Cummins or Hurricane?

[AH64ID]

10504 rpm @ 1hp = 2 lb/ft ?

2626 rpm 1 hp = 2 lb/ft.

The higher the rpm the lower the ratio. I did have a typo on 2626 rpm and have corrected it.

 

[petersonj]

@AH64ID , I do not challenge what you have written, in fact I agree with your points in the relationship between horsepower and torque.

The reason I say that the horsepower rating is not important to me is because in most cases the marketed horsepower rating is usually at the highest rpm capable for a particular engine. It is a great marketing ploy, but it is not realistic because the engine will be rarely (if ever) be operated at the rated horsepower.

I used my own truck as an example in my previous post. The far majority of my driving, empty or heavily loaded, the tach is reading in the 1500 - 2000 rpm range and once in a while at 2200 rpm in fifth gear pulling a grade. So, the 245 hp @ 2900 rpm rating is at 700 rpm higher than the maximum rpm that I operate the engine. Consequently, the 245 hp rating is not important to me.

The 500 hp Hurricane engine is likely to have that horsepower rating at or near the 6100 engine rpm mentioned. In real life, it is not likely the engine will be operated at that rpm.

It would be nice if vehicle manufacturers would provide engine performance charts that would show maximum horsepower, torque, and fuel consumption for a any given engine rpm. In the late 80's, I installed a new Cummins 4BTA 3.9 liter diesel engine in my 1984 Ford E150 van. I based my decision for doing that installation on a detailed engine performance chart provided by Cummins. I was not disappointed.

Also, I would like to mention that I appreciate the knowledge that you have shared over the years through this forum. You are a well respected member.

- John

 

[Tuesdak]

The 500 hp Hurricane engine is likely to have that horsepower rating at or near the 6100 engine rpm mentioned. In real life, it is not likely the engine will be operated at that rpm.

HD Pickups are likely to Work rather then be a DD getting groceries.

And when extended high RPM is due to "need" ... Most would poop their pants to hold redline up a grade towing: with good reason as A/C belts depart the engine and other things blow up from extended high RPM. Of Course the thinnest oil we can use in the transmission and it's better B.S. ... Torque Converter Blue from slipping at extended high RPM full power towing grades that go for miles here with a good amount of vaporized transmission oil condensed on the rear tailgate and trailer towed. What A Mess and delay with vehicle out of service during warranty of the transmission.

The water cooled manifolds have GM Cooling System DISASTER Heat Load written all over it esp. when towing up said demanding grade the wussies avoided for their SAE J2807 Tow Tests. A B O N E - S T O C K 6.5TD IDI diesel from the late 1990's could make the test route. I suggest the route from Phoenix to the Mogollon rim when it's 115F+ out would be something to "survive" as I have blown several engines between here and there and avoided leaving yet another "burn scar" among numerous other scars on the side of the road: Some vehicle fires, like a cement truck, have started major forest fires.

SAE J2807 Tow Tests
https://www.motortrend.com/how-to/1502-sae-j2807-tow-tests-the-standard/

Modern variable turbo's are better than the WG or oversize turbo's that did not need a WG.
Having an engine that choked on a turbo over 2200 RPM matched to a REV happy automatic wanting to see the useless 3600 RPM redline is the other thing GM did to ruin the Diesel market. 200 HP with ZERO torque to back it up is useless. Driving the engine fan at full lockup... Does it have the TORQUE to back up the Horsepower at RPM?

There are times "There is No Replacement For Displacement" applies. Pour the gas down it vs. TCO for a Diesel is a moving target.

To shove this engine in a HD truck that "Works" for a living isn't the same as a light duty daily driver people hauler.

 

[KCJackson1]

A couple of things...

The current 6.4 used in the Ram is also a very high revver: 410 hp @ 5600, 429 lb-ft @ 4000, redline 5800. I don't care what form of fuel you use, 4000 rpm torque peak for a near-medium duty truck is probably too high. So if the HO Hurricane can indeed bring in, say 450 lb-ft (of its peak 475) at 2350, it already has a significant advantage over the Hemi.

The HO Hurricane will also still be putting out the grunt at redline. Stellantis says at least 90% of max torque from 2350 rpm to the 6100 rpm redline - that yields the following theoretical numbers:
475 x .9 = 427.5 lb-ft @ 6100 -> (427.5 x 6100)/5252 = 496.5 hp @ 6100 - pretty close to that claimed 500.
So the HO Hurricane would appear to out-torque the 6.4 from every point on the torque curve between 2350-6100 rpm. As noted earlier in the topic, the octane requirement is the real drawback. The 6.4 only needs 87 to the HO Hurricane's 91.

Interestingly, the SO Hurricane may also be comparable to the Ram 6.4. At 400/450, it would be very close to the 6.4's 410/429 rating, get the peak numbers at lower rpm, and potentially get 15% better mileage.

I expect the refreshed 2023 Ram HD to be unveiled in January like the refreshed 2019s were. Rumors have been out for a while about the new Duramax in the area of 500/1085, and Ford's 7.3 gasser has gotten a notable number of buyers away from the Powerstroke at 430 hp/5500 and 475 lb-ft/4000. I think we'll see a couple of new engines under the Ram HD hood in about 8-9 months.

 

[promisedland]

I have noticed that tubo engines have the peak torque at a lower rpms.
Wait and see.

 

[Ozymandias]

Every natural aspirated combustion engine is a revver. The turbo is the game changer, no matter if it is diesel or gasoline.

 

[petersonj]

Another concern not mentioned is hold-back power. I don't think a 3 liter engine is going to hold back a load very well when negotiating long downgrades. It would do better if equipped with an integrated exhaust brake function on the twin turbos, but I will bet that doesn't happen.

I have noticed that tubo engines have the peak torque at a lower rpms.

Not necessarily. Peak torque at low rpms starts with how the engine is built - with or without a turbo. When the stroke length number of a piston becomes equal or greater than the cylinder bore diameter number, then peak engine torque is developed much earlier in the rpm range. A longer stroke means you have a better lever. Also, a longer stroke means the engine has to operate at a lower peak rpm, otherwise things would start coming apart. This is especially true in larger CID engines. However, the trade-off is good because you get peak torque at low rpms.

Example from the past:

My old 1984 E150 Ford Van with a 300 cid in-line six ... 125 hp @ 3,200 rpm and 245 lb-ft @ 1,800 rpm (Bore & Stroke 4.0 x 3.98)
The same year comparable 302 cid V8..........................150 hp @ 3,600 rpm and 250 lb-ft @ 2,600 rpm (Bore & Stroke 4.0 x 3.00)

Note there is very little difference in peak torque between the two engines, but the peak torque happens much earlier in the rpm range on the in-line six (the longer stroke engine).

Cummins 5.9 liter bore and stroke: (4.02 in × 4.72 in)
Cummins 6.7 liter bore and stroke: (4.21 in × 4.88 in)

It is no wonder these engines offer massive torque at low rpms.

I think the Hurricane engine's bore and stroke is 3.31 x 3.54. If that is true, that is good news.

- John

 

[sag2]

To keep the load moving they are more than likely going to have to spin them up pretty good. My 1500 Hemi ran at 4-5k plenty of times pulling long steep grades. It just didn't have enough power to recover if you let the speed drop so it spent plenty of time spinning fast to keep up with the diesel trucks.
Also the amount of boost on the Hurricane is very impressive, especially with the fairly high compression ratio that stated both engines have. Most turn gas engines are in the 8-9 compression ratio, not 10.5.

 

[AEdelheit]

I absolute love driving my X5/N55 ( BMW I6 Direct injected turbo), it takes 91 as well but overall for me it doesn't add up to too much more every month. At .30 cents more a gallon, 20mpg, 50 gallons a month comes to about $15 more a month. With how much people spend on Fancy coffees or at the bar everyday I dont see it as a big expense.

 

[Tuesdak]

Interestingly, the SO Hurricane may also be comparable to the Ram 6.4. At 400/450, it would be very close to the 6.4's 410/429 rating, get the peak numbers at lower rpm, and potentially get 15% better mileage.

I absolute love driving my X5/N55 ( BMW I6 Direct injected turbo), it takes 91 as well but overall for me it doesn't add up to too much more every month. At .30 cents more a gallon, 20mpg, 50 gallons a month comes to about $15 more a month. With how much people spend on Fancy coffees or at the bar everyday I dont see it as a big expense.

My "Disposable Income" for Fancy Coffees is G O N E due to fuel prices that have nearly doubled. $5.00 in Fancy Coffee would get me through the day. $5.00 in fuel will get me to the next pump, maybe. It's $125 to fill the tank taking two swipes as they cut you off at $75. In a prior life when we hauled auto parts going 550 miles a day this was ~78 gal per day. I point out what a straw man argument this really is, but, Starbucks is in trouble @ $35 a week and their fancy coffee prices have gone up. It's not even a rare treat for me and family anymore.

Today's fuel prices are causing injuries to those running to raise prices to keep up as Diesel is jumping from $4.99 to $5.25 as I was looking up current prices.

87 Octane is $4.69, midgrade is 89 octane irrelevant to this engine's requirement, and Premium 91 octane is $5.29. That is a $0.60 increase to go from "Put Fuel in the damn thing." to "Put 91 octane fuel in it." This makes Diesel Fuel cheaper than 91 Octane.

One would have to run the math on the current MPG of a 6.4 Hemi Screamer both towing, unloaded, and loaded vs. what this engine gets to accurately compare the increased fuel price. 15% better MPG is vague and the nationwide difference in the cost between low octane and premium is another variable.

Direct injection gasoline also has a low speed ping problem that may make a mistake at the pump expensive. Extra operator training cost at the end of a 12 hour day...

Looks at Gasbuddy and other apps for cheap, cheap, cheap: drive 50 miles for lower fuel price mindset, eh? ... And knowing fleet managers and what a PIA it would be to have "Special" gasoline for just the pickups on a remote jobsite... The HD pickups need to run on 87 Octane. The Light Duty 1/2 tons on the job ALSO need to run on 87. 15% better MPG isn't going to pay for a new/extra 91 Octane fuel tank setup.

 

[AEdelheit]

My "Disposable Income" for Fancy Coffees is G O N E due to fuel prices that have nearly doubled. $5.00 in Fancy Coffee would get me through the day. $5.00 in fuel will get me to the next pump, maybe. It's $125 to fill the tank taking two swipes as they cut you off at $75. In a prior life when we hauled auto parts going 550 miles a day this was ~78 gal per day. I point out what a straw man argument this really is, but, Starbucks is in trouble @ $35 a week and their fancy coffee prices have gone up. It's not even a rare treat for me and family anymore.

Today's fuel prices are causing injuries to those running to raise prices to keep up as Diesel is jumping from $4.99 to $5.25 as I was looking up current prices.

87 Octane is $4.69, midgrade is 89 octane irrelevant to this engine's requirement, and Premium 91 octane is $5.29. That is a $0.60 increase to go from "Put Fuel in the damn thing." to "Put 91 octane fuel in it." This makes Diesel Fuel cheaper than 91 Octane.

One would have to run the math on the current MPG of a 6.4 Hemi Screamer both towing, unloaded, and loaded vs. what this engine gets to accurately compare the increased fuel price. 15% better MPG is vague and the nationwide difference in the cost between low octane and premium is another variable.

Direct injection gasoline also has a low speed ping problem that may make a mistake at the pump expensive. Extra operator training cost at the end of a 12 hour day...

Looks at Gasbuddy and other apps for cheap, cheap, cheap: drive 50 miles for lower fuel price mindset, eh? ... And knowing fleet managers and what a PIA it would be to have "Special" gasoline for just the pickups on a remote jobsite... The HD pickups need to run on 87 Octane. The Light Duty 1/2 tons on the job ALSO need to run on 87. 15% better MPG isn't going to pay for a new/extra 91 Octane fuel tank setup.

Sounds like its not the best option for you , doesn't mean its not for others.....

 

[BigPapa]

At .30 cents more a gallon, 20mpg, 50 gallons a month comes to about $15 more a month.

Like Tuesdak, your numbers don’t add up to me. I don’t know where you’re buying your gas, but in middle TN it’s $0.60 a gallon difference between 87 and 91. At 1600 miles a month, my 25mpg Accord would cost me $38/month more for 91 over 87. A 20mpg truck would cost me $48/month more for 91 over 87.

 

[AEdelheit]

Every place here in OR is .30 cents more for 91 then 87 and yes obviously the more you drive the more fuel you use.

 

[promisedland]

Maybe this was said, 91 gas is recommended but not required.
As per Marspeed

 

[KCJackson1]

Maybe this was said, 91 gas is recommended but not required.
As per Marspeed

91 is recommended for the standard output (SO) Hurricane. It's required for the HO Hurricane - see Stellantis' own specs here:
SO specs: https://media.stellantisnorthamerica.com/download.do?id=23664&mid=1
HO specs: https://media.stellantisnorthamerica.com/download.do?id=23662&mid=1

 

[Tuesdak]

Sounds like its not the best option for you , doesn't mean its not for others.....

The best option "for me" is not what I am focusing on. Me with just ONE pickup chosen by my preferences with TCO far down the list. (Ok my preference for ONE pickup: that's a big part of the Diesel pickup market. Individuals who want a Diesel regardless.) To avoid revving up a modern gasoline engine towing an RV on the long grades here I chose a Diesel: not because there is any "economy" left in it. Unloaded a Hemi in a 3500 Long bed runs "Door handles" with the HO Cummins. $10,000.00 option cost, extra oil, and $100 each for two Diesel fuel filters would buy a lot of gasoline.

A modern Cummins is night and day towing at 15 MPG over the 6.5TD (GM IDI) at 7 MPG. Turbo too small forcing the need for more cooling fan use were the biggest problem along with the 10% IDI over DI MPG loss. The grades with an engine that's working too hard really shows the MPG difference.

Now the Company Owner who has a fleet of 600+ pickups ... Loved the 4.3L V6 GM 1/2 ton pickups because they didn't have expensive options like a V8 engine. The MPG was a plus. You grabbed a bigger rig like the lowboy, an (oilfield) A frame MD truck, etc. to tow anything.

A lot of the older MD trucks had gas engines with MPG so low that it was GPM at times. Trailer just didn't make a difference. In the oilfield laying or servicing pipe with the engine running powering the A Frame and not moving: MPG is not a valid number. When you can't obtain oilfield equipment due to typical surge demand you run stuff from the 1960's, 1970's, 1980's dumping the gasoline down it and still make money. Nothing else available anywhere to do the job. Real Fun to get these old rigs through the annual emissions test. Walked to the boneyard many times with the question of: can we get it to run again, ASAP?!

Bluntly neither the fleet manager or company owner would entertain 91 Octane fuel requirements any longer than it would take to laugh the fleet sales people clean off the property.

IF this engine could deliver on 87 Octane it's a different story. Esp. if it's the base engine. The pressure on the OEM's to reduce "extortion" payments for emissions credits or CAFE applied to 1/2 ton pickups: towing MPG is not the #1 concern. Government MPG tests and Emissions are.

HD trucks working hard is the question. Ford's Eco gas turbo whatever doesn't exactly have anything but a gas guzzler reputation when towing. Specifically choose Eco OR Boost and they are noted to wind the turbos out before redline. The Big Gas engines get better MPG "working hard" say in ambulance, Tow Truck, Motorhome, towing ...

So I have questions and concerns that other OEM's already tripped over.

 

[AEdelheit]

Ya im sure Ram did no market testing, will go bankrupt from this and then we will all be driving Fords and Chevys.............

 

[bcbender]

IMHO.. squeezing every last available bit of power out of these small displacement engines via super turbo charging just means that the OEMs will reduce the total engine life and thus sell more engines... either in replacement vehicle or repower form, planned obsolescence? May make sense for some but not anyone using their tow vehicle to its designed potential. I for one liked the old 300 six in my 93 F150 but would not trade my 6.7 for it even if it had 3x the power.

 

[Ozymandias]

3 Liter gasoline Turbo is around the Globe considered a HUGE engine. Except in the US.

 

[SnoKing]

3 Liter gasoline Turbo is around the Globe considered a HUGE engine. Except in the US.

I was going to post that earlier together, that around the globe people get by with much smaller engines. Big engines in the US are a bit of a phallus symbol.