Quote:
Originally Posted by Truckdobe
Have those of you that are stating that you "don't buy into this" actually tried it?? Or are you just stating your opinions??
Not opinion, but rather decent analysis. No I haven't tried it, probably wouldn't work with my Volvo engine.
It's not hard to understand, if you ram more air in the engine, it will become more efficient. Efficiency is BSFC (Brake Specific Fuel Consumption) which is the amount of fuel in lbs that is required to make one horsepower for an hour. Diesels are usually around .30, gas engines around .40. Lower is better, obviously.
Diesel fuel has a set amount of BTU's in it. You can convert directly from BTU's to horsepower, and doing this you'll discover most engines are around 30% efficient. The rest of the "lost heat" goes out either the rad or the exhaust. If your engine was 100% efficient, you wouldn't need a rad and the exhaust would be the same temperature as the air going into the turbo.
If you knew how efficient your engine was (bsfc), you could actually figure out how much average HP you need to travel down the highway.
Now given all of this, to increase fuel mileage you must create more horsepower-hours with the same amount of fuel. OR use LESS fuel and make the same horsepower with it.
Now this is where it gets tricky. "wasted" horsepower. This is HP that we're using in excess of what the truck actually needs. You travel faster, you're wasting more HP.
All I'm saying is with more HP, you have the potential to waste more HP. Up until the "original" HP of the engine(say a 475 HP cat turned up to 600), the engine behaves exactly the same as the old engine, efficiency and all.
Another thing I'm saying is that "turning up the engine" does not increase fuel mileage. All you're doing when you turn up the engine is inject more fuel, nothing more, nothing less.
If you allow the engine to breathe easier, remove restriction in the exhaust, reduce friction in the engine, increase compression, you both increase HP and increase efficiency. You CANNOT do one or the other. You aren't injecting more fuel, so if you made the same HP, you are exactly the same efficiency-wise.