Yes, but is there really a 5 psi difference at what ever elevation we are talking about?

Also, there are ways around that, I'm not sure if PSD employ those or not though.

 

Exactly, it's the BARO (barometric) and MAP (manifold) sensors that provide this information to the PCM.

 

I did not know that. I was under the impression that it was calibrated to sea level.

 

alright, so I found this site that tells you the pressure at a give altitude. Assuming he's at 7500', that comes to 584 mmHg, or 11.3 psi.

Altitude.org | Altitude air pressure calculator

Now 14.7 - 11.3 = 3.4

3.4 psi loss at 44.7 psia (or 30 psig of boost) is a 7.6% loss of power.

While that may cause some power loss, lets look at compression ratio (another method would have been to look at turbo shaft speed, but they will have about the same result).

So, to compress 14.7 psia of air to 44.7 psia of air, your compression ratio is 44.7/14.7 = 3.05. The compression ratio at 7500' with a pressure of 11.3 and achieving a final pressure of 41.3 psia, your compression ratio will be 41.3/11.3 = 3.65.

This means at that altitude the the turbo has to spin 20% faster to create the same 30 psig boost. That can cause some significant lag.

You add the lag to the fact the engine is producing 7% less power pretty much all the way through boost range, you will have certainly have reduced performance.

Which one has the greater effect? Depends on what your doing. Accelerating the lag will definitively hurt you, climbing a mountain and maintaining speed, the power loss may hurt you more.

 

But the V10 is making something like 22% less power at that height, so the PSD still clearly has the advatage even if it does still lose some power.

 

We are getting too theoretical
When I drove heavy motorhomes over Tioga Pass (about 10,000) I recorded higher mpg than on flat freeway.
Stunned at first, it come clear after some thinking. In big motorhomes the air drag plays way bigger role than weight rolling resistance, so climbing the grades at 30 mph was saving me fuel .
Tell me how many 10,000' passes in US have 70 mph freeways on them?
The I-80 going over Sierra is about 9,000' and it has 55 mph limit from what I remember.

 

ANY turbocharged (or forced induction in general) vehicle will, that's just a fact.
JL

 

What, 25,000 miles a year? Thats not that big of a deal for any truck.

 

Sure. Try it year after year for 7 years ?
What is mileage on your van?

 

My one-way commute is over 45 miles a day. Not adding in any trips out and about to meet customers, or going to jobsites, I'm at roughly 22K miles/year. My old faithful F150 with the V10's little brother, the 4.6L-has 245K miles without a single mechanical failure. That's over 27K miles a year if you look at the truck's year model alone. It's got the original waterpump, alternator, starter, transmission, rear axle, etc,etc,etc. It's easily going to see 300K,and I'll be the first to tell you I DRIVE my vehicles. I maintain them properly, but I work them.
JL

 

175K.

When I started towing with it 2 1/2 years ago it had 102K.
Its not getting used any were near as much for the last 6 months though.

 

My brother-in-law runs two 2005 Ford vans, one an E250 w/4.6L, the other the the 5.4L, both with the 4R75W tranny. Both are 2-valve not 3-valve.

They go out loaded every day to the gills with marine parts and supplies, sometimes two loads a day, the 250 at around 3-4K lbs, the 350 at around 4K lbs, driven by people who don't give a darn. About 1/3rd the time, they are overloaded because they just keep piling stuff in until it don't fit anymore. They are both at or above 170K miles, in 5 years having been purchased in 2005. That's around 35K miles a year, and go out and do 150-200 miles a day, 8 hours a day, four days a week, all on Long Island, mostly stop-and-go, and idle while deliveries are made. They are not shut off. In terms of hours, they sit about 25-50% of the day idling. That's an average of 18.75 to 25 miles per hour. That's horrible on a motor.

Neither of them have ever been in for warranty work, just oil changes and plug changes (and other regular maintenance) when necessary as dictated by maintenance schedules. They continue to run like the day they were bought, with no major out-of-warranty work besides brakes, and tires. I don't think they've even had any front-end work done to them yet.

My brother-in-law says these Ford vans are the best vehicles he's ever owned in the 30 years he's been in this business. The only thing that came close was a Dodge w/a 318 he had before these two, and that thing had all sorts of engine electronics issues, rear-end bearing and gear replacements, tranny work, front-end work, and it barely made it to 160K miles before it was blowing blue smoke out the exhaust and leaking from every seal and gasket.

He has owned various other brands, both GM, Dodge, Isuzu NPR (two of those, both of which proved they needed turbos at about the same frequency as PSD's but were mechanical injection setups so they didn't have anywhere near the problems.

On paper, and in reality, they have proven their worth, and continue to do so so much that he is not contemplating purchasing another new truck for at least another 2 or 3 years. At which time they will be over the 250K mile mark by a large margin. Unless they catastrophically grenade themselves for no reason there is no indication whatsoever of impending doom.

Now, these Ford vans I speak of aren't a Class A or C motorhome, but the V10, both 2-valve and 3-valve in the F53, or the 2-valve in the Class C, has proven itself to be in the same class.

I have to hand it to Ford, they finally made a jewel of a van. The bodies are shot because they are driven by idiots, but what do you expect of warehouse delivery vehicles?

 

is that how long this thread has been running? jk

 

I don't get why this thread is still going... Y'all will never be able to say either engine is better, but in most cases where extreme towing is involved along with a lot of miles the diesel will be better suited everytime. Mileage, reliability, etc. That is not what this thread is saying though. We are just getting people saying well my truck does everything i need it to and b/c i don't drive a lot the mileage doesn't matter or whatever.

Each engine has it's weaknesses and strengths. Although IMO a V10 has no strengths for how I would use the truck, that doesn't mean that it won't work for someone else. Why even argue it. I like my truck and it does what I need it to do, but a V10 wouldn't. My diesel would do what your V10 does, but if it's not needed then why have it?

Still waiting on Bill to come out run my PSD on the track. We should hook up 10k lbs on a trailer and pull them down the track. LOL

 

I don't really think I can out run a 380 RWHP PSD.
We are going to do that as soon as I can though.

As far as doing it with 10K, I'm game if you are.