Hi Guys...
I just installed a Blackwing & Carbon Fiber Air Duct with connector last week on my '03 50th Coupe w/4sp Auto. Basically everything else is stock (so far) and I just rolled over the 1000 mile mark.
I'm running 91 octane fuel and the weather is unseasonably warm although operating temp seems to stay under 200.
I seem to have developed (or maybe I'm just starting to notice) a slight ping when I accelerate at lower r.p.m..
Nothing radical just annoying.
Question is... is this normal for 91 octane, considering the weather, the intake mods, etc., or should I have it tuned.
Any input appreciated. Thanks in advance.
Regards,
Dave
Azusa, CA

 

50-50,

That must be a beautiful car with ~1000 miles on it!!

Welcome to the world of modding. I will make the suggestion to get yourself a good scan tool now that you have a complex car that you're modding. It doesn't sound like this is the end of your mods also so this would be a great thing to do. I like Autotap. It's easy to use and requires a laptop computer. Once you have this you can post what you're seeing around the knock that you're hearing. It may be a fluke tank of low octane gas (not necesarily 91) or it could be that your blackwing has leaned it out a little for you.

The first step may be to put the stock pieces back on with this same tank of gas and see if the knock goes away.

In my experience, if you actually "hear" knock on an LS1/LS6 engine you're pulling about 10-12 degrees of timing and that's pretty bad. It's definitely something not to ignore. On the other hand, drive the car around a little more to see if your PCM adjusts AFR's for you and perhaps the knock will go away.

Sorry for all the verbage, but there's a lot that can be happening here. :cool:

 

Also have experienced some annoying engine ping while accelerating in 2nd, 3rd, and 4th. Like Ca., we only have the 91 octane stuff in Arizona. Have tried different gas brands lately, mostly Chevron, and pinging has been less. Am thinking that may be the answer. BTW, also have a Blackwing on my '99 FRC, but pinging did not start until months after I installed.

Mike

 

Thanks for the quick reply Brian...
re: verbage...never TOO much if it involves the Corvette! :cheers:
I appreciate the help. I'll give it a liitle more time to "learn", then maybe take it in to the dealer (God help me) for their 2 cents worth.
I think I'm definitely in the market for a tuner or scanner. I'm watching the forum for everybodies take on the different brands.
As I've said... the Corvette Forum "rocks". Great place for ideas & help from great folks like yourself!
Now look who's being verbose!
Regards;
Dave


[Modified by 50-50, 7:31 PM 1/15/2003]

 

A slight pinging is not a bad thing. You get optimal performance just before pinging..
You might try another brand of gas. As long as the ping is not getting longer or louder, you should be fine. I doubt it has anything to do with the air filter.
If it is related, the ECM will learn and adjust accordingly.
Enjoy the car!
Mike :steering:

 

Thank you too, Mike!

Hell, if we could find 93 octane out here, I probably couldn't afford the darned stuff anyway!


[Modified by 50-50, 6:06 PM 1/15/2003]

 

Not bashing anyone, no amount of ping (knock) is good. There is a lot of knock that can occur that is inaudible and even THAT is bad. So get that taken care of. I really don't think your local dealship will have the answer you're looking for.......they'll most likely tell you to put on the original intake. :crazy:

 

:iagree:
If you can hear it that is not good. It is surprising how much knock retard you can have and not hear it.

 

50-50,

Mine is bone stock and I get the same thing, especially when the engine is warm and the rpms haven't come up. It's due to that wonderful 91 octane you and I have been buying.

If you make it to Pasadena, at the southern end of Arroyo Parkway, there is a 76 station that sells the 100 octane stuff. It ain't cheap, but that will surely fix your ping.

According to GM, some light pinging is not a problem. In my experience, what I am hearing is just some occasional light pinging, so I don't worry about it.

 

dave,

I would reccommend that you get your PCM tuned. I know this expert cutom tuner... he can eliminate your ping, and give you increased HP, cooler running engine, and keep your engine longer lasting. Send me an email or instant message, and I'll give you his phone number.

Jonny A.

 

:iagree:

Most likely you are running lean and your computer is not dumping enough fuel at WOT. I autotaped my friends 01 Z06 and he is running 5.5% lean at WOT which is real bad considering your 02's aren't suppose to add fuel at WOT. Most of the 01+ cars I see run lean after airintake mod's your best bet is to go in with someone and get ls1 edit and a autotap. Then search a forum called ls1tech to get idea's how to dial it in.
:D

 

I stand by my statement about some ping being normal.
Below is a note from a GM engineer that was published about 4 years ago.

"Now on the subject of a properly tuned engine pinging. Yes, they should ping, a little under certain conditions. Engineering is a field of compromise. You want the most power, the best fuel economy, the cleanest emissions, and the longest longevity out of any engine. But each of these conditions requires different tuning, generally opposite from each other.

An engine needs to be tuned to operate at a sweet spot that is the compromise of all requirements.

As I said earlier, pinging can be the result of high combustion temps, and this is the type you would expect to occur. High temps are caused by a combination of lean fuel and advanced timing. Lean fuel produces higher combustion temps and hence more power. It also produces higher emissions and potential engine damage.

When the engine is under sever load and a low RPM (like climbing a steep hill in top gear) then engine temperatures rise and will begin to ping. That is normal. That is desired. Yes, you are damaging the engine and melting the piston. (More on that later). That means that you have crossed the line are no longer is that compromise zone. That is good because engines are not meant to be operated in that fashion. PINGING MEANS IT IS TIME TO DOWNSHIFT.

Engines, particularly motorcycle engines, make their power in the upper 1/3 of the RPM range. If you are under sever load, you want the tachometer up near red line. That is where the engine was designed to run and it is by far the easiest on the motor. When you are lugging an engine, the oil pressure drops and the piston rods begin hammering against the crank shaft because there is no longer a high-pressure film of oil to prevent it. Likewise, the crankshaft in turn hammers against the block (or case). In either case, the damage you are doing to the bearings is far worse than the slight amount of aluminum being burned away. If you switch to a higher octane fuel to prevent the pinging, you may not realize you are destroying your bearings.

You could also retard your timing or richen the carbs to prevent pinging under severe load on whatever octane gas you desire. But again, this will mask the bearing damage you are doing. It also moves the threshold of that "sweet spot" downward. Now you will not have pinging under sever load, but you will also not have complete combustion under normal conditions (such as cruising), and that can lead to poor fuel economy and excessive carbon deposits.

In a nutshell, the engine should ping if properly adjusted, under low RPM, severe load conditions. Next, you should use your transmission to avoid those conditions.

Mike :seeya

 

If an engine is setup with the proper A/F ratio and timing for maximum power there will be no pinging at all assuming there is no carbon buildup to cause hot spots in the combustion chambers or cooling issues that cause overheating. This was true when I tuned cars by changing carb jets, building distributor curves and power timing on the dyno. Using this Stone Age technology no car I ever tuned ever pinged under any conditions. With today’s advanced technology there is no reason to expect or put up with pinging.

I have never experienced pinging in my A4 when it was bone stock with 2.73 gears under any conditions including low RPM acceleration on days of 100+ temperatures and over 225 coolant temps. Since I live in California I have always used 91 octane.

And I had no pinging under any conditions when I when I installed my Blackwing and LS6 manifold. However, when I put my car on the dyno I was running off the chart lean (over 18:1) with almost 10 degrees of knock retard and no audible pinging. The dyno operator cut the first pull off early, after some discussion allowed a second pull but wouldn’t do a third because he was afraid it would damage the engine :eek:

If you’re experiencing audible pinging under any conditions then you have a problem and I wouldn’t ignore it :nono:

 

I would check for air leaks behind the MAF. Low RPM pinging is IMHO not normal. How does it sound as you drive more aggressively?

 

Mine makes a sound that I think is mild pinging at around 1000-1400 RPM under relatively light acceleration. It seems more noticeable when the car is cold. It does sound like it could be some sort of air leak instead of pinging, but if that were the case I don't think the sound would go away at higher RPM.

 

Wicked,

Where did you get that useless information? All EFI vehicles are designed to add more fuel at WOT. It just makes sense. You need more fuel to cover the extended loads incurred at WOT. That is truly an incorrect statement. :crazy:


[Modified by Mr Cowl Hood, 7:29 PM 1/17/2003]

 

QUOTED BY C5 Missle

I stand by my statement about some ping being normal.
Below is a note from a GM engineer that was published about 4 years ago.
"Now on the subject of a properly tuned engine pinging. Yes, they should ping, a little under certain conditions. Engineering is a field of compromise. You want the most power, the best fuel economy, the cleanest emissions, and the longest longevity out of any engine. But each of these conditions requires different tuning, generally opposite from each other.

C5,

I'd really like to see that article. Do you have the name of the periodical that came from? I couldn't disagree more. There is no reason for any knock (after all let's call it what it is) unless, for example you're driving your 6 speed in 6th at 30 mph and you want to hammer the gas. You'll certainly hear knock, and that's bad bad bad, but understandable. Still bad.

 

Dave, I scanned a 6 speed yesterday for a guy who thought he had pinging. It was pretty obvious pinging and not while lugging the motor. So we thought. The car is a little rich and not one bit of k retard, anywhere. Maybe a scan is in order first. :chevy :auto:

 

Has anyone ever tried Toulene to boost Octane?

 

If it were mine, I first buy some octane booster, add that to a tank of new fuel and see if the ping goes away. If it does, that should prove thats its an octane related ping and only buying better gasoline will fix it. I'd try other brands too. If it doesn't go away, I'd put the stock air intake back on and see if you have it. If you still have it, I'd go back to the dealer and see if something is wrong. I don't think they should ping under any conditions, its not good for the engine, I don't care what some engineer said. The knock sensor may not be working right, and it will only get worse.