What is the Dataviewer Telling Me?

[daswi]

I'm attaching a data log. I think of interest in this log is my WOT run from 5:47 to 5:53. Can any of you smart gearheads out there tell me what's happening? Im running Exxon 93 Oct on an 09 Challenger R/T Automatic.
Mods:
MM 85mm TB
JMB CAI
Blastin Bobs Resinators
BT Catch Can
DS U7135
Rev 9r17
DS Perf 91Oct CAI Tune

[duster360]

You have some knock.

If you would have logged RPM, I would have suggested you remove 2 degrees at that RPM, reset the PCM and retest.

1-2 step colder plugs might be a good idea too.

[daswi]

Thanks duster, I log rpm and re-run test. Not sure what your telling me about the plugs tho.

[Mike_Levy]

Don't worry about the plugs. You don't need them. Not worth replacing 16 plugs when you can tune out the knock by adding fuel.

[duster360]

Don't worry about the plugs. You don't need them. Not worth replacing 16 plugs when you can tune out the knock by adding fuel.

Richer A/F = less HP
Lower timing to reduce Knock = less HP

daswi, how much is MORE Hp "worth" to you?,,,obviously at least $400 you already spent on a Predator. Is the price of 16 spark plugs too high of a cost to bare?

give me a break

Champion RE10PMC5 (2 steps colder than RE14) ~$2.50 each total cost $40
Seems like a bargain to me.

[Mike_Levy]

I don't see the point in spending money for maybe half a horsepower when you can get close enough for free. With all my mods (see sig), on a BASE TOON (not even dyno tuned yet!), I have no KR and am running STOCK plugs. He has a fraction of what I do, so theres really no reason for him to change them either.

This isn't the 70's anymore. Computers and programming can compensate for just about anything. You just gotta let them.

[duster360]

Computers and programming can compensate for just about anything.

That statement alone should tell anyone they ought think twice about taking your dubious "advice." Comparing the performace of your engine(which is drastically different) is irrelavent and just another indicator that better advice should be sought elsewhere. It would make just as much sense if I said,

"The wife's minivan didn't need colder plugs, so don't worry about it"

And about that "This isn't the 70's anymore" wisecrack,,,,fyi: my 1974 Duster 360 has a fullY MODERN stand alone SMPI designed, installed and tuned by your's truely.

[DGatzby1]

So you guys post here asking for advice, then someone who has lots of experience tells you what is best and you not only tell him he does not know what he is talking about, you openly call him names? Why would anyone else or Mike L give you anymore help?
I looked at your log, your have ST knock without WOT! Your car is knocking so much you have woke up the LT knock part of the program and that is a sign of real bad gas if you have not modified the 91 oct canned tune. You got five degrees of knock at WOT, I would say save your cash on those plugs and keep trying different gas until you find some that does not give you knock. Look we all have the same problems, right? We all don't go out and buy different plugs to cure the problem, we have found that the GAS is the biggest difference to the knock problems, NOT CHANGING SPARK PLUGS. OR == your car is hearing false knock from one of your add-ons, check everything and make sure nothing is rattling around and causing a false knock to be heard by the sensors.

I also may add that it is not true that making your particular car richer will result in less HP. Since YOUR vehicle is pulling timing presently, adding gas will stop the advance retard and result in more HP. But check the noise and try some other gas before doing anything else. You bought the tool to tune your car, try to tune first since you sound like you have experience from the "70's". FYI you are with lots of others who share the same talents, interests and experience.

[duster360]

your car is hearing false knock from one of your add-ons, check everything and make sure nothing is rattling around and causing a false knock to be heard by the sensors.

daswi, I agree that "false" knock is a possibility.

I also may add that it is not true that making your particular car richer will result in less HP. Since YOUR vehicle is pulling timing presently, adding gas will stop the advance retard and result in more HP. But check the noise and try some other gas before doing anything else. You bought the tool to tune your car, try to tune first since you sound like you have experience from the "70's". FYI you are with lots of others who share the same talents, interests and experience.

Most gains from the 91/93 tune are from leaning the A/F. Adding fuel WILL limit any gains. Will it lower HP more than leaving the A/F where it is and removing 2 degrees and/or Spending less than 1 tank of gas on plugs? You say no,,I say yes.

Just because none of "the cool kids" replace their plugs, doesn't automatically dismiss it as a valid strategy. Leaner A/F and/or more timing WILL increase chamber temps and consequently the plug tip. imo I'd rather spend $40 once, than be handcuffed to a particular gas pump forever.

[Quick]

Ummm, with our fragile ring lands and tight gap tolerance I don't think we can stand much of an increase in chamber temps.

[duster360]

Ummm, with our fragile ring lands and tight gap tolerance I don't think we can stand much of an increase in chamber temps.

As long as there's no detonation there less of a concern about "chamber temp".

A piston thats too hot will show damage from its center outward.
A piston damaged by detonation will show the damage from the outer edges.

So if you're worried about "fragile ring lands" then Knock is your #1 priority.

[Quick]

A piston thats too hot will show damage from its center outward.

The new hemis have a rather tight ring gap (and then some have been found out of tolerance on tight side) and a rather narrow top ring land. Mainly a concern with FI, but a common failure is over temp causing the ring gap to close. The ring usually survives but it breaks the top land. I believe there have been a couple of NA engines that blew up this way. Don't remember what timing they were running or mods. Maybe it's not that much of a concern without major mods but our engines have less tolerance for raising the chamber temps than most. The ones that do fail from getting too hot almost always break on the outside. I'm not sure I remember seeing any with a hole burnt in the center.