Knock Sensor questions...
03-17-2005, 11:11 AM
#41
Let me know when you need another VE30DE. The knock that damages your engine you cannot always hear. But oh well
Originally Posted by 92SE_Dave
I fully plan to bypass my knock sensor.
Why spend big bucks to have a sensor whos only purpose is to retard your timing ??
I agree that the sensor is not necessary. It is only an added feature for people who cannot adjust their own timing or take the care to use proper fuel and LISTEN for a knock (it is NOT a discrete sound, very noticeable). When you find you are getting knock with premium fuel, retard timing by 1-2 degrees, until knock is gone. Static base timing is far preferable for gas milage and power.
Why spend big bucks to have a sensor whos only purpose is to retard your timing ??
I agree that the sensor is not necessary. It is only an added feature for people who cannot adjust their own timing or take the care to use proper fuel and LISTEN for a knock (it is NOT a discrete sound, very noticeable). When you find you are getting knock with premium fuel, retard timing by 1-2 degrees, until knock is gone. Static base timing is far preferable for gas milage and power.
03-17-2005, 11:13 AM
#42
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Originally Posted by Jeff92se
Let me know when you need another VE30DE. The knock that damages your engine you cannot always hear. But oh well
03-17-2005, 11:15 AM
#43
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Originally Posted by Jeff92se
Let me know when you need another VE30DE. The knock that damages your engine you cannot always hear. But oh well
03-17-2005, 11:18 AM
#44
ACtually it wouldn't matter if it was silent or not. As there is no ks
Originally Posted by 92SE_Dave
If this was the case then wouldn't ALL cars without KS's be dying an early death do to the "silent" knocking ?
03-17-2005, 11:18 AM
#45
You won't hear any because the ks would be sending a signal to the ecu to retard the timing before you can actually hear it. But go ahead and run the resistor mod. A JDM VE30DE is about $800-$1000 when I did the swap for a friend of mine from Oregon.
Originally Posted by 92SE_Dave
Also, WITH a KS, you will likely not hear any knock, since you need the rythm to identify it, not a single knock which will retard the timing instantly.
03-17-2005, 11:26 AM
#46
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Originally Posted by Jeff92se
ACtually it wouldn't matter if it was silent or not. As there is no ks
But everyone knows that a properly tuned performance engine will have timing set by finding knock point, then retarding from there slightly. Yet according to you there is still "silent" knock occuring even after we reatrd the timing slightly... yet among the MILLIONS of cars without knock sensors, that have the timing retarded slightly behind the knocking point, we don't have an epidemic of cars dying due to "silent" knock... why ?!?!
03-17-2005, 11:27 AM
#47
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Originally Posted by Jeff92se
You won't hear any because the ks would be sending a signal to the ecu to retard the timing before you can actually hear it. But go ahead and run the resistor mod. A JDM VE30DE is about $800-$1000 when I did the swap for a friend of mine from Oregon.
03-17-2005, 11:31 AM
#48
Because engines w/o knock sensors were designed that way. ie.. lots of safety margin. Lower compression, lower hp values. What engines are you talking about? Old arsed engines with dist,points,rotors and carbs?? Come on now. You really think something like an early Ford 5.0 liter making a measly 190hp is really tuned ANYWHERE near it's potential? There are 4 cylinder Hondas making that much hp now.
But I digress by 2-3 posts by now.
But I digress by 2-3 posts by now.
Originally Posted by 92SE_Dave
Of course there is no knock sensor, that's not what I was saying.
But everyone knows that a properly tuned performance engine will have timing set by finding knock point, then retarding from there slightly. Yet according to you there is still "silent" knock occuring even after we reatrd the timing slightly... yet among the MILLIONS of cars without knock sensors, that have the timing retarded slightly behind the knocking point, we don't have an epidemic of cars dying due to "silent" knock... why ?!?!
But everyone knows that a properly tuned performance engine will have timing set by finding knock point, then retarding from there slightly. Yet according to you there is still "silent" knock occuring even after we reatrd the timing slightly... yet among the MILLIONS of cars without knock sensors, that have the timing retarded slightly behind the knocking point, we don't have an epidemic of cars dying due to "silent" knock... why ?!?!
03-17-2005, 11:32 AM
#49
What makes you think you can hear the same frequencies that the KS's piezoelectric sensor can detect?
Originally Posted by 92SE_Dave
I know that is exactly what I was saying... you won't hear any knock with the KS in, because it reacts quickly, it doesn't mean the knock is silent though.
03-17-2005, 11:33 AM
#50
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Originally Posted by 92SE_Dave
Also, WITH a KS, you will likely not hear any knock, since you need the rythm to identify it, not a single knock which will retard the timing instantly.
KS is safety feature: If all is well, ping does not happen. If ping does not happen ever, KS will not activate ign retard never. Summarum: that which is never used, can be thrown outta window.
Safety features are needed only when smtg is endangered. Stupid people have myriad ways to ruin cars, that is why we have myriad safety features all around. KS is one of them. Take blondies off the street, and increase speed limits 50% and death ratse still decrease...
But dont give u car to blondie if theres a way to fillit with 87. NOW THAT is a safety feature.
03-17-2005, 11:39 AM
#52
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Originally Posted by Jeff92se
What makes you think you can hear the same frequencies that the KS's piezoelectric sensor can detect?
I Think that is not necessary. Also one can read the plugs and determine if engine runs on the edge.
Btw, somewhere must be the list of this nissan V6 history. Without knowing, I think the z cars have had more hp without ECU and/or KS
Where could one find such engine historical list? This V6 must have started in 70's already.
03-17-2005, 11:40 AM
#53
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Originally Posted by Jeff92se
What makes you think you can hear the same frequencies that the KS's piezoelectric sensor can detect?
03-17-2005, 11:42 AM
#54
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Originally Posted by Jeff92se
You guys want to run this mod?? Go right ahead. I don't really care.
But Matt and I have been there and done that already. Have fun
But Matt and I have been there and done that already. Have fun
03-17-2005, 11:43 AM
#55
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Originally Posted by Jeff92se
You guys want to run this mod?? Go right ahead. I don't really care.
But Matt and I have been there and done that already. Have fun
But Matt and I have been there and done that already. Have fun
I do, 95. Silkroad, 17.5BTDC.
Not fun, but gimme 400$ to get it done at stealership. Me lazy resistor...
03-17-2005, 11:55 AM
#57
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Originally Posted by Jeff92se
..............
[/b]
[/b]
Somewhere must be the list of this nissan V6 history. Without knowing, I think the z cars have had more hp without ECU and/or KS.
Where could one find such engine historical list? This V6 must have started in 70's already.
03-17-2005, 11:57 AM
#58
https://maxima.org/faq-1-General.html#5
although this is written for a VW , it still pertains to all knockered vehicles.
although this is written for a VW , it still pertains to all knockered vehicles.
Well I'm sure Mark Shaw could probably explain the electronic part of this.
Basically the engine has different spark advance needs at different rpm, at
different throttle settings, different mixtures, etc (many variables here).
The engine, with each intake stroke wants to breath as much as possible
through the intake manifold, but can't because the throttle stands in the way.
Since the throttle stands in the way, at light throttle the engine will
breath a less dense charge of fuel/air on each stroke, and at full throttle
it will be significantly denser (how dense depends on rpm, intake manifold
design, cam lift/duration, intake valve size, etc.) Given that a dense
mixture burns at a higher rate than a less dense mixture AND given the fact
that no matter what the density you want the mixture to burn so that the
pressure spike peaks just after the cylinder reaches the top (for best
torque), you need to vary the spark timing - advance it more for light
throttle settings and retard it a bit for full throttle.
Each motor has a knock limit, determined mainly by its combustion chamber
design, piston top (dished, domed, or flattop), compression ratio, quality
of the fuel and how it is delivered, temperature of the intake charge,
and lots of other nifty variables) which determines how much you can advance
the engine under full throttle conditions without encountering knocking.
(this is starting to look like a nested procedure or something!)
So for maximum torque at all rpm for full throttle you have a graph of spark
advance (btdc) versus rpm. Then for your 9.6-10.0:1 A2 GTI you have the
plotting points for the knock limit:
...........................................KKKKKKK KKK
....................................KKKKKK
...............35 |.............KKKK..*************
...................|........ KKKK..***
......Spark......|.......K...*****
......Timing....|......K **
...................|.....K..*
......deg........|....K.**
......btdc.......|...K**
...................|..K*
...................|K *
.................6.|*
...................+______________________________ __________
....................1......2.....3.....4....5..... 6.....7
* = degrees advance (btdc) for maximum torque
k = knock limit in degrees (btdc)
(these data points are for illustrative uses only)
Typically with a low compression ratio you'll be able to run the engine
at its optimal spark advance for best torque at WOT without running into the
knock limit curve. On a high compression motor like yours you are
running the advance curve very close to the knock limit curve - close enough
that under some conditions the optimal spark timing curve bumps into the knock
limit curve and you have better back of the timing for that cylinder or risk
engine destroying detonation. This is because the knock limit curve moves
up and down depending on a lot of factors like carbon build up (increases
compression ratio), hot spots in the chamber, cooling system efficiency,
etc. The knock sensor detects the vibrations from the block for the firing
cylinder and signals the knock sensor circuitry to retard the timing (lower
the spark advance curve at that rpm point). Timing is retarded for that
cylinder by 3 degrees for the next firing cycle. If more pinging is detected
then it backs it off even further up to a limit. If it doesn't detect
pinging for that cylinder it will attempt to advance it back to the optimal
spark advance. Timing for the other cylinders is kept at the optimal
advance unless they ping as well. The knock sensor circuitry stores the
advance maps in a "3d" map in memory for the wide open throttle setting and
the different curves for varying levels of load (different throttle settings).
It senses the load via a vacuum line running to the k.s. control unit for
CIS-E (and with digifant via a potentiometer in the air vane assembly) to
determine which timing curve to use.
In this way the knock sensor ignitions allow gains in efficiency due to high
compression, thereby increasing fuel economy, and torque, while
preserving the motor from detonation. So it doesn't really sense the octane
of the fuel but how the motor reacts to the fuel, and runs as much advance
as possible with that fuel. If you noticed in my graph above spark advance
started at 6 and went to 35. 6 is the stock initial timing and this is
controlled by the distributor position relative to the flywheel. If you
advance initial timing you shift the whole advance curve up by that many
degrees and running that much closer to the knock limit. Optimal initial
advance (torque wise - maybe not longevity wise) has been shown to be
12 btdc, however we tried advancing my friend's 92 digifant Golf to 12
and in some rpm ranges it would start to audibly ping and then stop pinging
as the ks. retarded timing. So if you can get away with 12 btdc without
ping go for it. If you can't don't worry about it. I'm currently running
my 2.0 with 12 degrees initial advance with 10.5:1 compression and it doesn't
ping at all during hard running with 93 octane.
Hope this helps in understand the VW k.s. ignition at least partially.
Just my $0.02 worth!
Peter Tong
'82 2.0 8V Cabriolet
Basically the engine has different spark advance needs at different rpm, at
different throttle settings, different mixtures, etc (many variables here).
The engine, with each intake stroke wants to breath as much as possible
through the intake manifold, but can't because the throttle stands in the way.
Since the throttle stands in the way, at light throttle the engine will
breath a less dense charge of fuel/air on each stroke, and at full throttle
it will be significantly denser (how dense depends on rpm, intake manifold
design, cam lift/duration, intake valve size, etc.) Given that a dense
mixture burns at a higher rate than a less dense mixture AND given the fact
that no matter what the density you want the mixture to burn so that the
pressure spike peaks just after the cylinder reaches the top (for best
torque), you need to vary the spark timing - advance it more for light
throttle settings and retard it a bit for full throttle.
Each motor has a knock limit, determined mainly by its combustion chamber
design, piston top (dished, domed, or flattop), compression ratio, quality
of the fuel and how it is delivered, temperature of the intake charge,
and lots of other nifty variables) which determines how much you can advance
the engine under full throttle conditions without encountering knocking.
(this is starting to look like a nested procedure or something!)
So for maximum torque at all rpm for full throttle you have a graph of spark
advance (btdc) versus rpm. Then for your 9.6-10.0:1 A2 GTI you have the
plotting points for the knock limit:
...........................................KKKKKKK KKK
....................................KKKKKK
...............35 |.............KKKK..*************
...................|........ KKKK..***
......Spark......|.......K...*****
......Timing....|......K **
...................|.....K..*
......deg........|....K.**
......btdc.......|...K**
...................|..K*
...................|K *
.................6.|*
...................+______________________________ __________
....................1......2.....3.....4....5..... 6.....7
* = degrees advance (btdc) for maximum torque
k = knock limit in degrees (btdc)
(these data points are for illustrative uses only)
Typically with a low compression ratio you'll be able to run the engine
at its optimal spark advance for best torque at WOT without running into the
knock limit curve. On a high compression motor like yours you are
running the advance curve very close to the knock limit curve - close enough
that under some conditions the optimal spark timing curve bumps into the knock
limit curve and you have better back of the timing for that cylinder or risk
engine destroying detonation. This is because the knock limit curve moves
up and down depending on a lot of factors like carbon build up (increases
compression ratio), hot spots in the chamber, cooling system efficiency,
etc. The knock sensor detects the vibrations from the block for the firing
cylinder and signals the knock sensor circuitry to retard the timing (lower
the spark advance curve at that rpm point). Timing is retarded for that
cylinder by 3 degrees for the next firing cycle. If more pinging is detected
then it backs it off even further up to a limit. If it doesn't detect
pinging for that cylinder it will attempt to advance it back to the optimal
spark advance. Timing for the other cylinders is kept at the optimal
advance unless they ping as well. The knock sensor circuitry stores the
advance maps in a "3d" map in memory for the wide open throttle setting and
the different curves for varying levels of load (different throttle settings).
It senses the load via a vacuum line running to the k.s. control unit for
CIS-E (and with digifant via a potentiometer in the air vane assembly) to
determine which timing curve to use.
In this way the knock sensor ignitions allow gains in efficiency due to high
compression, thereby increasing fuel economy, and torque, while
preserving the motor from detonation. So it doesn't really sense the octane
of the fuel but how the motor reacts to the fuel, and runs as much advance
as possible with that fuel. If you noticed in my graph above spark advance
started at 6 and went to 35. 6 is the stock initial timing and this is
controlled by the distributor position relative to the flywheel. If you
advance initial timing you shift the whole advance curve up by that many
degrees and running that much closer to the knock limit. Optimal initial
advance (torque wise - maybe not longevity wise) has been shown to be
12 btdc, however we tried advancing my friend's 92 digifant Golf to 12
and in some rpm ranges it would start to audibly ping and then stop pinging
as the ks. retarded timing. So if you can get away with 12 btdc without
ping go for it. If you can't don't worry about it. I'm currently running
my 2.0 with 12 degrees initial advance with 10.5:1 compression and it doesn't
ping at all during hard running with 93 octane.
Hope this helps in understand the VW k.s. ignition at least partially.
Just my $0.02 worth!
Peter Tong
'82 2.0 8V Cabriolet
03-17-2005, 12:38 PM
#59
Senior Member
Join Date: Feb 2005
Posts: 136
Originally Posted by Wiking
I do, 95. Silkroad, 17.5BTDC.
Not fun, but gimme 400$ to get it done at stealership. Me lazy resistor...
Not fun, but gimme 400$ to get it done at stealership. Me lazy resistor...
I used to have a 5.0 and would run it at 16 degrees on 93 sometimes.
Spark advance has to be one of the most overlooked (and free!) power enhancers possible.
My stock 89 5.0 mustang did 14.8 with 12 degrees on 87, and down to a 14.32 by bumping the timing up to 16 degrees on 93 octane (no knocking at all). Huge, NOTICABLE increase.
03-17-2005, 12:52 PM
#60
what compression was your rustang running?
what compression is your max running?
what compression is Wikings max running?
think about all of that, and then decide how you like your piston soup
what compression is your max running?
what compression is Wikings max running?
think about all of that, and then decide how you like your piston soup
03-17-2005, 01:17 PM
#66
Originally Posted by 92SE_Dave
Question, how close to 500k ohm does bypass have to be ??
I'm asking because the closest combination I could get with any 2 resistors (not having to parrallel them) is a 470 and 22k to make 492K... is that good enough ??
I'm asking because the closest combination I could get with any 2 resistors (not having to parrallel them) is a 470 and 22k to make 492K... is that good enough ??
just remeber it is for testing purposes only.
03-17-2005, 04:07 PM
#67
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Join Date: Feb 2005
Posts: 136
Originally Posted by internetautomar
what compression was your rustang running?
what compression is your max running?
what compression is Wikings max running?
think about all of that, and then decide how you like your piston soup
what compression is your max running?
what compression is Wikings max running?
think about all of that, and then decide how you like your piston soup
Wikings I have no idea... same as mine I'd guess ??
I'm thinking... thinking.... I'll take the power and monumental risk over the $130 bill.
03-17-2005, 11:07 PM
#71
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Posts: n/a
Originally Posted by Jeff92se
Just open the hood and take a look around. There are lots of existing places to bolt the ks to. Technically, I'd bolt it to the block as that's where the the oem on is bolted to. Yes, imho the ks ability to sense knock is dimenished but it's better than the resistor mod.
03-17-2005, 11:23 PM
#72
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Join Date: Dec 2004
Location: EU Scandinavia
Posts: 4,323
Originally Posted by 92SE_Dave
mustang I believe 9:1, Maxima I believe 10:1 (but may be wrong...)
Wikings I have no idea... same as mine I'd guess ??
I'm thinking... thinking.... I'll take the power and monumental risk over the $130 bill.
Wikings I have no idea... same as mine I'd guess ??
I'm thinking... thinking.... I'll take the power and monumental risk over the $130 bill.
Heaven will fall down - huge risk. The glob all war muppet show starts as summer comes again, freezing colds forgotten...
Maxima I believe 9:1
Following clicks at least tell that:
http://63.105.19.158/automotive/datsuns/datsun_tech/
http://www.auto.vl.ru/catalog_eng/25129/
http://www.cardomain.com/memberpage/177457/8
http://www.nissannews.com/site_libra...st/specs.shtml
03-18-2005, 08:44 AM
#74
Senior Member
Join Date: Feb 2005
Posts: 136
Anyway, I have the resistor in, no knocking and already have noticed increase especially in the low end. 
I guess it's only a matter of time now until my crank explodes into 7 million pieces sending shards of superheated metal through the firewall.
I guess it's only a matter of time now until my crank explodes into 7 million pieces sending shards of superheated metal through the firewall.
03-18-2005, 08:56 AM
#75
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Join Date: Dec 2004
Location: EU Scandinavia
Posts: 4,323
Originally Posted by 92SE_Dave
Anyway, I have the resistor in, no knocking and already have noticed increase especially in the low end.
I guess it's only a matter of time now until my crank explodes into 7 million pieces sending shards of superheated metal through the firewall.
I guess it's only a matter of time now until my crank explodes into 7 million pieces sending shards of superheated metal through the firewall.
Its just question of ignition timing. As long as timing is ok and gas octane is in line with timing setting, no problem. ECU is satisfied as KS will rest uselessly. Bypass KS and nothing has changed. KS is a blondie safety measure; surely useful.
03-18-2005, 09:00 AM
#77
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Join Date: Feb 2005
Posts: 136
Originally Posted by Wiking
During next 1000years its gonna happen.
Its just question of ignition timing. As long as timing is ok and gas octane is in line with timing setting, no problem. ECU is satisfied as KS will rest uselessly. Bypass KS and nothing has changed. KS is a blondie safety measure; surely useful.
Its just question of ignition timing. As long as timing is ok and gas octane is in line with timing setting, no problem. ECU is satisfied as KS will rest uselessly. Bypass KS and nothing has changed. KS is a blondie safety measure; surely useful.
The reason is that safety devices have fail safe mechanisms... in this case a failed sensor will fail to safe mode ie retard timing.
03-18-2005, 09:11 AM
#78
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Originally Posted by Jeff92se
You guys have 91 octane down there right?
Two octanes available: 95 and 98.
Mirror that to nissan ign/octane settings, i suppose my 17.5BTDC is still hugely conservative.
In my teens I personally ruined one rambler 232 due to too advanced setting: that did not warn me at all before blowing crank bearings. hurts still, but the only way to learn for stupidos. My Opel starts a real concert if timing goes too far; seems that engines are individuals.
GeneRally it pays to be too careful, nothing wrong in that.