I have recently upgraded the fuel delivery system on the SSS with a Facet electric fuel pump and pressure regulator, bigger fuel line and bigger needle and seats ( from 170 now to 200's ) in the Dellorto 40DHLA sidedraughts. I had been running a standard mechanical pump and factory fuel line.
While it has always had a problem coming out of the tight, left-hand hairpin at Ruapuna spluttering between roughly 5-7500 rpm I have always driven around the issue by short shifting into 3rd and the problem had gone by the time I grabbed 4th gear. This was the only corner between both Ruapuna and Levels Raceway that the car ever played up on.
Now, with the upgraded fuel system the problem is at every left-hand corner and pretty much killing any chance of a decent lap time as I simply cannot get any sort of exit speed out of the corners. I might add that all this was with half a tank of fuel.
The car runs great in a straight line.
I have had my mechanic look at the float levels and adjust them but it has made no difference at all.
I talked to an old school Datsun campaigner ( a very talented driver/ race car builder ) today who was very aware what the problem was but unfortunately was not going to give the info away how to fix it and was too busy ( and 2 hours drive away ) to get him to do the job.
He did mention that some machining of the carbs was required.
Interestingly enough spoke to a chap yesterday with a pretty worked A14 full of goodies from B Pro and Pitt Road ( he is running 45 OER carbs ) who was experiencing exactly the same problem around Ruapuna.
Anyone come across this before and can shed some light on the problem?
Cheers
Dave