WWDiesel wrote:
TURBO-DIESEL-FREAK wrote:
Horsepower and efficiency go hand in hand.
To a point, but to make more HP requires more fuel which can offset economy.
HP makes the engine rev up fast, but it is torque that gets you down the road and maintains speed.
Increasing torque without having to add additional fueling will increase economy & efficiency.
You can have the HP, give me the torque any day...
But it is HP that moves you down the road. Your Jeeps engine is doing "work" to push the jeep along and over come air drag and rolling resistance. Work is force over distance. How quickly your do that work and cover the distance is power, Horsepower. If you had 0 HP you wouldn't move. If you want to drive at 60mph then you need more HP than to drive at 40mph. HP is a combination of torque and RPM. If you make a lot of torque at a lot of RPM, you make a lot of HP.
A Bugatti Veryon Supersport wouldnt do 268 MPH if it made 1106 ft-lbs at 1 rpm because it would only be making 0.2 HP. And for the very same reason, a cummins ram wouldnt tow a 10,000 lb trailer up a mountain at 65mph if it made 930 ft-lbs at 100 rpm cause its making 17 HP.
All our Jeeps do(and all diesels) is make a lot of low end HP(relative to something like the 3.7 V6) by making more low end torque. That low end HP is what lets you climb a 7% grade without downshifting or towing a trailer on flat ground in 5th gear. It gives us the sense that our 2.8L are powerful by seeming doing these things with ease. The reality is the peak HP of our engines is low and at 2000 rpm they are already making 75% of the total power they can make. That's why they are not fast in the 1/4 mile, they fall on their faces at high speed(>80mph) and they bog down when you tow a trailer up a big hill.
If you want to improve these things(acceleration, passing, towing) you need more HP. If all you wanna do is pick up groceries and drive to work then the jeep is fine at currently accessible power levels. You can get more HP by either having a tremendous amount of torque at low RPM(which will probably kill your motor) or a moderate amount of torque at high RPM. I could make 250HP at 2000 rpm, I just need 650 ft-lbs and about 45 PSI of boost to get there(good luck). I could also make 250 hp at 4000 rpm with just 325 ft-lbs and ~28 PSI of boost. That's far more reasonable goal.
No single turbo that spools like stock is ever gunna make 45 psi. DieselGuy's turbo lets us achieve a 250 hp goal by letting the engine breath better at higher RPM while still spooling like the stock turbo. The turbine can handle the extra flow and the compressor allows us to hit the boost we need to cram enough air in.
The efficiency would come from the freer flowing turbine allowing the engine to push the exhaust gas out with less effort. The beauty of this turbo is that if will drive like stock. If you simply need a new turbo because your stock one died, this will work. You dont need to run it at 250 hp to see benefits, but the option is there.