tip in knock with turbo

[jamesm]

i've been working on building a new base map for my car and i've run into one of the same issues i had with the old tune, tip in knock. i have always had some knock when tipping into the throttle, usually at the moment that the manifold pressure goes positive. my previous tune had the ecu pulling -3 or -4 degrees sometimes, but usually -1 or -2. my new map is registering knock at the exact same time, only now it is always -1 degree. there is no knock under heavier loads or at any point after the initial tip in. usually the corrections are very quick, like < 100ms, sometimes longer in the range of 200-300ms.

the first thing i did to combat this was gradually pull a couple degrees of timing from the offending areas of the base timing map, which seems to have had no effect up to -3 degrees or so.

next i looked into the tip-in enrichment tables, since that was something i had to tune for my injectors and could've done wrong. tip in tables are in ipw, so i had scaled them as part of the initial injector scaling, then had to tweak it from there to get it to what i think is just about right. i have it now so that on tip in the afr goes just a bit rich, really not much at all, depending on the throttle delta. i'm not sure if that is correct or completely wrong, but it feels a whole lot better than the prior tune (which didn't touch the tables and would go to 9:1 or so on tip in). tweaking these tables slightly one direction or the other didn't seem to do anything, and the tip in knock remained the same.

the last thing i've looked into is the open loop transition. my theory was that maybe it was holding open loop for a bit too long and the lean afr was causing the knock. the logs seem to support this. i set all of the timers to zero per mad_sb's post in such a manner that my fuel map dictates the transition. the logs show that this was effective in getting the afr down to target by the time the load ramps up (with manifold pressure). still no effect on the tip-in knock.

i'm about to start checking for rattles. any other ideas? i'd appreciate the help, being a noob always sucks lol.

[brn12345]

Originally Posted by jamesm

i've been working on building a new base map for my car and i've run into one of the same issues i had with the old tune, tip in knock. i have always had some knock when tipping into the throttle, usually at the moment that the manifold pressure goes positive. my previous tune had the ecu pulling -3 or -4 degrees sometimes, but usually -1 or -2. my new map is registering knock at the exact same time, only now it is always -1 degree. there is no knock under heavier loads or at any point after the initial tip in. usually the corrections are very quick, like < 100ms, sometimes longer in the range of 200-300ms.

the first thing i did to combat this was gradually pull a couple degrees of timing from the offending areas of the base timing map, which seems to have had no effect up to -3 degrees or so.

next i looked into the tip-in enrichment tables, since that was something i had to tune for my injectors and could've done wrong. tip in tables are in ipw, so i had scaled them as part of the initial injector scaling, then had to tweak it from there to get it to what i think is just about right. i have it now so that on tip in the afr goes just a bit rich, really not much at all, depending on the throttle delta. i'm not sure if that is correct or completely wrong, but it feels a whole lot better than the prior tune (which didn't touch the tables and would go to 9:1 or so on tip in). tweaking these tables slightly one direction or the other didn't seem to do anything, and the tip in knock remained the same.

the last thing i've looked into is the open loop transition. my theory was that maybe it was holding open loop for a bit too long and the lean afr was causing the knock. the logs seem to support this. i set all of the timers to zero per mad_sb's post in such a manner that my fuel map dictates the transition. the logs show that this was effective in getting the afr down to target by the time the load ramps up (with manifold pressure). still no effect on the tip-in knock.

i'm about to start checking for rattles. any other ideas? i'd appreciate the help, being a noob always sucks lol.

Jamesm,

Might not be directly the same as your problem but I am getting tip in knock on my car, I can actually hear it clearly even though it just registers -1 on the logs. Whats baffling is that my IAM drops like a rock for no apparent reason during normal driving. Check this post out there are logs and pics, maybe you can find something useful to you there. I have it on good knowledge from a friend in the know that oil temperatures have a significant impact on ignition timing, yet none of the available definitions has any table related to oil temp compensations.

http://www.ft86club.com/forums/showp...2&postcount=56

[jamesm]

Originally Posted by brn12345

Jamesm,

Might not be directly the same as your problem but I am getting tip in knock on my car, I can actually hear it clearly even though it just registers -1 on the logs. Whats baffling is that my IAM drops like a rock for no apparent reason during normal driving. Check this post out there are logs and pics, maybe you can find something useful to you there. I have it on good knowledge from a friend in the know that oil temperatures have a significant impact on ignition timing, yet none of the available definitions has any table related to oil temp compensations.

http://www.ft86club.com/forums/showp...2&postcount=56

my iam is dropping because of it too... down to 0.5 last run. that's the only knock registered is the tip-in -1's. the previous tune had the advance table zeroed (in the lower load areas) so the iam would never go down because of it, a bandaid i guess.

[stugray]

Originally Posted by jamesm

the last thing i've looked into is the open loop transition. my theory was that maybe it was holding open loop for a bit too long and the lean afr was causing the knock. the logs seem to support this.

What are you using to log? Is it fast enough?

Does the log show that you are in OL or CL when the knocking is occurring?

[ft_sjo]

I can confirm you still get hideous tip-in det even when purely open loop. I've mapped the transient fuel and spark to the best of my abilities and it's still there. Too many un-defined tables. There are probably over a hundred transient tables in an ECU like this, i've got access to maybe half a dozen.

[mike the snake]

Would a standalone system like the Hydra be more capable of dealing with this?

Next week I'll be installing my turbo kit tuned with the Hydra EMS.

[jamesm]

Originally Posted by stugray

What are you using to log? Is it fast enough?

Does the log show that you are in OL or CL when the knocking is occurring?

i'm using brzedit personal for logging now. it's fast enough, around 60ms sample rate with what i'm collecting.

[brn12345]

I am using BRZedit as well. Great logger and analysis tools.

[jamesm]

Originally Posted by brn12345

I am using BRZedit as well. Great logger and analysis tools.

i love it as well, the software itself is fantastic. customer support is 100% non-existent, but whatever. i plan to switch back to ecuflash/romraider once logging is available that way. i had to buy brzedit personal just for the sake of logging maf voltage lol.

[brn12345]

Originally Posted by jamesm

i love it as well, the software itself is fantastic. customer support is 100% non-existent, but whatever. i plan to switch back to ecuflash/romraider once logging is available that way. i had to buy brzedit personal just for the sake of logging maf voltage lol.

Have to disagree on the customer support. Epifan went above and beyond to get me sorted.

[jamesm]

Originally Posted by brn12345

Have to disagree on the customer support. Epifan went above and beyond to get me sorted.

they were quick to respond to the initial drm-satisfying process, but since then i've sent two emails with no response at all. i think they're a bit selective as to what they respond to. buying something? two minutes. question? maybe sometime.

[brn12345]

Originally Posted by jamesm

they were quick to respond to the initial drm-satisfying process, but since then i've sent two emails with no response at all. i think they're a bit selective as to what they respond to. buying something? two minutes. question? maybe sometime.

Well your buying a tuning software solution. It works. What questions do you have? Maybe we can discuss here and find answers.

[jamesm]

Originally Posted by brn12345

Well your buying a tuning software solution. It works. What questions do you have? Maybe we can discuss here and find answers.

my question was regarding the license and if it is time limited. i.e. do i get updates, and if so for how long? the other question i answered myself by experimentation (getting loglink to work). i also had a question about saving roms in oft format (an advertised feature from the last update). i don't seem to have the option to do that.

[arghx7]

How do you know these are all cases of real knock?