Patrick G

iTrader: (14)

First off, the reason why I'm hearing pinging is because I've got one of Nine Ball's knock-out boxes...works like a champ. Here's the rub. I've got a heads/cam LS1 that came out of another car. In the other car, it ran 11.20s at 121, so it's pretty stout. In that car, the motor ran 30-32 degrees of timing with no knock retard (MTI tuning). The car had 1 3/4 G-Hann headers with no cats. O2s were always in the .880-910mv range.

Well in this new car, the motor has a little bit different setup. The new car has 1 7/8" Whisper headers with dual cats just past the headers and Ed Wright tuning (with unported stock MAF). O2s are perfect (.880-.910mv) and my timing goes from 24 degrees at low rpms to 26 degrees at high rpms. I got the knockout box because I was getting false knock, but now that it's gone, I can hear the audible pinging. I run 93 octane all the time. If I run race gas, the pinging goes away. Why would the motor ping in this car with low timing and not in the other car with high timing? I've heard some suggest deleting cats, but I'd rather not if at all possible. Tuning seems good. I'm stumped.

Ragtop 99

iTrader: (7)

did you resurfaced/mill the heads before putting them on the 'vert? Does the vert have stock pistons? Looking for anything that raises compression.

Coolant temp ok? 160 T-stat with fans on at the right time?

Maybe the 02's are bad and you're really leaner?

How do the LTRIMS look during cruise? Did you change any MAFT settings?

Patrick G

iTrader: (14)

OK,

Let me be a little more specific. The motor came out of one car and into another...NO CHANGES! Same 160 degree thermostat. O2 sensors respond very well in new car (no need to replace them). LTrims on the new car are dead 0% (remember, I'm running the stock unported MAF). I do not have a MAFT on the new car (but don't appear to need one judging by the excellent O2 readings). Truthfully, about the only thing different about the set-up is the exhaust in the old car (G-Hanns with off-road pipe) vs. new car (Whisper Headers with dual high flow cats) and the tuning MTI vs. Ed Wright.

How in the world does the same exact motor show 0 kr in one car with 30-32 degrees of timing and pull 3 degrees of kr in a car with 26 degrees of timing? Same O2 readings, same fuel, same heads, cam and compression. WFT?

Kenny H

I had a similiar situation last year, turned out my cats were clogged....

Patrick G

iTrader: (14)

Kenny,

Are you running cats now or did you chuck 'em into the dumpster?

Kenny H

I had my cats replaced with new factory units. I am still running those same cats now.

Patrick G

iTrader: (14)

Anyone else have any ideas?

VINCE

iTrader: (1)

That is really weird.. What is your compression by the way..? I informed Ed Wright that I was getting some high compression heads and he said the timing has to be pulled back.. Others with the same high compression heads are seeing 29* WOT timing. My car right now is seeing 30* WOT timing. I hope I do not have the same problem. If I do then I know it has to be the programming.. Only difference I see that you mentioned was the programming and exhaust..

Nine Ball

iTrader: (38)

Patrick, get rid of the cats. My car pings in 5th gear under load when I have the cats on it. Never pings without cats. They hold too much heat in the header and cause the pinging.

Besides, your car didn't pass emissions anyways (hehe)

Tony

Patrick G

iTrader: (14)

LOL Tony,

You're right, 'ole Ed didn't get my tuning Wright, so I had to find an emmissions tester with a good sense of capitalism. Do you think gutted cats will flow close to a straight pipe? The reason why I ask is because this exhaust is a work of art and I'd hate to make a "Frankenpipe" exhaust out of it like we did on my Black Car. If the car picks up with gutted cats, it might do even better with straight pipes, but then I'd have to cut it up. Mandrel bent stainless from the headers back is a thing of beauty. <img src="images/icons/smile.gif" border="0">

blackhawk2000

Different O2's from 1 car to the other, mean different A/F from car to car. Use a MAFT if you have one to eliminate the audible pinging. Stock O2's readings are mearly a hint as to what your A/F really is.

Pro Stock John

iTrader: (34)

So the motor in your 98SS vert is the last hydraulic motor setup that was run in your old car, right? But when SAM ran your old car at the track was it run on a race gas or straight pump? Judson strikes me as someone who would run a blend.

Can you add fuel via a MAFT?

I drove a heads/cam M6 car that pinged in higher gears under load... I added 5 gal of 100 and it was fine. I always wanted to play with the MAFT but Norm at Westech said nope.

Colonel

Ditch the cats. Gutting them will be fine (sounds better than a straight pipe too.)

Patrick G

iTrader: (14)

PSJ,

Yes, this is the last hydraulic cammed motor Judson had in the Black Car, but he always ran straight 93 otcane in it as it never rattled with it. No need for a MAFT on this motor now since the LTrims are 0% and the O2s hover in the .880-.910mv range, about perfect. Just hard to see how cats could make the car ping vs. an off road pipe. <img src="images/icons/frown.gif" border="0">