!!!read Here!!!(why You Shouldn't Use An Lt4 Km)
05-13-2003, 01:48 PM
#16
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Join Date: Mar 2003
Location: Franklin, TN
Posts: 248
Originally posted by Z95m6
I am just wondering what do the LT4 fbodys have? The LT4 km was probably used on the vettes did they use it on the fbodys too?
I am just wondering what do the LT4 fbodys have? The LT4 km was probably used on the vettes did they use it on the fbodys too?
05-13-2003, 01:57 PM
#17
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Join Date: Mar 2002
Location: near waco tx.
Posts: 2,058
Originally posted by I CORNER1
I too plan on changing it to the LT4 sensor and module, as my knock retard pegs at 10 deg even with racing gas
I too plan on changing it to the LT4 sensor and module, as my knock retard pegs at 10 deg even with racing gas
no need to change the knock sensor, its the same on the lt1 as the lt4 its the module you change.
and if its pegging on to 10 degrees on a stock engine with race you may have some other issues to address.
Last edited by 97Z-M6; 05-13-2003 at 01:59 PM.
05-13-2003, 02:36 PM
#19
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Join Date: Jul 2002
Location: Bloomfield Hills, Mi.
Posts: 276
Originally posted by Z95m6
I am just wondering what do the LT4 fbodys have? The LT4 km was probably used on the vettes did they use it on the fbodys too?
I am just wondering what do the LT4 fbodys have? The LT4 km was probably used on the vettes did they use it on the fbodys too?
05-13-2003, 03:20 PM
#20
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Join Date: Sep 2002
Location: Palm Bay, Florida
Posts: 334
Someones confused>>
Your changing the module, not the sensor.
It's true that if you change the input impedance to a filter you'll change the filter, but you're not doing that in this case. The knock Sensor is the same as the LT4 car, the PCM is the same as the LT4 car (except for programming), so the only thing you're changing is the filter itself (the knock module) and both the LT1 and LT4 knock modules are tuned for the same input and output impedance due to the same sensor and pcm's on both cars.
And although I am not an expert on the knock module's design, I would imagine that the filter is an active one and that it is tuned to the exact same frequencies, but the gain is reduced in the LT4 module so to not trigger the spark retard from the harmonics generated by the roller rockers and roller timing chain. But any potential knock in both engines would happen at the same frequecies, so the filter would have to be tuned to the same pass bands.
-Dave C. '97 Z28
1997 Camaro Z28 w/ 454cid Big Block
(I don't need no stinkin' knock module!!!.......oh wait, yes i do....)
1995 Corvette LT-1 6-spd...
It's true that if you change the input impedance to a filter you'll change the filter, but you're not doing that in this case. The knock Sensor is the same as the LT4 car, the PCM is the same as the LT4 car (except for programming), so the only thing you're changing is the filter itself (the knock module) and both the LT1 and LT4 knock modules are tuned for the same input and output impedance due to the same sensor and pcm's on both cars.
And although I am not an expert on the knock module's design, I would imagine that the filter is an active one and that it is tuned to the exact same frequencies, but the gain is reduced in the LT4 module so to not trigger the spark retard from the harmonics generated by the roller rockers and roller timing chain. But any potential knock in both engines would happen at the same frequecies, so the filter would have to be tuned to the same pass bands.
-Dave C. '97 Z28
1997 Camaro Z28 w/ 454cid Big Block
(I don't need no stinkin' knock module!!!.......oh wait, yes i do....)
1995 Corvette LT-1 6-spd...
05-13-2003, 05:42 PM
#21
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Join Date: Dec 2000
Posts: 677
I'm no EE either, but I did talk to someone about this issue who is, and he echoed those ideas expressed by Injuneer and Shoebox. Based on that info, I put the LT4 Km in my car after doing HC and RR. Whereas, last year I was consistently pulling small amounts of timing without the HC or RR, this year, I get no knock retard under any circumstance that I noticed on the 2 occassions that I logged data.
IOW, it works for me and it works well!
IOW, it works for me and it works well!
05-13-2003, 06:06 PM
#22
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Join Date: Jan 1999
Location: Pembroke Pines, FL
Posts: 129
I think you are missing the point of the KM in an LT4 car. If you added roller rockers they make more mechanical noise, and this bypass those frequencys. The idea of different impedance is incorrect. The formula for impedance for a coil is
6.28*F*L F=FREQUENCY L=HENRYS (A measure of coil reactance)
If the L and 6.28 stay the same and only the frequency changes that the only way the impedance will change. All the LT4 KM is doing is bypassing the known frequencys that are made by roller rockers.
6.28*F*L F=FREQUENCY L=HENRYS (A measure of coil reactance)
If the L and 6.28 stay the same and only the frequency changes that the only way the impedance will change. All the LT4 KM is doing is bypassing the known frequencys that are made by roller rockers.
05-13-2003, 10:39 PM
#23
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Join Date: Dec 1999
Location: Annapolis Md. USA
Posts: 754
Yet another LT4KM user here. I received aon average 9 degrees of falst knock at WOT after the installment of headers. The LT4 km took care of this problem, and I also like other here did the "tap " test to ensure it could pick up real knock.
05-13-2003, 10:50 PM
#24
Banned
Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
thats just plain old well written sillyness-
kind of like this one
http://web.camaross.com/forums/showt...hlight=pretzel
well written but i wouldn't take it as gospel
kind of like this one
http://web.camaross.com/forums/showt...hlight=pretzel
well written but i wouldn't take it as gospel
05-15-2003, 11:17 AM
#28
Banned
Join Date: Aug 2001
Location: looking for a flow bench so Brook and I can race
Posts: 3,505
Originally posted by RealQuick
Can we run without a KM? Example: I f we feel we are getting false knock, can we unhook the module from the computer and still run fine?
Can we run without a KM? Example: I f we feel we are getting false knock, can we unhook the module from the computer and still run fine?
05-15-2003, 11:26 AM
#29
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Join Date: Feb 2002
Location: Bridgewater, MA
Posts: 5,645
Originally posted by treyZ28
fine with 12 degrees of knock retard
fine with 12 degrees of knock retard
