pretty sure LT4 engines came with an LT4 KM in the PCM. LT4 KM was designed for the LT4 engine anyways..don't see why they would ship an LT1 KM with an LT4 engine...

 

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.

 

I have never heard that before and can't find any documentation that backs up that statement.

 

Yep the lt4 fbody's came with an lt4 KM. I checked to make sure when I changed the cam and headers.

 

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...

 

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!

 

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.

 

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.

 

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

 

The LT4 km reduces the timing less than the stock one does.

 

My car only has one. There is a plug in the hole on the driver side bank.

 

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?

 

fine with 12 degrees of knock retard

 

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?

 

If you unplug it it pulls timing... that's what he means.. it isn't that easy to 'bypass''..