Prediction Coefficients

[JBZ]

Does it ever end? Will I ever not have a laptop in the passenger's seat?

LOL...i agree. I have an aeroforce that sits in the center stack that is really quiet . I would really like to go to using it to monitor and leave my tuning laptop at home for awhile. But cant ever seem to get it just right. Maybe its novice problems or im stuck to road tuning that makes it an endless cycle.

[realcanuk]

I did the constant logging and adjusting thing for a couple of seasons. I finally realized that it will never be perfect. Now I leave the laptop at home and drive the car. Much more enjoyable. My advice would be don't drive yourself crazy. As long as the car runs good, and nothing is obviously too far off, just enjoy it.

[JBZ]

I did the constant logging and adjusting thing for a couple of seasons. I finally realized that it will never be perfect. Now I leave the laptop at home and drive the car. Much more enjoyable. My advice would be don't drive yourself crazy. As long as the car runs good, and nothing is obviously too far off, just enjoy it.

yeah I believe I will have to come to that point eventually. not being a pro or having the correct tools (I.E. Dyno) there is only so much I can do. I am trying to tune my VVE again and that has me struggling to understand volumetric efficiency. but otherwise most things seem to be OK.

[cc-rider]

I tried to zero out the predicted tables once. Don't recall the exact details, but it made burst knock go bonkers. I happen to like the burst knock feature (I know some just kill it), so ended up just going back to the OEM settings.

Looks like I have something else to experiment with..... Does it ever end? Will I ever not have a laptop in the passenger's seat?

No kidding?! I think you may have just solved an issue I have been dealing with regarding burst knock. See my thread on it here: http://www.hptuners.com/forum/showth...st-knock-issue

Is that what happened to you as well with burst knock when you zero'd out the prediction coeff? I get this repeated triggering of BKR. Check out the pic in my post.

[Michael_D]

I'll have to look. I do recall posting about it, just not when, where or why...lol

[GHuggins]

Zeroing out the prediction coefficients seems to screw with cylinder air mass calculations. An example of this is to zero them out then do a pull. The first pull will be lower in the air mass cells and have the equivalent spark knock to put timing right where you have it in the higher air mass cells. After the time out period it does some sort of cancelation on this part of the equation and goes back to registering in the correct air mass cells. For what ever reason it won't do this reset for the burst knock, SO you have to either substantially detune it or zero it out. Not sure why it doesn't screw with the regular knock parameters the same way, but they don't seem to be affected.

[realcanuk]

I zero out the coefficients and turn off burst knock and its perfect. Doesn't worry me at all to turn bk off.

[GHuggins]

If timing is dialed in, you shouldn't have any problems IMO...

[cc-rider]

I'll have to look. I do recall posting about it, just not when, where or why...lol

I'm with you in that I like the idea of burst knock as well. Especially for a positive displacement blower like I am running. They just throw so much boost at the engine so fast. I get KR when banging gears and shifting hard, but if I shift smooth, it will take the timing with no problem. So the idea of being able to pull a very brief amount timing back as it barrels into boost is really a nice feature for a PD blower application.

[Michael_D]

If timing is dialed in, you shouldn't have any problems IMO...

Not when forced to use shitty fuel. I also find it prevents aggressive downshift and throttle KR. I do however dial it back significantly.

[mowton]

Not when forced to use shitty fuel. I also find it prevents aggressive downshift and throttle KR. I do however dial it back significantly.

I leave it active (read somewhere's deactivation can cause hidden issues) and multiply the table by .2 just to leave a little bit :-)

Ed M

[GHuggins]

Nearly every application I do is a positive displacement blower. I don't have any problems with this. Perhaps what I thought wasn't the best fuel actually is decent? I also thoroughly dial in transient fueling, injection timing and of course ignition timing in a somewhat controlled environment though.

[cc-rider]

I leave it active (read somewhere's deactivation can cause hidden issues) and multiply the table by .2 just to leave a little bit :-)

Ed M

When you say that you leave "it" active...are you saying that you leave prediction coefficients active? Or leaving burst knock active?

[cc-rider]

Nearly every application I do is a positive displacement blower. I don't have any problems with this. Perhaps what I thought wasn't the best fuel actually is decent? I also thoroughly dial in transient fueling, injection timing and of course ignition timing in a somewhat controlled environment though.

Do you have a rule of thumb for injection timing that seems to work for PD blowers? Or is this something that varies a decent amount on each set up?

[JBZ]

Do you have a rule of thumb for injection timing that seems to work for PD blowers? Or is this something that varies a decent amount on each set up?

Injection timing is based off of your cam and the valves opening/closing events vs your injection start and end. Its pretty fun to play with and i saw a noticable (and i only know from my butt dyno and watching the wb) difference.

By the way Gregs the man when it comes to injection timing...sorry Greg to throw you under the bus like that im so anxious to throw my car back on the dyno and see wht gains it made...if i feel it then it has to be some what substantial.

[GHuggins]

Under the bus? Not sure how you threw me under the bus Just glad your liking it Josh - think your really going to like the gains that the ability to add timing will give you

I pretty much do injection timing different than anyone out the cc-rider... As Josh and others have seen - it even works rather well with stock cams...

[cc-rider]

Under the bus? Not sure how you threw me under the bus Just glad your liking it Josh - think your really going to like the gains that the ability to add timing will give you

I pretty much do injection timing different than anyone out the cc-rider... As Josh and others have seen - it even works rather well with stock cams...

Got it. I'll PM you. I know you do this for a living and I completely respect that, and I have no qualms about paying some money to have you help me dial this in.

[JMsquared]

I appreciate each of your input, there is not much on the 4 cylinder board when it comes to my 2.4SC\E67 combo.
I will make the request.
The explanations about the volume and the estimated MAP maximum gives me hope.

[JBZ]

Under the bus? Not sure how you threw me under the bus Just glad your liking it Josh - think your really going to like the gains that the ability to add timing will give you

I pretty much do injection timing different than anyone out the cc-rider... As Josh and others have seen - it even works rather well with stock cams...

Lol...i was kind of joking but kind of not. I was a pest and dont want to name drop you as the guy who can make it happen and get people knocking your door down.

Got it. I'll PM you. I know you do this for a living and I completely respect that, and I have no qualms about paying some money to have you help me dial this in.

And on that same note as above. I learned alot from Greg and also from all the leg work i did to understand injecting timing for myself. I absolutely dont mind sharing what i know with you as well and atleast get you the basics of what you need to find out your current injection events. Now for calculating where you want it to be...i can only tell you what worked for me and what greg has told me and posted in other threads as the limits... Im pretty sure its a lot of trial and error.

Here is a great thread that gives a lot of info on injection timing. Start on page two and do what i did...read it about 400 times.
http://www.hptuners.com/forum/showth...for-help/page2
Ohh and i see no KR anymore.

[cc-rider]

I'll read through that. Thanks for sharing. And I know what you mean by read through it 400 times to understand it. But that's what makes self tuning kind of a challenge and fun.