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timing After tdc
Posted: Tue Aug 26, 2008 9:33 pm
by Ron B.
Ok,I am almost ready to sort my ignition on my Mercedes 6.3 . The timing specs call for the timing at cranking speed to be 4 degrees after TDC.
Whats the best way to do this?,begin the map at 0 or -4 degrees?.
Can I in fact do this?.
Standard specs call for the ignition to begin advancing at 0-4 BTDC and at 600RPM.This a picture of the standard ignition curve.
Posted: Tue Aug 26, 2008 9:44 pm
by brentp
Hi Ron,
Unfortunately you can only set timing down to 0 degrees BTDC.
0 degrees is pretty close to 4 ATDC, so your engine *should* start without problems. Who knows, perhaps you won't notice any difference?
What MJLJ are you running? If it's a V4 controller, you can set the cranking RPM in the global configuration options:
http://www.autosportlabs.net/MJLJ_V4_Op ... Parameters
In the V3 controller, the ignition advance cell in the upper left corner of the map is the advance used during cranking.
Let us know how it works out.
Posted: Mon Sep 01, 2008 2:47 am
by Ron B.
Mine is a V3 ,but i have it starting OK with 0 advance at 500RPM. In the pic i posted the right hand graph is the vacuum graph for a standard engine. How could i go about translating that into the load bins ? In the pic the vacuum is expressed in mm of mercury. Cheers!
Posted: Mon Sep 01, 2008 1:40 pm
by DannyP
Buy a vacuum pump w/gauge or a vacuum pump and separate gauge. Hook it up to the MAP sensor, and translate mm of Mercury into the kPa of your sensor. Then it should be easy to copy the curve into the tables.
Posted: Mon Sep 01, 2008 6:02 pm
by 910esprit
Ron B. wrote:Mine is a V3 ,but i have it starting OK with 0 advance at 500RPM. In the pic i posted the right hand graph is the vacuum graph for a standard engine. How could i go about translating that into the load bins ? In the pic the vacuum is expressed in mm of mercury. Cheers!
1 mm Hg - 133 Pa
Posted: Mon Sep 01, 2008 8:33 pm
by Ron B.
910esprit wrote:Ron B. wrote:Mine is a V3 ,but i have it starting OK with 0 advance at 500RPM. In the pic i posted the right hand graph is the vacuum graph for a standard engine. How could i go about translating that into the load bins ? In the pic the vacuum is expressed in mm of mercury. Cheers!
1 mm Hg - 133 Pa
or 1.33 Kpa? Thanks guys I'll give it a go and see how we run!
Posted: Tue Sep 02, 2008 8:25 am
by Gilesy998
Hold on mate, one KiloPascal is 1000 pascals, not 100. Doesn't that make 0.133Kpa in your case?
Posted: Tue Sep 02, 2008 9:04 am
by Ron B.
It's OK,i think I have it . The car is running well,in fact it's insane. I still have to reorganise the Map to settle it in the 1000 1500 RPM range to give it a smoother transition. These engines develop big torque from 1000 RPM so it's difficult to get the feel for what is right or wrong until i can more miles into it. I've mounted the coils close to where the distributor was mounted,there aint' much room anywhere else.
