Gas vs PSD
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,679
From: Stephensville WI
Just commenting on a diesel as an actual aircraft engine. The Jumo 205 aircraft diesel engine fascinate me. It has 2 crankshafts and opposing pistons sharing a bore (12 pistons total). A supercharger was used, but not for added power, instead it blew in the fuel/air mixture and evacuated the spent fuel/air.
Post Fiend
Joined: Nov 2008
Posts: 23,849
Likes: 20
From: McKenzie River
My fault for stealing this somewhat long-winded thread, Kel.
Just commenting on a diesel as an actual aircraft engine. The Jumo 205 aircraft diesel engine fascinate me. It has 2 crankshafts and opposing pistons sharing a bore (12 pistons total). A supercharger was used, but not for added power, instead it blew in the fuel/air mixture and evacuated the spent fuel/air.
Just commenting on a diesel as an actual aircraft engine. The Jumo 205 aircraft diesel engine fascinate me. It has 2 crankshafts and opposing pistons sharing a bore (12 pistons total). A supercharger was used, but not for added power, instead it blew in the fuel/air mixture and evacuated the spent fuel/air.
Senior User
Joined: Dec 2008
Posts: 362
Likes: 0
Me and my buddy have identical trucks, except mines a 6.0 and his a v10. I get 12-13mpg and he gets 9-10. When we hook chains i pull him every time, I know this means nothing, but its fun.lol I blow his doors off in a drag race, And i canpull the same trailer easier. When i say these trucks are the same imean it.lol Same year, lift, tire size, and gears. Hes sellin his and gettin a PSD.lol
edit: But you have to pay to play with the big boys.lol
edit: But you have to pay to play with the big boys.lol
Senior User
Joined: Aug 2007
Posts: 141
Likes: 1
Me and my buddy have identical trucks, except mines a 6.0 and his a v10. I get 12-13mpg and he gets 9-10. When we hook chains i pull him every time, I know this means nothing, but its fun.lol I blow his doors off in a drag race, And i canpull the same trailer easier. When i say these trucks are the same imean it.lol Same year, lift, tire size, and gears. Hes sellin his and gettin a PSD.lol
edit: But you have to pay to play with the big boys.lol
edit: But you have to pay to play with the big boys.lol
What a good example of a very uneven match. I love how you diesel guys say "even" when your "optional" gearing is 3.73.
The equivalent to a 3.73 geared diesel would be 4.30 on a v10.
If he's running 38" tires with 3.73s on a v10, your buddy is a fool and deserves to get out pulled.
Senior User
Joined: May 2004
Posts: 407
Likes: 0
From: Humble, Texas
So Destroya your position is that the V10 needs taller gears to hang with a psd? If the psd has the taller gears, will the V10 need even taller gears?
The red neck logic test dictates that a comparison would only be valid if both engines were running with the same gears. Which gears are standard or optional on each truck is irrelevant. To me, that would just be Ford understanding that one engine just needs taller gears and the other one doesn't.
Where did I go wrong?
The red neck logic test dictates that a comparison would only be valid if both engines were running with the same gears. Which gears are standard or optional on each truck is irrelevant. To me, that would just be Ford understanding that one engine just needs taller gears and the other one doesn't.
Where did I go wrong?
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Cargo Master
Joined: Nov 2004
Posts: 2,751
Likes: 3
From: So Oregon
Maybe each engine makes peak power in a different RPM band and it makes sense to get those bands near each other related to mph, since most people drive around 55mph. I guess if you put 4.30 gears in a diesel it'd be fair? I don't think so. I think the diesel would top out at whatever, say 35mph, pulling a grade with no problem. The V10 on the other hand would pull the grade at 55mph, both being in their respective "power bands". Gearing does mean something, and logically it doesn't make sense to make the two trucks have the same gearing. It makes sense to have them reach peak power so that the trucks pull a load at a mph that is relative to how people drive. That's only if you want to compare trucks that do a similar job, or want to compare Super Duty trucks with various engines.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
You went wrong with regard to the fact that the PSD has a significantly shorter powerband, with a lower redline.
The modular V8 and V10 develop nearly 90% of their peak torque from as early on as 1,500 RPMs. This carries through to a HP peak of 4750 RPMs.
The current gen PSD, however, generates peak torque at 2,000 RPMs, and peak HP at 3,000 RPMs. So, in order to get the engines to be closer matched, the V10 needs to be able to rev higher in a given gear than the PSD would, otherwise the PSD will have a huge advantage.
You can't compare apples to oranges with the same rear end ratio...doesn't work!
The modular V8 and V10 develop nearly 90% of their peak torque from as early on as 1,500 RPMs. This carries through to a HP peak of 4750 RPMs.
The current gen PSD, however, generates peak torque at 2,000 RPMs, and peak HP at 3,000 RPMs. So, in order to get the engines to be closer matched, the V10 needs to be able to rev higher in a given gear than the PSD would, otherwise the PSD will have a huge advantage.
You can't compare apples to oranges with the same rear end ratio...doesn't work!
Senior User
Joined: Aug 2007
Posts: 141
Likes: 1
The red neck logic test dictates that a comparison would only be valid if both engines were running with the same gears. Which gears are standard or optional on each truck is irrelevant. To me, that would just be Ford understanding that one engine just needs taller gears and the other one doesn't.
Where did I go wrong?
Where did I go wrong?
Unfortunately, gas engines need gear reduction to make torque as they tow with rpm rather than torque. Diesels benefit from gear reduction also, but with a lower numerical gear as they would run out of RPM at higher speeds. The optional gearing for towing on a 6.0L is 3.73. On a V10, the standard gearing is 3.73 (or was). 3.73 gears on a V10 was a gigantic mistake ford made until recently (4.10 is the standard now). The optional gearing for a V10 is 4.30. Had this guy had the 4.30 ratio gearing and an equal amount of power adding devices (such as a blower) the test would have been more accurate.
So in the end, the diesel guy just threw more money at his oil burner and proved just about nothing and bragged about it.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
Furthermore, as to the comment on if they hook chains to each other, it's meaningless! That particular pissing match hinges on traction way more than power. A PSD truck, with it's ~800 lbs greater weight, will ALWAYS have the advantage there.
Take a 5.4L F250 and throw 3,000 lbs in the bed, and try again. You'll find that "weak" 5.4 dragging you around the parking lot.
Take a 5.4L F250 and throw 3,000 lbs in the bed, and try again. You'll find that "weak" 5.4 dragging you around the parking lot.
