Tag: Fuel Injection

Now that The Winter Trial is behind us and Silverado has returned to TwinSpark Central to be serviced, it is time to evaluate how it behaved and what we have learned.

Tyres
We ran Vredestein SnowTrac2 15x6x185 in the front and the same size SnowTrac3 in the rear. The rear tyres were changed at the eleventh hour, when a blister had appeared on one of the 1 year old SnowTrac2’s. The Snowtrac3’s initially felt weak due to their soft side walls, but once the car was fully loaded and we had covered some distance, they seemed firmer. Steering became more twitchy when running without spares, luggage and co-driver and I’m convinced this had to do with the rear tyres in combination with the 26 mm rear torsion bars. Job for the next time: find snow tyres with stiffer side walls, but with the solid traction of this type of profile: we never had to [...]

Two weeks ago the Dutch Historic Automobile Racing Club (HARC) announced that it will add two new divisions to the National Historic Touring & GT Championship, in line with FIA TC and GTC classes. Having lobbied for this move a year ago we were delighted to see that HARC now believes such championship for cars homologated between 66-75 and 76-81 is viable.

Team TwinSpark will be entering its two RSRs: Woodstock 73 and The Hulk 74 driven by Lex Proper and myself. It looks like at least one of our R Gruppe buddies, Ronald Aardse, will enter as well with a 2.8 MFI engined RS clone. However we are sure that this convenient two weekend, 6 race event will draw out quite a few more Porsches from the 66-75 era and not just from Holland. You can mark down May 14-16 and September 10-12, both at Zandvoort’s Grand Prix track.

We will be competing [...]

The Mechanical Fuel Injection set up on early Porsches was allegedly derived from the need to fly upside down. In the Second World War aerial combat developed into serious forms of aerobatics and there was an advantage to be had by those pilots who could manage their throttle and therefore acceleration, irrespective of the position of the plane. Traditional carburetion was inadequate as carburettors rely on gravity to keep the float chambers filled. Trust the German engineering cadre to come up with a solution. Their Messerschmidt aircraft could pull negative G’s thanks to this technology and the British Spitfires could not follow their trail without stalling their carburetted engines.

The constant fuel pressure combined with excellent fuel atomization, leading to a maximum fuel burn ratio in gasoline engines, had Mercedes, Porsche and later BMW, apply this expensive and complex technology on their race and production cars. MFI was overtaken by Electronic Fuel Injection only 20 [...]