Twin carbs or weber?
Discussion
I'm rebuilding a fast road engine into a hillclimber and changed from a 286 to a 296 cam, along with a sccr box etc etc. I have a pair of HS4s but have been adivsed to go for a weber 45. Problem is the expense and aggro of fitting a weber. The twin su manifold aperture is only 1.25" while the ports are 1.5", has any one tried the Maniflow tubular manifold with any great sucess, is the cost justified? Has any one had sucess with twin HS4s and a 296 or is the weber really the best option?
Excellent, so many replies so quickly, thanks for all the advice. My inclination is to stick with the twin HS4s for now, particularly as i'm not after winning championships, just improving on my own times. The manifold is from avonbar which they claim has good flow, its just that the manifold port size is that much smaller than the head. I'm inclined to go fo the fabricated manifold, although if it isn't going to offer significant benefits i might as well put the £100 towards a weber in the future.
miniman said:
Hi Haynes. How did you get into hillclimbing? This is something I'd like to try one day, but I've done some research on the web and I'm still a bit baffled. Any advice appreciated!
It can be baffling, but it really is so so easy and brilliant fun. I live near Guston Down and they do school days where you take your own car and receive instruction. To compete you just send off £30 for a MSA non race national B licence and you have to join an appropriate club who run the events, in my case the BARC, another £30. You then apply for the individual events at £70 or so. Check out www.gurstondown.org You will also need overalls and a helmet, to the required standards. You can start with a standard road going car and develop it as and when. Find out where the local hillclimbs are and go along to find out more.
phil hill said:
Personally I like to see an A-series on SU's, the Webber/Delorto just doesn't look right to me....... I think there is a lot of myth and mystery about what equipment you "need" to be serious or competetive, Coop's (and many others) have shown you don't need a Webber to have a powerful, flexible engine.
Packaging is always a problem with a Webber because to get the best from them you need a long inlet manifold. To fit the long manifold you will have to modify the bulkhead, which is fine if your prepairing the car from scratch but not much fun if you're developing as you go along.
SU's can be modifed if you have the skill and nerve, later HIF's are reputed to flow better than earlier H's and HS's (most Rover V8's had a pair of HIF6's if you're looking for some), and the Maniflow tubular twin inlet manifold is a work of art.
If you're feeling really flush, and the regulations allow, how about "proper" twin-point injection ?? See <a href="http://www.mberaceengines.co.uk/ecu_kits.html">www.mberaceengines.co.uk/ecu_kits.html</a>
>> Edited by phil hill on Wednesday 25th February 08:49
But does the maniflow manifold work, ie what sort of power / flow increase does it offer, and is it worth the £100?
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