Add a Knock Sensor to a B18B??
10-27-2003, 10:49 PM
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Add a Knock Sensor to a B18B??
What is the best knock sensor to use on a boosted B18B, and what is the best mounting location for maximizing its ability to hear knock? This is on a bone stock B18B so I don't have to worry about built engine noise for now. I've searched and found a bunch of half assed information, I figure in this forum I am more likely to find people that are using knock sensors on their B18Bs... I'm running the AEM EMS, so the ECU and wiring aspects are not a problem, I just want the best knock sensor for my setup and the best mounting location 
10-27-2003, 11:09 PM
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Re: Add a Knock Sensor to a B18B?? (mskibbz-T)
I had put one on my old b18a. I'll take a pic to show you where I did mine.
Not sure if the b18b is exactly the same on the back of the block or not.
Not sure if the b18b is exactly the same on the back of the block or not.
10-28-2003, 02:28 AM
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Re: Add a Knock Sensor to a B18B?? (mskibbz-T)
On, my old LS/Vtec block, I mounted it where the alternator bracket was. You need to modify the bracket(cut off part of it), tap the right size thread where the alternator bolt was, and just plug it in.
10-28-2003, 04:00 AM
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Re: Add a Knock Sensor to a B18B?? (intekragsr)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by intekragsr »</TD></TR><TR><TD CLASS="quote">On, my old LS/Vtec block, I mounted it where the alternator bracket was. You need to modify the bracket(cut off part of it), tap the right size thread where the alternator bolt was, and just plug it in.
</TD></TR></TABLE>
Or drill the hole bigger on the inner-most bolt(toward the passenger side), and drill/tap the block for the appropriate size to accept the 02 sensor. If you dont go too deep w/the drill, you should still be able to use a bolt later(if youd ever want to remove it) on to bolt the bracket down properly again.
</TD></TR></TABLE>
Or drill the hole bigger on the inner-most bolt(toward the passenger side), and drill/tap the block for the appropriate size to accept the 02 sensor. If you dont go too deep w/the drill, you should still be able to use a bolt later(if youd ever want to remove it) on to bolt the bracket down properly again.
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10-28-2003, 10:19 AM
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Re: (mskibbz-T)
Hard to see but here's where I had mine
It's above and to the right of where the oil filter would go
Where I put it was just some empty spot.
I was using the OEM knock.
It's above and to the right of where the oil filter would go
Where I put it was just some empty spot.
I was using the OEM knock.
10-28-2003, 12:20 PM
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Re: (DA-MAX)
Firstly, you need to be able to filter the KS output so that the EMS responds to the certain frequencies that actually indicate engine knock. A KS is not a pass/fail indicator like a switch, and general engine vibration will cause a large portion of feedback that will render unfiltered KS output into a total waste of time and effort.
I'm sure the EMS can be set up to do the DSP (digital signal processing) required for this task, but my hands on time with one wasn't long enough to delve into that aspect. Since you are running a stock engine (without turbo or other power adder, I ASSume), you have an excellent opportunity to get a base KS output signal logged on the EMS... then jack the timing forward so you spark knock, at idle as well as under throttle. Play around with the signal logs where you transition into audible knock, as the high frequency knock (unhearable to the human ear) taking place can be read by the KS.
As far as fitment, I currently have a Bosch unit bolted into one of the bosses for the intake manifold brace, located on the block just to the right of the oil filter. I get knock, my boost gets cut. Handy ****.
I'm sure the EMS can be set up to do the DSP (digital signal processing) required for this task, but my hands on time with one wasn't long enough to delve into that aspect. Since you are running a stock engine (without turbo or other power adder, I ASSume), you have an excellent opportunity to get a base KS output signal logged on the EMS... then jack the timing forward so you spark knock, at idle as well as under throttle. Play around with the signal logs where you transition into audible knock, as the high frequency knock (unhearable to the human ear) taking place can be read by the KS.
As far as fitment, I currently have a Bosch unit bolted into one of the bosses for the intake manifold brace, located on the block just to the right of the oil filter. I get knock, my boost gets cut. Handy ****.
10-28-2003, 08:24 PM
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Re: (J. Davis)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis »</TD></TR><TR><TD CLASS="quote">Firstly, you need to be able to filter the KS output so that the EMS responds to the certain frequencies that actually indicate engine knock. A KS is not a pass/fail indicator like a switch, and general engine vibration will cause a large portion of feedback that will render unfiltered KS output into a total waste of time and effort.
I'm sure the EMS can be set up to do the DSP (digital signal processing) required for this task, but my hands on time with one wasn't long enough to delve into that aspect. Since you are running a stock engine (without turbo or other power adder, I ASSume), you have an excellent opportunity to get a base KS output signal logged on the EMS... then jack the timing forward so you spark knock, at idle as well as under throttle. Play around with the signal logs where you transition into audible knock, as the high frequency knock (unhearable to the human ear) taking place can be read by the KS.
As far as fitment, I currently have a Bosch unit bolted into one of the bosses for the intake manifold brace, located on the block just to the right of the oil filter. I get knock, my boost gets cut. Handy ****.
</TD></TR></TABLE>
Thanks for the detailed information! My LS has been turboed for quite some time, I'm currently looking for a new stock block, don't ask
I'd like to get a knock sensor in there so I can take it farther and have some peace of mind. Are you using a J&S Safeguard? Cutting boost based on knock would be ideal for my street car, or at the very least flashing my idiot light so I can do so manually. My tuner was concerned about trying anything more than conservative timing on my last setup due to the fact that I was missing a KS, he guessed that I could have easily made another 15whp, for 275+whp, by advancing the timing a bit.
Thanks for all the useful info guys!!
I'm sure the EMS can be set up to do the DSP (digital signal processing) required for this task, but my hands on time with one wasn't long enough to delve into that aspect. Since you are running a stock engine (without turbo or other power adder, I ASSume), you have an excellent opportunity to get a base KS output signal logged on the EMS... then jack the timing forward so you spark knock, at idle as well as under throttle. Play around with the signal logs where you transition into audible knock, as the high frequency knock (unhearable to the human ear) taking place can be read by the KS.
As far as fitment, I currently have a Bosch unit bolted into one of the bosses for the intake manifold brace, located on the block just to the right of the oil filter. I get knock, my boost gets cut. Handy ****.
</TD></TR></TABLE>
Thanks for the detailed information! My LS has been turboed for quite some time, I'm currently looking for a new stock block, don't ask
I'd like to get a knock sensor in there so I can take it farther and have some peace of mind. Are you using a J&S Safeguard? Cutting boost based on knock would be ideal for my street car, or at the very least flashing my idiot light so I can do so manually. My tuner was concerned about trying anything more than conservative timing on my last setup due to the fact that I was missing a KS, he guessed that I could have easily made another 15whp, for 275+whp, by advancing the timing a bit. Thanks for all the useful info guys!!
10-28-2003, 08:36 PM
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Re: (mskibbz-T)
No, I'm not running a J&S, or any other brand name piece of equipment. It's for a mildly warmed-over Saab APC, set up for switchable hi/lo boost. I have some circuits for scramble boost and VSS based boost almost together, waiting for my lazy *** to wire them in.
11-10-2003, 10:31 AM
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Re: (J. Davis)
If I have a ls/vetc running a gsr ecu, and I put a knock sensor in it would it function just like it would on a gsr?
edit: since the block would be built with forged internals, should I still add the knock sensor - I read the piston slap gets mistaken for knock.
edit: since the block would be built with forged internals, should I still add the knock sensor - I read the piston slap gets mistaken for knock.
11-10-2003, 02:05 PM
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Re: Add a Knock Sensor to a B18B?? (mskibbz-T)
stolen from c-speedracing.com: Using a 10.9 mm drill bit, opened up the hole on the bracket and the block. Then carefully tap the hole with a 12 mm x 1.25 thread pitch tap. Be sure to clean up the shavings and then screw the knock sensor. This will keep your ECU from throwing any codes.
11-10-2003, 03:26 PM
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Re: Add a Knock Sensor to a B18B?? (Jumpmann23)
You want to be as close to #2 cylinder as possible as its usually the first to let go. Try to get it between where the top of the piston is at BTC. In any case, you should be alble to "supress" the KS output with the AEM to account for normal driving noises at certian rpm's. When you get your "supression" down then you're pretty much set. The OEM honda knock sensor is actually very good. Its the ECU's fault that it can't be put to better use. First, honda engineers didn't deem it necessary to take out at most a few degrees max. Secondly, the OEM ECU can't react quickly enough anyways to do much of any good. Its really a pity. The OEM KS is also the right "size" for your motor. It turns out that different pizeoelectric sensors work better on different displacement engines.
If you need more data on the how/what/ and why's of knock sensors look into the turbo buick and DSM sites. THey both rely largly on KS to tune.
If you need more data on the how/what/ and why's of knock sensors look into the turbo buick and DSM sites. THey both rely largly on KS to tune.
11-10-2003, 03:32 PM
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Re: Add a Knock Sensor to a B18B?? (danl)
I tought #3 was the first to go, usually? If I use a chipped ecu, with say uberdata and since the block would be built with forged internals, should I still add the knock sensor - I read the piston slap gets mistaken for knock - or can I do something about it?
J.Davis can you elaborate on your setup?
J.Davis can you elaborate on your setup?
11-10-2003, 03:40 PM
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Re: Add a Knock Sensor to a B18B?? (slashDEVslashNULL)
THe second one from the drivers side of the motor "typically" goes first on inline 4 cylinders. It might be better to say any of the two inner cylinders however.
11-10-2003, 07:40 PM
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Re: Add a Knock Sensor to a B18B?? (danl)
I also have a b18b block and I noticed that the "b" blocks come w/ a cast iron bracket unlike the "a" block which look more like a stamped metal type. Can I use the bracket from a b18a block or is there anywhere else I can mount the ks?
11-11-2003, 07:00 AM
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Re: Add a Knock Sensor to a B18B?? (slashDEVslashNULL)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slashDEVslashNULL »</TD></TR><TR><TD CLASS="quote">I tought #3 was the first to go, usually? If I use a chipped ecu, with say uberdata and since the block would be built with forged internals, should I still add the knock sensor - I read the piston slap gets mistaken for knock - or can I do something about it?
J.Davis can you elaborate on your setup?</TD></TR></TABLE>
J.Davis can you elaborate on your setup?</TD></TR></TABLE>
11-11-2003, 08:56 AM
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Re: Add a Knock Sensor to a B18B?? (danl)
OEM knock sensors are a pain, will make you lose power, and won't save your motor. I did a write up a while back on the knock sensor, I'm not going to repeat it all so I'll just say you're better off without it.
11-11-2003, 09:13 AM
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Re: Add a Knock Sensor to a B18B?? (trbob16a)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by trbob16a »</TD></TR><TR><TD CLASS="quote">OEM knock sensors are a pain, will make you lose power, and won't save your motor. I did a write up a while back on the knock sensor, I'm not going to repeat it all so I'll just say you're better off without it. </TD></TR></TABLE>
Who said anything about a stock ECU?
Who said anything about a stock ECU?
11-11-2003, 01:50 PM
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Re: Add a Knock Sensor to a B18B?? (trbob16a)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by trbob16a »</TD></TR><TR><TD CLASS="quote">OEM knock sensors are a pain, will make you lose power, and won't save your motor. I did a write up a while back on the knock sensor, I'm not going to repeat it all so I'll just say you're better off without it. </TD></TR></TABLE>
Are you saying that in general all OEM knock sensors are a pain? If so, I have a bone to pick with you. If you are saying that the way the Honda ECU uses the OEM knock sensor, then I agree. However, it would be completely ignorant to say that in general, knock sensors when properly implemented don’t save motors.
Are you saying that in general all OEM knock sensors are a pain? If so, I have a bone to pick with you. If you are saying that the way the Honda ECU uses the OEM knock sensor, then I agree. However, it would be completely ignorant to say that in general, knock sensors when properly implemented don’t save motors.
11-11-2003, 02:30 PM
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Re: Add a Knock Sensor to a B18B?? (slashDEVslashNULL)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slashDEVslashNULL »</TD></TR><TR><TD CLASS="quote">J.Davis can you elaborate on your setup?</TD></TR></TABLE>
I'm a big fan of doing your own homework, and anyone who isn't a tinkerer won't be able to follow me anyway, so here's the quick and dirty rundown:
Netsearch for Saab APC, tweak your APC, and townsend. There is a plethora of information out there on how to modify these things to act as a standalone boost controller for any vehicle. I'd provide links, but I never bookmarked the sites and netsearch anytime I need them - so can you.
The APC will draw off boost under engine knock. It also has provisions for communicating with the Bosch LH-Jetronic ECU to retard ignition under knock - it grounds pin 19 for a minimum of a half second when it detects knock. Whi8ch is a nice way to actuate a pulldown for pin 1 of 27C512, switch to an alternate set of ignition maps if you wanted, hint hint. Or just ground a 12V LED to act as a dashboard mounted knock detector.
The "usual" hacks will render the APC a linear boost controller, meaning it doesn't start tapering down boost after 4800 rpms as it does in stock form. Boost becomes readily adjustable on the P potentiometer... make quick and sleazy with a DVOM and you have the desired resistances to use in place of the P potentiometer for lo/high/multiple switchable boost levels.
A common hobbyist IC is the LM2907/LM2917, which can be used as an RPM activated switch or to render input frequency into a DC voltage. In this case, the higher the freq, or higher the VSS freq I should say, the higher the output DC voltage. A couple of opamps set to trigger at whatever voltage levels would feed the desired resistances across where the P potentiometer used to be, and set your boost level according to vehicle speed.
You can set the above device up with a number of potentiometers, so you can adjust the VSS points and the desired boost for each point. Not super bling, but goddamn you can do it yourself in a couple hours with free samples extorted from all the major IC manufacturers, and you end up knowing more about what you're talking about than the average HT member who is still on the pay-to-play tip.
I'm a big fan of doing your own homework, and anyone who isn't a tinkerer won't be able to follow me anyway, so here's the quick and dirty rundown:
Netsearch for Saab APC, tweak your APC, and townsend. There is a plethora of information out there on how to modify these things to act as a standalone boost controller for any vehicle. I'd provide links, but I never bookmarked the sites and netsearch anytime I need them - so can you.
The APC will draw off boost under engine knock. It also has provisions for communicating with the Bosch LH-Jetronic ECU to retard ignition under knock - it grounds pin 19 for a minimum of a half second when it detects knock. Whi8ch is a nice way to actuate a pulldown for pin 1 of 27C512, switch to an alternate set of ignition maps if you wanted, hint hint. Or just ground a 12V LED to act as a dashboard mounted knock detector.
The "usual" hacks will render the APC a linear boost controller, meaning it doesn't start tapering down boost after 4800 rpms as it does in stock form. Boost becomes readily adjustable on the P potentiometer... make quick and sleazy with a DVOM and you have the desired resistances to use in place of the P potentiometer for lo/high/multiple switchable boost levels.
A common hobbyist IC is the LM2907/LM2917, which can be used as an RPM activated switch or to render input frequency into a DC voltage. In this case, the higher the freq, or higher the VSS freq I should say, the higher the output DC voltage. A couple of opamps set to trigger at whatever voltage levels would feed the desired resistances across where the P potentiometer used to be, and set your boost level according to vehicle speed.
You can set the above device up with a number of potentiometers, so you can adjust the VSS points and the desired boost for each point. Not super bling, but goddamn you can do it yourself in a couple hours with free samples extorted from all the major IC manufacturers, and you end up knowing more about what you're talking about than the average HT member who is still on the pay-to-play tip.
11-12-2003, 01:42 PM
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Re: Add a Knock Sensor to a B18B?? (J. Davis)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis »</TD></TR><TR><TD CLASS="quote">
I'm a big fan of doing your own homework, and anyone who isn't a tinkerer won't be able to follow me anyway, so here's the quick and dirty rundown:
Netsearch for Saab APC, tweak your APC, and townsend. There is a plethora of information out there on how to modify these things to act as a standalone boost controller for any vehicle. I'd provide links, but I never bookmarked the sites and netsearch anytime I need them - so can you.
The APC will draw off boost under engine knock. It also has provisions for communicating with the Bosch LH-Jetronic ECU to retard ignition under knock - it grounds pin 19 for a minimum of a half second when it detects knock. Whi8ch is a nice way to actuate a pulldown for pin 1 of 27C512, switch to an alternate set of ignition maps if you wanted, hint hint. Or just ground a 12V LED to act as a dashboard mounted knock detector.
The "usual" hacks will render the APC a linear boost controller, meaning it doesn't start tapering down boost after 4800 rpms as it does in stock form. Boost becomes readily adjustable on the P potentiometer... make quick and sleazy with a DVOM and you have the desired resistances to use in place of the P potentiometer for lo/high/multiple switchable boost levels.
A common hobbyist IC is the LM2907/LM2917, which can be used as an RPM activated switch or to render input frequency into a DC voltage. In this case, the higher the freq, or higher the VSS freq I should say, the higher the output DC voltage. A couple of opamps set to trigger at whatever voltage levels would feed the desired resistances across where the P potentiometer used to be, and set your boost level according to vehicle speed.
You can set the above device up with a number of potentiometers, so you can adjust the VSS points and the desired boost for each point. Not super bling, but goddamn you can do it yourself in a couple hours with free samples extorted from all the major IC manufacturers, and you end up knowing more about what you're talking about than the average HT member who is still on the pay-to-play tip.</TD></TR></TABLE>
J thanks a lot!
I'm a big fan of doing your own homework, and anyone who isn't a tinkerer won't be able to follow me anyway, so here's the quick and dirty rundown:
Netsearch for Saab APC, tweak your APC, and townsend. There is a plethora of information out there on how to modify these things to act as a standalone boost controller for any vehicle. I'd provide links, but I never bookmarked the sites and netsearch anytime I need them - so can you.
The APC will draw off boost under engine knock. It also has provisions for communicating with the Bosch LH-Jetronic ECU to retard ignition under knock - it grounds pin 19 for a minimum of a half second when it detects knock. Whi8ch is a nice way to actuate a pulldown for pin 1 of 27C512, switch to an alternate set of ignition maps if you wanted, hint hint. Or just ground a 12V LED to act as a dashboard mounted knock detector.
The "usual" hacks will render the APC a linear boost controller, meaning it doesn't start tapering down boost after 4800 rpms as it does in stock form. Boost becomes readily adjustable on the P potentiometer... make quick and sleazy with a DVOM and you have the desired resistances to use in place of the P potentiometer for lo/high/multiple switchable boost levels.
A common hobbyist IC is the LM2907/LM2917, which can be used as an RPM activated switch or to render input frequency into a DC voltage. In this case, the higher the freq, or higher the VSS freq I should say, the higher the output DC voltage. A couple of opamps set to trigger at whatever voltage levels would feed the desired resistances across where the P potentiometer used to be, and set your boost level according to vehicle speed.
You can set the above device up with a number of potentiometers, so you can adjust the VSS points and the desired boost for each point. Not super bling, but goddamn you can do it yourself in a couple hours with free samples extorted from all the major IC manufacturers, and you end up knowing more about what you're talking about than the average HT member who is still on the pay-to-play tip.</TD></TR></TABLE>
J thanks a lot!