8V92T no cooler?

[HETvet]

I have been thinking about this thread. I'm curious now; we can add more fuel by turning up the IP and changing out injector, and we can increase boost pressures and air flow by converting to a twin turbo set up, and installing an after cooler/air to water heat exchanger/meth/water injection, but how do we get the DDEC to play nice? I know there is a MAP sensor and if memory serves me right; it's good for 24psi. Can we get the MAP to accurately read higher pressures? Also, can we change injection timing? I know the injectors are fired from the cam shaft, but could the cam be degreed to advance or retard the injection timing a few degrees? I have heard that lift pumps help these engines, so would it be more beneficial with the increased fueling? Additional filtering and water separation is always a good thing, but is there a risk of cavitation?

 

[BiffJ]

I can now see how the Detroit is in a tough situation for cooling the air as it has the turbo that heats up the air then the roots blower. And it would only make sense that the cooling would be most efficiently done after the last addition of heat. So it sounds like the location of the cooler is in the right place, and leaving out wether the specific cooler is large enough or efficient enough, it seems that its main drawback is that its engine cooled. I am talking theoretical as I don't even know what the water to air cooler looks like in this application. But maybe you could provide it with its own radiator with a circulating pump? Not sure if it would be a good idea or not and wether its worth the trouble, but at least it wouldn't be dependent on the engine temperature. Then if you added a pre air to air cooler you wouldn't have the later addition of engine coolant heat.

Pretty much anything is doable with enough time, effort and cash. The question is will you gain enough to make it worth the trouble. With the installed cooler you won't be able to drag race perhaps but as previously noted having intake air temps of 200 deg F is a lot better than 300-400 deg F. The installed cooler uses water from the block and putting something else in there is going to be tough. You'll have to come up with some means of feeding coolant into it as well and since the blower is blocking access its going to be tough. Putting an intercooler on the turbo is probably not a bad idea but screwing with the aftercooler on the blower isn't worth the trouble in my opinion. Your gains are not much and the pain is severe. Your HET is limited to about 45 mph anyway and an extra few HP won't get you anything. Efficiency and fuel economy obviously aren't the issue or you would be driving a new Kenworth or something of that type....
Just my thoughts
Good luck

Frank

 

[Hawssie]

Yeah but the military thought they needed more power. And we always think that about everything.

 

[tim292stro]

The V71 V92 engines don't have a common rail fuel system, just a gear driven lift pump mounted on the front of the roots blower - the only way to "turn up the fuel" is to put in larger injectors ($$$). Even with the DDEC engines the cam shaft charges the injector, DDEC only allows the release of the fuel into the cylinders. Getting more air into the cylinder will require replacing cylinder liners to increase the size of the intake ports - I think the air restriction you get with the aftercooler is a large reason for the performance guys pulling it out and installing an intercooler.

As for feeding the after cooler with something else other than engine cooling water, from my recollection, the plumbing is external to the block since it was a factory option - you should be able to block of the factory outlet/inlet from the block, and simply plumb the aftercooler from another source - but see previous paragraph's last line.

You have inspired me to dig out my full shop manual for the v92 engines to share - I even have the field service guide for service techs that I picked up from my local DD shop when they were getting ready to stop working in 2-strokes. Getting DDEC to play nice will require that you make very good friends with someone who has a DDEC programmer - this'll take software changes.

Again, I'll suggest that if you're looking for power, or thinking of making any changes to a 2-stroke DD, talk to Don Fairchild - he's apparently still around and working on these, finding skilled people to work on 2-strokes will become increasingly harder as the days, months, and years go by.

Yeah but the military thought they needed more power. And we always think that about everything.

The military and every car-tinker-er channels their inner Clarkson: