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Discussion Starter #1
Pickuptrucks dot com did a dyno test of 1/2 tons. Long story short crunching the numbers it looks like the Cummins Nissan drivetrain is 87% efficient. I find that very hard to believe. Here is a comparison of drivetrain loss from that test based on dyno'd HP v.s Advertised HP.

Ford 3.5 Eco - 16.5%
GM 5.3L - 19.5%
GM 6.2L - 23%
RAM Hemi - 25%
Toyota 5.7L - 25%
Nissan ISV 5.0L - 13%

So the question is how can the Nissan with a transmission from a 1 ton truck and a larger axle have a significant efficiency advantage? Or is Nissan/Cummins sandbagging the ratings? Looking at baseline dyno's from the 6.7L Cummins it seems that Cummins has a storied history of sandbagging it's actual power ratings. For example I found a 2011 6.7 HO baseline dyno of 325hp in a 3500 ram. That engine was advertised at 350 hp.

Back to the test's in the article. If you take the average drivetrain loss from all 6 participants you end up with the normally accepted 20%. Re-calculating the advertised hp numbers using the dyno numbers + 20% ends up like this:

Ford 3.5 Eco - 380
GM 5.3L - 350
GM 6.2L - 400
RAM Hemi - 365
Toyota 5.7L - 360
Nissan ISV 5.0L - 335

No this is far from scientific but I though it was interesting. It looks like Ford is seriously sandbagging with their Ecoboost numbers as well.
 

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I would not doubt that there is some going on, defiantly would not put it past Ford lol those guys are a bunch of Scabs.
But not every engine is the same, and every engine doesnt have the same HP/TQ. Some will make a bit more some make a bit less.

If everything is tight the torque locks up good, heat and friction is minimal it is possible for a truck to see better numbers.

Only way to really see the numbers is to dyno every component and than calculate it all up. Seems like a lot of work

For me if I can get the engine rated HP/TQ plus a bit (like 350 hp and 650tq) at the wheels I'm happy.
 

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Discussion Starter #3
What I was really hoping to find was a 4x4 ram 3500 dyno with the aisin transmission so that a rough drivetrain loss comparison could be made and carried over to better figure out the actual power of the Titan. But and the end off the day you are right - unless someone out there is willing to yank the engine from their truck and put it on and engine dyno. I would love to see that happen.

I cannot wait for the first "real" tune to come out for this truck. With this engines ability to rev I think we could see some Volkswagen or BMW diesel HP numbers with a good tune.
 

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Discussion Starter #4
Lol re-reading that sounds ridiculous. I don't mean overall HP. I mean HP per liter.
 

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Discussion Starter #6
It would be nice to know exactly what the 30% difference is and weather or not it reduces/increases durability/power potential compared to 100% ISV. I'm guessing it is the emissions and turbo setup but same internals?
 

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nissan seems to put the HP/TQ numbers closer to the power at the wheels then any other maker does. instead of inflating them and posting exaggerated crank numbers.

on paper 1st gen titans are super slow.........
 

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This engine is not the same as the ISV. If I remember correctly, its based heavily on it, I think like somewhere around 70%.
Heads, block, internals are 100% ISV, the glaring difference is the charge air system (Holset M2 Turbo setup) so maybe 88%;) The base ISV (as advertised for class "C" RV's and school buses) utilizes a Variable vane single turbo unit and dyno rated outputs of up to 275hp/560lb.ft. So other than the intake side of the house, they are pretty much identical. I also agree with the statement of powertrain efficiency not adding up previously mentioned. The transmission being essentially the AS69RC from the dodge 3500 and the AMM 9.84, makes you wonder if Aisin sprinkled some fairy dust throughout the inside...lol. Most dynos I've had time on (mustang/dynojet), show parasitic losses in the neighborhood of 15-25% typically, not only for driveline but rubber meeting the rollers. Now to get a really precise reading without tearing things apart, axle dynos would be a better measurement tool.

BigRed
 

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Discussion Starter #10
I'm curious if one has been dyno'd with a few thousand miles on it. Im willing to bet the numbers are quite different.
 

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Discussion Starter #11
So I found this on Cummins website. Does anyone know of any other trucks with the 5.0 Cummins? Or coming soon? The 500-600lbft torque rating has me confused. So is it 500, is it 555, or is it 600?
 

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Those Numbers are Up To 600 depending on what the customer orders ( it's just different programming) . Nissan chose the middle. This motor is used in Buses, Rv's & Marine applications.
 

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Discussion Starter #13

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Discussion Starter #14
So I filled out the contact us form on the Cummins website asking for more information. We'll see if they deliver anything of worth.

I noticed on your site that the pick up truck version of the ISV 5.0 is rated between 500 and 600 lbft of torque. I was curious why this range exists since the only currently available option is 555 lbft in the Titan XD. Also, I know that many people are eager to see a white paper of the durability testing and the B50 rating of this engine and was hoping you could provide that. Actually any information that is not already available would be nice and the current Titan community and future buyers would love to see it.
 

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So I found this on Cummins website. Does anyone know of any other trucks with the 5.0 Cummins? Or coming soon? The 500-600lbft torque rating has me confused. So is it 500, is it 555, or is it 600?

555 for now unfortunately. Neat thing is that if you compare the Hp/Liter of the VM 3.0 in the dodge 1500 and interpolate that to the ISV...it gives you an idea of the potential of this engine. With the cooling strategy developed in the XD, there shouldn't be any problem keeping her cool and happy at higher power levels. Nissan can always play the hp game at a later date, although not to where the big boys are, still would make for welcomed improvement.

BigRed
 

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Discussion Starter #16
Yeah the big 3 are making insane power. It is amazing what competition can do for development. The next refresh for them will bring 1,000 lbft of torque to the market.

A guy would be smart to make diesel truck only parking spots with rollers for generators so big diesel owners could go shop and leave their truck running and get a credit on the way out. They could turn a big electric load just by setting the high idle in drive.

Sent from my XT1565 using Tapatalk
 

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Yeah 1000lbft of torque is not far away from the factory, I really don't see that being a good thing tho for the everyday joe because 97% of the time they don't even utilize the power or feel any difference. Unless your working that truck there is no need for that much TQ IMO.

Don't get me wrong I love HP/TQ but there is a Big line between "Safe and boring factory 900+TQ and a truck that is been tuned to 900+ torque. Ill take the truck that's been tuned all day for the fact that if i want 100% of my power right now it will give it to me.

What really holds the new trucks back is the torque management and how it delivers the torque. The new rams are powerful yes but they are just brutal to drive on a day to day the dead pedal is just awful same as our titan.

I just wish they would get rid of the torque management all together or at least have it an option on the dash, if i want that feature activated ill hit the button.
 

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Discussion Starter #18 (Edited)
So here is what Cummins had to say

Good morning Kadoi,

The specs that are found on our website are the specs for Cummins. The reason why the ISV engine has 555 lb-ft of torque would be because of the equipment that Nissan uses that may require to set the torque at a particular level.

Chrysler also changes the power out of the engines that are in their trucks. They have to de rate the power so it works with the transmission they go with and they use their own programming to make those changes.

Nissan does the same thing. If this engine was in another application, like a motorhome, the peak torque my be different than whats in the Titan.

In regards to the B50 rating, you may need to contact Nissan about that. Nissan purchases these engine from us without warranty so they can apply their own warranty. That means, they have the rights to the engine so they lock some of the information so that we can’t view it. They house the information.

Thank you for contacting Cummins Care

I thought it was interesting that he specifically mentioned the need for Chrysler to de-rate for the transmission and then goes on to say that Nissan does the same thing. I imagine he is talking about the de-rating in the 2500 for the manual and 68re transmissions. Who knows why Nissan would de-rate it. I will try there next.

The last part about the B50 rating does not give me a warm fuzzy though.
 

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I thought it was interesting that he specifically mentioned the need for Chrysler to de-rate for the transmission and then goes on to say that Nissan does the same thing. I imagine he is talking about the de-rating in the 2500 for the manual and 68re transmissions. Who knows why Nissan would de-rate it. I will try there next.[/COLOR]

The last part about the B50 rating does not give me a warm fuzzy though.
Probably for the transmission. I'd guess that Nissan had weight and cost goals for the transmission, and when they worked with transmission suppliers the the one that fit those criteria weren't durable enough at full torque. So they limit the torque to 555 ft-lbs (which is still a lot - as much as 1 ton trucks were making a decade ago) and everything lasts a good long time.

Just out of curiousity, what "B50 life" are you looking for? Time between overhauls? Time between dash lights? Why did you pick B50 instead of B10 or B5? I'm a reliability engineer for a semi manufacturer, so I'm curious what prompted your question. It is interesting that they claim Nissan owns the warranty. When we put Cummins ISX engines in our trucks, Cummins owns the warranty so they get the data and also pay the dealers. Though we do manufacture competing engines, so I understand why they don't want us to have that data.
 

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Discussion Starter #20
Time between overhauls
B50 is what I most commonly see as the standard for engine durability. Where B10 will typically be comprised of either end of tolerance failures or manufacturing defects the B50 is typically comprised of general use failure. So I would be more interested in knowing that if I could choose one or the other.

And that's why I didn't get a warm fuzzy from the last statement. Typically when manufactures choose cosmetically available components they choose them because they already meet a design requirement and because they are already warrantied. It makes me wonder if product development costs for the driveability of the new turbocharger lead to a compromise elsewhere that cummins did not want to directly warranty due to either not meeting their durability reliability testing or because the launch schedule would not have allowed it.

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