That would be a Stronberg.
The problem with the SU is poor flow when wide open - you only have to look at the design to realise why. All the competition BL cars dispensed with the SU and went to Webers. Before injection.
Or even Stromberg. I've misplace the correct specs. ;-)
I slimmed down the throttle spindle, the leading edge of the plate and radiused the rear edge. This really benefitted 3rd and 4th gear acceleration over 1/2 revs and improved throttle response over small openings. I was very tempted to radius the edges to the venturi and piston but didn't get around to it. I wasn't confident it would not upset the accurate fuelling ratio which already existed. I felt that rolling road sessions with sniffers would be appropriate to ensure that this modification would not unbalance the fuelling.
998cc was the short stroke Cooper S screamer.
It is the equivalent of a twin SU on the surface but in the Mini 7 category you were only permitted to use a single choke carb hence the 'single port' I mentioned previously. This usually resulted in a Weber 40 DCOE or a Dellorto 40 DHLA offset on a custom made manifold with half the carb hanging in mid air. The jets on the unused side were soldered up, the throttle plate and everything else like the choke and auxiliary venturi etc were also removed. Some even hacked off the unused bit of the carb in an attempt to loose even more weight
1200lb empty weight, 90bhp corrected at 8500rpm (on an honest engine dyno) with a straight cut dog gearbox and nice sticky Dunlop slicks. Somewhere in my archives I'll have the acceleration and in gear times, which in the days before affordable data logging were done with a huge video camera focused on the rev counter and homebrew digital speedo that read off a toothed ring shrunk onto a specially machined rear brake drum.Idle was around 1500rpm, more for getting the extremely undersized alternator supplying the ignition load than anything else. So not really usable in traffic, but with a lot of attention to the carbs there was little popping and farting and you could drive it to the shops, just a little bit more quickly than a standard car fitted with an SU.
Those aspects of the Weber have now been more or less fully understood, some five decades later :) such that it is possible to have perfect progression from idle and part throttle. Perfect in this case being measured by sniffing the exhaust gases with a wideband O2 probe and then proving it with a seat of the pants test.
998 was the Cooper and near identical to all other 1000cc engines with the exception of the head (12G295) the cam, a pressed steel three branch exhaust manifold and the twin 1.25" SU's.
There was also a 997 Cooper in the early days which was a POS due to the very small bore and restrictive valve size that made it very asthmatic :)
The 'short stroke ' Cooper S was the 970 having by a long way the shortest stroke of any A series with the same bore as the 1071 and
1275. Heads were identical across the three Cooper S variants.A 970 is quite unlike any other A series, I briefly drove one maybe 30 years ago and its a car that brings back smiles. Really smooth and it just revs forever. Prices secondhand were silly even then. Cranks were in very short supply and I suspect many got scrapped with tinworm or were fitted with the 1275 cranks.
By no coincidence, the 970 on a 20 thou (I think?) overbore became
999cc, just below an FIA class limit.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.