Manifold Developement

Since the introduction of our range of inlet manifolds for the side draught Weber/Dellorto range, they have gained in popularity quite significantly over the venerable and until now unchallenged, steel fabricated items. I have spoken to a number of renowned engine builders/racers worldwide who are now using them in preference to the steel ones - and note-worthy gains have been reported. Unfortunately said personages are not willing to divulge exact details as they do not wish to give anything away to the competition. The main reason for me wanting the infos is to see if we can make them any better for 'off the shelf sales, as it is our policy to continually assess our products in the quest for quality, perfection and performance optimisation.
I was chatting to my mate Phil Hepworth at Racespec in Warrington (he of Howley Racing fame) and he happened to mention that he was currently testing a customer's engine on the dyno that is a pretty trick motor. I twisted his arm a bit, and he agreed to carry out some back to back tests of our manifolds. This he agreed to do, as his customer (in Barbados) was wanting the best output from any currently available components. Aren't we all though? The test was to include a pair of split Webers, so the comparison should be pretty comprehensive. I hope to have the results in time to put in here before we go to press. Fingers crossed! I have also been looking at developing a manifold and down draught carb set up that should be as good as a side draught (for most road applications) for maximum power, but better mid range. It will also fit under the bonnet without anybody mods at all. I know that Weber already to a progressive choked DMTL conversion, but his just does not deliver the goods as far as power is concerned. It gives good economy and comparable power results with a filter box as on SU does open, particularly on mild road applications. The price, however, is a little high for, to all intents and purposes, a side ways step from an SU. I now have the relevant carb body I was after, and more or less finished designing an efficient manifold. The development has been delayed somewhat by other situations (to include the opening of our new northern depot), but will be resumed pretty soon. The set-up will be pretty versatile, useable in anything from a standard 1275 up to a serious 1430 on the road - and of course giving respectable gains over any SU set-up. A full report will be forthcoming once all the tests have been carried out and manifold design optimised. So far it looks promising though.
STOP PRESS, STOP PRESS, STOP PRESS
By the skin of their teeth, the manifold dyno tests have just fallen through the door. Talk about eleventh hour! OK, lets have a look. The engine on test is a 1400cc race unit with an Elgin cam (from the USA), Racespec head and all the usual
quality preparation Phil puts into his engines. Bearing in mind this was a customer unit, it was decided to restrict the number of tests so as not to wear the motor out before it got used by the customer. The decision was to optimise a Mangoletsi long manifold with painstaking modifications by lan (Racespec's head expert) and sorting ram pipelength. I did ask how long it took lan to mod the Mangoletsi job - all I was told was that it is now VERY modified. He basically just changed the manifolds one at a time, checked fuel mixture, then took a power run. This was the severest test we could think of, as our manifolds were to be left as supplied off the shelf and no optimising ram pipe lengths. The splits weren't tried to keep the
running time down on the engine.

The results were as follows:

RPM             BHP            BHP             BHP                 BHP
               Mangoletsi  Long M.5.  Medium M.5.  Short M.5.
4,000          72.63         70.5             71.06             66.66
4 ,500         82.97         83.25           81.84             76.90
5,000        101.34      103.10         100.81             95.33
5,500        112.25      111.85         112.44           108.75
6,000        119.08      121.17         123.51           120.33
6,500        126.26      128.52         131.05           129.43
7,000        131.04      134.45         137.18           136.43
7,500        133.01      137.70         138.52           137.70  

  RPM      TORQUE      TORQUE      TORQUE         TORQUE.
               Mangoletsi  Long M.5. Medium M.5.  Short M.5.

4,000        95.76           92.36           93.69               87.89
4.500        97.24           97.57           95.92               90.12
5,000      106.89        108.74         106.33             100.55
5.500      107.64        107.25         107.82             104.27
6,000      104.67        106.51         108.56             105.76
6.500      102.44        104.27         106.33             105.02
7,000        98.73        101.30         103.36             102.78
7.500        93.53          96.83            97.41               96.83            
                 
               
    Phil was very impressed with the fact that ALL the manifolds bettered the Mangoletsi item, and by a reasonable amount. He reckons there is even more to come through optimising each installation and probably as good as, if not better than splits. Phil also believes that some small amount of fettling - but minimal port modifications - of our manifolds would raise power outputs slightly too. But he stresses the "minimal" point. Incidentally, the Mangoletsi manifold in question had
previously out performed steel manifolds in its modified state - an old favourite of Phil's. So, the design as is of the Mini Spares manifolds was as conceived - to be the best available off the shelf - also appears to be the best available irrespective of whether others have been modified or not. I have to confess to being pretty chuffed! I have also talked Phil into letting us feature his amazing space-framed Mini racer in the next issue. It is a superb car, immaculately prepared, and powered by a COMPLETE Toyota 16-valve motor and gearbox!
Keith Calver