I've been thinking..... (not enough to be useful, just enough to be dangerous) about carby setups for fours.

Quad throttle bodies (twin webbers or injection) are always going to be the best solution. But are twin SU's really an improvement on a single large 2 barrel carby?

Twin SU's are set up on cylnders 1&2 and 3&4. These pairs of cylinders fire directly after each other (Ive always reckond a more logical way of looking at 4 cyl firing order is 2-1-3-4). This means that each SU is supplying fuel to 2 cylinders in rapid sucession and then doing sweet FA for the rest of the cycle.

To get consistent flow through a twin setup you would have to have to have 1 carb supplying cyl 1 & 4 and the other supplying 2&3. This way the fuel/air pulses would be directly opposite each other in the cycle. This would make for one mongrel of an inlet manifold if you sorted it out with equal length runners......

Which brings me to a single large carby. Flow through the carby is more or less constant as it feeds all cylinders. The main problem with them is the different length manifold runners. Without too much hassle you should be able to make an equal length inlet manifold for a large single.

So what do you reckon? Would it give an actual advantage or would the inlet just end up with too many corners in it?

(or is there actually a benefit from the twin SU setup that I have overlooked)