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Knock ******

M1ck3y

By M1ck3y
in Engines & Drivetrain

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M1ck3y Senior Enthusiast

M1ck3y

Posted
Posted (edited)

I tried searching and I couldn't really come up with anything. I'm trying to find out if there's an acceptable level of knock on the Gen V engines. Justin did up the tune for me and its been great, But I've been trying out e0 (tuned e10). I just filled up today and I'm pretty sure they've made the switch to winter gas now, and the log is showing a max of 4.8 degrees knock ******. Where as before it wouldn't move far from 3 degrees. Happens at wot, and low rpm going up a hill or accelerating without downshifting. Wot seems to be consistant around 3 degrees, its the low rpm/load that has me concerned. 

 

I don't have access to the tune, and it is on efilive... I'm just not sure if its safe to go through this tank then put in some e10 or if I should be looking for some octanium right now?

 

 

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Edited by M1ck3y
Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
16 minutes ago, M1ck3y said:

I tried searching and I couldn't really come up with anything. I'm trying to find out if there's an acceptable level of knock on the Gen V engines. Justin did up the tune for me and its been great, But I've been trying out e0 (tuned e10). I just filled up today and I'm pretty sure they've made the switch to winter gas now, and the log is showing a max of 4.8 degrees knock ******. Where as before it wouldn't move far from 3 degrees. Happens at wot, and low rpm going up a hill or accelerating without downshifting. Wot seems to be consistant around 3 degrees, its the low rpm/load that has me concerned. 

 

I don't have access to the tune, and it is on efilive... I'm just not sure if its safe to go through this tank then put in some e10 or if I should be looking for some octanium right now?

E-0 or E-10 matters not if the octane is the same. That pump number is pretty darn accurate. That said the difference in motor and research may be a bit different, a point or so. Summer, winter, doesn't matter as far as knock is concerned. 87 is still 87 and 93 is still 93. The ECU reads the knock sensor and retards timing until it reaches the knock threshold. Ergo the exact number or amount of ****** is irrelevant. The point of the sensor and ECU correction is to assure a safe BUT maximum amount of timing. 

 

Shorter? Don't worry about it. It's fine. On a hot day mine will back up 7 degree even if I am running 93 on a slow hill. Been doing it for 130K miles. It's fine.

  • Like 1
M1ck3y Senior Enthusiast

M1ck3y

Posted
  • Author
Posted (edited)

Thanks Grumpy. I forgot to add that I didn't really hear any knock either. I thought I could have heard something but it was to hard to tell if it was the valve train, injectors etc. or if it was knock. The truck is loud, makes it difficult to tell the difference. And I'm using the highest octane I can get here.

 

Justin was saying that the octane rating should be the same but doesn't usually work out that way. The ethanol seems to provide more knock resistance. It doesn't help that overall cdn gas seems to be worse.

Edited by M1ck3y
  • Like 1
CamGTP Senior Enthusiast

CamGTP

Posted
Posted

Low load part throttle knock is nothing to worry about, they will pretty much all do it. Especially if they are fighting the torque converter or the transmission is not wanting to downshift because of emissions/fuel economy reason they program into the calibration.

 

Wide open throttle stuff could be from a tad too much timing or improper commanded fueling at full throttle. I see a lot of tunes with real lean air fuel ratios, like 12.9-13.1. These engines can surely handle that but I've never been able to unless I run E85. I stay closer to 12.5-12.7 on pump gas and I get far less knock from being slightly richer.

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