Increasing MS3 fuel efficiency.

[rosskoss]

I drive my car pretty gently most of the time. I get as much pleasure from the handling performance as I do from the power. So I don't push it much.

Since it's my DD, it's in my interests to boost fuel efficiency as much possible. In theory, wouldn't it be possible in very light boost to minimize pumping losses and actually get the MS3 to be a very efficient 2.3L M3? Basically, use the turbo just to minimize pumping losses and get even better gas mileage than the regular 3?

This is a hard thing to do but with enough restraint and practice, you should be able to have a very fuel efficient car when you want (DD) and a nice hot hatch (for the weekends)

So anyone attempt this? Also, what's the best boost gauge in everyone's opinion for the 3? Can a scangauge give boost readouts?

 

[Super Unique]

the ideal driving mode for highest fuel efficiency I have encountered was several hundred miles of 55mph with cruise control on, windows up, ac on, flat ground @ sea level, temps in the mid 80s. Yield? 30mpg. thats about as good as it's going to get without reducing drag, less grippy and harder tires, and neutering the turbo....

 

[08ms3bm]

Cruise control adds a good 2-3 MPG. Going into boost at all is downright stupid for gas mileage. Turbo cars throw extra fuel in the cylinder just to cool down the chamber, which means less mpg for you. Just drive the car like a prius and you might get high 20's

 

[enviedsvt]

having the A/C on while driving highway speeds increases gas mileage?!

 

[jville]

having the A/C on while driving highway speeds increases gas mileage?!

yea it does cause there isnt the drag of the windows being open. Granny shift, i mean stay completely out of the boost 6th gear asap is ur goal. I basically idle everywhere lol.

 

[happy and angry]

yea it does cause there isnt the drag of the windows being open. Granny shift, i mean stay completely out of the boost 6th gear asap is ur goal. I basically idle everywhere lol.

Every study or test of this I've ever seen (Mythbusters, Consumer Reports) has put the extra load of the A/C unit being about the same as the extra drag on the vehicle from the windows being rolled down.

Also, can someone confirm this for me? Under normal or light acceleration, boost shouldn't be kicking in. You have to get onto the throttle pretty hard to get enough exhaust pressure to get the turbo spooled up, even from 3k to 5k. IE: Throw the car into 6th on the highway, slap cruise on at 60mph, and us the steering controls to speed up, and you shouldn't be hitting boost under that sort of acceleration, right? I'd check myself but, no DH or boost gauge.

 

[Super Unique]

65 on up your definitely into boost, since the throttle reaction is so immediate, and forceful.

 

[ericm]

I just used a tank of gas driving to a bike race. 80 mph up, 70-80 back, all on freeways, some passing, not much cruise control, AC on the way back. Even 4-5 miles of stop and go. 28 mpg calcuated, 29.5 on the trip computer. I'm real happy with this car!

 

[happy and angry]

65 on up your definitely into boost, since the throttle reaction is so immediate, and forceful.

That sort of surprises me. Under any acceleration, even extremely light, like cruise control uses? Also, cruising at 65, are you at partial vac or neutral pressure?

Anyway, shift under 3500 then and you can stay out of boost even under moderate acceleration.

 

[Young Roids]

I think mod wise getting lighter wheels and maybe downsizing your tires to 205s would help the mileage.

 

[Super Unique]

I don't have a boost gauge, but I can definitely feel the boost if you get into the throttle. I have never driven a 4 cylinder with the @ speed throttle response of these cars. But this could also be tip-in trickery with the ecu at work. Just because your not into 12 or more lbs of boost, doesn't mean your not giving it the beans

 

[happy and angry]

I don't have a boost gauge, but I can definitely feel the boost if you get into the throttle. I have never driven a 4 cylinder with the @ speed throttle response of these cars. But this could also be tip-in trickery with the ecu at work. Just because your not into 12 or more lbs of boost, doesn't mean your not giving it the beans

Aww man, I'm gonna have to get a DH.

And I know you can get partial boost, but I expect small throttle inputs to not produce enough exhaust gas to spool the turbo much at all. I can tell the difference between 50% throttle and WOT, for example, but at 5 - 10% throttle it's hard for me to tell if it's kicking in or not.

 

[SwampAss]

@ 65mph with CC on my car seldom gets over 0 psi. It usually hovers at about 10 Vac.

 

[Super Unique]

@ 65mph with CC on my car seldom gets over 0 psi. It usually hovers at about 10 Vac.

What reading do you get when your on cruise @ 70, and use the button on the steering wheel to bump it up to 80?

I am thinking you will be quite surprised at the results of this test

 

[evo2ms3]

AccessPort + Economy map.

 

[SwampAss]

What reading do you get when your on cruise @ 70, and use the button on the steering wheel to bump it up to 80?

I am thinking you will be quite surprised at the results of this test

Oh, I go the Ron Popeil rotisserie route.

 

[PeterC]

I thought an SRI or CAI greatly improves fuel economy, does it not?

 

[SwampAss]

define greatly. 1mpg or so.

 

[FrequentFlyer]

That's definitely not my idea of "greatly". However, gas is getting so expensive, that 1mpg can turn into quite a bit of $$$ over the course of a year. If you fill up once a week, 1mpg equals 12 miles more per 12 gallons, multiplied by 52 you get 624 miles, divided by an average 25mpg and that's 24.96 gallons saved at $4.10 a gallon for 93 and that's $102.34. Hey, a hundred bucks is a hundred bucks! I can find better ways to spend a hundred bucks than to watch it evaporate out the tailpipe. That's a lot of Starbucks. Of course if I was real concerned about gas mileage, I would have gotten a Fit or Prius.

 

[Super Unique]

Gas mileage on our car is a mixed bag. It's really all a matter of perspective. For instance, I came from a vehicle that got 13mpg on a GOOD day, many times it was as low as 11. So for me, the speed3 gets awesome gas mileage.

For someone coming from an small displacement compact car without a turbo, then our speed3 is an absolute pig.