more pinging questions

[Guest drknow]

Ok, so my stock Scura pings something awful when it's hot and under heavy load (i.e. full throttle) tall gears and mid rpm's. I've done the search and read a few threads regarding the detonation and see a variety of things that seems to affect it, and no, I haven't checked the TPS and yes, I run premium, or at least what they call premium here in California. I'm going to go with the Bub pipes, the pods, the power commander and maybe a cam and the FBF pistons. That brings me to my question. What do the folks that have the FBF hi-compression pistons and the other mods find regarding pinging? When I ride this thing, I often ride it hard, and have to find a solution that allows me to increase my horsepower a bit.

 

dk

[BrianG]

If you start from the basic point of understanding that "pinging" is actually pre-ignition, you can work your way logically through and attempt to resolve it.

 

Perhaps the most common, current issue is that manufacturers frequently tune their engines on the lean side, for emissions testing reasons. Enrichening the mixture, particularly in the mid to low RPM ranges will cure a multitude of drivability issues, no the least of which is "pinging". Having said that, creating freer flow in the intake or exhaust tracts will exacerbate the problem. The only way to accurately assess this situation is to get the thing on a dyno with an O2 sensor. Best power is in the 12.5:1 A/F area and safe, best economy is around 14:1.

 

Should the mixture turn out right, the next thing is the ignition timing. It's a good thing to check that it's in spec, to start with. You can try retarding the initial advance setting, because that's where WOT runs. Running 4-6 degrees retarded is as far as I'd take that, becasue you'll quickly loose power with much more.

 

Lastly comes the possibility that fuel quality vs compression ratio could be the culprit. Short of swapping out the pistons for ones of a lower c.r. you can try tightening up the valve lash a couple of thou. effectively increasing overlap and thereby decreasing the dynamic cylinder pressure. YOu don't want to go too far this way either, or you risk burning valves.

 

Hope this helps.

[Guest Nogbad]

I think, and this is only my that if you are going for hi comp pistons and the whole works, you need an ECU with access to the ignition timing and more sophisticated tweaks than the power commander. The PC only variably delays on and off the existing pulse from the ECU to the injectors. It doesn't help with ignition timing, and that is a big control factor in pinging.

 

I think you would be much better off with the Jeffries My15M custom ECU than the PC because sensibly you can see how this device can affect all your engine management. A PC only tweaks fuelling.

[Guest drknow]

Is there anyone out there using the high compression stuff that has conquered the pinging?

 

DK

[BrianG]

Yes, there are other ways around ping from high combustion pressure designs.

 

I have a couple of fanatic friends that are running 12.5:1 in normally aspirated engines........... on 110 octane VP racing fuel and alcohol injection.

[Guest drknow]

Ha ha, I mean V11's on pump gas...

[richard100t]

I put on a set of NGK racing spark plug wires & that seems to reduce the pinging. Its a relatively cheap fix compared to some of the other suggestions. Try getting new spark plugs & making sure they are the proper gap. Other than that prepare to open your checkbook wide! lol

[Guest SCURA275]

HELO MY FELLOW SCURA RIDER,

I HAVE ALSO SUFFERED FROM THE SAME PING NOISES. THE ONLY THING THAT I HAVE FOUND TOO HELP IS NOT TO RUN IN THOSE RANGES. SPEED CAN BE HAD WITH A GOOD RIDEING STYLE. IHAVE THE FULL WORKS IN MY BABY FROM FBF(PISTONS,OVERSIZED VALVES,AIR BOX LIDDLESS,PORTED/POLISHED,POWERCOMANDER,MOTO GUZZI TI EXHAUSTS,)AND IT WILL STILL PING. SO I MUST RUN 93 OCT AND THEN ADD MAXIMA HI TEST(8OZ TO A FULL TANK) THIS DOES HELP ALOT.I HAVE NOT HERD A PING FOR QUITE A LONG TIME AND I RIDE VERY HARD. ALL MY RIDEING BUDDIES HAVE LITER SPORT BIKE,AND MY GIRL DOES US ALL PROUD.

[BrianG]

Since the pinging is PRE-ignition, the sparkplug's electrical function isn't part of the picture.... however, the heat-range rating of a spark-=plug actually refers to the heat-dissipating capacity of the plug, by virture of it's construction. You will notice that the it's the relative size of the porcelain at the electrode that is the most apparent visual evidence of this.

 

Generally, I have used this to keep fouling sparkplugs clean, by going up (hotter) a level or two, but you might indeed get a significant effect away from preignition if it is actually initiating from the heat of the plug's porcelain. Certainly it's worth a try. I'd suggest "2 heat-range" increments.

 

Keep an eye open for fouling, though.

[Cliff]

Since the pinging is PRE-ignition, the sparkplug's electrical function isn't part of the picture....

59975[/snapback]

Not true in all cases. The combustion initiated from the spark can cause the pressure to rise too quickly too early. This will cause detonation of the unburnt mixture.

I've had detonation at times and cured it by backing the spark advance off a few degrees

[dlaing]

Not true in all cases. The combustion initiated from the spark can cause the pressure to rise too quickly too early. This will cause detonation of the unburnt mixture.

I've had detonation at times and cured it by backing the spark advance off a few degrees

59982[/snapback]

I think Brian was refering to plug wires being a solution to pinging.

Regarding adjusting the advance, the only reasonable solutions I know of are Cliff's My15, some slick ECU that is inside of the tachometer from some company in Europe, or the performance software from Techno Research.

Dear Mr. Laing,

Thank you for your request for product information.  I have attached two pdf files containing product specifications and pricing.  In answer to your questions, the key locks to the ECU of the bike thus requiring a Direct Link kit per bike. The price for this is $379.00 but you have the option to buy additional keys (one per bike) at $279.00 per key.  If you have further questions feel free to call our office 248-658-1800.

Laura Scaccia

Sales & Marketing Manager

TechnoResearch, Inc.

lscaccia@technoresearch.com

248-658-1800

 

Or the cheapest solution:

TuneBoy has completed the Mapping software, that will adjust fuel and timing, but the diagnostic software is not ready as of July 11th.

http://www.tuneboy.com.au/ but they don't list Guzzi...