False knock after some changes, ideas?

WildHorse

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I could put some isolators behind it though
Ok reason for the pic is cause there's a KS close to the #5 cylinder that could be picking up frequencies that could mimic a 'knock' scenario with the nitrous engaged. the further you can isolate the system, the better off it'll be.

 
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andrewtac

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Ok reason for the pic is cause there's a KS close to the #5 cylinder that could be picking up frequencies that could mimic a 'knock' scenario with the nitrous engaged. the further you can isolate the system, the better off it'll be.
I'll add something behind the mount, also need to add the parameters to my log file for individual cylinders.

I guess ultimately I can just say screw the ramp and start at 100%. This small amount probably won't blow the tires away; but would rather sort it out in order to use the function as I turn things up.
 

cbrtrx

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It's the nitrous solenoids causing it. Isolating them won't help, cause it reverbs down the hard line. You could try braided nitrous/fuel lines to see if it goes away.

Have been using nitrous since 2011 on coyotes with probably over 50 different combinations on them with no false knock issues at all.
 
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andrewtac

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I'm guessing its just too lean on tip in with the spray. Single foggers also have poor distribution on these cars although a 50 shot is small, what is the actual pill size? I only recommend plate kits for these.
Log shows around .8, is that to lean?
 

cbrtrx

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I think it was 38/23. I didn't have the fuel jet for 75 (41/25), and interpolated on the chart with the jets I had. I have more now, but haven't tried anything different.
Nitrous is at 1000 psi, fuel closer to 60. Double the length of the nitrous line, it helps the lean spike when using a fogger like that.
 


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andrewtac

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Nitrous is at 1000 psi, fuel closer to 60. Double the length of the nitrous line, it helps the lean spike when using a fogger like that.
Looked back at the log and it shows .84-.83.

I'll get a longer nitrous line.
 

TEXAS HEAT

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Looked back at the log and it shows .84-.83.

I'll get a longer nitrous line.
A longer n2o line or if you can control the nitrous and fuel solenoids separately, you can turn the fuel solenoid on 100rpm sooner to take care of the lean spike, which might be why it's knocking at the onset.
 
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andrewtac

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A longer n2o line or if you can control the nitrous and fuel solenoids separately, you can turn the fuel solenoid on 100rpm sooner to take care of the lean spike, which might be why it's knocking at the onset.
I already have a line that is twice as long, just haven't been home to install and test, hopefully Thursday.
 
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andrewtac

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20220309_093358_copy_450x1000.jpg

Nitrous line now double in length, maybe make some hits today.
 

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Hmm.. interesting setup. I'd prefer much closer to the TB. That'd IMO take care of the lean spike.
 
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andrewtac

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Hmm.. interesting setup. I'd prefer much closer to the TB. That'd IMO take care of the lean spike.
Well, I didn't know any better I guess. I called nitrous express and told them what I was thinking and they said it would work. The reason it is so far from the TB is that is the water meth ring, which is moved back in order to mix for IAT cooling (wish it was further back). I figured I'd just plumb it all in the same spot. First FI car and first nitrous car as well for me.

Now running 41/25 jets (75 shot, that is all I plan for until I build the motor or I am going for broke to make 8s).

So I made a few hits today. log files attached. I added individual cylinder knock to the logs and it rearranged the columns. run a and run c were from 3rd gear hit from low rpm. run b was on an asphalt road that I could not hook up on at all and had to ramp in the throttle. run b has a nitrous log as well, unfortunately I erased all the other N2 logs.

overall it does not seem to be lean at all, as the spray comes in it is rich and appears the commanded lambda is decreased throughout the run, this means it is rich correct?

there is something going on when I do a hit with a throttle slam from lower RPM. cylinder 4 shows up with some knock (2.4 on one run and 1.5 on the other at about 4800 rpms, right after slam). My trans has been out a few times recently, I'll look for something loose back there. Run b, where I rolled into the throttle around 5K I got no knock, and it actually advanced the timing 4.8 degrees on that pull (saw 22 degrees total). That was freaking violent, spray came on almost full as the WOT hadn't triggered the ramp yet and I was halfway through the band.

I also was able to finally log boost correctly now with an added sensor to the RTD. Car seems faster than before, found myself unable to monitor anything and just look at the road again. Need to go back to the track.

edit to add, I no longer think it is the ramp; as the run from a higher RPM still had some ramp and it didn't do it.
 

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TEXAS HEAT

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Hmm.. interesting setup. I'd prefer much closer to the TB. That'd IMO take care of the lean spike.
I think he's mainly using it for the charge cooling effect versus power, so the further away he injects it from the throttle body, the more time it has to cool the intake charge.

I don't disagree that the fuel could fall out of suspension in route to the intake manifold, but I think Nitrous Express could make a recommendation on the best location to inject based on his goals.
 
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andrewtac

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I think he's mainly using it for the charge cooling effect versus power, so the further away he injects it from the throttle body, the more time it has to cool the intake charge.

I don't disagree that the fuel could fall out of suspension in route to the intake manifold, but I think Nitrous Express could make a recommendation on the best location to inject based on his goals.
Correct, mainly for charge temp, however I'll take all the power I can get. Based on the logs, I don't think I am lean at all. If anything rich, if I am understanding it correctly. I am seeing commanded lambda of .65, doesn't that indicate it is pulling fuel?
 

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I dont have nitrous, but I had a tune that would immediately pull timing before my foot would even hit the floor. Switched tuners and all is good
 

 
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