[todds]

Hi, I was wondering if it is possible to replicate or approximate the ignition curve of a Euro (carbed) 2000 engine that has the bosch distributor on a US 2000 engine with its marelli distributor. I've seen the tuneup specs for both and the two are obviously different due to differences in the engines, such as carbs/fi and cams.

The static timing on all euro bosch distributors is 2-4 BTDC
on the us marellis it's a mix of before, after and at top dead center. Since this is set simply by the marks on the engine pulley, it's easy to replicate the euro models. Dwell is 60 for both (although point gap spec is different)

My question involves the rest of the curve, the max advancement spec is 27-33@5000rpm for the us marelli models. For the euro bosch models its 37-40@4600rpm. That's quite a bit more advance at a lower rpm, which would make a difference in top end power I would assume.

Even more importantly (to me) is low rpm operation because that's where I spend most of my time in traffic. The euro distributor seems to have different characteristics than the us models in this respect also, such as at which rpm the advance starts coming in, and how quickly it goes up or back down. Does anyone know anything about the low rpm specs of the euro vs. the us distributors? Anybody got a curve mapped out? I guess the only way to change these things is with either different springs or different weights. The other option is to source an original untampered-with euro bosch distributor with its original springs, anybody got one to sell me?