knock sum and knock voltage
Aug 30, 2010, 11:59 AM
#1
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knock sum and knock voltage
Guys, could you give me some Ideas. I have 2.0l engine with forged pistons. I use stock knock map, didnt change it. I have mostly 0 knock sum, occasionaly 1-3 knocks, nothing serious. But I looked at knock voltage and it's quite high, comparing to the stock engine. Should I worry about this ?
Aug 30, 2010, 02:04 PM
#2
If you havent changed the timing its not always bad that it has higher voltage than stock. What amount of voltage? I have seen legitimate knock at low voltage and almost no signs of knock (reading plugs) with high voltage.
Piston to wall clearance and piston material will also play into what you see as well. Balance shaft deleted?
Aaron
Piston to wall clearance and piston material will also play into what you see as well. Balance shaft deleted?
Aaron
Aug 31, 2010, 01:57 AM
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i, i have my bs deleted and my car is a 2.3 manley/wiseco 8:8.1 i know it gets ton of false knock i've put VP import in and gotten it..
I know how to turn down then sensitivity of the senors but how much..
also onpumpgas if i'm making 440whp and i'm making 5 counts.. turn the knock sensor down and make 505whp.. thats still really safe right?
I know how to turn down then sensitivity of the senors but how much..
also onpumpgas if i'm making 440whp and i'm making 5 counts.. turn the knock sensor down and make 505whp.. thats still really safe right?
Aug 31, 2010, 02:06 AM
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look dude.. motors will take some knock... what i'm asking is if that ammount is fine for my power level.
back in the day you could hear old chevys pinging going up hills.. **** i've herd my evo pinging before when a line shot off the FPR from rich knock.
Aug 31, 2010, 03:37 AM
#6
Take it easy. Waskarn is in Thailand, so I doubt he has had the opportunity to hear old Chevys pinging over there.
In your case, if the engine were truly knocking at 440whp, you'd never get to 505whp. When knock is truly evident, attempting to increase cylinder pressure (boost) or advance the timing in that range is not going to increase power. It will however damage or destroy the engine. Why? Because wherever knock is happening, you're already past the point of making best power.
Basically, what the ECU determines to be knock may or may not be knock. It's always best to err on the side of caution when playing with knock sensitivity settings. In your case however, the 5 counts you were seeing apparently resulted from noise, not knock. To form a second opinion on what truly is knock, one needs to invest time looking at knock sensor voltage in the logs for a particular engine and get a feel for what rpm range(s) tend to be noisy.
In your case, if the engine were truly knocking at 440whp, you'd never get to 505whp. When knock is truly evident, attempting to increase cylinder pressure (boost) or advance the timing in that range is not going to increase power. It will however damage or destroy the engine. Why? Because wherever knock is happening, you're already past the point of making best power.
Basically, what the ECU determines to be knock may or may not be knock. It's always best to err on the side of caution when playing with knock sensitivity settings. In your case however, the 5 counts you were seeing apparently resulted from noise, not knock. To form a second opinion on what truly is knock, one needs to invest time looking at knock sensor voltage in the logs for a particular engine and get a feel for what rpm range(s) tend to be noisy.
Sep 1, 2010, 07:46 PM
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Take it easy. Waskarn is in Thailand, so I doubt he has had the opportunity to hear old Chevys pinging over there.
In your case, if the engine were truly knocking at 440whp, you'd never get to 505whp. When knock is truly evident, attempting to increase cylinder pressure (boost) or advance the timing in that range is not going to increase power. It will however damage or destroy the engine. Why? Because wherever knock is happening, you're already past the point of making best power.
Basically, what the ECU determines to be knock may or may not be knock. It's always best to err on the side of caution when playing with knock sensitivity settings. In your case however, the 5 counts you were seeing apparently resulted from noise, not knock. To form a second opinion on what truly is knock, one needs to invest time looking at knock sensor voltage in the logs for a particular engine and get a feel for what rpm range(s) tend to be noisy.
In your case, if the engine were truly knocking at 440whp, you'd never get to 505whp. When knock is truly evident, attempting to increase cylinder pressure (boost) or advance the timing in that range is not going to increase power. It will however damage or destroy the engine. Why? Because wherever knock is happening, you're already past the point of making best power.
Basically, what the ECU determines to be knock may or may not be knock. It's always best to err on the side of caution when playing with knock sensitivity settings. In your case however, the 5 counts you were seeing apparently resulted from noise, not knock. To form a second opinion on what truly is knock, one needs to invest time looking at knock sensor voltage in the logs for a particular engine and get a feel for what rpm range(s) tend to be noisy.
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Mar 20, 2012, 09:09 PM
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bringing back an old thread. i am seeing up to 2.4 volts on the knock sensor at about 2500-3500rpm with a br 2.1. bs deleted manley pistons and rods and a stage 3 br head with tomei 280 cams. I have both cam gears degreed +5 cause of the deck height
(6mm taller) and a 1.3mm head gasket. Just wondering if that was a normal voltage for a built engine. I have only seen as high as 2 counts of knock on this build so far. Thanks for the imput guys.
(6mm taller) and a 1.3mm head gasket. Just wondering if that was a normal voltage for a built engine. I have only seen as high as 2 counts of knock on this build so far. Thanks for the imput guys.
Mar 20, 2012, 09:15 PM
#9
yes that sounds within reason.. if you're paranoid put it on a dyno or a really flat road with vd and sweep it again.
although looking at my logs at 2500-3500 i dont see 2 volts. the most i see is 1 volt.
after full boost 2+ is common though.
i see 2.0 at 3900 in a few logs.
good way to tell if its knock noise or not is if you are steady at 2,2,2,2,2,2,2 then all the sudden you go to 4 for example or 3.5..
then id question that area.
my car shows a random 4 volt uptop.. i lowered timing & i lost power.. so its not like a spike is always gonna be detonation either.
plot the volts in a line graph and if you see a massive spike then troubleshoot that area for reassurance.
although looking at my logs at 2500-3500 i dont see 2 volts. the most i see is 1 volt.
after full boost 2+ is common though.
i see 2.0 at 3900 in a few logs.
good way to tell if its knock noise or not is if you are steady at 2,2,2,2,2,2,2 then all the sudden you go to 4 for example or 3.5..
then id question that area.
my car shows a random 4 volt uptop.. i lowered timing & i lost power.. so its not like a spike is always gonna be detonation either.
plot the volts in a line graph and if you see a massive spike then troubleshoot that area for reassurance.
Last edited by tscompusa; Mar 20, 2012 at 09:54 PM.
Mar 26, 2012, 04:29 PM
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yes that sounds within reason.. if you're paranoid put it on a dyno or a really flat road with vd and sweep it again.
although looking at my logs at 2500-3500 i dont see 2 volts. the most i see is 1 volt.
after full boost 2+ is common though.
i see 2.0 at 3900 in a few logs.
good way to tell if its knock noise or not is if you are steady at 2,2,2,2,2,2,2 then all the sudden you go to 4 for example or 3.5..
then id question that area.
my car shows a random 4 volt uptop.. i lowered timing & i lost power.. so its not like a spike is always gonna be detonation either.
plot the volts in a line graph and if you see a massive spike then troubleshoot that area for reassurance.
although looking at my logs at 2500-3500 i dont see 2 volts. the most i see is 1 volt.
after full boost 2+ is common though.
i see 2.0 at 3900 in a few logs.
good way to tell if its knock noise or not is if you are steady at 2,2,2,2,2,2,2 then all the sudden you go to 4 for example or 3.5..
then id question that area.
my car shows a random 4 volt uptop.. i lowered timing & i lost power.. so its not like a spike is always gonna be detonation either.
plot the volts in a line graph and if you see a massive spike then troubleshoot that area for reassurance.
Mar 26, 2012, 04:33 PM
#11
try to smooth the timing out in the load & RPM areas that is occuring.. it could be ignition related. if not id check the static idle rpm settings in ecuflash and then tweak the iscv to compensate further. if that still doesnt fix, then look into the iscv.. they have seals that can leak overtime & gears that can strip.
Last edited by tscompusa; Mar 26, 2012 at 05:05 PM. Reason: typo lol
Jun 5, 2013, 05:20 PM
#12
I have a good local reputable shop working on and tuning my evo. The car has high knock sum (15-20 counts) in 5th and 6th gear only. It dosnt matter if its partial or full throttle. If it gets past about 4 k rpm it knocks. 1st-4th it runs hard and pulls strong. Its an evo ix mr btw. Any ideas?
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