Anyone point me to a good tech article on pinging?

[Jeff N.]

I'm looking for a good writeup that discusses some of the following:

- relationship of pinging to fuel mixtures. details on what ratio's seem to cause problems

- discussion on pinging detection. audible vs. non-audible

- tactics for tuning out ping

Anyone have a good article?

thx!

Jeff

[Bill R.]

Here (http://www.federal-mogul.com/cda/content/front/0,2194,2442_7359_7525,00.html)

And then just do a search on google for preignition....







I'm looking for a good writeup that discusses some of the following:

- relationship of pinging to fuel mixtures. details on what ratio's seem to cause problems

- discussion on pinging detection. audible vs. non-audible

- tactics for tuning out ping

Anyone have a good article?

thx!

Jeff

[Jeff N.]

Sooo...the car light "pings" (sounds pre-ignition vs the more severe detonation) at higher RPMs - 5k + with a "tuned" chip ala conforti, etc. Doesn't ping with the stock chip. Started after the cam timing mod from +4 to +8 degrees.

That article suggests mid RPM ping can be adjusted via retarding the cam. Doesn't mention high RPM ping.

My suspicion right now is one of the following:

- the modified chips have too much spark advance. Have asked Mark D. for a little info on what changes the tuners make in advance in that area. He's traveling so no feedback yet.

- the engine's going a bit lean. This could be either due to the early(ier) closing intake valve limiting the intake charge at higher RPMs or if the tuners also lean out the fuel map at the upper RPMs...

Off cam (2-4k), the car's livelier with the tuner chip vs. the stock chip. On cam +5k RPM, with the stock chip, no ping. With tuner chip, ping. The "perfect" chip (at least for now) seems to be a tuner chip below 4.5k or so and stock mapping above taht point.

We could also backoff the cam 1 degree to a +7 setting if Martin let's me try his Korman cam gear. That would leave the valve open a tad longer and reduce the static compression....

Thoughts?



Here (http://www.federal-mogul.com/cda/content/front/0,2194,2442_7359_7525,00.html)

And then just do a search on google for preignition....

[632 Regal]

zero the cam back!!! if you advance it you effectivly increase compression (dynamic vs. static) which the engine knock sensor cannot adjust for. That if most likly the whole problem, nice for low end but detrimental for a highly efficient 4 valve engine. Once you zero it back you will realize that you will probably still have the same low end and an increase in mid-top end power. Try again!

lol....i did this crap with 455 buicks in the 80s and learned some basics.

[Jeff N.]

Car is short lowend, thus the advance. Ultimately, cam may be too hot with stock compression...

BTW, this is on a M30. 2 valves, single cam. No knock sensor.




zero the cam back!!! if you advance it you effectivly increase compression (dynamic vs. static) which the engine knock sensor cannot adjust for. That if most likly the whole problem, nice for low end but detrimental for a highly efficient 4 valve engine. Once you zero it back you will realize that you will probably still have the same low end and an increase in mid-top end power. Try again!

lol....i did this crap with 455 buicks in the 80s and learned some basics.

[632 Regal]

yahoo me...clarkstondude

[Unregistered]

I too need help with pinging/knocking on accel. i hear a rattle/ping
right at upshifts and a slight ping between on moderate accel.
1995 E34 with M50 auto.