ECMlink Using DSMLink to tune for knock on a 2g

[zippyshoe]

I'm a newbie to tuning with DSMLink, and have just finished tuning my global fuel and deadtime values for my upgraded injectors. So now I am starting to tune for WOT operation. One of the parameters that I'm logging is Knock/KnockRetard. I was wondering if there is an "acceptable" level of knock permitted when tuning at WOT? Ideally, there should be no knock whatsoever, but on my first WOT run, I logged a maximum of 0.7 degrees of knock (equivalent to a KnockRetard value of 2) in the upper RPM range at a boost level of 15psi. I plan on doing another WOT run at 13psi (the lowest boost pressure I can achieve) and checking for any knock detected. But I was wondering if 0.7 degrees of knock would be considered "acceptable"? Thanks for any input.

 

[RedTurboEclipse]

As long as my CE light does not flash showing there isnt high counts of knock, I don't worry too much. Check the setting where you can see/adjust how many knock counts before the CE light flahses. But if it stays lit I definitely back off the pedal. Might want to consult the dsmlink forums for answers from the veterans.

But it is good that you are being very careful and safe, something a lot of DSM owners don't do resulting in the unreliablity and perhaps the end of their vehicle.

 

[Staytuned]

I tune for less than 1 degree of knock, so yes I would be happy with that .7 degrees. There is no sense in allowing more knock as it just pulls timing anyway.

 

[andymoraitis]

Tuning for 1 count is fine, but remember that the 2G ECU holds timing at 7 counts and then retards one degree of timing for every 3 additional counts up to 43. For pump gas, 1 or less than 1 is fine. I usually tune for 2-3 and then back down 1 degree of timing, but it seems like you're right on the mark.

Keep in mind that for pump gas, you want a WOT tune at a safe 11:1 A/F. Going leaner isn't worth it.

Good job!

Andy

 

[daren_p]

.7 deg of knock is fine, obviously zero knock is better but that is so minimal that it could be a number of different things causing it. Is it just a little blip or does it continue throughout the whole pull? Most of the time I see zero knock but the odd time will get a spike here & there, one or 2 deg isn't anything to worry about. From DSMLink the CEL is set to flash at 5 deg, at this point you would want to let off if you see it flash. Im cautious so I set my CEL light to flash at 3 deg. I get off the throttle for a sec if it does flash durning a WOT pull but it rarely happens.

 

[zippyshoe]

.7 deg of knock is fine, obviously zero knock is better but that is so minimal that it could be a number of different things causing it. Is it just a little blip or does it continue throughout the whole pull? Most of the time I see zero knock but the odd time will get a spike here & there, one or 2 deg isn't anything to worry about. From DSMLink the CEL is set to flash at 5 deg, at this point you would want to let off if you see it flash. Im cautious so I set my CEL light to flash at 3 deg. I get off the throttle for a sec if it does flash durning a WOT pull but it rarely happens.

I believe I am probably seeing genuine knock - I see a few small blips in third gear, but in fourth gear (automatic) I see a continuous knock level of 0.7 degrees (2 counts) from 4900-5100 rpm (I am running out of road at 5100 rpm and stop the run). I'm thinking I may be heat soaking my stock intercooler (hot, humid day, 103 degree F intake temperature). I also have my CEL set to flash at 3 degrees of knock and never had any flashes during the run. Incidentally, this run was on 93 octane pump with my timing sliders and WOT fuel sliders all zeroed-out.

 

[zippyshoe]

Well, I just finished another WOT run with the boost turned-down to 13psi. Even at 13psi, I see 1 to 2 counts (0.3 to 0.7 degrees) of knock in third gear. In fact, I saw a 0.3 second interval of 3 counts (1.1 degree) of knock in third gear. My injector duty cycle never goes above 60% and my front O2 voltage is at 0.94 volts, which leads me to believe that I have plenty of fuel. My WOT fuel sliders are all zeroed-out, so my car should be running pretty rich (factory rich). I'm wondering if my stock intercooler is contributing to this knock? Thanks again for your input.

 

[Staytuned]

Here is my best third gear log to date. 25 psi 94 octane.

 

[daren_p]

If you trims are inline and you said all your sliders are at zero, defently shouldn't be to lean knock. More then likely its do to the stock SMIC, even with the upgraded HRC SMIC that I first ran with my evoIII I would usually see random knock in 3rd & 4th and its twice the volume of the stocker, plus is a more efficient bar/plate core. Once I switched to the fmic, the knock issue was gone, setup run perfect @ 20 psi through all gears. I think your looking in the right direction, ditch that stock SMIC.

If you want to start to tuning abit, there is a tuning guide on a sticky on the dsmlink forums, under the download thread. It lists how much fuel to remove at the different rpm sliders to get your desired air/fuel ratio plus some info on factory fuel & timing maps that isn't covered in the users manuel.

 

[FORMONTOYA]

I personally don't add timing until 4500RPM. One thing I did notice in the timing sliders is that you have a weird jump at 1500@3 degrees, 2000@1 degree, and then 2500@4 degrees, then 4, 6, and 7 afterward to 3500. And that's with +2 added from 500 to 3500. I would zero out the timing sliders and get the fuel portion closer first, everyone has their own way though.

I noticed that at 6000 the fuel goes from "estimated" 11:1@5500 and 11.4:1@6000 which is probably why the second knock set is coming on. If this is on pump I wouldn't try any leaner than 11:1. I noticed 11.2:1 in this area and would add a touch there.

I also set my CEL to flash at 3 counts. And on my HRC side mount I see some occasional random knock at the top of 3rd, and even rarer at the top of 4th.

But now that you have DSMLink, don't hesitate to go to the forums as there is a wealth of knowledge and experience for more "hands-on" answers.

 

[zippyshoe]

I personally don't add timing until 4500RPM. One thing I did notice in the timing sliders is that you have a weird jump at 1500@3 degrees, 2000@1 degree, and then 2500@4 degrees, then 4, 6, and 7 afterward to 3500. And that's with +2 added from 500 to 3500. I would zero out the timing sliders and get the fuel portion closer first, everyone has their own way though.

I noticed that at 6000 the fuel goes from "estimated" 11:1@5500 and 11.4:1@6000 which is probably why the second knock set is coming on. If this is on pump I wouldn't try any leaner than 11:1. I noticed 11.2:1 in this area and would add a touch there.

I also set my CEL to flash at 3 counts. And on my HRC side mount I see some occasional random knock at the top of 3rd, and even rarer at the top of 4th.

But now that you have DSMLink, don't hesitate to go to the forums as there is a wealth of knowledge and experience for more "hands-on" answers.

I'll assume that you are referring to Staytuned's log file since I haven't posted a log of my run yet. Something else that I thought of today to check is my base timing to verify that it is indeed at 5* BTDC. The other item I thought of is to either clean my stock intercooler or, better yet, replace it with an upgraded intercooler of some sort.

 

[zippyshoe]

If you trims are inline and you said all your sliders are at zero, defently shouldn't be to lean knock. More then likely its do to the stock SMIC, even with the upgraded HRC SMIC that I first ran with my evoIII I would usually see random knock in 3rd & 4th and its twice the volume of the stocker, plus is a more efficient bar/plate core. Once I switched to the fmic, the knock issue was gone, setup run perfect @ 20 psi through all gears. I think your looking in the right direction, ditch that stock SMIC.

If you want to start to tuning abit, there is a tuning guide on a sticky on the dsmlink forums, under the download thread. It lists how much fuel to remove at the different rpm sliders to get your desired air/fuel ratio plus some info on factory fuel & timing maps that isn't covered in the users manuel.

Thanks for the feedback, daren_p. Yeah, I think my stock intercooler is what is constraining me at this point. I downloaded the DSMLink tuning guide a couple days ago - it looks like it has a lot of useful information on WOT tuning.