The importance of Knock Sensors

[Jon-MooredPerformanceLLC]

Let’s talk knock sensors. Logging Knock Retard is not enough. You also need to log knock sensor volts. If your knock sensors are desensitized or turned off just looking at knock retard you will think everything is fine. We have seen cars with the knock sensors completely turned off. There are legitimate reasons to desensitize knock sensors. A smaller pulley can generate more noise for example. There are many ways to rule out real and fake knock like pulling power from the car or using higher octane fuel and if the knock is still there it is most likely fake. Here is a picture of the stock knock sensor volts from a stock tune so you can get an idea of where knock volts should be.

 

[DavidKFla]

You're going to need to check mine out and see where everything is set.

 

[Paladin06]

You're going to need to check mine out and see where everything is set.

Never fear he will hook you up. My Redeye was a dog compared to my Hellcat, for over 2 years until @Jon-MooredPerformanceLLC worked his magic.

 

[DavidKFla]

Never fear he will hook you up. My Redeye was a dog compared to my Hellcat, for over 2 years until @Jon-MooredPerformanceLLC worked his magic.

That seems to be a common problem coming from redeye owners.

 

[DGatzby]

My Redeye is a completely different car now. Hardly nothing similar from mellow driving and certainly when you give it the shit. If I was blindfolded. I would swear it is not the same automobile. The supercharger screams again for example, they had that SOB nearly shut down before I loaded a corrected calibration on it.

 

[DavidKFla]

My Redeye is a completely different car now. Hardly nothing similar from mellow driving and certainly when you give it the shit. If I was blindfolded. I would swear it is not the same automobile. The supercharger screams again for example, they had that SOB nearly shut down before I loaded a corrected calibration on it.

I don't know how they got the horsepower numbers advertised with the stock tune.

 

[DGatzby]

I don't know how they got the horsepower numbers advertised with the stock tune.

Cold absolutely perfect day and doing a couple pulls before it really heated up. It previously acted like that. On a cool morning or evening and doing your first pulls, very impressive. Let it heat up a bit and it went to hell. First day in 2019 we took it to BIR it was a fifty degree morning. It ran much different that time that EVERY other time since that first day. Strange! That very first tune version with no power added, had incredible differences in performance.

 

[DavidKFla]

Cold absolutely perfect day and doing a couple pulls before it really heated up. It previously acted like that. On a cool morning or evening and doing your first pulls, very impressive. Let it heat up a bit and it went to hell. First day in 2019 we took it to BIR it was a fifty degree morning. It ran much different that time that EVERY other time since that first day. Strange! That very first tune version with no power added, had incredible differences in performance.

Charger acted the same way. One of the reasons I started trailering it to the track.
I would get there and have it cool for about 90 minutes. Then after 1 pass on a warm day it would suffer heat sink.
Let it sit and drive back home.

 

[DGatzby]

Imagine some of my painful days where every two hours you do 25 minutes of drag racing corner to corner!

 

[DavidKFla]

Imagine some of my painful days where every two hours you do 25 minutes of drag racing corner to corner!

How about only 11 seconds at the time??

 

[Jimmy N.]

I would get there and have it cool for about 90 minutes.

In Florida, that means parking in an air conditioned trailer, right? How else could it possibly cool down.

 

[DavidKFla]

In Florida, that means parking in an air conditioned trailer, right? How else could it possibly cool down.

That's a great idea. And I've only been air conditioning myself.

 

[Magnified]

My Redeye is a completely different car now. Hardly nothing similar from mellow driving and certainly when you give it the shit. If I was blindfolded. I would swear it is not the same automobile. The supercharger screams again for example, they had that SOB nearly shut down before I loaded a corrected calibration on it.

Who did that?

 

[DGatzby]

How about only 11 seconds at the time??

Missing the point, David. Yes, most drag racers go for 9-11 seconds. Then you all get to let it cool. On a road course, we run it a ton harder with multiple WOT events over as much as 25-30 MINUTES without a break.

On the big tracks anyway we are “drag racing” corner to corner with constant basically roll races going on for the duration of the session at WOT. For a lot longer than 11 seconds. For example, beginning of a lap at BIR; after coming out of the last turn - #10 which is about 200-300 yards from the starting line, which I normally cross at about 100 mph, 11 seconds WOT, gets me about halfway down the quarter at BIR each lap (about every two minutes) then we still need to travel the remainder of the quarter, and over another quarter which is the NHRA runout, (at that point your speed is 160-170mph), THEN we set up (brake like you stole it) for the fastest banked corner in the USA. I just looked, my best sector time in there is 17 seconds! Most of that is WOT in that sector alone. A good driver/Hellcat enters #1 at 120-130mph, then we get to rip it again WOT to about 150mph or more with this tune, and brake into #2 to about 100-110, and so on and so forth for many laps. That is a big difference btw that and an 11 second drag race for the engine/systems. For this thread, Jon knows we need those sensors to work, due to the heat going on any changes or anything that may go wrong, and to assure me the dumb ass added the correct amount of expensive gas to the tank after filling it up.

 

[DGatzby]

Who did that?

@Jon-MooredPerformanceLLC

 

[DavidKFla]

Missing the point, David. Yes, most drag racers go for 9-11 seconds. Then you all get to let it cool. On a road course, we run it a ton harder with multiple WOT events over as much as 25-30 MINUTES without a break.

On the big tracks anyway we are “drag racing” corner to corner with constant basically roll races going on for the duration of the session at WOT. For a lot longer than 11 seconds. For example, beginning of a lap at BIR; after coming out of the last turn - #10 which is about 200-300 yards from the starting line, which I normally cross at about 100 mph, 11 seconds WOT, gets me about halfway down the quarter at BIR each lap (about every two minutes) then we still need to travel the remainder of the quarter, and over another quarter which is the NHRA runout, (at that point your speed is 160-170mph), THEN we set up (brake like you stole it) for the fastest banked corner in the USA. I just looked, my best sector time in there is 17 seconds! Most of that is WOT in that sector alone. A good driver/Hellcat enters #1 at 120-130mph, then we get to rip it again WOT to about 150mph or more with this tune, and brake into #2 to about 100-110, and so on and so forth for many laps. That is a big difference btw that and an 11 second drag race for the engine/systems. For this thread, Jon knows we need those sensors to work, due to the heat going on any changes or anything that may go wrong, and to assure me the dumb ass added the correct amount of expensive gas to the tank after filling it up.

I know. You missed my point that I only got 11 seconds, actually not even that, until it started pulling back power.

 

[DGatzby]

Who did that?

Oh who shut down the SC? Last year when they replaced the motor, I don’t know what calibration they put in it. But the SC whine was way down in sound. Now it is back way up in sound. Even at low and partial throttle, it is very different.

 

[Speedy!]

Also of note is how low the factory thresholds actually are in the knock sensor tables. It's a 0-5V sensor for reference.

 

[DGatzby]

I know. You missed my point that I only got 11 seconds, actually not even that, until it started pulling back power.

Oh, I know. It becomes apparent as the thing begins shifting like shit and the power drops and after doing everything I can with the boat driving it the lap times SUCK!!!

 

[DavidKFla]

Oh, I know. It becomes apparent as the thing begins shifting like shit and the power drops and after doing everything I can with the boat driving it the lap times SUCK!!!

Mine was laying over at 1/8 mile. Nothing like watching cars fly by you