Quote:
Originally Posted by zcoker
Don't the euro cars run 29 degrees full advance? Only heard of vacuum retard at idle on those motors, single pot dizzy, no boost retard. What's up with that?
|
Very interesting question!
I have been wondering about that and we need to verfy if that is the case.
However, that would not add up from what I understand so far. From my reading Vac-Advance is to premote fuel economy when not under load and Vac-Ret is to permote heat for emmissions.
Thus, I can see why we have Vac-Ret added to a smog 930.
However, with a turbo we have to have "boost-retard" for safe running under boost.
As the Euro and 3.0T's only have one conection to the can on the dist we can not have both vac-ret & boost-ret.
Thus, somthing is not adding up unless there is two different euro cans. One with two conections and one with a single conection.
Further, the euro has a broder timming range by 2 deg (see below). Is that extra range in the mechincal advance or in the Vac-Retard (if it has such)? I do not know.
I would guess a euro turbo that have a can with one vac/boost line conection would just have boost-retard.
As such, timming at idle (conected) sould start at somthing like -11. It would have mechanical advance to take it up to -29. Under boost timing would be pulled back to about -19 (to run w the better euro fuel).
Dose anyone have the timing igntion specs for a 75-77 3.0 turbo? Or, is there an early euro timming spec?
From another post, the specs for US and Euro:
--------------------------------------------------------------------------------------
USA 1 +/- 2degs at idle (950rpm +/-) Vacuum Hose CONNECTED
Euro 2 +/- 2degs at idle (950rpm +/-) Vacuum Hose CONNECTED
And to adjust timing:
USA 26 +/- 1deg BTDC at 4000rpm Vacuum Hose DISCONNECTED
EURO 29 +/- 1deg BTDC at 4000rpm Vacuum Hose DISCONNECTED
--------------------------------------------------------------------------------------