Changing from LS1 to L92

[OWIKA]

I currently have an LS1 in my car. But I am thinking about building a L92 N/A to be around 550hp or more if I can. When I install a cam and delete the vtb and change it to 24 tooth can my computer and wire harness work with the 6.2L

[digitalsolo]

If you put a 24X crank in it, you could.  Are you changing the crank/reluctor?

These boxes can adapt a 24X ECU to run a 58X engine:  https://www.lingenfelter.com/product/L460065397.html.  Never run one myself, but never had any issues with stuff from Lingy's in the past.

[OWIKA]

I don’t have the engine yet but I am hoping that if the wire harness and everything will work that I can pull my LS1 out and put the modded 6.2L in it’s place. I just wasn’t sure what headaches I was going to run into. Like I am not sure if I can use an aftermarket cable throttle instead of the electric throttle body. Not sure if there is anything else I am missing.

[jwvand02]

I went from an LS1 to an LS3, and also went to a holley at the same time which simplified some things, so if you are sticking with the factory computer caveat here is there may be more problems I didn't have to deal with.

This was a few years ago now so I unfortunately can't remember everything and it will also depend on exactly what setup you want to use, but I'll give you some stuff to think about/research:

• The Gen4 motor will work with a cable throttle body but the throttle bodies are bigger, so I used a summit-brand 92mm
• The gen3 injectors were not big enough to run the 6.2, depending on the age of the motor your injectors may have different connectors and need a new injector harness
• As digitalsolo mentioned, the reluctors are different, but the location of the crank position sensor is different as well on gen4 motors. If my memory serves, you can swap the gen3 timing cover over to the gen4 motor to make this work. Not sure how this may change with the ligenfelter box.
• PCV routing is different on gen4 motors (through the valley cover like the LS6)
• I had to do a bunch of messing around with oil pressure/temperature/water temp sensors. I think the threads on the head for the water temp sensor might be different and the oil pressure sensor didn't have the same clearance? I can't remember for sure if this was a self-caused problem or not.
• One thing that really caught me off guard is the map sensors changed connectors and the gen3 won't fit the gen4 intake. You can get cheap adapter harnesses but I didn't figure this out until literally time to start the car and it was a big bummer!
• The gen4 alternators are wired/activate differently. You will need to swap your gen3 alternator over.

[FC3S Murray]

Yep, jwvand02 covered most of it.


If I were you, I would just pull your harness and PCM and upgrade to the newer style harness & superior E38 PCM.


Way less headache then trying to convert everything to an older style 0411/P59 PCM.


PSI Wiring offers nice stuff for an affordable price: https://www.psiconversion.com/products/standalone-wiring-harnesses/ls-58x/HAR-G4WM.html

[OWIKA]

Yes I currently am running a PSI wire harness for the LS1 setup. That is why I was hoping to keep most of that. The motor is pulled out of the Escalade and has all the factory harness and plugs so wasn’t sure if I could just splice in the connectors or get adapter harness connectors.

[shainiac]

I don't know if someone already mentioned it, but Gen4 have the cam sensor in the timing cover, not at the back of the block like Gen3, it's. So you'll need a Gen4 timing cover, cam sensor, and a 1X reluctor for the 3-bolt cam (Gen4 are 4X). I think the GM PN for the 1X cam reluctor is 12576407.

Gen4 also has no knock sensor studs in the valley plate, they're on the sides of the block below the engine mounts.

There's also basically only one car OEM intake manifold option for L92/LS3, but it's a good one.