rgh0 wrote:msd1107 wrote:Thanks for the info, Mike.
While it is an interesting technical challenge to see how much power you can get from a Stromberg head you will always be limited by its siamesed ports compared to what you can get from the equivlaent level of development in a non siamesed port engine.
cheers
Rohan
Without being drawn into a slanging match, as this discussion seems to be verging on at times, I have to agree with the power limitation issue of trying to get the air through a siamesed port.
Before being swallowed into the addictive monster that is Lotus, for more years than I remember I have been an enthusiast of the classic Mini Cooper. My 1967 1275 'S' race car sits nose to tail in the garage with my Elan +2.
After over 50 years of 'A' series tuning, the major problem has always been trying to squeeze power out of an engine with just 2 inlet ports.
After millions of hours of tuning what is evident is that fitting a large weber gives virtually no benefit on a road engine over single or twin SU's, and on a full race gives only marginal benefits over a large single HIF SU. If a 'swan neck' manifold is used then there is no difference at all through restricted flow, and only a long 6 or 7 inch manifold produces the goods at high revs (and on my own 1380 race engine There is no power difference noticable between my 45 Weber and single 44mm SU HIF below 6000 RPM. Only above those revs does the Weber come into its own.
What this means in relation to the Lotus? I cannot possibly see a Weber 45 on a swan neck manifold giving much if any improvement over a pair of well set up strombergs, and if it does it will be at revs seldom used. It may SOUND faster, but I doubt it is.
What about working on a much simpler conversion to run twin SU 44HIF's instead of the similar strombergs. They are bloody cracking carbs (originally from the MG Metro and Maestro engines), cheap, tunable, readily available and highly revered and tuned by Mini, Midget and Sprite racers across the world.
Just a suggestion.
Mark.