Pinging, adjust timing or add fuel?

[Twisted]

I noticed some slight pinging at WOT from ~3500 and up. I have a diablo predator and am running the 91 octane tune. The car only gets 91-93 octane. I understand the pinging is the fuel igniting before it should by the heat/pressure in the cylinder. My question is should I advance or retard the timing? Would adding fuel help?

 

[Stan Weiss]

What is your A/F ratio. If it is lean adding fuel will help. Does it do this on 91 and 93 octane or just 91?

 

[mogs01gt]

Whats the timing set to?

 

[Twisted]

Using the data log feature of the diablo looks like base tune is 14. At +5500 I see numbers as high as 41.

 

[Twisted]

What is your A/F ratio. If it is lean adding fuel will help. Does it do this on 91 and 93 octane or just 91?

I noticed it autocrossing Saturday and was on 91. I filled up with 93 on the way home and will test it out in a little while. A/F is unknown, running the diablo tune unchanged.

 

[Twisted]

Did some WOT runs today on 93 octane. Seems to be better. I cannot always find 93 octane though, so what would be the safest thing to adjust, fuel or timing?

 

[san~man]

Well, if you can't always run 93, then the obvious thing is to retard timing.

 

[thomas91169]

either or. it really doesnt matter how you do it, I would add fuel before backing down timing, but thats just me. if im getting detonation/knock i will try to add fuel in small increments, if that doesnt work, then i will pull timing. once i get to the point of no knock/predetonation, i will try to take some of the fuel away that i added and see what happens. of course, tuning a mustang is a little different than a dsm.

 

[03ghoststang]

first off is it the generic tune that you have or did you modify it a bit ..... like add more timing.......... you should add about 5% more fuel....

on my tune i have the timing maxed out with the fuel set at 23% more richer on both ends to give me a 13.7 A/F ratio WOT

 

[comporange04GT]

on my tune i have the timing maxed out with the fuel set at 23% more richer on both ends to give me a 13.7 A/F ratio @WOT

I don't mean to hi-jack this thread but what is a safe A/F ratio to run at WOT. My tune has the A/F between 12.6 and 12.9 at WOT and I think that is a little on the rich side for an NA motor but I have been told it is on the lean side.

 

[Twisted]

first off is it the generic tune that you have or did you modify it a bit ..... like add more timing.......... you should add about 5% more fuel....

on my tune i have the timing maxed out with the fuel set at 23% more richer on both ends to give me a 13.7 A/F ratio @WOT

It is an unchanged Diablo Performance Tune. I'll add a little fuel at a time and see if that helps.

 

[mogs01gt]

What fuel did you fill up with when you started to ping?

 

[Twisted]

91. That is what the tune was for. On 93 it seems better, but I cannot always find 93. I just want to adjust the 91 tune to get ride of the ping.

 

[mogs01gt]

I meant what company. Please tell me it wasnt BP or Speedway.....

 

[03ghoststang]

I don't mean to hi-jack this thread but what is a safe A/F ratio to run at WOT. My tune has the A/F between 12.6 and 12.9 at WOT and I think that is a little on the rich side for an NA motor but I have been told it is on the lean side.

for a N/A lighty modified motor (i.e, CAI, TB, plenum, just your basics) an 13.0-13.7 will be good now if you have cams head work and other little things then 12.0-13.5 would be a bit more on where it should be

 

[03ghoststang]

It is an unchanged Diablo Performance Tune. I'll add a little fuel at a time and see if that helps.

ok just keep adding fuel till it goes away but dont just add in big increments add like 2% at a time

 

[DBMSTNG]

to make a proper correction, you need to know the a/f ratio. if there is too much timing, dumping more 91 octane in to fatten the a/f ratio isn't going to fix the problem.

 

[Twisted]

I only go to mobil or sunoco.

 

[mogs01gt]

I only go to mobil or sunoco.

Then it sounds like you need to drop the timing back to 13 degrees or go get on a dyno and see what your a/f ratio is.

 

[BurningRubber]

Mine pinged when I advanced it 5 degrees, backed it down 2 degrees and all is well, at least to my ears.