D19 Turbo on D15?

Theoretical question: If a D19 diesel trubo went on a D15 diesel, what would the effects be on the engine? Reliability, horsepower increase, easier starting, better fuel economy?

You wouldn't see any easier starting since when starting the turbo wouldn't make any boost to raise the compression ratio.  I'm not sure the exact displacement of a D15D, but I'm sure it's considerably less than the 262 of the D19D.  Which means that the only time you will probably see any improvement is when you are wide open throttle to create enough heat and exhaust volume to spool the turbo.  Hypothetically you will see a few horsepower increase without changing the fuel delivery to add more fuel, but probably not a lot of change (geussing 1-5 HP).  The engine will probably run with less smoke when the turbo is spooled, but will depend on how well it can spool the turbo.  Most likely you wouldn't see any real loss in engine longevity since you wouldn't be adding hardly any boost to create more pressure/wear on the engine.  If you turn the fuel up with adding the turbo, then it will respond better since you'll be creating more exhaust flow and heat to spool it better.  With the fuel increase, you'll also see a heat increase of your engine since it's making more power and may get to a point that the cooling system will struggle to keep the engine cool enough.  Also with the added fuel, you'll be creating more boost and put more stress on the head, rods, and block to hold the extra power.  I haven't been around a D15 diesel to know if they are an energy cell head or not, but if they aren't direct injection (like a 301 or 426), then they will be more prone to cracking the heads due to the increase of heat (WD45D, D17D, and especially the D19D are notorious for this problem).

Randy from Mo. fabricated one and had it at Boonville . I will try and find a pic tonight and post it

Randy had me rebuild the turbo for the D15 over a year ago and have talked to Randy about how it's doing four or five times and it's A-OK. He works this tractor day in and day out and it's not a show toy, he mows a lot with it.  

My car is a Ford Fiesta 1 liter EcoBoost. They claim 123 hp at 6500 RPM. Its about the same weight as the 2002 2 liter naturally aspirated VW Golf it replaced but a little faster in the 0 to 60 test. And the Fiesta gets around 40 vs 33 mpg for the Golf.

The three cylinder Fiesta engine works smoothly from about 850 to 6500 RPM (red line on the tachometer and in the computer) but gets rough if loaded at 850 or below. The 5 speed manual transmission has wide range gears and 2nd gear is good from less than 3 mph to over 60 mph. Sometimes I can start from standing still in second gear on level ground. Sometimes I kill the engine trying.

It has no carburetor, its direct fuel injected. And all run by computer. It runs fine on E10. Lots of performance from a little engine. I'm sure the bottom end of the engine is sturdier than a naturally aspirated engine with more cylinders producing half the horsepower. It has to be sturdy to stand that RPM range and well balanced too.

I'd think adding a turbo to a tractor engine would want to run faster to make good use of the turbo (preferably  matched to the engine displacement) which probably would show up problems with balance and wouldn't do much for performance until the injection pump was turned up to get the optimum fuel to air ratio for good combustion.

Gerald J.