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Discussion Starter · #1 ·
well, I finally got a predator. I LOVE the lower torque management! it really lunges.
NOTE: car has 95K miles, STOCK thermostat and NO catch can. And Im a newbie to this whole thing :)

I installed the 91 CAI tune, and noticed I get alot of part throttle pinging, between 10-35 mph, when given a "blip" of gas at low RPM. Same 91 gas that was in it before, with no pinging. I used the datalogging feature and got these results:
run 1:
ACT: 120.4 degrees (variable between 116 and 176 degrees)
ECT: 210.4 degrees (variable between 205 and 212 degrees)

LT knock max 3.5 degrees
ST knock max 6 degrees (the reading was set at 6, so its probably higher).

Then I added 3% more fuel across the board and a can of octane booster, getting these results:

run 2:
ACT (air charge temp): 131.2 degrees (variable between 116 and 179 degrees)
ECT (engine coolant temp): 206.8 degrees (variable between 205 and 210 degrees)

LT knock max: 1.5 degrees
ST knock max: 6 degrees


Whats causing all this ST knock!?
I would be happy to send you guys the logs so can take a look. Any help is REALLY appreciated. Im going to get a 180 T-stat in a few days.
 

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You really want to be looking for knock at WOT through a full gear (usually all of 2nd gear or all of 3rd gear if you have the space). The knock sensors are very sensitive and prone to hearing false knock, especially when the tranny shifts.

You're also into the temp range where the PCM is more likely to pull timing. Below about 190*F you're in good shape, above that there's timing being pulled.
 

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Discussion Starter · #3 · (Edited)
Thanks for the quick reply, I will do another log later tonight with a 2nd to 3rd pull.
a 180 Tstat is on to do list ASAP.

also, if they are reading false knock (possibly) whats with the audible pinging?
 

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At part throttle, lots of us with CAI systems hear an amplification of the EGR valve. If the Predator isn't logging knock when you hear the sound, it's probably not actual knocking.

A quick test to see if that's it or not is to use the Predator to turn off EGR. If the sound goes away, it's likely just the EGR valve and nothing to worry about. I leave my EGR enabled but trimmed the tube; some (like AWD_Gabe) have turned off their EGR system permanently.

Here's info on trimming the EGR tube:
http://www.chargerforums.com/forums/showthread.php?t=110699
No info yet on the long term engine effects of doing this mod. Some speculate that it could cause abnormal intake variations which would result in uneven cylinder temperatures.
 

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Discussion Starter · #5 ·
I thought the false knock from the EGR was a 5.7 only thing....Ill try it anyways nothing can hurt.
 

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Discussion Starter · #6 ·
OK, so I did a log like you said. I pulled from 1st, 2nd and half of 3rd. My knock sensors went nuts....I have the log and If any of you could take a look at it that would be awesome Id be glad to send it.

This is on an unmodified canned 91 CAI, no extra fuel.

Through the pull, I got:
ACT 100.6-136.6 deg
ECT 205-212 deg
LT 2.5 deg
ST 5.5 deg

Im thinking I desperately need a thermostat and a catch can.
 

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I thought the false knock from the EGR was a 5.7 only thing....Ill try it anyways nothing can hurt.
It is.

The 6.1 doesn't have an EGR valve ;)
 

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Discussion Starter · #9 ·
Update: I installed the 176 degree 4127 thermostat today and noticed that it really helped with the pinging. Fans were adjusted accordingly. Its almost 100 degrees here today, so engine temps were between 185-195. I can still hear a little pinging at part throttle blips low rpm low speed.
My next step will be a catch can and I will look to see if there is garbage in the intake that needs to be cleaned. I will also try different gas.

Mike- I will datalog and send you the logs tonight when its a little colder out, so you can compare both runs. Thanks so much for the help
 

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FYI - as much as you might want to just get rid of any knock you may have, knowing what's causing the knock in the first place is step #1. Changing too many things at once (catch can, ambient temperature, different gas, adjusted tune, etc.) won't help identify which of them was contributing to knock.

Once you've minimized (not necessarily eliminated) your knock, don't make any changes and drive it that way for a tank or two, then do more logging to see if it's stable or if it was a fluke. The adaptives also tend to have a small effect, even at WOT.
 

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I guess i need to turn off egr or lower temp thermostat
 
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