!!!read Here!!!(why You Shouldn't Use An Lt4 Km)
05-15-2003, 10:40 PM
#31
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Join Date: Dec 1969
Location: Little Rock, AR
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Originally posted by RealQuick
Sorry bro, I dont understand what you are saying? Can we physically unhook it and not worry about knock if we are confident we have good fuel etc. Like on the dyno or making a run at the track?
Sorry bro, I dont understand what you are saying? Can we physically unhook it and not worry about knock if we are confident we have good fuel etc. Like on the dyno or making a run at the track?
05-29-2003, 01:47 AM
#34
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Join Date: Jan 2002
Posts: 956
Originally posted by Brent94Z
While it sounds well written, is it accurate? First off, my 96 only has one knock sensor so that bit of info right there puts the entire thing in question.
I've been using the LT4 knock module in my cars for a very long time. They serve their purpose for me. In fact, I once got a bad batch of gas... I would get 10 degrees of knock retard everytime I barely stepped on the gas. Filled up with good gas later on and all was back to normal. This little non-scientific test along with the "hammer test" show that noise/knock can still be detected when using a LT4 module in a OBDI PCM.
While I realize I am reducing the ability for my PCM to detect real knock, I do know that the ability for the PCM to detect pinging is still there... just "desensitized" so to speak. Or, in other technical terms
... it just won't detect real or even false knock quite as good as the stock knock module. But, since that is exactly what I want and I'm willing to accept the risks involved, the LT4 knock module serves ME well 
While it sounds well written, is it accurate? First off, my 96 only has one knock sensor so that bit of info right there puts the entire thing in question.
I've been using the LT4 knock module in my cars for a very long time. They serve their purpose for me. In fact, I once got a bad batch of gas... I would get 10 degrees of knock retard everytime I barely stepped on the gas. Filled up with good gas later on and all was back to normal. This little non-scientific test along with the "hammer test" show that noise/knock can still be detected when using a LT4 module in a OBDI PCM.
While I realize I am reducing the ability for my PCM to detect real knock, I do know that the ability for the PCM to detect pinging is still there... just "desensitized" so to speak. Or, in other technical terms
... it just won't detect real or even false knock quite as good as the stock knock module. But, since that is exactly what I want and I'm willing to accept the risks involved, the LT4 knock module serves ME well
05-29-2003, 02:38 AM
#35
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Join Date: Jul 2000
Location: Norfolk, VA. USA
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Is there a reason my 95 LT1 has 2 knock sensors? Came out of a Caprice 9C1. Both of mine look like **** and I don't want to buy 2 if I don't have to.
Oh, and I just had a though, could it be because of the iron heads the b-body's got?
I have 94 Vette heads on my LT1 now.
Oh, and I just had a though, could it be because of the iron heads the b-body's got?
I have 94 Vette heads on my LT1 now.
05-29-2003, 10:34 PM
#36
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Join Date: Nov 2002
Location: Stuart, Florida
Posts: 52
My 1996 Impala SS (OBDII) came with 2 knock sensors. I always assumed it was associated with OBDII requirements. It is possible that a 1995 Caprice LT1 (California car) may have also used OBDII. Or ... just speculating, but maybe the iron heads (transfers heat more slowly than aluminum) required 2 knock sensors instead of 1 to detect detonation.
Note that after a mechanic did some warranty work, I noted pinging in the Impala. When I crawled under the car, I noted that the driver's side knock sensor connector had been left unplugged. When I plugged it back in the pinging went away. Therefore, I would conclude that disconnecting the knock sensor will not necessarily cause the computer to retard timing to the maximum default. This is contrary to what another post stated. In my case, it caused the computer to maintain full timing even though the car was pinging.
Otherwise my 1994 Z28M6 has only 1 knock sensor. I plan on replacing the module with a LT4 unit, as my spark retard pegs at 10 degrees retard for the whole quarter mile at WOT, using headers (which transfers more noise towards the knock sensor), even with 100 octane race gas. There is never any audible detonation or pinging, but it sure kills the performance of the car. My car had previously run 1/4 mile trap speeds of over 108mph, but is now hovering around 102mph.
Has anyone ever installed a 2nd LT4 knock sensor in F-Body LT1 block (driver's side) to better cover detonation, as LT4 sensor/module is less sensitive?
Note that after a mechanic did some warranty work, I noted pinging in the Impala. When I crawled under the car, I noted that the driver's side knock sensor connector had been left unplugged. When I plugged it back in the pinging went away. Therefore, I would conclude that disconnecting the knock sensor will not necessarily cause the computer to retard timing to the maximum default. This is contrary to what another post stated. In my case, it caused the computer to maintain full timing even though the car was pinging.
Otherwise my 1994 Z28M6 has only 1 knock sensor. I plan on replacing the module with a LT4 unit, as my spark retard pegs at 10 degrees retard for the whole quarter mile at WOT, using headers (which transfers more noise towards the knock sensor), even with 100 octane race gas. There is never any audible detonation or pinging, but it sure kills the performance of the car. My car had previously run 1/4 mile trap speeds of over 108mph, but is now hovering around 102mph.
Has anyone ever installed a 2nd LT4 knock sensor in F-Body LT1 block (driver's side) to better cover detonation, as LT4 sensor/module is less sensitive?
Last edited by I CORNER1; 05-29-2003 at 10:36 PM.
05-29-2003, 10:43 PM
#38
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Location: Norfolk, VA. USA
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Originally posted by shoebox
4th gen F-bodies have one knock sensor on the lower RH side of the block. There is no wiring for a second sensor. LT1's in other applications can have two sensors.
4th gen F-bodies have one knock sensor on the lower RH side of the block. There is no wiring for a second sensor. LT1's in other applications can have two sensors.
05-29-2003, 11:02 PM
#40
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Location: Norfolk, VA. USA
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Originally posted by shoebox
I have not seen an explanation for that.
I have not seen an explanation for that.
Maybe if I flash my PCM from an f-body bin this may eliminate the need for 2.
What are your thoughts on this?
05-29-2003, 11:06 PM
#41
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Location: Little Rock, AR
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Originally posted by Zepher
Now I am concerned. I have the LT4 knock module that I am putting into my b-body PCM. The module is what reads the knock sensor, right? So, the LT4 module was stock in the 96 Vettes, and they probably only had one knock sensor, so can I assume that I can run one knock sensor without any problems?
Maybe if I flash my PCM from an f-body bin this may eliminate the need for 2.
What are your thoughts on this?
Now I am concerned. I have the LT4 knock module that I am putting into my b-body PCM. The module is what reads the knock sensor, right? So, the LT4 module was stock in the 96 Vettes, and they probably only had one knock sensor, so can I assume that I can run one knock sensor without any problems?
Maybe if I flash my PCM from an f-body bin this may eliminate the need for 2.
What are your thoughts on this?
05-29-2003, 11:45 PM
#42
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Join Date: Nov 2002
Location: Greenbrier, TN
Posts: 143
I have heard that too, about corvetes having 2 knock sensors. I can see where it would go, we have a knock sensor on the passenger side and a drain plug on the drivers side. Guess the vettes motor mounts are difft and they can get a sensor in there??
Jason
Jason
05-30-2003, 12:20 AM
#43
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Join Date: May 2000
Location: Haverhill MA
Posts: 406
Correct me If I be mistaken, If you order from GM isnt the LT4 KM now the part that is cross refferenced when you want a LT1 KM ? I thought I read somewhere that the LT1 KM's were no longer avail from GM, they use the LT4 KM.
If I am wrong forgive me, I suck.
If I am wrong forgive me, I suck.
05-30-2003, 01:48 AM
#44
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Join Date: Feb 2001
Location: BC, Canada
Posts: 3,843
the ONLY thing that i can think of which would be "wrong" about using an LT4 KM with an OBDI KS is that ... the LT4 motor came out in 97 .. hence the LT4 KM was designed to be used with the OBDII KS .. now i dont know exactly what the differences are between the OBDI and OBDII KS's .. but i know u cant use one instead of the other
so if the LT4 KM was designed for the 97+ cars .. hence for OBDII cars using OBDII KS .. then putting it in an OBDI car using an OBDI KS "could" be problematic
on the other hand i've been running it in my car for 2 years .. and its never helped me much .. still get false knock up t he ying yang !! next step for me is to zero out my KR tables in LT1 Edit
so if the LT4 KM was designed for the 97+ cars .. hence for OBDII cars using OBDII KS .. then putting it in an OBDI car using an OBDI KS "could" be problematic
on the other hand i've been running it in my car for 2 years .. and its never helped me much .. still get false knock up t he ying yang !! next step for me is to zero out my KR tables in LT1 Edit
05-30-2003, 01:55 AM
#45
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Location: DeKalb, IL
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Originally posted by sideways_Into_3rd
the ONLY thing that i can think of which would be "wrong" about using an LT4 KM with an OBDI KS is that ... the LT4 motor came out in 97 .. hence the LT4 KM was designed to be used with the OBDII KS .. now i dont know exactly what the differences are between the OBDI and OBDII KS's .. but i know u cant use one instead of the other
so if the LT4 KM was designed for the 97+ cars .. hence for OBDII cars using OBDII KS .. then putting it in an OBDI car using an OBDI KS "could" be problematic
on the other hand i've been running it in my car for 2 years .. and its never helped me much .. still get false knock up t he ying yang !! next step for me is to zero out my KR tables in LT1 Edit
the ONLY thing that i can think of which would be "wrong" about using an LT4 KM with an OBDI KS is that ... the LT4 motor came out in 97 .. hence the LT4 KM was designed to be used with the OBDII KS .. now i dont know exactly what the differences are between the OBDI and OBDII KS's .. but i know u cant use one instead of the other
so if the LT4 KM was designed for the 97+ cars .. hence for OBDII cars using OBDII KS .. then putting it in an OBDI car using an OBDI KS "could" be problematic
on the other hand i've been running it in my car for 2 years .. and its never helped me much .. still get false knock up t he ying yang !! next step for me is to zero out my KR tables in LT1 Edit
In 97, they switch to LS1/C5s.
And to answer the other guy's question.... yes, Vettes had 2 knock sensors just as B-bodies did.
EDIT: I meant to say the LT4 was installed in cars beginning 96. It was installed on 97 LT4 SS and Firehawk cars too, but not on Vettes.
Last edited by madwolf; 05-30-2003 at 02:01 AM.