JohnC

Tuning L99 for Heads, Cam, Exhaust, Converter, etc.

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I never touched them. :no:

They were handed over new in the box with all the other parts when Diz put the car together for me.

I'll re-gap them when I get time though. :yes:

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1 hour ago, JohnC said:

I never touched them. :no:

They were handed over new in the box with all the other parts when Diz put the car together for me.

I'll re-gap them when I get time though. :yes:

Yeah, I meant when you pulled them recently, not when they went in the motor.  Just looks like a big gap.  Could just be an optical illusion.

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Ive only used Iridiums in one car (ST) and I had to regap them from where they came.  Luckily they needed the gap closed up if I remember right so it was easy enough.  Was warned to be careful adjusting the gap AND checking it so as not to damage the tiny tip.  Part of me hopes its NOT an illusion so that it can be the magic fix-all but were not all that lucky are we LOL

Matt

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4 hours ago, Disney said:

I bet optical illusion. They are Iridiums IIRC, which can't be gapped AFAIK.

I kept thinking they were pre-gapped from NGK but Googling their site I didn't see anything about it.

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Well, I added 64 ounces of Torco that would bring my octane up 11 full points.

http://www.torcousa.com/torco_product/un_acce.html

Add that E85 is 100 to 105 octane and my current octane should be between 111 to 116 now.

I logged my drive to work. I still have knock, even with timing pulled way back.

My conclusion is that it has to be false knock. 

I think we need to turn down the knock sensor sensitivity a little at a time until the false knock goes away while I have this high octane in the tank.

Opinions?

@gammey4

@Mike

@Disney

 

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Flase knock doesn't go away till you find the source and correct it.  Do what the other smarter folks suggest but I wouldn't mess with the sensitivity of the sensors until I exhausted every potential source, exhaust touching, motor and trans mounts, headers and flanges, radiator, cold air, oil catch can...anything loose that could rattle or bang around when driving.  Slow down, focus on this one issue then move forward and you will get the tune ironed out and happy!!!!

Good luck.

Matt

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14 minutes ago, 66sprint6 said:

Flase knock doesn't go away till you find the source and correct it.  Do what the other smarter folks suggest but I wouldn't mess with the sensitivity of the sensors until I exhausted every potential source, exhaust touching, motor and trans mounts, headers and flanges, radiator, cold air, oil catch can...anything loose that could rattle or bang around when driving.  Slow down, focus on this one issue then move forward and you will get the tune ironed out and happy!!!!

Good luck.

Matt

You'd have to ride with me to understand how loud this car is inside.

My sunroof vibrates, the back trunk area, etc.

I don't think it's loose stuff. It's just so much exhaust noise and vibrations resonating in the car causing it. 

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I don't know bout GM sensors but mines loud as hell at WOT and isn't false knocking. It WAS however when the header was BARELY touching a bracket.  Rap on the pipes with a mallet and if it rattles find it and fix it.  I would check things over really well before assuming it's just a loud exhaust, again unless it's a common issue with every LS car with an aftermarket exhaust.  My only worry is what happens when you get a bad batch of e85 or 93 and your knock sensor sensitivity is dialed down and can't do their jobs properly when actually needed? 

Either way, I still wish you luck getting it right and seeing what it's worth when 100%

Matt

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11 hours ago, JohnC said:

My conclusion is that it has to be false knock. 

I think we need to turn down the knock sensor sensitivity a little at a time until the false knock goes away while I have this high octane in the tank.

Opinions?

Yes, it's most likely false knock.  Do do any knock related tuning when you have the highest octane in there.  Wait until you run a tank of 93 through it before you fine tune sensitivity. 

 

I also think you have a non tune related isse.  Could be some part of your headers touching, could be noisy valvetrain etc.

The knock sensors are tuned for high frequencies, the exhaust drone is a very low frequency that the knock sensor can't pick up. 

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Issues with your virtual torque will also show up as knock retard even though it isn’t actual knock retard. Your virtual torque table is completely stock and should have been tuned by your tuner. Just like your vve table, it’s stock and should have been tuned as well. Log your commanded vs actual throttle position over rpm and you will see your throttle closing around 5,400. This is because predicted torque is lower than delivered torque. The ecm will first pull spark to bring torque back and then cut airflow by closing the throttle body. The virtual torque table also makes a huge difference in the transmission shifting as well.

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8 hours ago, gammey4 said:

Issues with your virtual torque will also show up as knock retard even though it isn’t actual knock retard. Your virtual torque table is completely stock and should have been tuned by your tuner. Just like your vve table, it’s stock and should have been tuned as well. Log your commanded vs actual throttle position over rpm and you will see your throttle closing around 5,400. This is because predicted torque is lower than delivered torque. The ecm will first pull spark to bring torque back and then cut airflow by closing the throttle body. The virtual torque table also makes a huge difference in the transmission shifting as well.

Guess that explains the dip in my dyno chart and why it feels like it stops pulling up top!

I'll log the commanded vs actual throttle position over rpm on my next drive to work. :up:

So how do I tune it properly is the question....

 

 

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25 minutes ago, JohnC said:

Guess that explains the dip in my dyno chart and why it feels like it stops pulling up top!

I'll log the commanded vs actual throttle position over rpm on my next drive to work. :up:

So how do I tune it properly is the question....

 

 

It’s just my opinion, but I think given all the changes you’ve made, you should consider taking the car somewhere that has a dyno on-hand and has extensive experience tuning high-performance GM vehicles.  I understand it might not be cheap, but it could be money well spent if it allows you to enjoy the car instead of continually chasing your tail trying to figure out what is going on.

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Guess that explains the dip in my dyno chart and why it feels like it stops pulling up top!

I'll log the commanded vs actual throttle position over rpm on my next drive to work. :up:

So how do I tune it properly is the question....

 

 

You can make error charts to correct it. I did that Sunday on a 14 Sierra that I tuned. Your commanded vs actual will be the one you use to apply a percentage change to it to “rough” it in. Then make a chart using predicted vs delivered torque to make final adjustments. It’s not so bad once you wrap your head around how it works. Also set up a chart watching dynamic airflow vs rpm so you can make sure you’re going in the right direction. If your airflow is dialed in you shouldn’t have any issues, if not you can end up chasing your tail for a little while.

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10 hours ago, gammey4 said:

Your virtual torque table is completely stock and should have been tuned by your tuner. Just like your vve table, it’s stock and should have been tuned as well.

That's not good.

What actually got tuned?  If he only edited the maf curve, that a very poor excuse for a "tune"

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1 hour ago, Nostalgic1 said:

It’s just my opinion, but I think given all the changes you’ve made, you should consider taking the car somewhere that has a dyno on-hand and has extensive experience tuning high-performance GM vehicles.  I understand it might not be cheap, but it could be money well spent if it allows you to enjoy the car instead of continually chasing your tail trying to figure out what is going on.

I second this. :up:

Matt

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That's not good.

What actually got tuned?  If he only edited the maf curve, that a very poor excuse for a "tune"

He added 2 grams of air to the braf, changed the cam timing tables and not much else. I don’t know who tuned it so I’ve kept my opinion to myself. I also don’t know exactly what was agreed upon to do to the tune either. John and I will be meeting up later this week so I can try and correct the issues he is having.

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@johnc post your last tune file before you took your car to Disney’s and the first tune file after you got it back from the tuner. Go tuners will let you see the differences. Editor-open main file (before work)- compare-open compare file (first tune after you got it back) then under edit view comparison log. Then we will all know what was changed.

And Disney I didn’t say he only changed two things. He just didn’t tune two important parts of it. I also said I didn’t know what was agreed upon to be tuned either.

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I think he was to be delivered a car that was pretty well tuned and might only need some more minor tweak, He did say that the E85 quest was causing problems and advised to abandon that. Also said to get with him with any issues and he would take care of them. Sounds like JohnC is having some issues he should get with him on....

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