development and sent the smaller diameter blower pulley.

I don't have any idea what spark plugs ESS uses in their kits or why they would need to be changed so often?

Before I bought it, the car only got driven about 6000 miles a year, so it was on a yearly oil change schedule at the local BMW dealership and they used the recommended Castrol.
In 2014 it got parked until I bought it in August of 2018.
I switched it to Liqui-Moly 10-60 at that time.
I do the oil changes myself at 5000 miles, more often than that if there are track days in the mix though.

Chris

[Davisca455]

Originally Posted by SilverSlug

@Davisca455 you should download Mileage Keeper from the AppStore, it's free, and the best one I've found to track mpg.

Sometimes when I'm in a hurry, just take a phone of the gas pump showing how much you fueled up and paid, the price of gas, and your odometer, and input the data when you get home.

(although usually I just do it right there at the gas station though, takes 1 minute).

The first leg of my trip home today I went 308 miles on 15.5 gallons. That's 19.87mpg. The dashboard was still on 19.9, so pretty close.
AC on, 85ish mph with plenty of spirited maneuvering thru traffic. Probably got flipped off once or twice.
Once I came down off the mountains in Oregon and dropped into California it bumped up to 20.1mpg. That's a new PR.

[SilverSlug]

Wow... that’s mind blowing. Do you suppose the second tune refined the fuel delivery to make it more efficient?

Is that typical of setups running superchargers? Or just G-Power?

[Scharbag]

These cars are pretty good at highway speeds but are absolute trash around town.

But I just do not care. 😝

[SilverSlug]

Originally Posted by Scharbag

These cars are pretty good at highway speeds but are absolute trash around town.

But I just do not care. 😝

I completely agree. However in this case we are talking about ~100% difference in MPG (9-10mpg vs 19-20mpg). There is something to it.

Does the Harrop and ESS kits also require a retune a bit after installation?

[Davisca455]

To be clear, I believe the second tune/smaller pulley was an option, not a requirement. This was an early kit and G-Power had continued development on their product in the meantime. The conversation went something like "If you want, we can give you another 20hp, but you'll have to send the DME back to Germany and install a new pulley onto the blower pump."

My fuel mileage hasn't dropped below 19.2 since I've owned it, and that was after five 25 minute sessions at Thunderhill. Then I drive my normal routine of in town and occasional freeway trips and it settles in at 19.6. The bumps to 19.9 and 20.1 are pure highway numbers.

Chris