False knock after some changes, ideas?

[andrewtac]

Whats the total timing at? Probably check the plug gap again. Could be worse tho my old procharged 13 would pull 9* on a hard shift. Never was able to remedy it, just moved on to a whipple.

It stops about 18-19, used to go to 20-21 on the e70 tune. I have an e85 tune I was planning on trying again that goes to 22.

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[Basspro302]

Try and get some known good fuel sunco e85r or one ethanol.

 

[andrewtac]

Try and get some known good fuel sunco e85r or one ethanol.

I have fuel that tests about 87-88 percent. I just filled up again with it, prior to the fuel line sensor indicated 84, I expect it higher.

 

[engineermike]

Do you know anyone with an MVPI2?

 

[andrewtac]

Do you know anyone with an MVPI2?

No, but I could buy one.

 

[engineermike]

Iirc the gen3 uses per cylinder knock advance up to about 5000 rpm. After 5080 it switches to global (the least common denominator). Vcmscanner can log and graph each cylinder’s knock advance so you can watch them advance together and see which cylinder knocks first, which isolates the problem and helps determine how real and repeatable it is. You can also log spark source, mbt, and borderline to see if something else is limiting it.

 

[andrewtac]

Iirc the gen3 uses per cylinder knock advance up to about 5000 rpm. After 5080 it switches to global (the least common denominator). Vcmscanner can log and graph each cylinder’s knock advance so you can watch them advance together and see which cylinder knocks first, which isolates the problem and helps determine how real and repeatable it is. You can also log spark source, mbt, and borderline to see if something else is limiting it.

I have an RTD, should be able to do that. Thanks, might try some hits tomorrow if the weather is nice, maybe it is gone.

 

[andrewtac]

log file from today. I need to add parameters to look at the things mentioned above, this is the channels that Lund uses. I went through some old logs and compared todays as well. The -2 thing is probably not issue, but I was seeing some positive when spraying.

I think with the nitrous off, and it only going to -2 is just a function of it not having enough time on the pull to get to -4. On most of my old logs where it was a single gear pull it only goes to about -2. At the track from a standstill (rather than a roll) it builds to -4 much quicker than if I was already moving. Though I did find one log where I did two pulls in the same log from a roll, and one went to -4 and the other -2.

There is something going on with the nitrous though, as it went positive on this pull today, +1 (like some of the other pulls) and ramped out to -2. This coincides with when I have the ramp come in. My previous ramps were time based, 2 seconds starting at 4500 rpm. Looking a log from the first nitrous test, as soon as the spray starts goes to +1.4, then ramps to 0 in about 2 seconds. I changed the ramp to come on at 4500 rpms (0%) and 100% by 6500. The knock goes to +1 at bit about 5000, then ramps to 0 by 6500, then slow goes to -2. What is wierd is I did a pull the other day with the solenoids on, and the bottle not hooked up. I verified with the nitrous log file, the solenoids were firing, but on VCM it did not show +KR values (0 to -2). So it is related to the nitrous, I am fairly certain but don't think it is the solenoid firing. Only when actual spray gets shot is it going positive. I am using a nozzle in the intake pipe, perhaps it is the high pressure nitrous opening up on the intial shot hitting the pipe? Though what is wierd is the ramping out of the positive value follows the nitrous ramp, so maybe it is because the spray is coming on and off during the ramp. I'll call nitrous express monday, I might be able to change the frequency a bit to help.

 

[cbrtrx]

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.

 

[WildHorse]

Only when actual spray gets shot is it going positive.

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.

 

[andrewtac]

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.

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.

 

[andrewtac]

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.

Then why doesn't it do it when the fire but there is no nitrous hooked up? This was my first thought as when I was testing them they sound like a woodpecker. I do have braided lines. I might try to put some rubber behind the mount.

 

[WildHorse]

Then why doesn't it do it when the fire but there is no nitrous hooked up? This was my first thought as when I was testing them they sound like a woodpecker. I do have braided lines. I might try to put some rubber behind the mount.

let see a nice clear pic of where the solenoid is mounted.

 

[andrewtac]

let see a nice clear pic of where the solenoid is mounted.

Unfortunately this is probably impossible

 

[andrewtac]

I could put some isolators behind it though

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