Weber with centre speedo

[tomkidd]

How do guys. Im looking at installing a weber box, but would like to keep centre clocks/speedo. I have seen the clocks mounted slight further forward and fastened to the top dash rail using the standard binnale/surround.

My question is, what is the best option for the weber and manifold allowing me to run centre clocks?

I simply cannot fit a 6inch manifold, I know that for a fact.

I have seen a historic touring car mini run centre clocks and a weber in this way, but Im trying to figure out whether its worth the hassle of fitting a weber box, if I wont get as much power as some good twin carbs due to the manifold space restrictions.

Many thanks

[DanGT]

You can get inlet manifolds that can fit a weber. The shorter the inlet manifold the less performance you get. Depending what you are after it is worth looking at a large SU HIF44 or twin SUs. Hope this helps.

[FWDRacer]

Don't fit a swan neck manifold.

[tomkidd]

Would a 100mm manifold be worth fitting? Or would it not be worth using a weber if that was all that would fit?

[Cooperman]

I've never found the Weber set-up to give much of an improvement over twin H4 SU's. You will gain a bit at the top end, but will really need a hotter cam to get the benefit, thus meaning a lower diff ratio.
I built a Clubman GT rally car a few years ago with a 40 DCOE, a 286 cam, offset rockers, big valves and all the usual bits. Basically it was the same spec as my 'S' which runs a twin H4 set-up. It gave no more at the wheels than my 'S' despite having 37 cc more capacity(i.e +0.060" as opposed to +0.020&quot.
It really depends on how much a few extra BHP will be worth to you at the expense of mid-range torque. I think that to get best results with a Weber you need a Kent 296 or a 649 cam.

[tomkidd]

Well the car will probably be a 1380 or upwards to 1399 and its a hillcimb/sprint car. Im at the stage of doing the bodywork and would like to figure out whether I need to install a weber box before I get it all painted.

Obviously torque will be very important on the shorter circuits...

But if I really dont need a weber then I can carry one with the shell as per normal and run twin SUs

[Cooperman]

I once had a 1330 Cooper 'S' rally car with twin HS6 carbs on a good inlet manifold and an original BMC 544 cam with a Longman head at 10.5:1. It had great torque and with a 3.9 diff on a S/c, C/r box it was very quick in the mid range (i.e. 4000 rpm to 6000 rpm).
I never like cutting the aperture for the Webor box and it does make it even more noisy inside. But, yes, at the top end a Weber will give a few more bhp, but not at mid-range really.

[lowandslow]

i'm not that hot with carbs but have you thought of a downdraft webber?

not sure if it'll be as good as a sidedraft but i run a nikki downdraft on my 998 and i made a few BHP but my torque figure went up quite alot

[tomkidd]

Cheers lowandslow but within the regs of the racing I cannot alter the silhouette of the original car...

[lowandslow]

both the webber and nikki downdrafts sit inside the bonnet.

[tomkidd]

Ahhh, does the nikki not have the filter sticking through the bonnet?

[lowandslow]

nope it has a flat pancake filter. i can take a pic of mine if you want

[vodkakid]

My downdraft fits under the bonnet

[DanGT]

For max power and reliabilty i would go for the weber 45 at that CC. With the bulk head box. You want trumpets fitted to the carb and the right size air filter. The distance from the end of the trumpits to the plate of the filter (K and N style) can help flow. When talking to K and N 30mm is about wright(worth checking). A good place will let you know the diffrent flows of there inlet manifolds.

[tomkidd]

What are your opinions on sock filters on the webers?

[DanGT]

tomkidd said:

What are your opinions on sock filters on the webers?

Sock filters are better than no filter. But all info I can find suggests that thay are not the best way to go. The area the air has to pass throw is smaller (depending ot sock trumpet size). Also there is this advantige in having a flat plate at a distance from the trumpet. I do not know if this will make only a small or a big advantage (I do not have the time and money to try back to back tests). If any one has any other opinions or have tryed diffrent setups I would be vary intrested to know.

[haynes]

Maniflow tubular manifolds are the way to go. 3" gives more top end but 5" gives more torque. I also fitted a 5" long K&N which most mini places dont sell, mine came from southern carbs, this allows a decent lenght of ram pipe, also good for the torque you want on a hillclimber. My webber box came from min-its, cheapest one i found and decent quality, fit it 1" off centre with the bottom level with the fold in the bulkhead.

Cant remember if youre running a 286 at the moment. My fast road engine on twin HS4s and a 286 just didnt really have the grunt for a hillclimb, good fun and a good starting point but if youre going to do more of it, youll eventually want to go up to at least a 296 coupled with a webber dcoe45, but youll benefit from a close ratio box, drop the final drive to 3.7 if you still want to drive on the road, if not 4.1 or 4.3.