I seem to notice a trend that my gas mileage is not getting better but worse. With this last tank, I reset the average MPG computer and drove it nice and easy (well, ok, most of the time nice and easy, all of the time is just not possible in a mini) and have 18.9 mpg. I used to average more like 21 for easy driving around. I haven't had my first service yet. Is there something I can check or make sure to mention when I take it in for my first service?

 

Do you have a large throttle body?

 

You could...
...Check your oil.
...Make sure the Denso's are still torqued properly (19-20ftlbs)
...erm... thats all I got.

 

You could figure your gas milage the old fashion way to see if the OBC is correct.

All that rabbit said and a clean air filter.

 

Have you checked the tire pressure?

 

That sounds like a pickup line. "Hey baby, do you have a large throttle body?"

Now, to get serious, I haven't changed the TB from the stock 2006 automatic throttle body.

 

both our 06 MCS and 05 MCSa get around 19-22 based on the OBC. my wife has a bit of stop & go in the MCSa, and I beat on the MCS a little harder.... Almost 100% around town miles. Her's just did almost 30 on a trip to & from the beach (2 hours each way)

stock pullies on both (for now)

 

I just realized that I have been running air conditioning more and more recently, as it has topped 100 degrees these last few days. I have always heard that the AC can lower gas mileage, anyone know how much?

Do higher temperatures mess with the supercharger and make it less efficient, hence lower MPG? I know how for performance purposes the colder it is outside, the more performance you get...can the opposite be true that the hotter it is the less efficient the MPG?

 

That's a good point. I haven't checked my plugs at all. Any tips or suggestions for that?

I'd check the air filter as well... That was already said though, just an echo.

 

I agree with checking the air filter and that tire pressure makes a VERY big difference. I think running the a/c and running the supercharged MINIs in hot weather affects their mileage.

Although when I was motoring through Texas in April, and it was 85+F, I was getting almost 42 mpg for one of the legs! And Wanda has the K&N Typhoon CAI, Alta 15% pulley, Unichip...(this was pre-Milltek, Denzos, and HR Compound Rear Swaybar)... I average 29-32 mpg on most tanks, which includes plenty of stop-and-go driving in Los Angeles.

 

All great info thanks. I am taking it to Edgeworks next Tuesday and will have them check everything you mentioned and have them change the oil as it is about time.

 

Ooops, meant Edge Motorworks

 

If i'm averaging 18-19 mpg...I'm jumping for joy. 18-19 is on the high side of what I average..even under calm driving. AZ heat+A/C at full blast+99% city driving=crap gas mileage. I have to try really hard to get 19mpg average...I'm normally around 16.9-17.5 according to the OBC.

 

Temps will affect it not sure how much, A/C is the biggest MPG killer beyond a driver who has the tendancay to rest there foot at WOT, I think the # was upwards of 20% depend upon who report you trust.

 

All this MPG talk makes me wanna stay stock for now. I'm getting 24 and thats basically all around town driving. I dont really "beat" on my car but I do drive spirited occasionally. Are these mods causing these problems or do you guys just drive your car harder than I do?
Steve

 

My knee jerk reaction is, "It isn't the mods!" And I really don't think the mods themselves have an impact. HOWEVER, once you get the mods, you do tend to drive it harder, so yes, the mods do have an impact.

That being said, I get 25-27 highway driving and after reading everyone's posts today, I am feeling strongly that it is the temp and AC that has impacted me recently.

 

I'm up from 24 to 28 with a CAI (actually the differance was a little more extreme but I've learned to put my foot in more and don't have the option to traverse the roads I got 35.5 MPG on (Twisites on the AL GA boarder).

 

Actually, Mythbusters did an episode on exactly that last fall. AND, they claim they busted that myth. Running identical cars on a track at the same speed one with windows up and A/C on and the other with A/C and windows down.

At 50+ mph you get better MPG with the A/C (because of the aerodynamics). At 30 or lower speeds, its marginally better with A/C and windows down.

 

I agree with mythbusters, but with the windows up in both cases, you have to burn more gas with the AC on vs. AC off.

 

Not too tough... I did a little write up on my plug install... it may help.

http://www.geekshocker.com/Claire/engine/ngk.php

 

At least on my 06 MCS gas mileage has improved slightly but consistently, 3 to 5 mpg with the mods.

It took some practice to keep from WOT and chirping tires in 1st, 2nd and even 3rd, but the gas prices justify it.

I tend to also try to keep the rpms lower in town whenever I can as long as I'm not lugging.

And yes, I try to keep the AC turned off whenever I can

-- VBG

 

ethanol?

 

Mmm, I'd prefer Nitrous...

 

I have a similarly modded MCSa and I get 28-30mpg if I set the cruise. Thats it. Leave it alone for a long, long time. Such as don't flutter the throttle and let the computer do its thing. Then around town with my heavy foot I manage 20-22mpg.

But the key is keep the speed constant for a long time.

 

Hmmmm...

Maybe this is worth mentioning here, it so happens that in the My VGS install (with pics) thread in this forum today there was mention of bad fuel economy as a result of a bad Fuel Pressure Regulator.

https://www.northamericanmotoring.co...ad.php?t=59533

Toward the middle of page 1, from Lord of the Flies...

Best of good fortune here...

-- VBG