What is your Twin plug timed to?

[ficke]

I have a 1978 930 with a twin plugged engine, I am running 15 degrees full advance when at no boost.
What are others running?
Does anybody have data from dyno timing their twin plugged turbo?
I am really curious what others are running, thanks in advance.
Also does any body know who made this distributor?

[jwasbury]

No idea on the dizzy, but I run twin plug with Electromotive XDI2 ignition. Light load or under manifold vacuum conditions, my max advance is probably 26BTDC (+/-). I have hooked up the laptop and done on the fly tuning. My observation is that even at light load setting, small throttle openings, the MAP sensor usually doesn't see vacuum. At that point the turbo is pushing enough air to at least have atmospheric pressure in the manifold. Typically only see vacuum when the throttle is fully closed. Above atmospheric pressure (~100kPA) I start to pull timing out little by little to ~16BTDC at full boost.

I might be able to cut and paste my map from the Electromotive software into XL if you're interested.

I think if your max mechanical advance is 15BTDC, you should be pulling a few degrees off that on full boost assuming boost retard is functioning - means you might be leaving some performance on the table the way its set now.

[ficke]

Thanks Jacob, very helpful.
My distributor has no vacuum advance, all mechanical.
My boost timing retard is working.
I was thinking of running a little more advance timing, like you suggest.

[xbmwguy]

Max timing @ cruise is 34' full boost 22' until 22lbs then down to18'. Over boost set to 16' at 26lbs.

[jwasbury]

You running any sort of knock sensing Frank? Just curious if that's part of your EFI implementation.

[ficke]

Originally Posted by xbmwguy

Max timing @ cruise is 34' full boost 22' until 22lbs then down to18'. Over boost set to 16' at 26lbs.

Sounds close to factory specs. for a single plug engine? How did you come to chose those specs? for your twin plug set up?

[xbmwguy]

With This build which is way more aggressive than my past 2 I had the Benifit of building and installing 3 other megasquirt Efi conversions. So far I have only run 1 tank of 93 pump gas for a base tune for the flex fuel sensor and the rest e-85. I think it's a happy compromise between the twin plug and pulling timing and the e-85 adding timing.my last build was with ms2 and e-85 , boost in the 18-20lb range and the motor at tear down was perfect. I am running same numbers for timing big IC 1100 injectors and a much bigger turbo with great results . I think I am somewhat conservative with timing which I hope to confirm next week with an approaching cold front and some dyno time. No dyno for me in 98 degree weather

[xbmwguy]

Oh yea Jacob wires are run for sensor just need sensor and hook up