924Board.org

Raize · Joined: 18 Sep 2013 Posts: 447 Location: Scotland

Does anyone have the curve for a RoW S1 931 ignitions vacuum/boost advance/retard?

Failing that, does anyone know the maximum amount of degrees of boost retard that is applied, and how many PSI of boost it takes to reach that maximum value?

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

http://924board.org/viewtopic.php?t=37214
_________________
80 Turbo - Slightly Modified

Raize · Joined: 18 Sep 2013 Posts: 447 Location: Scotland

There's a curve for USA 931 but not for RoW. Not sure it's a safe assumption that they have the same curve given that the USA model had only 140hp and the RoW 170hp.

Not sure it's really relevant anyway, I was looking at swapping a 931 vacuum can onto a 924 distributor to get boost retard for a supercharger but they're horribly expensive and/or NLA. There doesn't seem to be a cheap option for this.

I wonder if the vacuum can is adjustable in any way. If I could add 5-10 degrees more vacuum advance, pull 5-10 degrees from the static timing, and use manifold instead of ported vacuum to keep a decent idle then it would achieve the right effect.

With the prices of 924 bits these days I don't really want to start drilling into vacuum cans though. The days of this being a cheap car to get parts for seem to be gone.

Carrera RSR · Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK

Aldon Automotive can make modify a distributor to any advance/retard curve within reason. If not going stand-alone ecu route you could take a look at 123ignition dizzies. Either their stock bodies or the Mittelmotor option which are both programable with boost input.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252