New Dodge Diesel

[EKUgrad]

Ya really, I mean where did you get your stats. Look at the STOCK torque curves "NOT PEAKS" of Dodge, GM, and Ford.
Dodge has a consistently high curve throughout. And as far as the I6 VS V8, the ECM will only take you so far when "adding power" Every "truck shop" around here that spray bed liners chips, banks, ect. All recamend a dodge.

People can say what they want about the 6.0 ford, but the turbo was placed in a bad spot and causes overheating. And the truck to overheat or turbo go out. As for their new truck and setup, I have heard that due to emissions it may never hit the market.

GM - A dealer himself told me to stick with Dodge, the duramax for '07 will jump in price and lose power due to some change ups.

The Dmax goes up in price, true, but so will the Powerstroke and the Cummins. All of them will also enjoy a bump in power as well.

As far as the Powerstroke never hitting the market -- another false report -- for I have seen them already on the ground and running.

 

[DiamondSCattleCo]

Here's a couple real world torque curves that are indicative of what I used to see when running trucks on the dyno:

First the LBZ:

http://www.edgeproductsinc.com/chevy_duramax_lbz.html#

And now a 2005 600 Cummins (actually a 610):

http://www.edgeproductsinc.com/dodge_600.html#

Those dyno graphs are actually several dozen trucks having been run several dozen times. Elevation, IIRC on that dyno is around 5000 feet.

The Dmax doesn't exceed the Cummins torque until 2600 RPM. Unfortunately, these charts don't drop below 1800 RPM, but if they did, you'd see the Dmax take a sharp drop, partially due to the engine, partially due to the Alisson.

Don't get me wrong, I've got nothing against any of the big 3 diesels (although I'm not fond of the 6.0L), but lets stick to the facts.

As far as the rising torque curve goes, you DO want a flat curve for the exact reason you specify. If you're hitting a hill, and your RPMs drop, it means that you're currently exceeding the engine's torque output. How would having less torque at the new lower RPM help you? An example:

You're cruising along at 2000 RPM, lets say our imaginary engine has 600lbft of torque at 2000 RPM. You hit a hill, and have to feed more fuel to maintain 2000 RPM, however you're a little overloaded, so planting the go pedal does nothing.

Now, engine #1, at 1800 and 1900 RPM has 600 lbft of torque, and engine #2 at 1900 RPM has 590 lbft of torque, and at 1800 RPM has 575 lbft of torque. Which engine is going to hold RPMs better? Bear in mind, the ONLY reason you're dropping RPM right now is because the 600 lbft of torque isn't enough to keep the truck and load moving.

Torque rise is a meaningless number, meant to impress soccer moms and farmers who don't comprehend how torque and RPM work on a load. A rapidly rising torque curve feels nifty on the butt, whereas a flat curve feels boring, however the flat curve gets you places.

Rod

 

[allenfarms]

What's your opinion of the new ford with the dual turbo I was told It was gonna put out almost 500ponies and 700ft/lb torque

 

[EKUgrad]

Interesting Diamond,

I don't profess to be an engineer or expert on these matters -- I just listen (intently) to those who do.

I liked the Dodge the best when I bought mine, although I did want an auto at the time and did not trust the Dodge auto due to bad experiences in the 90's. I believe that the 6.7 6 speed auto will be very good.

I really want a King Ranch Ford -- love those things -- but their engines continue to scare me. I know that they turn out more good ones than not, but with my luck, I would get a dud.

The dyno curves that I was using for reference came from press releases or presentations on the new motors when introduced. They may or may not have been "stock" as we buy them, but they were pitched that way.

There are a few things about Dodge trucks that I wish would improve, but the drivetrain is not on the list.

 

[EKUgrad]

What's your opinion of the new ford with the dual turbo I was told It was gonna put out almost 500ponies and 700ft/lb torque

Warranty concerns will preclude a jump like this. I am afraid that the new 6.4 will be overly complicated and suffer accordingly. Even with all that, I still will consider buying one (and trading the thing before warranty runs out).

Cummins approach to EGR, turbo design, etc, appears to be the simplest, but it is a new design as well and may have the problems inherent to new designs. They do have a good track record for getting thing right, though.

 

[DiamondSCattleCo]

What's your opinion of the new ford with the dual turbo I was told It was gonna put out almost 500ponies and 700ft/lb torque

I had a press release around here somewhere with the new Ford stats, but can't find it right now. 700 lbft was not on it though, but they are within a sniff of it right now. The 700 would be nice, however that 500 HP number scares me off. That means that the 700 lbft of torque is mostly sitting at high RPM, where it just doesn't belong on a tow rig. Most of my diesel experience is from big trucks and Cummins rigs, where 3000 RPM is about the max (except for the few sled pulling machines we built). So a 500 pony rig is kicking out 1200 lbft of torque.

The twin turbos are a much better solution than the Cummins VGT, in so far as reliability is concerned. VGT is elegant, but the heat encountered with turbochargers just doesn't lend itself to sliding equipment. Cat finally gave up on VGT and went with twins. We played with VGT a bit, but gave up on it. Lubrication is too much of a challenge at 1500F.

Rod

 

[DiamondSCattleCo]

I don't profess to be an engineer or expert on these matters -- I just listen (intently) to those who do.

I really want a King Ranch Ford -- love those things -- but their engines continue to scare me. I know that they turn out more good ones than not, but with my luck, I would get a dud.

I'm not a trained engineer either, but I spent a few years building aftermarket performance parts for the Big 3 trucks, and I also worked very closely with a couple of the other big names in diesel performance who did have trained engineers on staff.

One of those guys was a Cummins engineer with over 30 years of experience, and this whole rising torque curve thing is deja vu 2002 all over again When the first common rail 2003 was delivered (We get them in Canada first and I took delivery of the 6th to hit Canuck shores), I was working with this engineer on their fueling box. I was impressed with the flat curve and even more impressed with how much extra torque we could get on the bottom end (at 1200 RPM for example). But it was "boring". Off the line, you'd plant your butt in the seat, and never really get a sensation of how quick you were moving. The engineer changed the curve to a rising curve, which was much more "exciting" to the butt, but we lost a full second in the quarter mile...

Rod

 

[backhoeboogie]

The problem I have is running through the pastures and the suspension. I am not talking "off road" playing. I am talking pulling heavy loads such as a 17,000 lb caterpillar on a trailer across a few miles of pasture. The Dodge front end didn't make it 50K for me.

If I needed a city truck, I might consider Dodge again. They are cheaper. Nothing wrong with the power. For what I do with a truck, I can't afford a new Dodge every year. Diesel engines are heavy and more weight on the suspension. Until Dodge fixes their suspension problems, I will drive something different.

 

[NamVet_Farmer44]

I do believe that what Rod is trying to say is "Redneck Bull**it aside, from a scientific standpoint as well as common sence says that A dodge Diesel is the most powerful truck on the market!

Also after further investigation, Record Holding Modified Truck pull Champ since 2001 is a 1200HP 5.9L cummins w/ 1800 ft/lb of torque.

Also the fastest truck in the world is a banks powered cummins.

I will definetly be buying a dodge.

:roll: Yeah, record holding modified pull champ and world's fastest truck...who cares...When it comes down to a real world truck, that doesn't mean s***...Them trucks have 100's of thousands of dollars put into them...That's great, if you have the money to fork into them

 

[DiamondSCattleCo]

For what I do with a truck, I can't afford a new Dodge every year. Diesel engines are heavy and more weight on the suspension. Until Dodge fixes their suspension problems, I will drive something different.

Unfortunately, the front suspension problems are shared by all of the Big 3 trucks, due to the weight of the diesel engines. Dodge is known to have the most capable front suspension for work, due to the solid axle, but its certainly not without problems. Many of the issues could be resolved by not replacing front end components with stock parts, but rather heavier aftermarket parts. But then, the same could be said for the Chevy and Ford solid axles (but not the IFS stuff, I hate that junk).

Rod

 

[EKUgrad]

DiamondSCattleCo,

My understanding is that the sequential turbo system on the 6.4 utilizes a smaller, fixed vane turbo to feed a variable vane turbo similar to the current turbo on the 6.0.

Why could they not have used a conventional wastegated turbo with no moving vanes or sliding nozzles?

 

[Earl Thigpen]

The formula for CALCULATING horsepower (as in a pony brake) is torque times RPM divided by 5252. In other words, horsepower is DERIVED from torque and RPM's.

Diesels tend to have heavy reciprocating parts because of the way they support combustion. Pistons are heavy, rods are heavy, wrist pins are massive and the crankshaft is very heavy. When you get all that heavy cast iron spinning it produce copious amounts of TORQUE at a fairly low RPM which is exactly the reason you get that feeling of being able to pull a house down with your diesel truck off idle. You can do the same thing with a puller at the county fair, the only difference being RPM. The diesel PU will pull the house down at 3000 RPM but the puller can do the same thing but at 9000 RPM (and a lot more HP because of the RPM).

While you are correct that _some_ of the torque of a diesel is simply derived from the heavier rotating mass, its a relatively small part of the equation. Most of the torque is derived from diesel having more stored energy and efficiency of combustion.

Take a look at a torque curve of an inline 6 versus a V8. The inline motor, whether it be gas or diesel, is able to generate more bottom side torque due to all the pistons generating the same straight line push on the crankshaft. V series engines are simply not able to transfer as much of the energy to the crankshaft and some gets wasted.

Bringing us back to the topic at hand, neither the D-Max nor the Powerstroke are able to generate as much bottom side torque, due to their being a V design. Take a gander at the published torque curves. The Cummins reaches torque peak at 1400 RPM while the V engines peak at around 2500 RPM (give or take a couple hundred, depending on the engine). While Chevy and Ford have been able to work around this with gearing, if you were to plant a 600 lbft Cummins into a Chevy (or Ford), replacing the 600 lbft V series engine, you _would_ have better acceleration and pull the same load faster. You will also have better lugging ability in hills, as the V series torque curve is linear, not flat. This means that as you drop RPMs, you're losing torque. You lose torque, you drop RPMs faster, and it becomes a viscous circle. The flat torque curve on the other hand will lose RPMs, but not anywhere near as quickly since when you drop RPMs, you're not losing any torque.

Rod

I'm having a hard time getting my point across. Of course there are a lot of things that modify the torque charateristics of an engine not the least of which is valve timing, injector timing and duration, compression ratio, blower boost, piston speed, bearing speed (friction) but the point I have been trying to get across is that horsepower is calculated while torque is measured. Torque is real and is used to CALCULATE horsepower. If you modify torque you will modify horsepower as a result. It has nothing what-so-ever to do with the "curve". If you do something to increase the torque of an engine at a GIVEN RPM the HP will go up. Period.

One last thing and I'm not coming back here. Pony (prony) brake, also known as an engine dynamometer, measures torque at the flywheel. It does not measure torque at the wheels or after a transmission. So none of those things enter into the calculation for HP. And probably the most important thing is that the torque measurement on a engine dynamometer does not account for a marketing person pencil whipping the specs to sell more vehicles. And if don't believe that, pull the engine out of your vehicle and bolt it up to a dynamometer and see how close you can get to the "factory" stated values.

yaw'll have a good one.

 

[allenfarms]

I do believe that what Rod is trying to say is "Redneck Bull**it aside, from a scientific standpoint as well as common sence says that A dodge Diesel is the most powerful truck on the market!

Also after further investigation, Record Holding Modified Truck pull Champ since 2001 is a 1200HP 5.9L cummins w/ 1800 ft/lb of torque.

Also the fastest truck in the world is a banks powered cummins.

I will definetly be buying a dodge.

:roll: Yeah, record holding modified pull champ and world's fastest truck...who cares...When it comes down to a real world truck, that doesn't mean s***...Them trucks have 100's of thousands of dollars put into them...That's great, if you have the money to fork into them

First of all they DON"T have $100's of K's in em'
Second It does mean something becouse they couldn't do it with a Ford or Chevy!
And if you want tuff and power Look at the dodge Power Wagon.
You find One stock truck ANY STOCK truck that is anywhere close to the Power/Tuff combo of this truck!

 

[NamVet_Farmer44]

I do believe that what Rod is trying to say is "Redneck Bull**it aside, from a scientific standpoint as well as common sence says that A dodge Diesel is the most powerful truck on the market!

Also after further investigation, Record Holding Modified Truck pull Champ since 2001 is a 1200HP 5.9L cummins w/ 1800 ft/lb of torque.

Also the fastest truck in the world is a banks powered cummins.

I will definetly be buying a dodge.

:roll: Yeah, record holding modified pull champ and world's fastest truck...who cares...When it comes down to a real world truck, that doesn't mean s***...Them trucks have 100's of thousands of dollars put into them...That's great, if you have the money to fork into them

First of all they DON"T have $100's of K's in em'
Second It does mean something becouse they couldn't do it with a Ford or Chevy!
And if you want tuff and power Look at the dodge Power Wagon.
You find One stock truck ANY STOCK truck that is anywhere close to the Power/Tuff combo of this truck!

Try building a modified pulling truck that can rank nationally and let me know how much it cost you :roll: ...I can bet you it won't be cheap...It means something huh?...Yeah, means you can throw money into them and make them pull for 300 yards or so? Wow...that sure means a lot to me :roll:

 

[McPherson Fencing]

Well, I'd have to say their all good. But nothing pull's
like a cummins. The Ford's are great truck's too, their
built like a truck need's to be big & heavy. Chevy's are
nice, but if you want true diesel power get a dodge.

 

[Crowderfarms]

Well, I'd have to say their all good. But nothing pull's
like a cummins. The Ford's are great truck's too, their
built like a truck need's to be big & heavy. Chevy's are
nice, but if you want true diesel power get a dodge.

I agree.May not have the best bodies, but will pull a house down.

 

[oscar p]

So Oscar, 4 door quad cab? or Mega cab?

I have a 4door quad cab. But I like the mega cab Alot.

 

[DiamondSCattleCo]

My understanding is that the sequential turbo system on the 6.4 utilizes a smaller, fixed vane turbo to feed a variable vane turbo similar to the current turbo on the 6.0.

Why could they not have used a conventional wastegated turbo with no moving vanes or sliding nozzles?

Actually, according to the Ford press release I read, the primary (large turbo) is a fixed vane type, and they're using a small VGT as the secondary. The exerpt from the release I had:

"High-tech, series sequential turbochargers provide improved response and better low-end performance. The unique system uses a small, electronically controlled, smart remote variable geometry turbocharger that comes on at low rpm to provide extra boost at take-off. As rpms increase, the larger fixed turbo joins the smaller turbo to boost power through the middle of the torque curve. As optimum speed is reached, the larger turbo takes over. Tests have shown zero-to-60 times of more than a second faster than the outgoing 6.0-liter."

One of the challenges in twin design is finding a secondary with a tight enough exhaust turbine to spool fast, but not so tight to restrict flow to the large primary. Since that was pretty much impossible, most of us went to using large external wastegates on the small turbo to bypass the turbine. I think all that Fords doing is using VGT to feather the vanes, once the primary gets spooled up. External wastegates aren't all that reliable, and tend to develop leaks over time as they can't seem to handle the vibration of the big diesels.

Rod

 

[Agboy]

I just wish Dodge built a better quality truck to hold up like a Ford does. I cant believe how flimsy some off the interior components are as well as the over all build quality. If you have had a Ford superduty an go to a Dodge youll notice those things right away. The Cummins is a good motor but the truck itself really lacks the quality. The Cummins will last along time but youll have to remove the engine an stick it in another truck because the truck will be long gone before the motor dies. Sorry just my 2 cents.

 

[EKUgrad]

My understanding is that the sequential turbo system on the 6.4 utilizes a smaller, fixed vane turbo to feed a variable vane turbo similar to the current turbo on the 6.0.

Why could they not have used a conventional wastegated turbo with no moving vanes or sliding nozzles?

Actually, according to the Ford press release I read, the primary (large turbo) is a fixed vane type, and they're using a small VGT as the secondary. The exerpt from the release I had:

"High-tech, series sequential turbochargers provide improved response and better low-end performance. The unique system uses a small, electronically controlled, smart remote variable geometry turbocharger that comes on at low rpm to provide extra boost at take-off. As rpms increase, the larger fixed turbo joins the smaller turbo to boost power through the middle of the torque curve. As optimum speed is reached, the larger turbo takes over. Tests have shown zero-to-60 times of more than a second faster than the outgoing 6.0-liter."

One of the challenges in twin design is finding a secondary with a tight enough exhaust turbine to spool fast, but not so tight to restrict flow to the large primary. Since that was pretty much impossible, most of us went to using large external wastegates on the small turbo to bypass the turbine. I think all that Fords doing is using VGT to feather the vanes, once the primary gets spooled up. External wastegates aren't all that reliable, and tend to develop leaks over time as they can't seem to handle the vibration of the big diesels.

Rod

Yeah, man, I read that too -- it was retracted or corrected, I guess, later. Apparently this was another case of marketing not getting everything straight from engineering. They had it backwards according to all of the other documents / press releases / auto rags.

Here is a link to a Ford presentation highlighting the 2008 SD improvements. It is a 5mb presentation, so it may load slow depending on the speed of connection. This has been unofficially dubbed the "6.4 Bible".

http://www.backglass.org/duncan/ps64_ma ... erview.pdf