So what the heck is an EGT? Is Centain the same as Octain? There is so much about diesel I don't understand. I don't know what all the mods are for other than making more power??? Can you say GREEENHORN!!!!!!!!!!
EGT = Exhaust Gas Temperature Simply put, to make more power, you inject more fuel. Unlike a gas engine, Diesels get HOTTER as the fuel mixture gets richer (overfueled). As a result, more boost is necessary to keep the EGT down. Moral of the story, more fuel, more boost, more power. More fuel by itself, more power, but higher EGT. More boost, but no more fuel and you get............... Nothing.
EGT = Exhaust Gas Temperature. When you start pushing the diesel engine for more output than it can "breath well" at, the EGT goes up FAST. This usually cooks the turbo and kills the engines potential logevity. So, we install pyrometers in the exhaust manifold (some do post turbo too) to make sure we keep things reasonable. I can run my "Juice" box on the +90 hp level (seems like that gives around 400 hp/800 ft/lbs on the dyno?) with no EGT problems around town, but towing I turn down to the +60 level or lower depending on the load and terain. My "box" also monitors EGT and starts backing out "fuel" (more specifically, the over-fueling) at around 1250* EGT, and backs it all the way out before I hit 1350* (the generally accepted max EGT for the DMax turbo before problems become more likely). And if it's going to be a long pull, I manually back it out or force a down shift to reduce the EGT to much lower levels. I don't want to see it stay over 1300 for more than a few minutes, and I change my oil (which gets cooked by a hot turbo and is what leads to most related problems) after every "cross the Rockys" hard pulls, regardless of mileage. 10 qts of oil and a filter is much better than hurting my DMax...
Very good explanation Tim. But you left out free breathing exhaust and a few other things that can bring EGT down besides boost (though they often combine). I could drop my EGTs by 100-200* just by doing a "cat back", without any significant change to boost pressures (limited by computer).
Ahhhh OK Thanks a ton! I love my 05 DMax and I have no plans to change anything as I don't 'feel' I 'need' them. No I have only had it sence November and have put on about 8500 miles on it so far so who knows how I will 'feel' a year from now. Hell the only thing I have towed with it so far is my 12ft duck hunting boat hahahaha I literally could not even feel it behind me. hahahaa Thanks again Burt PS what the hell is a 'finger stick'???
As far as the fuel and air thing that Tim and Russ were talking about....this is where a lot of diesel folks stop or really move on. The larger boxes like the Edge Juice, TST, (and others I can't think of) are capable of fueling an engine beyond the amount of air the stock turbo can push into the engine to match the incoming fuel, and in some circumstances, the fuel system can't keep up with the big boxes. This is the cross road.... Keep the box down with maybe a good intake system and free flowing exhaust and be happy, or move on to a bigger turbo, injectors, etc that will be able to handle the fueling the boxes are capable of. It's like a gas engine.....with your new 454. If you went with bigger cam, and fuel system you would probably want a bigger set of heads available from the aftermarket that could breath big enough to take advantage the best it can of the more aggressive cam and carb( or in your case MPFIwaytogo ) The extra problem with diesels there is instead of just choking out a motor with "small" heads you can burn up the diesel from it getting too hot on the exhaust side from not enough "flow."
There are a number of ways to reduce EGT and still make mondo power. That's a topic for another thread I suppose.
