Anyone know a good link or resource outlining the advance curves for the mechanical/vacuum distributors fitted to late bays '76 onwards? (1600) googled it but I've a feeling Bentley may have them...don't have the Bentley unfortunately
Unlikely Bentley would have the full curves... I'm told that if you can get hold of an old Bosch catalogue/manual from the 70s, they used to list full curve data.
Cheers @Dicky ....I'm after the advance curves for svda dizzys fitted to buses from '75 onwards (not the ones with adv/retard) The idea being that if i go through with the megajolt set-up, I'll programme in a standard curve as a base map to get the thing in the ball park and then work from there Had a look at the Ratwell ones, but he's just spun up some old dizzys to compare and contrast (without wishing to sound derogatory). Bosch/VW will have detailed graphs of the curves for every dizzy they used to date....
Having said that....the above will be good enough to get the thing up and running.... The other thing is, I've no idea what my motor will top out at RPM wise, but can't imagine it's going to be more than 4000...i'll go deaf
Yes I know...@Snotty....I wasn't being sacarstic (just in case you misinterpreted) Eventually... Just found a run down for the Aircooled net SVDA (basically a slightly modified 034 mexico dizzy) it gives the mechanical advance in 100 RPM increments it also gives the vacuum advance at different loads (in Hg) So in essence....you put a vac gauge on the manifold take off and measure the draw in Hg at say 900RPM (note it down), then repeat this in 100 RPM increments. If i know that VW specified 10 degrees of mechanical advance at 1500 plus 3 degrees of vacuum....you add the two together and punch it into the data base which comes with the megajolt software..... Eventually you build up a stock(ish) advance curve (20 mins at the most) The beauty of it is that once it's up and running, you simply alter the figures in real time, by whatever amount, until the curve is absolutely bang on for your particular engine... Sounds like an ar*e compared to buying a new SVDA and throwing it on, but worth it in the long run....no points, no dizzy, no crappy coil, bespoke timing that never wavers...
Is it true that a vw dizzy retards the timing on No 3 cylinder by 3-4 degrees to try to keep it cooler on type 1 engines @zed ? I'm also going mega jolt for the S/C
Nope, popular myth. If you've got a doghouse for the oil cooler, there's nothing special about no 3 cylinder. Wasn't the case on earlier type 1s, where the oil cooler was inside the fan housing.
Keep me posted....Are you planning on the full fat version, with Data logging etc. or just as an ignition replacement?
Theres a nice thread on early.bay, a couple of guys have done mega jolt/ trigger ignition with some good info http://forum.earlybay.com/viewtopic.php?f=4&t=45777&hilit=Trigger
