1 HS4 or two sir?

[00/63484]

So, the blueprinted 1500 engine in my 13/60 convertible ran beautifully all summer on the old plugs I took from my 1954 Morris Minor. The engine is a belter with excellent pressure, no leaks or major rattles and has not let me down since the ebay 4 way plugs disaster last year. The blighter starts and runs beautifully.

I have a question for my learned not-seen fellow enthusiasts...concerning the use of fuel...and the question is two fold, one answer dependent on the other I reckon.

I have decent long branch exhaust manifold through a fat pipe to a standard silencer (the wife's not a fan of that 'roar'). Above this arrangement there sits two nicely balanced and maintained  HS4 carbs which are fed air via a late double filter housing with no filters inside - which is in turn fed through 2 pipes to chrome motor cycle type filters to the side of the radiator in the main airflow. It works a treat.

My point is - if I were to drop to ONE HS4 carb - what detrimental 'real world' effect would it have? Major power loss or just some top end loss? Less or more fuel used? Any other side issues?

Question2 - what manifold can  I get to do this and has anyone got one should I feel like experimenting?

HNY or HND to all.

D

 

 

 

 

[sulzerman]

I switched my herald 1500 from twin su's to a single stromberg as an experiment.

Car seemed run out of steam fairly quickly, couldn't wait to get SU's back on. Acceleration was poor on a single carb

Correctly set up twin carbs shouldn't use more petrol, and are much better than a single carb.

[Clive]

There is a good article by John Thomason about single and twin SU's. Properly set up on a rolling road, so a proper comparison. He used the twins for racing, single for everyday use. Figures over large mileages covered were kept. (and he won the race series hands down!)

Twins gave a little more power (not much) and single a little more economical (again not much)

 

He used a dolomite 1300 inlet manifold, gives equal length inlet tracts, and a better design than the herald item.

A bit of research should turn the article up, it was mentioned on here a month or so ago....

[Pete Lewis]

just to add if economy is the driving force then the right foot has more effect than any carb or fueling modification 

if you want less power and more mpg  just reduce the throttle to open much less than full,    fit a strong return spring   etc.

having only one carb improves the reliability traits of the SU and only one to  twiddle   but all ends up with a lot of work for little gain 

keep it triumph and keep the smile 

Pete

 

[rlubikey]

Here you go, Single carb or more ? from back in November.

Cheers, Richard