My 5L VP that I have mentioned before on these pages runs dual fuel and has some sort of custom spark map - see attached image.
My question is, in the MAP columns 30 and 20, especially 1600 rpm and up, it starts to reduce the spark advance quite a bit. I would have thought it would at least have stayed flat so that if you get into this area when cruising on very light throttle you have a chance of staying that way. Is it to stop burbling on overrun, or might there be some kind of instability? I'm interested in taking the curve out flat to MAP 20. Any comments?
VP V8 LPG - why reduce advance at very low load?
-
Circlotron
- Posts: 235
- Joined: Mon Apr 25, 2011 6:12 am
- cars: VP 5L LPG
VP V8 LPG - why reduce advance at very low load?
You do not have the required permissions to view the files attached to this post.
-
yoda69
- Posts: 1226
- Joined: Sun Mar 15, 2009 12:20 am
- cars: 2004 VYII Acclaim Wagon V6 Auto LPG/Petrol
2004 VYII Berlina sedan V6 Auto
2005 VZ Monaro CV8 manual - Location: Geelong, VIC
Re: VP V8 LPG - why reduce advance at very low load?
Typically anything under 30 MAP is on the over run.
Not sure of exact reason, but could be to help engine braking, or at the higher revs (2000+ RPM) to stop backfire, as this is also usually where DFCO is active.
yoda69
Not sure of exact reason, but could be to help engine braking, or at the higher revs (2000+ RPM) to stop backfire, as this is also usually where DFCO is active.
yoda69