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Ignition Spark Timing and You!


cryo

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It's odd to see so much knock on such a "smooth running as advertised by Subaru engines" just free reving, never seen it on my inline 4's so was a little worried :).

 

Do these knock sensors have an RPM limit where they become useless due to engine noise? On my inline 4 the knock sensor becomes useless after 4800rpm, just too much engine noise after that.

05 LGT 16G 14psi 290whp/30mpg (SOLD)

12 OBP Stock 130whp/27mpg@87 Oct

00 G20t GT28r 10psi 250whp/36mpg

22 Ascent STOCK

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The knock sensor itself is trustable in the higher rpms but there are some other things that must be looked at to conclude if its noise or true knock.

 

All manufactures systems have similarities and differences when it comes to the sensitivity of knock control.

 

Subaru tries to take a very safe approach...if its potential knock they would rather drop timing to adjust, even if it may not be optimum.

 

Dave

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Providing unmatched customer service and a Premium level of Dyno/E-tuning to the Community

 

cryotuneperformance@yahoo.com

facebook.com/cryotuneperformance.

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Good post, thanks for the info. Is there something in particular that might cause 10 degree pulled timing under load? AFR seems normal, but butt dyno says many many fewer torques are reaching it. Just changed plugs (1 step colder), checking turbo and vacuum leaks next.
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Hello there,

 

For the car to pull 10degree's under heavy load normally means there is a lot of mechanical noise to trigger the sensor.

 

It could be because of regular noise BUT when its under heavy load I'm more apt to believe something is actually triggering it ie true knock.

 

What was the part number for the plugs you put in? If all was well before the plug change I would look in that direction.

 

Dave

[sIGPIC][/sIGPIC]

Providing unmatched customer service and a Premium level of Dyno/E-tuning to the Community

 

cryotuneperformance@yahoo.com

facebook.com/cryotuneperformance.

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All wasn't well, I was getting hesitation. Figured I'd start with the plugs and go from there, since I'm at 115k anyway (almost time to change anyway). The hesitation appears to be gone now, just for s's and g's I ran with that diagnostic tool on there. PN LFR7AIX on the plugs. BUT, we were thinking there might be a vacuum leak and I found that the TB hose wasn't seated, so I fixed that and now it seems to be doing better. Will try to run the diag tool again.
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  • 3 weeks later...

I am trying to put something cool together and was hoping any customer tuned by Cryotune Performance could help out.

 

I would like to get the nicest picture you have of your car sent to Cryotuneperformance@yahoo.com.

 

I Know some of you have sent pic's already so that's not needed unless you have an updated picture that looks more professional or a better back drop. These could include pictures on the road/dyno/mountains/park/ etc.

 

Thanks and hope to get quite a few together

 

Dave

[sIGPIC][/sIGPIC]

Providing unmatched customer service and a Premium level of Dyno/E-tuning to the Community

 

cryotuneperformance@yahoo.com

facebook.com/cryotuneperformance.

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I'm trying to find a trend with timing retarding. Some runs I'll do will run full timing, then next run will be 5-10* less. It seems like some days it's more knock prone then others, even at similar temperatures.

 

Definitely one of the most painful cars to get consistent Virtual Dyno numbers on :lol:

05 LGT 16G 14psi 290whp/30mpg (SOLD)

12 OBP Stock 130whp/27mpg@87 Oct

00 G20t GT28r 10psi 250whp/36mpg

22 Ascent STOCK

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Found the issue, two actually, both have to do with Feedback Knock Correction, one was my heatshield hitting the WG line (needed to be trimmed), this caused ECU to think there was knock.

 

Another one is actually related to the road I drive on, it's a rough road to my house & to the road I use for virtual dyno pulls, well because of that knocksum increments and FBKC starts pulling timing back, then by the time I do a dyno run, FBKC hasn't counted down to 0 yet. Going forward added it as a gauge and only doing WOT runs after it's at 0.

05 LGT 16G 14psi 290whp/30mpg (SOLD)

12 OBP Stock 130whp/27mpg@87 Oct

00 G20t GT28r 10psi 250whp/36mpg

22 Ascent STOCK

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hi all,

i have a jdm lgt 2.0L 5eat

i tuned it to 17.5 psi peak boost tappers to 14 psi,

total timing 24 at revlimiter, e10 gasoline and with WM injection 50-50 mix,

the issue is that

the performance almost the same bet low timing map with 20 total timing and 24 degrees

the 80-180 kph time is exactly the same.

am i reached the MBT or its a TCU tuning issue?!

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