Hey Parry,
Ive done both LH2.2 and LH2.4 variants of 240 turbos. The LH2.2 setup was the first one I did back in 2011. It was a B230FX and I bought a 740 turbo donor car and @VolvoHordz and @Philia_Bear helped me swap it all over. By all accounts it was pretty reliable and I put alot of kms on that setup. It was initially running a 12b and then eventually a 15g. I ran ~12psi of boost and aside of the boost onset knock which ALL LH boxes will do, it made good power.
The second is the 245L that I still have which was a Kjet car that I installed LH2.4 into to support the turbo components. It is running a B23ET that I got from @Spac . Between the two, id say there is minimal difference between the two when driving. LH2.4 is "smarter" than 2.2 and will learn as you drive it to adjust the maps to suit your driving style. LH2.2 goes full rich when you come into boost.
If I can remember, 2.2 uses the knock sensor + MAF to determine when you are on boost. When it sees knock when it adds fuel to stop that knocking. 2.4 can adjust its timing advance so will use a combination of fuel and advance to manage boost.
If I were to be building a car 240 turbo today I would use an aftermarket system. Both LH systems are pretty antique now and the cost of an aftermarket system is pretty approachable now. If your 242 already has 2.2 installed and you can find some turbo computers cheap enough then thats what I would do. You will need to also obtain a LH2.2 EZK wiring to go with your turbo 2.2 fuel ecu. You cannot use the NA "Chrysler" setup. Its very aggressive with timing and you wont get much more than 5psi out if due to how aggressive the timing curve is. The ezk is much more stable and suited to a turbo setup.
I think I might even have a turbo 2.2 computer here. Its not in a case anymore because I was using the case for something else but im sure it worked last time I had it plugged in.
