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Discussion Starter · #1 ·
Hi All,

I have been conversing with Christian @ Cobb about this part throttle knock. I am really worried about issues related to this problem. He says it's no problem. I truly find it hard to believe our cars can get away with such retardation of the timing and be correct. I can understand that the car is protecting itself. But it should be no where near these high values. Today I found a more disconcerting issues related to this KR. I was in 6th gear at about 3K RPM (80mph) and if you feather the throttle just right where you are at the cusp of adding slight boost, the car will start to show sustained KR up to 7 DEGREES! I mean you can watch the AP continuously showing KR for several seconds. This does not seem correct at all.. I need someone with a dashhawk or other means of logging to see how bad the KR is in 6th gear on a stock car with no AP.

Anthony
 

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are you running oem plugs? You may want to pick up a set of denso 1 step colder plugs since you're running more boost now.
 

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same thing happens to me. I am not worried about it. This is from something Christian sent me, I hope he doesn't mind that I post a sample. It should give people a taste of what is coming for ATR.
"The MS ECU will usually switch between ignition tables based on whether or not the ECU is recognizing Knock Retard (KR). If no KR is reported, then the ECU will use one table or set of tables, if KR is reported then the ECU will use another table or set of tables. Generally speaking, the ECU will try to run as much ignition advance as possible during part-throttle conditions in order to determine Minmum spark advance for Best Torque output."
 

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I get the same 6th gear kr as well. I've been monitoring my timing closely and I've pretty much determined that this motor has an issue with timing jump for some reason at part throttle. It will be sitting in the 30's then jump to 50's and throw 7-8 degree kr. However, there is no audible knocking whatsoever so I highly doubt its doing any damage. Going along with what Christian said, I think when the knock sensor THINKS its knocking it switches to another timing table....being waaaay less than the 50 degree advance its currently in. Hence you get a massive KR reading but no real knocking. The motor does this stock and with AP btw.
 

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While it is not possible to completely eliminate knock part throttle the ATR will allow you to modify part throttle tables.
 

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Discussion Starter · #6 ·
What about a custom tune from Cobb? Will this fix this KR problem? I already have the new plugs to answer the previous question.
 

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I ran the dashawk on a completely stock car for about 3 months. It did this the whole time. If it is only partial throttle knock retard while cruising, its normal. A lot of people have reported this. The car just does this. When I see it I just let off the gas and it goes right away. Probably is not knock anyways like previous posts have said.

So my experiences are:
Did this same thing stock
Did the same with just a CAI
Still does it with the CAI and AP map, not any more or less frequent either.

I really would not worry about it.
 

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yes its normal and a custom tune wouldn't change the problem. It is just how the ecu functions. It wants to run the most timing possible to be efficient. So it runs more timing and pulls it back when necessary. If you tune it for no kr your car will be less efficient and your gas mileage will probably suffer. The best thing you can do is stop looking at KR reports at part throttle. I did and now I don't worry about it.
 

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[quote author=dread link=topic=137242.msg2958824#msg2958824 date=1235514377]
yes its normal and a custom tune wouldn't change the problem. It is just how the ecu functions. It wants to run the most timing possible to be efficient. So it runs more timing and pulls it back when necessary. If you tune it for no kr your car will be less efficient and your gas mileage will probably suffer. The best thing you can do is stop looking at KR reports at part throttle. I did and now I don't worry about it.
[/quote]

+1,

I see kr between 3.5~6.0 at partial throttle. It always happens around 3000 rpms when partialy accelerating. Never in 1st or 2nd, but in 3rd, 4th, 5th, 6th. One thing I have learned is always downshift when going wot. I have seen the worse knock when going wot in 4th or 5th at around 3000~3500 rpms.

As long as you remember this you should not have a problem. Going wot, the right way, I have only seen 0.0~1.3 kr with Stage1 +SF 93 v103.
 

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[quote author=prototype_x9 link=topic=137242.msg2960683#msg2960683 date=1235584893]
cruising at 70 mph below 3K RPMs I see over 7 degrees of KR every single day. It only happens when the car has almost no load on it.
[/quote]

+1, mine's usually 5.9. Oddly enough it usually only does during the first few minutes of my trip on the interstate so I'm wondering if it's associated with the engine still being a little cold.
 

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Well, the engine retards timing when fist started to help bring cats up to temp faster.

Direct-injection allows a homogenous fuel/air mixture around the spark plugs, effectively retarding misfire. Ignition timing can then be retarded, which helps raise exhaust-gas temperatures. The engine’s lightweight, single-scroll turbocharger also contributes to this by limiting heat loss in the exhaust system. As a consequence, the catalytic converter heats up quickly – producing fewer emissions.

http://www.autoweb.com.au/cms/A_107073/title_Mazda3-MPS-Turns-Up-The-Heat/newsarticle.html
 

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I never really see KR at partial throttle... the most I have seen is .3 ~ .7

What I'm worried about is the 1.5 - 3+ KR I get at WOT.
 

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go back to stock, and you will see that the stock ECU does the exact same thing. don't worry about it, imo...at that load level, there's not enough force behind it to actually damage anything anyways...
 

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another thing to note: when this knock happens, you're usually running 30+ degrees of timing as it is...5-7 degrees off of 30+ degrees? not really anything serious, imo...
 

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[quote author=Sacrilicious link=topic=137242.msg2962839#msg2962839 date=1235663730]
another thing to note: when this knock happens, you're usually running 30+ degrees of timing as it is...5-7 degrees off of 30+ degrees? not really anything serious, imo...
[/quote]

Ya I noticed KR was about 0.7 to 1.4 on the stock map. So we should pretty much just make sure were not hearing any actual Knock.

I havent heard any knock, but I've seen KR anywhere from 0.3 to 1 in 3rd and 1.5 to 3.5 in 4th and up.
 

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Also, I had a mix-up in what I should have my gap set at on my ITV-22 plugs... When I ordered my AP from Cobb the guy on the phone said .30 but I've heard it should actually be .28? Should I take out my plugs and gap them to .28?
 
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