Hi guys, Because in another thread about this subject people started to bash on other things I'd thought a new thread would be better (so my view on the subject get fresh new attention).
The cons:
- It could break down more easily. Jup, could be, dunno, time will tell. If it is Chrysler only technology changes are the first 3 years it will break down bad. After that, DC will have cured the problem and the engine will be rocksteady for the next 20 years.
The pros:
- Mileage. If an engine runs as efficiently as possible, the amount of fuel burned per second depends on 2 things. First: cubic inches. Second: revs.
If you have a large engine and want to have a decent fuel usage per second you'll have to get the rpm's down. Otherwise it won't happen. If you go from 3000 rpm to 1500 rpm your engine will use half the amount of fuel a second. Now, because a typical torque curve goes way down below a 1000 rpm it is impossible to gain something there. The engine will simply stall (which of course gives you zero fuel usage a second but you won't get anywhere either).
The only thing that remains is to decrease the engine size. By shutting down have the cylinders the engine size is halfed too. Now you have the same engine useage at 2000 rpm as you'd have at 1000 rpm with all 8. And because of the way torque goes down you'll have more power as well. Now you might worry if the smaller engine (still almost 3 litres) is powerful enough to drive at cruising speeds.
Well, my 2.5V6 Stratus has about 170 horsies at 6500 rpm. Driving 120km/h (75mph) my car does about 2500 rpm. So the car uses
170 / ( 6500/2500) = 65 horses at that speed. Now, the new 300 is heavier so lets assume it needs 75 horses to drive at the same speed.If the cars has a maxrpm of 5500, it would go 75 x 5500 / 330 = 1250 rpm at 75 mph. At 60 mph the engine would have to go to higher gear to avoid stalling. Of course you haven't noticed any large engine car stall at
60mph. That's because the engine runs at higher revs, and gives you more horsepower even if when you don't need it. But that extra power will cost you. Now, with 4 cylinders shut, the car will do 2500 rpm at a steady 75 mph, and 2000 at 60 mph.If the new V8 will be able to activate the 4 sleeping cylinders fast enough to release its full power when needed I think Chrysler has a good hand of carts. As fuel prices will go continue to go up, a normal large V8 has no future.
I realize I've neglected gearing in the above, but there's only so much to win there. Besides that, the 4 cylinder shutdown is a 50% fuel cut. There's no way gearing can solve that without using at least a 8 speed. And the engine would still stall below 750 rpm.
To be honest, noone needs a 300 HP car, but I won't start that war now. Besides that, I want a 300 HP car as well. :) Martin