'cept if it's the "6/1970 Mini K 1152, '731 cam, '295 head, 2xHS2s, LCB,", it could have vastly different consumption to a standard 1100 or 998

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did I tell you that I won a trophy?

Per my sig, it's a 60 thou overbore (1152cc), has a 12G295 head (unmodified I think, it was installed by the PO), twin 1-1/4" SU's on a stock Cooper S manifold, Perry (I think) 3-1 extractors into a 1-3/4" stainless exhaust, a reasonably lumpy cam (270* duration I think, again installed by the PO). Oh, I also just installed a 123ignition distributor as well.

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Simon

The adventures of an owner builder in the Tallarook Ranges

Actually, I've wondered about that. The induction, head and exhaust should actually improve the efficiency, while the cam probably reduces it a bit. Certainly the electronic ignition will improve things a bit, so overall it's probably going to be on the better-than-standard side of the consumption equation.

The best I ever got out of an 1100 was brimming the tank in Albury, and running dry underneath the Seaford Road overpass on the Frankston Freeway (don't ask ) According to Google Maps, that's 361km out of 25L.. that's 6.9L/100km with a bog standard, probably poorly tuned 1098. It'll be interesting to compare that mileage with this trip..

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Simon

The adventures of an owner builder in the Tallarook Ranges

You asked about 998/997 Cooper Diffs above.

Well I dunno how hard they are to get.

With stock 145/80/R10 (I think that's stock at least), and a 3.44 diff, 100kph is at 3759rpm.

But with a Cooper, 3.765 diff (which according to my 'dodgy' information is the same as 850 and 970S), 100kph is at a higher revving 4110rpm.

In the UK, once again according to my 'dodgy' off the internet info. the Cooper had an optional 4.133 diff, 100kph with that would be a crazy 4490 rpm and 110kph at just under 5000rpm. - Obviously for racing NOT highway cruising!


The 1100 whould be able to cope with a 3.444 diff, and would give it an acceptable 100kph speed, I wouldn't try that diff with a stock 998 however.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

should be.... if you've got higher than standard compression so you can make more squish/bang for the same amount of fuel, and better breathing so you're not wasting engine effort in getting fuel in, and exhaust out, then you ought to get better economy.... as long as you're maintaining the same speed, and not flooring it at every chance you get

will be very interesting to hear what your economy figures are - lighter brakes and all ...

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did I tell you that I won a trophy?

In terms of efficiency ;

Four things and four things only decide the efficiency and the power.

1. How fully you can fill the piston and chamber with a fuel air mixture.

2. How quickly you can do that and how well you can compress that mixture.

3. How big a bang you can make of that mixture and how complete a burn it is.

4. How quickly and completely you can empty the cylinder of burnt mixture.

My personal opinion is that with an engine made more efficient by some modifications (head, carbies, extractors etc etc) the mostly you can achieve the same rotation of the engine with a lesser throttle opening but make no mistake it is gulping more fuel at that lesser throttle opening than it was in the unmodded form.

So if 100 kph previously took a throttle to be open a third of the way open the modded form only takes the throttle to be open a quarter to achieve that fictitious 100 kph.

As Simon said - if you go pumping away on the throttle pedal you are going to use more fuel than previously because the engine is now designed to gulp more fuel on each induction stroke.

Mike