19 replies to this topic

[AlexM]

The stoichiometric ratio is the ideal combination of air/fuel in an engine. All carburation systems try and achieve this ratio but fuel injection does it the best being electronically variable based on air density, load etc, all these factors, which various sensors moniter.

Its usually 14.7:1

This meaning 14.7 parts of air to 1 part fuel.

Resistance of an engine is similar for most cars wheras the weights of cars varies hugely. A land rover discovery weights 2.7 tonnes wheras our beloved mini weighs about 750kg.

[sheepo]

gotcha!! sounded a bit complicated but wasn't really. Sprocket was probably just trying to confuse me!!

[MinipixMatthew]

Our first Mini was a 998 City, completely standard engine. When she was running at her best we were getting about 55 mpg out of her, which was fairly respectable. I've now got a 1275 spi Sidewalk, so I've got a lot more power under the bonnet, but at the expense of the economy. I reckon I'm only getting about 30-35 mpg at the mo. I've not done much to the engine yet, put an RC-40 cat back exhaust on but that's about it. I know I need to replace the air filter element, hoping to put a K&N in, hopefully that will give me slightly better economy and performance!

From what I can tell, economy is a lot to do with how and where you drive too. As has been said, modifications you do for better economy are basically what you do to get better performance, so it's largely up to the driver to make sure you don't thrash it all the time! Also, driving round town and in traffic can hamper your mpg, as can driving fast on motorways - I find that I get much better mpg at 60 than at 70.

Greasing the car sounds like an original idea! Maybe if we take a few of the wheels off we'd reduce our rolling resistance too...

Edited by MinipixMatthew, 20 August 2006 - 07:28 PM.

[Jammy]

Make sure your mini is always on the back of a recovery lorry. It will get awesome MPG then!

[sheepo]

haven't had many probs with that recently!! Got a tow behind my mate's van the other day and got some outstanding MPG returns!!

I was slipstreaming him too, about 1 metre behind, bloody scary. And he dented my front valance when the tow rope straightened out (was looped round the subframe). OOoooppps...