Is 4.6L Superior to 5.4L
Technical Article Contributor
Joined: Dec 1997
Posts: 9,417
Likes: 11
From: Windsor,Ontario,Canada
For all you back yard engineers here is some additional info about our engines.
On paper the rod length on the 4.6 is 150.7mm and the 5.4 is 169.1mm. The corresponding strokes are 90mm and 105.8mm. That will yield a rod to stroke ratio of 1.6744 and 1.5983 respectively.
According to some of the sources I could find the ideal ratio is 1.75:1. Others stated that if you are building an all out high rpm race engine then the closer to 2 you are the better. For use in a wide band rpm application 1.6 to 1.8 is best. It would seem that the specs on both the 4.6 and 5.4 engines are close, less than 5% difference. But if you want to go by the paper the 4.6 is better suited as it has a higher rod/stroke ratio than the 5.4. You can compensate for these differences by adjusting runner length head design and cam specs. So before anyone starts thinking that the 4.6 is inherently better look at the intake manifolds on the engines. Both engines share the same heads and cams but use different intake manifolds. So maybe the heads and cams were a compromise for both engines and the intake manifold differences make up for the heads and cams. Food for thought.
JMC
On paper the rod length on the 4.6 is 150.7mm and the 5.4 is 169.1mm. The corresponding strokes are 90mm and 105.8mm. That will yield a rod to stroke ratio of 1.6744 and 1.5983 respectively.
According to some of the sources I could find the ideal ratio is 1.75:1. Others stated that if you are building an all out high rpm race engine then the closer to 2 you are the better. For use in a wide band rpm application 1.6 to 1.8 is best. It would seem that the specs on both the 4.6 and 5.4 engines are close, less than 5% difference. But if you want to go by the paper the 4.6 is better suited as it has a higher rod/stroke ratio than the 5.4. You can compensate for these differences by adjusting runner length head design and cam specs. So before anyone starts thinking that the 4.6 is inherently better look at the intake manifolds on the engines. Both engines share the same heads and cams but use different intake manifolds. So maybe the heads and cams were a compromise for both engines and the intake manifold differences make up for the heads and cams. Food for thought.
JMC
Senior Member
Joined: Jan 2005
Posts: 5,389
Likes: 0
From: Fort Worth,Tx
Originally Posted by JMC
For all you back yard engineers here is some additional info about our engines.
On paper the rod length on the 4.6 is 150.7mm and the 5.4 is 169.1mm. The corresponding strokes are 90mm and 105.8mm. That will yield a rod to stroke ratio of 1.6744 and 1.5983 respectively.
According to some of the sources I could find the ideal ratio is 1.75:1. Others stated that if you are building an all out high rpm race engine then the closer to 2 you are the better. For use in a wide band rpm application 1.6 to 1.8 is best. It would seem that the specs on both the 4.6 and 5.4 engines are close, less than 5% difference. But if you want to go by the paper the 4.6 is better suited as it has a higher rod/stroke ratio than the 5.4. You can compensate for these differences by adjusting runner length head design and cam specs. So before anyone starts thinking that the 4.6 is inherently better look at the intake manifolds on the engines. Both engines share the same heads and cams but use different intake manifolds. So maybe the heads and cams were a compromise for both engines and the intake manifold differences make up for the heads and cams. Food for thought.
JMC
On paper the rod length on the 4.6 is 150.7mm and the 5.4 is 169.1mm. The corresponding strokes are 90mm and 105.8mm. That will yield a rod to stroke ratio of 1.6744 and 1.5983 respectively.
According to some of the sources I could find the ideal ratio is 1.75:1. Others stated that if you are building an all out high rpm race engine then the closer to 2 you are the better. For use in a wide band rpm application 1.6 to 1.8 is best. It would seem that the specs on both the 4.6 and 5.4 engines are close, less than 5% difference. But if you want to go by the paper the 4.6 is better suited as it has a higher rod/stroke ratio than the 5.4. You can compensate for these differences by adjusting runner length head design and cam specs. So before anyone starts thinking that the 4.6 is inherently better look at the intake manifolds on the engines. Both engines share the same heads and cams but use different intake manifolds. So maybe the heads and cams were a compromise for both engines and the intake manifold differences make up for the heads and cams. Food for thought.
JMC
Senior Member
Joined: Jan 1999
Posts: 7,030
Likes: 3
From: WINDSOR, ONTARIO, CANADA
Originally Posted by Faster150
nah 5.4 is a taller deck making it a biger block
Senior Member
Joined: Oct 2003
Posts: 4,920
Likes: 5
From: Washington
Originally Posted by Neal
HI!... YES, taller deck, not a big block. Same bore, same bore spacing, same crank bearings, same rod bearings, same heads, same oil pump, same oil pan....................
btw i started the tear down of my 5.4L
started a few of my own questions i need to learn some answers to... lol
oil pump, low torque spec?
timing chains, guides, gears ect. all mine have a small amount of play, i have not measured it out but it feels minimal, something around 1/64th of play between the teeth and chain. about the same amount of play between the main drive gear and the key. the keyway on the gear looks a little sloppy.
tomorrow i tear into the heads, save myself a $30 disassembly fee lol.
Global Moderator &
Senior Member
Senior Member
Joined: Aug 2005
Posts: 21,337
Likes: 158
From: DFW
Originally Posted by Faster150
Suppose that an elephant and a feather are dropped off a very tall building from the same height at the same time. Suppose also that air resistance could be eliminated such that neither the elephant nor the feather would experience any air drag during the course of their fall. Which object - the elephant or the feather - will hit the ground first? The animation at the right accurately depicts this situation. The motion of the elephant and the feather in the absence of air resistance is shown. Further, the acceleration of each object is represented by a vector arrow.
Again you are only digging yourself deeper on this one!
-Patrick
Senior Member
Joined: Jan 2005
Posts: 5,389
Likes: 0
From: Fort Worth,Tx
Originally Posted by Patman03SprCrw
How about a quote from your link...
So if both 5.4 and 4.6 had no wind resistance, they would fall the same speed, like you said in a vaccum. But heres the thing, where the hell are you going to get a vaccum that is long enough to drop them? It isnt possible for real world testing.
Again you are only digging yourself deeper on this one!
-Patrick
So if both 5.4 and 4.6 had no wind resistance, they would fall the same speed, like you said in a vaccum. But heres the thing, where the hell are you going to get a vaccum that is long enough to drop them? It isnt possible for real world testing.
Again you are only digging yourself deeper on this one!
-Patrick
a heavier object will accelerate to its maximum speed before a lighter object but in the end they both fall at the same speed. theres alot of variables in physics..
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
Patman03SprCrw: So if both 5.4 and 4.6 had no wind resistance, they would fall the same speed, like you said in a vaccum. But heres the thing, where the hell are you going to get a vaccum that is long enough to drop them? It isnt possible for real world testing.
Think your talking about "Vt" (Terminal Volocity) - Shape is redundent..
Example - Someone gives yuh the boot @ 30,000 ft. a speed of 50% of terminal velocity is reached after only about 3 seconds, while it takes 8 seconds to reach 90%, 15 seconds to reach 99% and so on.
"Vt" is the terminal velocity, "m" is the mass of the falling object, "g" is gravitational acceleration, "Cd" is the drag coefficient, "?" is the density of the fluid the object is falling through, and "A" is the object's cross-sectional area.
You have to set the drag, equal to mg, the gravitational force on the object.
Note : that the density increases with decreasing altitude, ca. 1% per 80 m (BARO). Well, the actual term is "barometric"... Anyway, for every 160 m of falling, the "terminal" velocity decreases 1%. After reaching the local terminal velocity, while continuing the fall, speed decreases to change with the local terminal velocity.
In other words Patrick - if you eliminate wind resistance , you eliminate the gravity factor - it would be "0".. Outer space maaannnn - cooollll.....
Last edited by jbrew; Jan 20, 2007 at 02:07 PM.
Global Moderator &
Senior Member
Senior Member
Joined: Aug 2005
Posts: 21,337
Likes: 158
From: DFW
Originally Posted by Faster150
a heavier object will accelerate to its maximum speed before a lighter object but in the end they both fall at the same speed. theres alot of variables in physics..
Eventually they will fall the same speed so what? The heavier object will get to the bottom faster.
Lets say we raced again without your chip. And we both pegged out at 99. Then we are both going just as fast right? have the same potential? But would it matter to you if you got to 99 faster?
And
Jbrew
Member
Joined: Jan 2007
Posts: 19
Likes: 0
I can't answer for the newer engines but my '98 f150 is as reliable and durable as they come. i now am going on 420,000 miles with the same engine and transmission. neither one has had any major work done to it only regular maintenance at scheduled periods. this truck not only still looks good it still drives like a dream. so i would say 5.4L is still the way to go 2v or 3v. 
Senior Member
Joined: Oct 2005
Posts: 590
Likes: 2
From: Palm Bay
Originally Posted by 98triton54l
I can't answer for the newer engines but my '98 f150 is as reliable and durable as they come. i now am going on 420,000 miles with the same engine and transmission. neither one has had any major work done to it only regular maintenance at scheduled periods. this truck not only still looks good it still drives like a dream. so i would say 5.4L is still the way to go 2v or 3v.
Senior Member
Joined: Oct 2003
Posts: 4,920
Likes: 5
From: Washington
Originally Posted by UberDude
now thats the kinda crap i like ta read.
https://www.f150online.com/galleries...864-179628.jpg
https://www.f150online.com/galleries...864-179630.jpg
https://www.f150online.com/galleries...864-179633.jpg
proof of what low octane does to an engine.
https://www.f150online.com/galleries...864-179631.jpg
https://www.f150online.com/galleries...864-179632.jpg