5 replies to this topic

[rod998]

I've just fitted Twin SU 1 1/4 carbs to my 1982 998 HLE.
They were fully set up and tuned by a mini specialist garage.

I've been running it for the last week and have calculated im getting roughly 29MPG, (120miles for £20 petrol)
Is this about average for Twin Carbs on a 998? Im used to running a single HIF 33 & getting nearly 40+ MPG!

Thinking about re-fitting the single for IMM Germany to keep fuel costs down!

[bmcecosse]

You've just discovered why the single carb is best! The only problem with the single carb on the 998 engine - is the horrible cast iron inlet manifold. Fit it on a good alloy inlet (so it doesn't get heat from the exhaust) - and it will go every bit as well as the twins (maybe even better!) - and give decent mpg. But - so saying - the twins you have should give better mpg than that - but maybe you are driving it harder. What colour are the plugs ? And - was it set set up by McDonalds ? I'm sure if you take it back - they will check it for you.

[rod998]

I haven't been driving the ass off it, but not like Miss Daisy either! Just expected a bit better MPG than that.
I use Miniworks as i know Simon & know he is spot on.
It is a cast iron inlet on the single, will have to find an alloy one for re-fitting!
Think thats the best idea as twins will cost a fortune covering 2000 mile round trip to Germany!

[bmcecosse]

Take it back to Simon (top lad!) - he will sort it out i'm sure.

[rod998]

Thanks mate

[Dan]

There is no reason the twin carbs should be dramatically more thirsty than a single. It's still the same engine, in fact if anything it should be capable of greater economy than before. You mention the trip to Germany as an example, we go to the 'Ring with the forum most years. The trip is about 550 miles from home to the 'Ring for us. We use about a tank and a half to two tanks of fuel to do that if memory serves, and we drive in a 998 with twin carbs and with a dirty great roof box fitted too. 40 to 50 mpg should still be no problem for your car.