Wastegate

As long as he didn't get crazy it will be fine. But he does need a pyro and boost gauge before doing any ecm tunes.

Edit to add: and he needs to find out what his engine model is to find out what it can safely handle

 

Call the truck dealer with the vin. They can get you a new one. You absolutely need to know what your engine model is before doing tunes or adding performance parts. The bw turbo is safe to add to any series 60, just need a pyro and boost gauge. But anything else is gonna need the model number. You don't want to put a high hp high torque tune in an engine that has aluminum pistons. You will melt them. However if it turns out you have a lower hp 12.7 it isn't a deal breaker, just means that when you rebuild it you put in the stronger steel pistons so that you can pump her up. 750 is very much doable out of a 12.7. Just requires careful monitoring of gauges when you are using that extra juice.

 

When you have a small A/R turbine housing, it focuses the exhaust gas and causes the turbo to spool up faster. The downside is it restricts flow effectively limiting the top end boost. A larger A/R turbine housing will flow more exhaust at the top end but it's slower to spool up. A wastegate allows you to use a smaller A/R housing to get the turbo to spool up faster and as the pressure increases, the wastegate opens to allow the extra exhaust to bleed off rather than just building back pressure similar to if you had used a larger A/R housing. So why do we see higher pressure on the gauge when we pinch off the wastegate? It's because now the cold side of the turbo is pumping air in faster than the hot side can get it out. You actually have exhaust from the last cycle still in the cylinder when the next cycle starts. The wastegate doesn't start to open until a few psi before its set pressure so pinching it off absolutely will not effect spool up. It will, however, limit heat dissipation and raise EGTs

 

It amazes me that even though there's countless websites and books explaining how turbos and wastegates work, there's still guys out there preaching pinch them off.

 

But the discussion isn't about all turbos for all vehicles. It's about a series 60 detroit specific stock turbo. The only reason detroit has a wastegated turbo is so they can use 1 turbo for all hp rated engines built in the same generation of engines.

That being said, i don't recommend pinching it off, my advice is doing away with it entirely by buying a good turbo designed for the hp your engine is producing. They are not expensive and easy to charge. I've seen them as low as 700 bucks. That's barely pocket change when talking about a truck.

 

You're telling me that Detroit used the same non-wastegated turbo for all hp settings on the DDEC 3 but had to use a wastegated turbo on the DDEC 4 for multiple hp settings?

 

What turbo to use is based off the hp the engine produces. Bw makes several. The reason the 171702 is mentioned so much is because most stock 12.7s fall with in its lower hp range and tuned 12.7s fall in the higher range. Without knowing what his 11.1 is producing we can't say if the 171702 will be good for it. But i kinda doubt it cause every 11.1 I've been around was only 350hp or less.