You really need to have someone have a nice chat with all that BS.
1- First of all the 11.1L has a different bull gear in the front of the engine and the camshaft timing is different. You will NEVER get any power from the different ecm's. We use the test ecm just to see if it will start on a 11.1. Never use it for anyother test.
2- as the above mentioned post on engine timing.
3- the injector size does reflect output, however the computer limits the output/amount of fuel to max power.
4-Turbo if the exhaust flow is NOT enough the turbo will not produce the correct pressure in the airinlet housing, the computer will not allow the 'full' amount of injection, likewise if the turbo is to small excessive turbo boost could occur and cause hoses to blow off or damage to the CAC also 'turbo burst' may occur due to excessive turbo speed.

There is a program available called the '357' this is basically 357 Hp program. $500 will get you the ecm reprogrammed.
Hope this answers some of your questions

 

The question is will the 11.1 ECM start the 12.7 engine ? You never answered the question exactly! Or is the timing different?

 

Thanks, Gone Fishen. I figured there had to be a disproof to that theory since the motors are 1) different displacement, especially noting the different stroke - meaning the timing is going to be different, and 2) Detroit is big into the whole computer thing. Your help is much appreciated.

 

let me see if I remember there are 7 different major items. crankshaft, rods, bullgear, timing wheel, injectors, turbo, piston assemblies[includes liner/piston done ect]. might be interesting to know the sereis 50 has the same bull gear, and rods.

 

Damn, been along time since I've seen an 11L.

 

I've owned a couple 12.7's and the first change is a Borg Warner Switzer turbo, for a 500 HP Detroit, its got an impeller thats 1/8" larger. Holds boost longer in the lower RPM range. PArt # 171702 $525 new

Detroit makes lots of different injectors with different fuel flows. If I remember right, most of the DDECII used a 4930, I have one that uses a 4970 its a larger injector.

I would also talk to Pittsburgh Power, they have options for the DDECII that can increase the 12.7 to 600HP, from larger turbo, to custom program that adds 65HP and the extreme a camshaft change.

I hate talking to anyone from Detroit, they all tell you the same thing NO, you can't do that, they're the biggest propganda spreaders since the USSR. Your going to be limited cause it is an 11.1L.
One cheap mod. Pull the angle fitting from the back of the head the return line attaches to. Drill it to 7/64" there was a common issue with early 60's that they didn't circulate the fuel fast enough to the return and would cause issues. I did it to my DDECIII and noticed a little increase.

For the record, I had a 470HP 12.7 when I dyno'd it at 1,000,000 miles it was putting 427HP to the ground. Only two mods was the drilling the fitting, and the 171702 Turbo.

 

You never answered exactly if the 11.1 ECM will start the 12.7 engine ! I'm having that problem now I bought a 11.1 the guy said it was a 12.7 but after taking it to get it programmed to my truck found out it's a 11.1 ECM . The truck want start with it want even hit so I'm assuming the timing is different ! That's the question I Google but can't seem to get a straight answer !