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Old 11-10-2005, 09:06 AM   #1
ride5000
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Default relocation of oem knock sensor



the above pic shows where i mounted my EXTRA knock sensor which is used by the txs tuner pro.

seeing as cylinder #4 is the problem child, wouldn't it make sense to relocate the oem knock sensor (which is the one actually used by the oem ecu AND the utec itself) as close to #4 as possible? ie, right where i put the extra sensor as shown above?

one thing i don't know is if the oem harness has enough slack to relocate.
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Old 11-10-2005, 10:47 AM   #2
hondaeater69
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interesting idea. I'd be curious to know why subaru placed their sensor where they did, i'm sure there's a reason. Most instructions for AM knock sensors call to mount as close to the stock position as possible (following the theory subaru has placed it in the "best" spot).
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Old 11-10-2005, 11:18 AM   #3
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sorry ken for the thread and image jack all in one post!

i broke the head off this bolt and am reluctant to try to get it out.



It looks like it just holds on the bracket that supports the heatshield.

Does anybody here think it's a problem if I just let it be?
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Old 11-10-2005, 11:55 AM   #4
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ken...ive been under the assumption (i could be very wrong) that once you hook up the tuna, the utec will read THAT knock sensor instead of the stock one.

is that incorrect?
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Old 11-10-2005, 12:06 PM   #5
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Old 11-10-2005, 12:25 PM   #6
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Quote:
Originally Posted by happasaiyan
ken...ive been under the assumption (i could be very wrong) that once you hook up the tuna, the utec will read THAT knock sensor instead of the stock one.

is that incorrect?
the utec will always read the oem sensor, wherever you put it.

the tuner itself will use the add-on, but only for its knock detection and detcans.

i'm about 99% certain of this. after all, there are some folks who use the tuner pro and never even install the knock sensor. that would be disasterous if the utec relied on the tuner's sensor.
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Old 11-10-2005, 12:26 PM   #7
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Quote:
Originally Posted by Quack
is that jorge's oem sensor, or is it an aftermarket (knocklink perhaps)?
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Old 11-10-2005, 12:34 PM   #8
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http://www.projectwrx.com/modules.ph...howpage&pid=14

"In this picture you can see that the circle on the left is where the stock knock sensor is located.

Note that I have bolted mine into a pre-tapped hole right above it. "
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Old 11-10-2005, 04:52 PM   #9
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I mounted my tuner sensor there too. My stock sensor is close to that area, tucked more fwd on the motor and down in near here.



Maybe it's there for the STi only.

The UTEC doesn't read the knocks that the Tuner sees. I have had the tuner set too sensitive and it'll light all of the front LEDs w/o recording a knock. The UTEC (at least in my case) just uses the oem piece for pulling timing etc...
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Old 11-10-2005, 05:22 PM   #10
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hmmm. i THOUGHT i remember the oem sensor being on the RH side of the block, but i very well could be mistaken. according to this diagram from the FSM, i am.



it looks like it's already RIGHT OVER cyl #4. i consider that a good thing.
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Old 11-10-2005, 05:26 PM   #11
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Quote:
Originally Posted by AaronWRX
sorry ken for the thread and image jack all in one post!

It looks like it just holds on the bracket that supports the heatshield.

Does anybody here think it's a problem if I just let it be?
well if you don't need that fastener, then i wouldn't stress about it!

i can't remember anything else being supported over there other than the IC bracket. the only heatshileld bracket left on my turbo area is the small one that comes off when you remove the downpipe.

ken

ps no worries about the thread/image jack.
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Old 11-10-2005, 06:28 PM   #12
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Quote:
Originally Posted by ride5000
hmmm. i THOUGHT i remember the oem sensor being on the RH side of the block, but i very well could be mistaken. according to this diagram from the FSM, i am.

it looks like it's already RIGHT OVER cyl #4. i consider that a good thing.
The stock knock sensor is mounted on the LH side of the block, just where you'd hope it'd be mounted.

I can't say I'd be happy mounting an aftermarket knock sensor where you have yours, that close to the transmission. Also, it looks like a lot of the sensor's lower face that should be in contact with the block (namely the outer perimeter) is, in fact, in contact with nothing but air.

Can't the TXS TunerPro use the stock sensor? Does TXS recommend against tapping the stock sensor for the TunerPro? If one were using a UTEC, simply tap the knock sensor wires on the harness between the UTEC and the stock ECU (i.e. after the UTEC is finished with the signal).

If TXS recommends against that, then I believe there's a mounting point on the RH block that's a mirror of the stock sensor mounting point. If so, I'd use that instead of what you have pictured.
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Old 11-11-2005, 11:44 AM   #13
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SOT - Don't forget the torque spec for the knock sensor bolt, should be 15 ftlbs as I remember it
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Old 11-11-2005, 12:46 PM   #14
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Quote:
Originally Posted by mick_the_ginge
SOT - Don't forget the torque spec for the knock sensor bolt, should be 15 ftlbs as I remember it
+1
Even the dealers forget that you can break the knock sensor very easily by over torquing them.

TMS
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Old 11-11-2005, 01:20 PM   #15
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Quote:
Originally Posted by AaronWRX
sorry ken for the thread and image jack all in one post!

i broke the head off this bolt and am reluctant to try to get it out.



It looks like it just holds on the bracket that supports the heatshield.

Does anybody here think it's a problem if I just let it be?
The problem with this location is flat mounting the sensor. There is a little hump in the IC brace that gives it more strength and this bump gets in the way of mounting it there.

I mounted mine in the same place I have seen on this thread. I too was concerned this was too close to the tranny. The bolt on the opposite side (mirror) of the block has oil under it and IIRC that is where you can put a oil pressure sensor. There really wasn't anything I could find that was feasible and in as good a location as the stock sensor.

Also, all I hear through my headphones is the consistent ticking of the injectors. What will detonation sound like in my headphones? I have only knocked on this engine 4 or 5 times and it was before I had the TunerPro and just had a Tuner.

Thanks,
Justin
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Old 11-11-2005, 03:52 PM   #16
ride5000
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Quote:
Originally Posted by crystalhelix
Also, all I hear through my headphones is the consistent ticking of the injectors. What will detonation sound like in my headphones? I have only knocked on this engine 4 or 5 times and it was before I had the TunerPro and just had a Tuner.
to my ears, detonation sounds like a pop, or a crack, more than a knock--at least while listening to the block through the tuner pro with the sensor mounted as in the pic.

because my thresholds are custom set to my engine, it never produces more than one POP before the CEL flashes and the timing gets yanked. ie, i've NEVER heard anything like http://ken-gilbert.com/wrx/knock.wav (from txs).
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Old 11-11-2005, 05:39 PM   #17
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Quote:
Originally Posted by crystalhelix
The problem with this location is flat mounting the sensor. There is a little hump in the IC brace that gives it more strength and this bump gets in the way of mounting it there.

I mounted mine in the same place I have seen on this thread. I too was concerned this was too close to the tranny. The bolt on the opposite side (mirror) of the block has oil under it and IIRC that is where you can put a oil pressure sensor. There really wasn't anything I could find that was feasible and in as good a location as the stock sensor.
The mounting point on the RH (passenger) side is an unused threaded hole in the block that is unrelated to the oil pressure sensor mod. It accepts the same bolt that's used with the stock knock sensor.

Here's a suggestion for how to tap into the signal from the stock knock sensor:
http://forums.nasioc.com/forums/show...7&postcount=81
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Old 10-29-2007, 02:57 PM   #18
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Why is 'clocking' the knock sensor important? The FSM says the stock sensor must be oriented so the wiring harness is about 60 degrees off the longitudinal axis of the car. Basically the wiring harness must be pointed towards the right side door.

Ken, I see that you've installed your secondary knock sensor so it's facing the same location as the stock sensor (although from a different direction).
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