MPG's

hi guys,

im in slowly bringing my 1.1L mk1 back on the road! was wondering what others get to the gallon? i expected 30-40 or am i dreaming?  I will be running it on 15's

I get about 25-28 and myns a formal-e. Its running pretty well aswell!
Dave

When my son first got his 1.3 Driver, we struggled to get it to do 30mpg.

After many months of tinkering and many £ of spending, we got it up to mid-30s.

A Weber carb helped a lot, as did Lumenition electronic ignition

Something's not quite right with the above figures (or the carb is just an inefficient one, or they're being thrashed) because I can get 38mpg out of my 2.0 16V if driven sensibly, and by no means slow driving etc.

paul_c said

Something's not quite right with the above figures (or the carb is just an inefficient one, or they're being thrashed) because I can get 38mpg out of my 2.0 16V if driven sensibly, and by no means slow driving etc.

That's carbs for you - I can also get high 30s out of my 450bhp 2-litre turbo Fiat (although not while producing 450bhp, admittedly)

At the end of the day, it only takes around 30 - 35bhp to keep a car at 70mph and if the engine is well-mapped, the fuel consumption will be very good indeed.

Face it, a carb'd car will never be fuel efficient

NigelO said

When my son first got his 1.3 Driver, we struggled to get it to do 30mpg.

After many months of tinkering and many £ of spending, we got it up to mid-30s.

A Weber carb helped a lot, as did Lumenition electronic ignition

This is only a half-truth.

If I drive the car on my normal commute (350 miles/week) at a normal speed (70mph on dual carriage way.. officer  :twisted: ) then the car will return 29-32 mpg.

It's only if I slow the car to 56mph behind trucks can i then return up to 35 mpg.

The car is too poorly designed to return high mpg, far too un-aerodynamic.

Wheels may make an adverse effect on the car, as they have the effect of 'gearing-up' your engine, which means that you may end up ploughing more throttle for any given acceleration. As has already been said, a 1.1 carb'ed engine will never be fuel efficient, it simply isn't built for it.

I get 38 MPG from my 2.0 8v GTI. And thats working it out from how many miles & volume of fuel, not using MFA.

NigelO said

When my son first got his 1.3 Driver, we struggled to get it to do 30mpg.

After many months of tinkering and many £ of spending, we got it up to mid-30s.

A Weber carb helped a lot, as did Lumenition electronic ignition

Same here, i'm getting mid 30's once you account for smaller wheel size, the only major change that i would make might to invest in a 5 speed gearbox, might help on the ratio's.

well i get about 65mpg out off my tdi when driving like a fart on a sunday but normaly get above 50mpg, 2ltr cars i haved i would still get 37mpg no matter how hard or slow i drove, on longer runs u see a inprovement

but as above said it takes little power to keep a car rolling when its moving, all about how u drive even on a badly set up carb, u should still be ok to a point, again the use off car makes a different are you get these poor results becuase u stop start sit in traffic

The issue here is about the size of engine relative to the size of the car. Often, a larger engine will actually return better economy, as it is having to work less hard for the same result. (particularly when accelerating, maintaining speed on a gradient etc)

There's often a moan about this from the polo guys, who expect great economy from 1L 6ns or 3 cylinder 1.2 9ns. Others with 16V 1.4s in their 6ns get significantly better economy. (the older cars were more closely matched due to the lighter weight)

As for setting a carb up, the setting is more of a compromise than it is with fuel injection - there's little or no monitoring of the engine with a carb, whereas a fuel injected car (assuming electronic management) is constantly receiving data and adjusting the mixture to suit.  The usual approach when tuning a carb is to tune for performance rather than economy- it's certainly easier, as the figures/feeling are instant (whether setting up on a rolling road, or working by feel. … "It goes better now" is a lot quicker to notice than "Give it a try, then come back in 100 miles of mixed driving and we'll see how your economy is")

Just my thoughts.