jagged dyno graph = detonation?

[isnms]

so what's this i'm reading about jagged lines on the dyno graph being an indication of detonation?
my timing is 10, new plugs, 93 octane and my graph is all kind of jagged after peek torque.
http://www.supramania.com/forums/showthread.php?p=64355&p=64355
just about every graph i'v seen, online and the night of dyno, had jagged lines :dunno:
btw, i don't hear any pinging.
if detonation. what should i be looking for?

 

[malloynx]

could be a number of things. were is your plug gap set at? how much boost were you running?

i have had the same problem before

 

[isnms]

plugs BCPR6EIX iridium at .030", boost was ~9psi

so, it is an indication of detonation?
i don't have any other signs. btw. what are other sign of detonation?
what else could the jagged lines indicate?

 

[isnms]

rpm reading was taken with tape on the crank pulley, not from induction. so it's not noise, right?
i am most certainly not running lean, 10.2:1 A/F. (all readings in the zt-2 datalogs.)

 

[isnms]

how likely could it be this:

Going back to the question of the chart looking ugly, those jagged spikes are from the Boost Controller trying to control the boost. It uses a solenoid valve which opens and closes very rapidly. This is not felt when driving the car but the dyno picks up everything. If we were using just a waste gate the chart is usually very smooth.

I have an hks evc IV

 

[Reign_Maker]

HKS EVC IV = teh suck... more like = teh pain in the ass! I have one... And I dont think that's whats causing your jagged-ness... Might just be your turbo, might be your fuel delivery too... Look at my dyno, it's not jagged, and we have the same boost controller...

 

[isnms]

but where's the graph?
i just installed my newly upgraded 50trim ct in june.
my fuel is all stock: pressure is tested good, injectors are all ticking ( haven't flowed tested and cleaned them though ), fuel filter new. coil pack test ok.

 

[isnms]

what about knock

As I have noticed from other posts on here, the SawTooth part of your dyno comes from the engine "knocking" and thus the Knock sensors kill fuel and timing. So they protect the engine then turn it loose. Then they hear "knock" again so they do their thing to protect, then turn is loose and so on. There are others that could tell you a little more in detail as to what is going on, but that is what I have been lead to believe is the reason for the SawTooth effect.

But I don't get knock code :dunno:

 

[Reign_Maker]

Where's what graph? My dyno? Look in my post about my turbo, first page...
Here's my dyno with the CT-26 60-1 trim on an auto tranny... *this is my OLD car, not the one I have now* Not perfect, but it was tuned with SAFC2, fuel and air was from a lex/550/walbro set up... I think you might be losing fuel...

Stock fuel sucks...

 

[isnms]

wow, that is much smoother than mine. looks like it has a smoothing factor of 3 and mine is 5 and mine is still much worse than that.

how, though, with an a/f of 10.2:1 am i loosing fuel?

 

[GrimJack]

I've been told that jagged graphs can be caused by uneven ignition.

 

[isnms]

what do i do to track down uneven ignition? cps, coil pack.(i have checked these before and they check ok to tsrm)
my timing is set to 10°btdc, timing advance is 12°btdc. the mark does jump a small amount, does that indicate uneven ignition?

 

[SuprAng]

mine does that too at high boost, my plugs couldnt handle it, i had to regap them, in your case it wouldnt be surprising that youre fouling them running so rich...

Ang

 

[isnms]

so if i get my safr tuned, it should straighten out my graph? :x:

 

[mk3ukr]

I remember somebody mentioning something about smoothing factor of dynojet software. probably on this particular dyno run it was too low (high ? )
Vladimir, 89T

 

[isnms]

do you mean smoothing on collecting the run itself or smoothing on the results?
the previous results graph was with smoothing 5, smoothest, here is one with 0. my engine has parkinsons

 

[mk3ukr]

do you mean smoothing on collecting the run itself or smoothing on the results?
the previous results graph was with smoothing 5, smoothest, here is one with 0. my engine has parkinsons

Then it is smoothing factor. It doesn't look like detonation IMHO, det is highest at peak torque and goes down when rpm rise. Your graph getting more jagged with higher rpm. It is strange why graph took dive at 3400rpm. I had similar dive when I injected meth/water too early. On the road I was able to feel car stumble at that point.
Maybe tires slip on rollers ? :icon_conf
Vladimir, 89T

 

[isnms]

... It doesn't look like detonation IMHO...

That sounds reassuring to me Tire pressure was checked/set 35psi before the run. to high, to low?

for now I'm hoping to go with Ang's suggestion:

...in your case it wouldnt be surprising that youre fouling them running so rich...

any thoughts on knock? remember - i have no knock code.

 

[lagged]

that dosnt mean shit. the code for the knock sensors indicate only that they are NOT working correctly.

when you knock, they simply do their job and pull timing. they DO NOT throw a code when knocking is detected.

 

[isnms]

okay, thank you, then, would you say that my dyno results indicate knock or not?
93 octane, base timing 10°btdc, .030" gap plugs, ~10.3:1 a/f, no audible pinging

edit:are knock and detonation the same?
am i chasing one term when an opinion has already been given on the other. am i :nuts: