Hi all,

I've seen a lot of stats about the fuel economy of stock mini engines, but I was wondering how much this can be improved by modification. Most of the simple modifications (i.e the stage kits, camshafts, rockers etc) say that better fuel economy can be expected, but by how much?

I'm running a standard 998 clubman, but I'll be fitting a stage 1 kit soon, and I'm curious. Anyone else made some measurements?

Back in the day David Vizard built his 50/50 Mini and drove it around the US. That's 50 mph average at 50 mpg.... don't remember if they were US or real gallons.

Basically anything that improves performance will improve economy as long as you don't use the performance.

And don't forget to add as much lightness as you can find.

Cheers, Ian

Where do I buy this 'lightness' you speak of? Does is come in solid or liquid form?

Both ,

solid is elbow grease and a drill/holesaw/scraper ,

liquid is the 6 pack you throw out the door to get rid of your freeloading mates who are sitting in your mini for a lift to the pub .

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Performance mods will increase economy to a point as they are all basically making the air move through the engine easier.
Go too far with the performance mods and you will end up with a race engine that doesn't work well at low revvs and needs more fuel.

So my tip is a good free flowing exhaust, ported head with bigger valves, manifold ported to match the head and carb choice and a mild cam, oh and a light foot

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Dean Hutton's first car was a Mini.

Or break new ground and fit a diesel, I,m sure there is a 1.3 ltr turbo diesel fwd motor that would fit, with the amount of torque it would be interesting to throw through some corners
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vizard sezzz


work the exhaust side of the motor from the combustion chamber outwards as much as you can.

But leave the inlet side stock.

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I've had plenty of weight reduction - rust is lighter than carbon fiber...

Yeah, after my stage 1 kit I was thinking a modified 12g202 head and perhaps a mild camshaft or rockers after that. But that's a while away yet - time and money and all that.

But has anyone done any fuel economy measurements on their modified minis? At the moment, I'm restricted to 80km/h on the highways (p-plater), and I'm getting about 36 mpg (tassie highways have hills, too).

I can't speak personally, but my dad drove a mini from Sydney to Adelaide back in the late 70's and was getting 800km per fill (thats twin tank clubman GT).

Regarding economy mods, I would aviod runing anything but a stock cam if MPG is the name of your game. As soon as they start getting extra over lap, mpg goes out the window.
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I would look at

-Descent set of extractors and a good muffler, (a set up that keeps the back pressure as low as possible)

-Use the standard size intake valve, maybe look at a larger ex valve

-In the ex ports, remove a substaintial amount of the valve guide bosses and smooth out the moulding bumps and ridges thru the rest of the port.

-a compression of 10:1 - 10.3:1

-If you've got twins ditch them and fit a single HS4 or better yet a HIF38

-get hold of something like a minispares intake manifold or and MG Metro manifold, and link up hoses for the heated manifold

-Good free flowing air filter
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The HLE metro (998) FACTORY ran 10.3:1 with a heated manifold and HIF38 (in the end) and managed 70-80 Mpg. The test was repeated by the AA and they got the same results.