A&Q about 350Z
Q:
We all know tha Diesels make more torque than gas engines but they simply lack high RPMs what limits them to such low speeds? Is it the burn rate of the fuel itself? Could that be sped up by higher boost pressure, and injecting the fuel a few degrees sooner? This is prob a stupid question pardon my ignorence on the subject I have not studied much on the combustion dynamics of compression ignition engines, and that is sad since I used to work on them 14hrs a day LOL. I know there have been a few attempts at building racing diesels in the past few years do yall know any good links to read up on this?
A:
You hit a few of them. Burn rate is key. After a certain RPM, you would have to start injecting less fuel since there is less time in which to burn it.
The hydraulic injector pumps of yesteryear (and still some today) don't take keenly to higher RPMs. The very high compression ratio starts becoming a limiting factor. The incredible stresses that much squeeze puts on the pins can lead to failures. The compression and forces on the piston also dictate that the rotating parts be heavy and beefy.
I've heard about some diesels that run pretty fast. Some of the 2-stroke diesels run up to 4000 rpms even in commercial applications. The older 6.2/6.5 family I think was good to over 4000.
I have to find out what diesels are in the older Crown school buses used by L.A.s schools here. They scream. If I find out that its 6000 I won't be surprised at all. On the highway the exhaust sounds like a Chevelle with 4.56 gears.
BTW, injecting fuel a tad sooner is the key that most aftermarket diesel programmers use. By getting it in sooner, they can get more in there, but since the fuel IS the timing, going too soon will raise cylinder pressures too soon, which will of course decrease power.
A:
The combustion can be sped up by increasing boost and compression because it raises the temperature, which raises the rate of reaction, and it raises the concentraion of air, which also raises the rate of reaction (grade 12 chemistry).
The problem with that, however, is that when you increase the boost and compression, you increase the stress on the block, pistons, con rods, crank, etc. so you need to use stronger and heavier internals. The problem with that is that with heavier moving parts, they can't accelerate and decelerate as quickly as lighter ones so they can't rev as high.
Bankspower.com is a great place to learn about diesel, Gale Banks is one of the most knowledgeable people when is comes to diesel.
For general info go to:
For Banks racing vehicles (you should check project D-Max Type-R) go to:
A:
He also made the fastest pickup truck in the world, 222mph, it's a dodge dakota with a 5.9L Cummins diesel, somewhere around 600-800hp and 1300lbs of torque. that thing beats a corvette in a straight line.