Huntindog
Phoenix AZ
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FishOnOne wrote:I watched the video again particularly the Chevy down hill section and noticed the truck would maintain the speed, but then the transmission would upshift which effectively reduced RPM's and reduced the effectiveness of the exhaust brake. A programming change to the shifting strategy when in Tow/Haul mode should fix this issue IMO. Or one could read the manual to learn how it works.
Huntindog
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Huntindog
Phoenix AZ
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ksss wrote:Whether GM can program a better engine brake or make mechanical changes, it needs to happen. Maybe that truck itself wasn't right, but they need to get more aggressive with the engine brake. The quicker offline acceleration is important. The ability to quickly get to highway speed from onramp or merge lanes is important. I am to the floor on every mnt pass I am on. The more I am able to stay with the flow of traffic the better. I am always at the mid thirties GCVW. I get everything that the Duramax has to give going up and down those passes. So in watching this, I was expecting the Ford to kill the Duramax. The way Ford dominated the 2020 Ike pull, I was expecting a similar result. What happened was a complete surprise, that extra 3k doesn't buy much except a decal, except resale to those that don't know better. I suspect that Ford is highly managing that power output, due to the fact it clearly gets warm. It may have the specs it says, but I suspect it is managed to the point you would likely never see it. I sure someone has a dyno run on the HO, it would be interesting to see what it puts to the ground. Whatever it is, it didn't mean much in this run, even though its got 250 more pound feet and 40 more hp. I do wish GM would tell you what gear your in like Ford does. All you gotta do is put the lever in low. Then select what gear you want with the +,_ buttons. It will show L5,L4 etc. on the dash, If you also pushed the EB button, you will experience impressive results. I can descend any mountain without touching the brake pedal. It would helpful it they read the manual to under stand how it works before doing such tests.
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FishOnOne
The Great State of Texas
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Huntindog wrote:ksss wrote:Whether GM can program a better engine brake or make mechanical changes, it needs to happen. Maybe that truck itself wasn't right, but they need to get more aggressive with the engine brake. The quicker offline acceleration is important. The ability to quickly get to highway speed from onramp or merge lanes is important. I am to the floor on every mnt pass I am on. The more I am able to stay with the flow of traffic the better. I am always at the mid thirties GCVW. I get everything that the Duramax has to give going up and down those passes. So in watching this, I was expecting the Ford to kill the Duramax. The way Ford dominated the 2020 Ike pull, I was expecting a similar result. What happened was a complete surprise, that extra 3k doesn't buy much except a decal, except resale to those that don't know better. I suspect that Ford is highly managing that power output, due to the fact it clearly gets warm. It may have the specs it says, but I suspect it is managed to the point you would likely never see it. I sure someone has a dyno run on the HO, it would be interesting to see what it puts to the ground. Whatever it is, it didn't mean much in this run, even though its got 250 more pound feet and 40 more hp. I do wish GM would tell you what gear your in like Ford does. All you gotta do is put the lever in low. Then select what gear you want with the +,_ buttons. It will show L5,L4 etc. on the dash, If you also pushed the EB button, you will experience impressive results. I can descend any mountain without touching the brake pedal. It would helpful it they read the manual to under stand how it works before doing such tests.
Yes if you manually select the gear you want I believe it will work just fine, but the goal of these tests have been to let the truck do the shifting right or wrong. Also they did press the exhaust button.
On this particular test they choose to utilize cruise control which I recall the GM's did really good in this mode in years past.
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cptqueeg
Idaho
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Does 12 gallons more fuel (and a local Ford dealer) make it worth buying a Ford for a long time GM fan?
We like the lonely stretches of NV a lot.
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ktmrfs
Portland, Oregon
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cptqueeg wrote:Does 12 gallons more fuel (and a local Ford dealer) make it worth buying a Ford for a long time GM fan?
We like the lonely stretches of NV a lot.
well, our 2004 duramax only had a 26gallon tank.... Even with the diesel when towing that meant some planning for gas stops and for a few trips carrying an extra 5 gallons.
With the 2015 and 35 gallon tank, not near the issue, if the 2015 had a 26 gallon tank I'd have installed an aftermarket. With the 35 it's now in the "barely adequate" rather than "almost adequate" category. 50 gallons, that would be a definitely adequate fuel tank size.
we do a 760 mile trip unloaded quite often and I need one fuel stop. with a 50 gallon, nice. and when towing 35 gallon is often not quite a days trip, 50 gallons... one days trip stop and the end of the day for fuel.
I'd definitely pay extra for a 50 gallon tank if it was an option.
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FishOnOne
The Great State of Texas
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cptqueeg wrote:Does 12 gallons more fuel (and a local Ford dealer) make it worth buying a Ford for a long time GM fan?
We like the lonely stretches of NV a lot.
Probably not... My dad is a dyed in the wool GM man. Ain't no fuel tank going to change that. Although he does miss the dual tanks from the square body generation.
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sayoung
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ktmrfs wrote:about the only thing I saw worth any difference between the two was the fuel tank size. Extra 12 gallons in the ford is nice.
I gotta stop way before 36 gal much less 48![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/embarrassed.gif "embarrassed")
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ktmrfs
Portland, Oregon
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sayoung wrote:ktmrfs wrote:about the only thing I saw worth any difference between the two was the fuel tank size. Extra 12 gallons in the ford is nice.
I gotta stop way before 36 gal much less 48
well I agree on that part as well, BUT rest stops are quick. I figure a gas stop is at least 20 minutes by the time you exit, get to the pump, pump get back on the road, often 30+ minutes. And then there is gas stop planning.
Much rather be able drive all day with only a fuel stop either in the AM before we leave or at the end of the day when we arrive or close to it.
36 gallons is marginal for that when towing, 48 gallons.. perfect.
As I mentioned in another post I'd gladly pay extra for a larger tank. Aftermarket tanks are way to expensive.
Course the downside to >35 gallons is Kroger shuts off the discount and stops the pump at 35 gallons, safeway at 25 gallons. So that plays into fuel stops as well.
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4x4ord
Alberta
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FishOnOne wrote:
On this particular test they choose to utilize cruise control which I recall the GM's did really good in this mode in years past.
Knowing how the exhaust brake and how cruise works kinda matters. I know with any truck I've ever had, stepping on the brake pedal cancels cruise.... With my Ford if I set cruise and let it apply the brakes automatically I can count brake applications by watching when the trailer brakes are applied automatically as they did in this video. As soon as I brake manually (say to slow for a sharp curve or because I find the set speed to be a little fast) cruise is cancelled and has to be reset. If I set the exhaust brake to automatic and let it do its thing the computer will exercise enough back pressure to hold the truck back to the speed it was going when the brake pedal or accelerator pedal was last released. If maximum exhaust braking is not enough to maintain the desired speed the wheel brakes (truck and trailer) are used to slow the combination down a little anytime the engine reaches redline. If while set to "auto" I find 4th gear is too fast for the exhaust brake to maintain speed down the grade I simply step on the brake pedal until the truck drops to third gear. When I take my foot off the brake it will try yo maintain that new set point and if 3rd gear is still too fast I can step on the brake again and slow to second gear. "Auto" exhaust brake is perfect for grade braking (better than cruise). If the exhaust brake is set to "on" the exhaust brake constantly tries to slow the unit even once it slows below my desired speed. "On" should be used for slowing down rather than for trying to maintain a desired speed on a downhill grade.
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Grit dog
Black Diamond, WA
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Bottom line, looks like GM is selling all the Duramaxes they make, even the new Chebbies with the family truckster front clips, so I suppose they don’t need to spend that extra little R&D to figure out how to install a bigger fuel tank (actually they could just buy them and make one of the aftermarket guys an OE supplier for $0 R&D, but I digress…).
However this is something GM should have kept up with or at least get on the ball. Considering it’s a real world great convenience, unlike the Ford that will back your truck up to the trailer ball within an inch or 2 of being in the right spot to actually drop the trailer on it, still requiring you to go back and move the truck once more….Hahahahaha
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