For those wanting to spin them faster...

[kas83]

IMHO, high rpm's on a diesel are about as usless as **** on a chicken

But chicken ******* are oh so yummy

 

[Freight_Train]

But chicken ******* are oh so yummy

Yea,after they are dead and burned up(Cooked).;p

 

[6 Nebraska IDIs]

IMHO, high rpm's on a diesel are about as usless as **** on a chicken

ROFL. Dude that one is awesome. Hahahahahahahaha

 

[rjjp]

I need a usable dependabl truck that works as hard as I do.

punk

I agree with Punk on this one, I'm sure that dyoung14 will chime in to say that higher rpm is better, but honestly I've had mine up to the redline twice and it's kind scary what that 7.3 will do there, for the most part though I'm happy at or below 2000 (unless I'm on the freeway then it's 2400) It's where I've got good torque and pull whatever I want.

 

[dansvan]

I am not referring to a pulling racing motor. I could care less that they make more power in one cylinder than the IDI. Drive it 100 miles. Then I'll be impressed. I'm talking our motors in the current configuration that 99.9 % of us run. Turning them to 4k even with a new cam, what would you gain? You can add 50 horse but costs you 40 to do it? For a new gain of 10? (hypthetical of course) The addded stress would reduce life expectancy. I'm all for innovation and thinking outside the box. I daydream about this stuff all the time. But in real world applications. What about shooting for 600 lb.ft. at 2000 rpm? or 2500 rpm? What can be done to increase power in our current powerband. I don't think thats been explored to it's limit. What about higher static compression? On a two stroke torque tends to go up with more compression. Keep our 15 psi boost limit and raise compression to 25-1 or 28-1? Just throwing stuff out there.

 

[emmer]

I dream of someday having my own designed diesel, with super thick cyl walls (1 inch), with a displacement of 500cu inch (inline 6) and a massive turbo ( 2 feet across) and a massive pump.......with monster injectors, bolted up to a 18 speed roadranger.

......something that would shake the house at an idle

 

[kas83]

But in real world applications. What about shooting for 600 lb.ft. at 2000 rpm? or 2500 rpm? What can be done to increase power in our current powerband.

Those numbers are already raising the current powerband, most of which comes from a different cam and raising the governed RPM of a diesel, as I've done in the past with another platform. If you're talking 600 lb ft at the wheels, and that the IDI's generally make torque at a 2:1 ratio to horsepower, you're talking a 300 rwhp IDI, which everyone says seems to be unattainable without extensive mods.

And upping the static compression, goes exactly against the exerpt from the article you posted earlier. More drag/friction, as the engine is pushing against the cylinders that are on the compression stroke. Will the torque produced from increased compression offset the extra strain of the compression? Hard to say. The added RPM will produce less drag/friction than drastically upping the compression IMO.

Also remember, as I've stated it before, that it doesn't need to hit 4000 rpm every shift, every time you take off, so on and so forth. Using the power/rpm wisely will still be very dependable, economical, and reliable. I can't show you an 1,800 hp DT466 that will survive a 100 mile trip, but I can show you 20 600+ rwhp, 5k+ rpm trucks that pull a sled on the weekends, and are hooked to construction/business trailers the following Monday, putting on upwards of 1,000 miles over the course of the week.

You're backtalking severely in this thread. The statement was that the diesel can't make power any higher than 5000 rpm, due to compression and slow burn of the fuel. Yet an example thrown out to making power at higher RPM is dismissed due to reliability issues? Where did the exerpt from the article say anything about reliability? Practicality is a very broad term.

 

[dansvan]

No one ever said, even the article, that no diesel could make power over 5k. they compared it to a production based 10k rpm race engine. Drag and friction have nothing to due with higher compression ratios. The amount of metal on metal surface stays the same. Pumping losses do change though. Most high compression 2 strokes loose their ability to rev out with higher compression. They turn into low rpm grunt motors. Added rpm will increase drag and friction simply because the parts are moving farther in the same time period. There is no backtalking here. The article stated you start to loose a % of gains at high rpm to friction. I asked what could be done at a lower rpm under our current redline to reach the same hp/tq numbers you are shooting for with high rpm. Your working/sled pulling trucks don't relate to our motors due to the electronic controls. I am asking about IDI's.

 

[pybyr]

I'll take an abundance of torque- and frugality and reliability over HP and RPM any day-- that's a major reason for the attraction of diesels.

Diesels have to have more stoutly designed and constructed internals because some of the forces produced by compression ignition are more violent and hard to handle than spark ignition. That same stoutness of internals is part of what gives diesels longevity-- but it also creates more reciprocating mass, which creates inertia against revving, and also becomes destructive to those same large moving parts when spun fast.

I'm sure you can make a quick-revving, high-revving diesel (at least in the relative sense) I just don't know why, except for the challenge of doing something unusual.

Even the Audi race diesel apparently has a powerband between 3000-5000 RPM, when regular racing engines are normally operating way above that.
http://autospeed.com/cms/title_Audi-R10-Diesel-Race-Car/A_2823/article.html
Since Audi presumably spared no expense to take the unusual step of a diesel racer- and has won with it- I have to assume that there's a reason that they didn't aim for screaming RPMs

 

[oldmisterbill]

While were on the power vs rpm chat.I have noticed that I don't hear much about Stroke vs connecting rod length (length has a big effect on transition speed from up to down for the piston wich effects the burn time to allow more or less time to buitl heat) vs bore dia vs cubic inches. That has a big effect on torque and hp and at what rpm they deliver it.I kinda like the idea of a lower rpm longer connecting rod -I love pure torque.Lets hash this around some. This discussion s very bennifical to many of us old & young,as it makes our brains smoke (Like an oil burner ) a bit in thought.

 

[Freight_Train]

if you want high RPM get a detroit......or figure out a way to convert to a 2 stroke.While it won't be a true high RPM it will give the illusion.A V8 detroit at 2100RPM sounds like a V8 at 4200RPM or a V16 at 2100RPM since every time the piston goes up the exhaust is open atleast for about 1/3 of the stroke when it turns into a compression stoke.Twice the exhaust impulses.

 

[idiabuse]

Over the past weekend, in front of a record 235,000 spectators, the Audi R10 took first place in the 24 hours at Le Mans, arguably the world's premier endurance racing event. This marks the most significant victory yet for a diesel-powered car in a major racing event, and possibly an important turning point in the perception (held by many Americans) that diesels are noisy, stinky, and slow: the Audis were the quietest, cleanest, and fastest cars in the race. Significantly, they were also the most fuel efficient

Unveiled late in 2005, the R10 is Audi Motorsport's all-new design that nonetheless looks remarkably like it's predecessor, the massively successful gasonline-fueled R8. It is powered by a turbocharged diesel all-aluminum 90° V12 with common-rail direct injection that generates 650bhp and 811 lb-ft of torque in competition form. The power band lies between 3000 to 5000 RPM, a range so low as to be virtually unheard of in modern race cars. But its primary weakness is weight: the engine is rumored to weigh upwards of 200 kilograms, about 50% more than a comparable petrol-powered engine.

 

[oldmisterbill]

"The power band lies between 3000 to 5000 RPM, a range so low as to be virtually unheard of in modern race cars."
"So low rpm for power band" I think this kinda hints at the point so many of you have been making. Slow burn = hot burn-many btus utilized ,less wasted ( connecting rod length will strongly affect this actually at any rpm range) its all revelant. Next what were they using for "deisel fuel" Deisel doesn't necessarly mean "oil" it means the type of ignition. (I think )

 

[kas83]

Your working/sled pulling trucks don't relate to our motors due to the electronic controls. I am asking about IDI's.

:***: Where did I mention electronic engines in this thread?

race engine

Where are you guys getting all your basis for a daily driven, dependable engine when the article is clearly comparing engines built for other uses?

Even the Audi race diesel apparently has a powerband between 3000-5000 RPM

So it already has a wider, usable powerband, than an IDI. Plus it's an electronic, high tech diesel, which is not allowable in this discussion, as it's not an IDI. Arguably, you have 1300 rpm to work with on an IDI, unless you like to really abuse it by lugging it below 1400. Everyone says they start falling on their face around 2700, and while they will turn 3300 stock, don't do much at that point. Yes, they have peak hp at point, but the torque curve has fallen way off, and the horsepower is purely a function of the RPM. So why not setup the engine, fuel, timing, etc, to increase the powerband from around 1500 up to about 3500? Believe it or not, the stresses of making power at a slightly higher rpm are lessened over lugging the **** out of it.

In my quest to build a high performance(so to speak) IDI, I'm wanting to build something that will hold together at 4,000 rpm, but only pulls hard to about 36-3700. Usefully extending the powerband while not killing the engine.

And why on earth would someone compare a 2 stroke Detroit, with maybe a 2-400 RPM powerband? They are great engines, I love them, but there is absolutely no comparison.

I don't want high rpm, I want a BROADER powerband, and that's what is available with pushing them a little. Will it detract from reliability? If used right, not one bit. You guys have your minds made up, and I'm just throwing facts out to supplement your opinions on engine, and what can be done.

And the one thing everyone seems to forget, is that if the motor produces a broad, linear torque curve, even as RPM, drag and friction increases, the power will continue to rise, as HP is calculated off RPM and torque. Hence my DT466 example.

 

[Jake S.]

So basically, we need a guinea pig to build a motor with studs thoughout, find a turbo that is efficient and aftercool it, and find a good ip that will stay in time. The ip sounds like the hard part.