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Engine Specific Info and Questions => IDI Engine => Topic started by: mbr on September 02, 2006, 08:27:19 am

Title: Max advance for diesel, will it ping?
Post by: mbr on September 02, 2006, 08:27:19 am: I'm trying to determine the max advance for an '82 1.6na diesel for high altitude and efficiency.
If a diesel is too far advanced, will it ping like a gasser?
What is the maximum safe advance you guys run on this engine? I don't mean what the manual says.
I had it at 1.1, but it's not enough.
Experienced answers please, guesses are not very helpful.
Thanks.
Title: Max advance for diesel, will it ping?
Post by: hillfolk'r on September 02, 2006, 10:44:41 am: i ran 1.21 on a old 81 na diesel
it sounded like popcorn popping at part throttle
a little like spark knock at part throttle in a gasser
me and the guys at work say "sounds like popcorn" for an advanced condition
Title: Max advance for diesel, will it ping?
Post by: voodoo on September 07, 2006, 09:41:52 pm: no it wont ping, it will only stretch the head bolts and blow a head gasket.
Title: Max advance for diesel, will it ping?
Post by: SMOKEYDUB on September 08, 2006, 08:35:55 pm: i will say yes it sounds like it pings like crazy. sounds like extremely high fuel injection pressures. im not sure what i had min at put it was loud.
Title: Max advance for diesel, will it ping?
Post by: coke on September 08, 2006, 08:40:36 pm: Advancing it too far will increase the pressure in the cylinders, and as forementioned, blow your gaskets. Its bad for them. Why do you want to advance it so far? Power?
Title: Max advance for diesel, will it ping?
Post by: SMOKEYDUB on September 08, 2006, 08:44:39 pm: increasing the fuel pressure will just open the injector sooner it doesnt inject more fuel or anything just sooner. i dont know why not just leave it alone instead of going to the max with timing. if you were that curious why not just loosen the pump bolts and start advancing until it pings and then back it iff a little bit. then measure and see were your at.
Title: Max advance for diesel, will it ping?
Post by: mbr on September 08, 2006, 09:04:11 pm: Quote from: coke
Advancing it too far will increase the pressure in the cylinders, and as forementioned, blow your gaskets. Its bad for them. Why do you want to advance it so far? Power?

I'm not trying to advance it "too far". Just like my original post said, "Max SAFE advance for high altitude". Gassers need to be advanced way past the specs at high altitude. I would imagine diesels would benefit for the same reasons.
Of course I don't want to blow a gasket. If you don't have experience with high altitude tuning, then you don't know the answer.
Title: Max advance for diesel, will it ping?
Post by: coke on September 08, 2006, 09:11:13 pm: You wouldn't have to advance the timing to get rid of high altitude problems. The 90 Jetta had a pump that dealt with this, and what it does, is leans out the fuel at higher altitudes. Therefore, just adjust the fuel screw and lean it out some. You get a more complete burn with the timing slightly retarded, or at least I do. I had my fuel screw turned up and it was smoking quite heavily under a load, so I retarded the timing some and it took care of the smoke and I didn't sacrifice any power.