I know this topic has been killed already but please bare with me.

I bought a used 2003 MCS with some upgrades. The car has been well taken care of and is in excellent condition. I cant seem to get over 24mpg out of it though. I have good driving habits and dont rev over 3500RPM. I have tested out a full tank with highway driving only and still only managed 24mpg while averaging about 75mph. Is this following list of upgrades actually having a negative effect on my mpg?

Installed: Dinan stage 3 engine software, Dinan cold air intake, Magnaflow exhaust, 15% pulley, and 18 inch rims and tires

Any input or advice would be much appreciated.

its probably the mods. im sure if u go to a dealer or shop they will just check for faults. make sure your air filter is clean. maybe try to sell u an injector cleaning and sens u on your way

I know this topic has been killed already but please bare with me.

I bought a used 2003 MCS with some upgrades. The car has been well taken care of and is in excellent condition. I cant seem to get over 24mpg out of it though. I have good driving habits and dont rev over 3500RPM. I have tested out a full tank with highway driving only and still only managed 24mpg while averaging about 75mph. Is this following list of upgrades actually having a negative effect on my mpg?

Installed: Dinan stage 3 engine software, Dinan cold air intake, Magnaflow exhaust, 15% pulley, and 18 inch rims and tires

Any input or advice would be much appreciated.

Where do I start? Off the top of my head, your wheels are oversized and heavy. The engine is punched up with upgrades, its 9 years old so parts like your oxygen sensors, spark plugs etc. may well be worn and affecting your mileage and you drive highways at 75 mph and you may have an automatic. If you want high gas mileage, try driving the highway at 50mph in 6th gear.

Thanks for the replies. I just got in checked out about 1000 miles ago. Everything was cleaned, including replaced oil filter and cleaning of the cold air intake. From what I was told, the spark plugs were recently replaced and they are high performance plugs. Its a 6 speed manual. I have actually read about oversized rims and tires but is the drop in mpg that drastic with larger tires? And also that drastic from 50mph - 70mph?

I guess I'll just have to try it out myself and see

Im not being funny but with all the mods you have I consider that 24 mpg is not that bad at 75mph (isnt the speed limit in the USA 55mph ???).

The MCS is not the most economical car before any mods, what sort of return do you think you should be getting ???

What sort of mpg should a MCS be getting?

I have a 2005 MCS with the JCW kit + some extras on it + 18' rims and wheels

I regularly get 30mpg (uk not us)

the effect of rimsize is negligable.

What octane are you running the car on? It runs best on higher octane.

I would get the car dyno'd and get the ecu checked for error codes. Also it might be worth getting the ecu reset so that the car learns your style of driving rather than the previous owners.

2003 MCS JCW here also running on 18" wheels. I'm getting 27mpg so far but I've only done about 400 miles since I bought it, almost all stop/start urban short runs. The only real run out I've given it to date was out of Glasgow, up loch lomondside via B roads and back down A82, about 95 miles round trip mixed between pushing hard on B's and cruising around 65mph on A82. I reset the computer before starting and I averaged 36mpg on that run).

I've only fed it bog standard unleaed so far, but am about to refill with premium just to see if the diffeence is noticeable.

Also it might be worth getting the ecu reset so that the car learns your style of driving rather than the previous owners.

I was thinking of doing this too, but I wasn't sure if a reset may wipe the JCW engine mapping back to stock MCS - I guess not, but I was too scared to risk it until I know for sure! Any ideas?

24 US mpg is 29 UK mpg.

24 US mpg is 29 UK mpg.

Thats good then, no problem as far as I can see.

awesome, thanks for the all advice guys...

the reason I panicked on my mpg was because i was reading people getting well over 30mpg (US) and I thought something was wrong with my engine. When i took a road trip I was still averaging the same mileage as I was in stop n go and city driving.
Also I was under the impression that cold air intake and a good exhaust would actually help me get better MPG.

the reason I panicked on my mpg was because i was reading people getting well over 30mpg (US) and I thought something was wrong with my engine. When i took a road trip I was still averaging the same mileage as I was in stop n go and city driving.

You should be getting better mileage on the highway than you do in stop and go driving. The following US driver reported quite a disparity ...

I have a May 2002 build MCS with the 210 bhp Works Kit and have gotten as low as 17 MPG in all city (averaging about 15 MPH) driving and as high as 34 MPG in all highway (averaging about 65 MPH) driving.

Multiply my figures by 1.2 to convert to UK MPG.
What kind of mileage do you have on your car?

Have you checked to see if your car is "throwing" any codes?

My car is a 2003 model with 80,000 miles on it. I took a road trip from San Francisco to Los Angeles on interstate 5, averaging about 75-80mph and only got 24mpg going both ways. I was quite shocked, I expected about 30mpg.

No I have no checked to see if my is "throwing" codes. Not exactly sure what that is. Can you explain please?

Hey!

First off i do not have a MCS just a wee Mini one :-( but! i do know what its like to think your getting poor MPG! can drive you insane!

What i did when we had some time off was to fill the tank and note the milage, we then went on some days out, 95% motorway driving, we got just under 400 miles twice with a full tank and this was refuelling the second the light came on so we didn't run the tank low! , So that was 2 full tanks and both times just under 400 miles when light comes on.

BUT

My partner uses the car most , she works only 1 mile from our home and goes to college 2 nights per week at about 14 miles round trip , then obviously the car gets used for the likes of shopping etc. When the car is used like this from the same full tank from the same and only petrol station we use we get 230 miles until the light comes on. I think you will agree that is a massive difference! But then again, take the car on a journey and get just under 400 miles to the same tank, so there is nothing wrong with the car, just a nightmare on MPG city driving.

Just my 2 cents worth and remember i am not driving the MCS just a wee mini one! lol

You guys must have a heavier foot than me,

In my MCS i average between 27 & 30mpg round town stop, start driving, I recently had a 70 mile trip on the motorway and averaged 47 at a steady 70 in 6th gear, I was delighted.:D

My car is a 2003 model with 80,000 miles on it. I took a road trip from San Francisco to Los Angeles on interstate 5, averaging about 75-80mph and only got 24mpg going both ways. I was quite shocked, I expected about 30mpg.
Above 70 mph, I would not expect to get 30 mpg.

No I have no checked to see if my is "throwing" codes. Not exactly sure what that is. Can you explain please?
If there is a problem (like a vacuum leak) a code will be recorded in the ECU. These codes can be retrieved with a reader like a Scangauge and used to diagnose the problem.

Is that MPG in US? I don't have a heavy foot at all. I hardly raise my rpms over 3000. Cruising at 70mph in 6th gear still gives me in the neighborhood of 25mpg :-(

Is that MPG in US?
Yes ... see my previous post for mpg reported by one US driver ...

http://www.mini2.com/forum/maintenance-mini-care/192108-why-am-i-getting-such-low-mpg.html#post3825897

How do I know whether my car will be displaying in UK mpg or US mpg as I'm in Russia where the standard measure is km/l? I assume it will be UK as I think the car was built there, but is there any way to check? Averaging about 20mpg city driving (MCS R56).

Averaging about 20mpg city driving (MCS R56).

That sounds really low, isnt the R56 turbo charged which means it should be more economical than the R53.

Don't know. I'm using unleaded 98 and sport mode, automatic/tiptronic and as i'm still in the break-in period (up to 2,000km) i'm not revving above 4,000rpm.