I'm having a little trouble getting my head around the reason for locking and or removing the centifugal weights from the distributor when you have a turbo kit involved. (A series engine)

Why would you want to stop the timing advance? Wouldn't this affect the performance of the engine at higher (when the centrifugal weights are 'working') revolutions?

I keep running it through my head but the more I think about it the more I get confused.

I managed to lock the distributor after consulting L18_B110 and then when I had finished I didn't actually understand the resoning behind it all.

EDIT: I'd really appreciate some advice because I bought that gorgeous turbo kit from Jake Herbert (frankthedolphintrainer) and I need to understand the entire system before I get it all going.

Stop the mechanical advance?

Naturally Aspirated of all types like around 35 degrees total advance when wide open throttle and higher revs (e.g. 3000 rpm or higher).

If you lock the mechanical/centrifugal advance, then you limit that to some lower value, namely whatever your static/initial/idle timing is.

Now a boosted engine might want less the 35 degrees advance, but that's usually done by modifying the weight stops, not by locking them.

When the turbo spools up and starts making boost the volume of fuel/air in the cylinder will not like timing advance and will detonate. Locking the distributor will give you a fixed timing setting and although may hinder performance off boost it will help the engine considerably on boost. Alternatively the best distributor to set up is a boost retard system which allows a small amount of mechanicle advance for no boost applications but depending on the amount of boost it will retard the timing as required to avoid fatal detonation. Boost reatrd also allows you to run a little more boost without water/meth injection.

Quote:Many boosted engines like 22 degrees total advance. .. but that's too much to start the engine, or is it?

My LPG engine has the base timing set at approx 18 BTDC so I would thing that 20 or 22 wouldn't be that too far a stretch. At least with petrol you can hear the pinging if it's too much.