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Old 09-18-2015, 10:39 PM   #1
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Brand: Thor Motor Coach
Model: Vegas 25.2
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THOR #2442
Thor Vegas 25.2 engine red line??

On my Vegas, the tachometer shows no red line, nor does the manual. The reason I ask is that the transmission in cruise control going up a hill will shift way down, making the engine rev at more than 4500 RPM and screams. What RPM should I avoid??
The engine is a 6.8L V10 305HP in an 2015 Ford E350 gas.
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Old 09-18-2015, 11:37 PM   #2
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THOR #1150
The redline is about 5800 RPM.

The V-10 is quite happy to run at the redline all day--the gas tank wouldn't be that happy but the engine would be. Its an overhead valve engine designed to run at high RPMs.

Put some ear plugs in and let it scream....
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Old 09-19-2015, 12:10 AM   #3
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Hilarious Jamie, I can't help it, I turn cruise control off every time I reach a hill because the engine sounds like it is going to blow up. It's hard to get use to, scares the hell out of me.
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Old 09-19-2015, 12:49 AM   #4
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Our Axis is our third V-10 powered vehicle. When we had the 5er I had first a F-250 and then a F-350 with the V-10. When I had the pickups I would read a lot at Ford-trucks.com. There was always someone new there asking the same question about the engine. Of course the answer was always the same.
Many commercial owners would chime in saying that the would tow 20,000 lbs on a regular basis with the V-10 and thus it would hit redline daily without issue.

It just gets a bit thirsty...
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Old 09-19-2015, 01:04 AM   #5
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THOR #2442
I'm Hyperventilating. I think the sound itself may keep me below the redline.
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Old 09-19-2015, 02:28 AM   #6
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THOR #1478
Quote:
Originally Posted by JamieGeek View Post
Our Axis is our third V-10 powered vehicle. When we had the 5er I had first a F-250 and then a F-350 with the V-10. When I had the pickups I would read a lot at Ford-trucks.com. There was always someone new there asking the same question about the engine. Of course the answer was always the same.
Many commercial owners would chime in saying that the would tow 20,000 lbs on a regular basis with the V-10 and thus it would hit redline daily without issue.

It just gets a bit thirsty...
This is reassuring to hear Jamie, it's just sounds scary.
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Old 09-19-2015, 04:07 AM   #7
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Quote:
Originally Posted by davidspixx View Post
On my Vegas, the tachometer shows no red line, nor does the manual. The reason I ask is that the transmission in cruise control going up a hill will shift way down, making the engine rev at more than 4500 RPM and screams. What RPM should I avoid??
The engine is a 6.8L V10 305HP in an 2015 Ford E350 gas
.
I have the same engine, just older, and I personally avoid high RPMs whenever possible.

Maximum power of 305 HP is rated at 4,250 RPM, and maximum torque of 420 lb-ft at 3,250 RPM, so from my perspective what would I gain from revving near red line? I'm not in that big a hurry that I can't slow down a little and maybe get the transmission to shift up one gear in the process, thereby lowering RPMs that much more.

At maximum torque speed of 3,250 RPM the engine already makes 260 HP, so it's not like we are squeezing that much more power out of engine above 3,500 to 4,000 RPMs.

Obviously, available transmission ratios can limit engine-power-versus-RPM choices, but in general I keep engine well below 4,000 RPMs.
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Old 09-19-2015, 06:35 PM   #8
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THOR #1147
After asking the same question, and getting the same answer, I no longer worry about it, but I too try to avoid it. I've learned to tap the brakes to disengage the cruise control before it causes baen sidhe mode.

Regards,

Randy
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Old 09-19-2015, 08:39 PM   #9
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I'm hoping that the new 6R140 transmission will address much of the reported tendency to over-rev on downshifts; which I expect is the result of a double downshift from OD to 3rd gear on the present 5-speed.

With the 5-speed if the engine was running at 2,000 RPM then a double downshift would increase RPMs to around 4,400 (plus any TC slip).

With the 6-speed a double downshift should increase RPMs from 2,000 to only around 3,400 RPMs. That should make a big difference.

If the transmission logic is set up right, it may not be necessary to take the motorhome out of cruise control on hills. But if programmed to do something stupid like a triple downshift from 6th to 3rd, I'd take it out of cruise control and shift it manually.
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Old 09-19-2015, 10:09 PM   #10
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On a related note, I suspect the redline indication is in the process of disappearing altogether. With a modern, ECU controlled engine I would expect the computer to prevent over-revving.

Randy
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Old 09-20-2015, 12:17 AM   #11
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THOR #2538
My 2 cents,
but 5 star tuning makes a great tune for this. We love it and now we can hear each other.
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