How to evaluate knock values on sct x4 - Mustang Evolution

Go Back   Mustang Evolution > 4 Cylinder | V6 | Classic Mustangs || Tech and Talk > 2011-2014 V6 Mustang



Reply
 
Thread Tools Search this Thread
Please support our sponsors and let them know you heard about them here!
Old 12-23-2014, 10:20 AM   #1
Registered Member
Regular
 
JR4288's Avatar
 
Join Date: Sep 2014
Location: San Antonio
Region: Texas
Posts: 220
How to evaluate knock values on sct x4

Can anyone tell me what the knock sensor values mean when datalogging using an x4. I know what knock is but I have negative and positive values on my datalogs and don't know what this means

Sent from my SAMSUNG-SM-G870A using Mustang Evolution mobile app
JR4288 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-23-2014, 10:22 AM   #2
Registered Member
Regular
 
Voltwings's Avatar
 
Join Date: May 2014
Location: Houston
Region: Texas
Posts: 3,448
The knock sensor PID is measuring crank degrees in the direction of rotation that are added to or subtracted from the normal (usually borderline knock table) spark timing.

When the KS PID reads positive numbers, it means there are more crank degrees at ignition, which means a spark that happens later than normal, and most people call that ******. A negative number means fewer crank degrees at ignition; sure enough, that's ADVANCE.

When you first encounter it, it seems odd, but once you understand it, it makes sense.

You should normally see negative numbers as the KS looks for incipient knock - that's how the gets the most power out whatever octane you're running. It hunts relentlessly for the edge of knocking. Positive values mean your spark tables are providing too much advance.

In laymen's terms, this means "negative knock," is the computer adding more timing, and "positive knock" means the computer is pulling timing due to actual knock.


Taken From: How to: Understand your datalogs
Voltwings is offline   Reply With Quote
Old 12-23-2014, 11:13 AM   #3
Registered Member
Regular
 
JR4288's Avatar
 
Join Date: Sep 2014
Location: San Antonio
Region: Texas
Posts: 220
In either case is there damage to the engine?

Sent from my SAMSUNG-SM-G870A using Mustang Evolution mobile app
JR4288 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-23-2014, 11:16 AM   #4
Registered Member
Regular
 
JR4288's Avatar
 
Join Date: Sep 2014
Location: San Antonio
Region: Texas
Posts: 220
I get negative at the beginning of the pull and then it's zero through the middle and then positive near the end of the run

Sent from my SAMSUNG-SM-G870A using Mustang Evolution mobile app
JR4288 is offline   Reply With Quote
Old 12-23-2014, 11:21 AM   #5
Registered Member
Regular
 
Voltwings's Avatar
 
Join Date: May 2014
Location: Houston
Region: Texas
Posts: 3,448
The ecu's logic allows the car to add timing to increase power. That's negative knock, and that's normal.

Positive would be the computer removing timing due to what it deems "knock events." Not going to cause any immediate issues if the numbers are not anything outrageous, but obviously even small amounts of knock should be addressed with your tuner.
Voltwings is offline   Reply With Quote
Reply

Lower Navigation
Go Back   Mustang Evolution > 4 Cylinder | V6 | Classic Mustangs || Tech and Talk > 2011-2014 V6 Mustang

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Torque Values for Spring Change nitrous2v 2011-2014 Mustang GT 5 03-31-2013 09:09 PM
No 2013 car values on KBB yet, whats up with that? BUSHGUTS 2011-2014 Mustang GT 2 02-13-2013 03:50 PM
Need values on 2 Mustangs? adom Classic Mustangs 5 03-18-2010 09:00 PM
Knock Knock *Language* Brent Pictures and Videos 3 04-03-2008 05:18 PM
It's time to re-evaluate our involvement Ken The Bar 3 04-22-2004 02:33 PM

» Like Us On Facebook



09:29 AM


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0

MustangEvolution.com is in no way associated with or endorsed by Ford Motor Company.