1.75" SU too big for a 998 with extractors and electronic ignition? Any advice?

Yep. You won't get the air speed through the carby. 1.5" should be more than enough for any 998

_________________
Cheap, Fast, Reliable. Choose two.

Assuming you haven't done much to the head and don't have too wild a cam I'd say yes it'd be too big . I've seen a single and even twin 1 3/4's on race 998's but these had ports and valves you could nearly drive a truck through , stick with a single 1 1/2 on a good manifold and match port the manifold/extractors to the head for a bit more kick .

_________________

Thanks guys, good advice. Stops me from making a silly purchase.

_________________
I'm guaranteed to break something every time, but there's nothing like getting under the bonnet and having a go!

Graham Russell spoke at a NSW Mini club function some time back. He spoke of a 998 with a 295 head, RE13 cam, extractors and a HIF44 on a GR manifold. He said that at peak revs the bell was wide open and sucking every bit of air and fuel it could get.

You just have to try it and see.

Thanks Mike but i'd be dreaming for that kind of setup.

_________________
I'm guaranteed to break something every time, but there's nothing like getting under the bonnet and having a go!

I still dont think its a silly purchase - the hif44 that is.
The beauty and the simplicity of the design is that it only sucks the air and the fuel it needs. Its not like a webber or something with a pump that tips buckets of fuel into the engine every time the carby is depressed.

The HIF with the right needle and the right manifold is a modern version of a tried and true carby.

Minis are under apsirated - that is they dont breath properly. Given a better air and fuel flow and a better burnt gas extraction system then even the humble 998 goes a LOT better. The amount of fuel (properly jetted and needled that is) is only related to the amount of throttle used.

For example my 308 holden ute is very economical unless i open the throttle. Because it just idles along not gasping for fuel or air. A similar car with a smaller carby needs more throttle opening to do the same job and hence it uses more fuel.

I know cams, big valve heads and the like seem a million miles away - but you will get their with judicial purchases and given time.

The HIF carby is worth it

hi ive been running a 1.75 on my 998 for over 2 years with no probs once it was set up

its only recently had the head ported and a decent cam put in and only then did i have any dramas with the carb, as in gettting it re set to the improved flow

Peter.

_________________
A almost Bog Stock 1977 LS
1969 morris mini panel van, a work in progress