New at this, trying to understand horse power
Guest
Posts: n/a
Re: New at this, trying to understand horse power
Brian? "prehistoric pushrod engine"? Say what? There is no modern OHC
engine that compare their horsepower and torque to any engine designed
and sold to the public during the fifties. When the public demanded
power, guess what, they brought back the old Hemi, and of course
performance cars such as Corvette, or the Ford and Chevrolet police cars
never stopped producing their small blocks.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Cherokee-Ltd wrote:
>
> First off, I thought you were talking about the glorified Nissan Maxima - I
> don't know the Infinity line up that well.
> Getting back to the question, you can't expect a prehistoric pushrod engine
> to perform anywhere near that of a high compression DOHC 24 valve engine.
>
> The 3.5 utilizes modern age technology to take advantage of;
>
> Volumetric efficiancy - high flow tuned induction, polished intake, 4 valve
> configuration, DOHC, electronic variable valve timing etc.
> Thermal efficiancy - aluminum block, intake and heads, high compression etc.
>
> Is it any wonder why the IRL used them? Mass produced, affordable race
> engines. You won't see too many 4.0's racing except of course for JeepSpeed
> where they need cast iron to keep the front end on the ground!
> http://jeepspeed.com/images/2a.jpg
>
> -Brian
engine that compare their horsepower and torque to any engine designed
and sold to the public during the fifties. When the public demanded
power, guess what, they brought back the old Hemi, and of course
performance cars such as Corvette, or the Ford and Chevrolet police cars
never stopped producing their small blocks.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Cherokee-Ltd wrote:
>
> First off, I thought you were talking about the glorified Nissan Maxima - I
> don't know the Infinity line up that well.
> Getting back to the question, you can't expect a prehistoric pushrod engine
> to perform anywhere near that of a high compression DOHC 24 valve engine.
>
> The 3.5 utilizes modern age technology to take advantage of;
>
> Volumetric efficiancy - high flow tuned induction, polished intake, 4 valve
> configuration, DOHC, electronic variable valve timing etc.
> Thermal efficiancy - aluminum block, intake and heads, high compression etc.
>
> Is it any wonder why the IRL used them? Mass produced, affordable race
> engines. You won't see too many 4.0's racing except of course for JeepSpeed
> where they need cast iron to keep the front end on the ground!
> http://jeepspeed.com/images/2a.jpg
>
> -Brian
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Brian Foster" <brianfoster@houston.rr.com> wrote in message
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Brian Foster" <brianfoster@houston.rr.com> wrote in message
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Brian Foster" <brianfoster@houston.rr.com> wrote in message
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
> Thanks for the insight. So the infinity uses "newer" technology if I
> understand you right?
Absolutely. The 4.0 design is a cast iron push rod engine that dates back
several decades. It's seen improvements over the years with fuel injection
and computer controls but the basic design is prehistoric. There are so many
wear areas (timing chain, lifters, pushrods, rockers) that the DOHC (dual
overhead cam) design eliminates (or reduces in the case of the timing
chain).
> The other responses almost all dealt with low RPM tourque in the old
> fashioned Jeep Engine VS the newer design infinity power plant. The lower
> end tourque is preferable with a Jeep type vehicle than the additional HP
> at higher RPM?
It depends what the engine is designed for. In the most basic way of
thinking, lower RPM produces more torque to initiate movement - higher RPM
is where horsepower is calculated. This statement is not completely accurate
but it might help you a bit. Think of an 18 wheeler. It uses a 12-14 litre
diesel engine that might put out 400 hp at 1500 rpm. That same engine will
also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0 litre 900 hp
F1 engine in that truck... rev it up to 17000 rpm and dump the clutch...
hey, where did the clutch go?
Now, to make matters even more confusing. Torque is a twisting force
measureable by a dynomometer. Horsepower is a calculation derived from
torque (RPMxTORQUE/5252). To base engine performance strictly on horsepower,
you have to consider it's ability to create RPM. How does this apply to the
3.5L/4.0L comparison? Lets exagerate for the sake of explanation.
The 4.0 with a larger displacement has to push heavier pistons up and down,
turn a hug crankshaft that's proably a foot longer than the V6 counterpart
which in turn drives a lunky timing chain to spin a massive camshaft. Wow,
lot of work so far but it's okay, the 4.0 has the torque to do it. Now, the
cam shaft converts the rotery motion back into reciprical motion and has to
push those 12 heavy lifters up and down all day. The lifters in turn push
the pushrods up to the rockers which pivot and push the valve down into the
combustion chamber.
The advantage with the 3.5 is;
Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
twice as many valves but they are much lighter than the 4.0 valves and are
able to move quicker. A major restiction on a 2 valve engine is the valves
floating (not returning to their seats fast enough). The way to avoid this
is with a heavier valve spring. The trouble with a heavier valve spring is
that it takes more energy to open the valve.
> Perhaps another stupid question, but couldn't gearing (transmission) take
> advantage of the higher HP at higher RPM without sacrificing tourque?
Absolutly... but.... when you play with ratios you either get better take
off or better top speed, not both. You may have noticed that most new
vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the newer
transmissions are able to better keep the engine in its peak operating rpm
range. With less gears, you have to wind it out beyond the engines peak hp
range or risk shifting back in well below the engines peak torque range.
Theorhetically, your best fuel consumption will occur if you shift out at
your engines peak hp range and back in at peak torqure range. RPM above or
below that window is wasting fuel.
> BTW did I notice that the 05 GC has a different engine with less
> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
It's about time! However, there is nothing wrong with the 4.0 if you can
deal with it's fuel consumption... they last forever.
> I like my Jeep but I also like the looks (and specs) on the Infinity FX. I
> don't do any offroading with my jeep. The Infinity looks like a brute road
> handling machine. 20 inch tires and 280 hp is pretty impressive. The
> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
> Jeep & a boat) for that kinda $$.
If you're not off-roading then the FX line is a pretty cool way to go.
Personally, I don't think I would want a GC for off-roading anyway... I'd
rather have an old Cherokee or Wrangler for the dirt and a 300C for the
ashphalt.
I hope I haven't further confused you,
-Brian
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Cherokee-Ltd" <nospam@home.com> wrote in message
news:a8ydnUjagN0zJkTcRVn-rw@rogers.com...
> "Brian Foster" <brianfoster@houston.rr.com> wrote in message
> news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
>> Thanks for the insight. So the infinity uses "newer" technology if I
>> understand you right?
>
> Absolutely. The 4.0 design is a cast iron push rod engine that dates back
> several decades. It's seen improvements over the years with fuel injection
> and computer controls but the basic design is prehistoric. There are so
> many wear areas (timing chain, lifters, pushrods, rockers) that the DOHC
> (dual overhead cam) design eliminates (or reduces in the case of the
> timing chain).
>
>> The other responses almost all dealt with low RPM tourque in the old
>> fashioned Jeep Engine VS the newer design infinity power plant. The lower
>> end tourque is preferable with a Jeep type vehicle than the additional HP
>> at higher RPM?
>
> It depends what the engine is designed for. In the most basic way of
> thinking, lower RPM produces more torque to initiate movement - higher RPM
> is where horsepower is calculated. This statement is not completely
> accurate but it might help you a bit. Think of an 18 wheeler. It uses a
> 12-14 litre diesel engine that might put out 400 hp at 1500 rpm. That same
> engine will also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0
> litre 900 hp F1 engine in that truck... rev it up to 17000 rpm and dump
> the clutch... hey, where did the clutch go?
>
> Now, to make matters even more confusing. Torque is a twisting force
> measureable by a dynomometer. Horsepower is a calculation derived from
> torque (RPMxTORQUE/5252). To base engine performance strictly on
> horsepower, you have to consider it's ability to create RPM. How does this
> apply to the 3.5L/4.0L comparison? Lets exagerate for the sake of
> explanation.
>
> The 4.0 with a larger displacement has to push heavier pistons up and
> down, turn a hug crankshaft that's proably a foot longer than the V6
> counterpart which in turn drives a lunky timing chain to spin a massive
> camshaft. Wow, lot of work so far but it's okay, the 4.0 has the torque to
> do it. Now, the cam shaft converts the rotery motion back into reciprical
> motion and has to push those 12 heavy lifters up and down all day. The
> lifters in turn push the pushrods up to the rockers which pivot and push
> the valve down into the combustion chamber.
>
> The advantage with the 3.5 is;
> Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
> chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
> valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
> twice as many valves but they are much lighter than the 4.0 valves and are
> able to move quicker. A major restiction on a 2 valve engine is the valves
> floating (not returning to their seats fast enough). The way to avoid this
> is with a heavier valve spring. The trouble with a heavier valve spring is
> that it takes more energy to open the valve.
>
>> Perhaps another stupid question, but couldn't gearing (transmission) take
>> advantage of the higher HP at higher RPM without sacrificing tourque?
>
> Absolutly... but.... when you play with ratios you either get better take
> off or better top speed, not both. You may have noticed that most new
> vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
> speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
> autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the
> newer transmissions are able to better keep the engine in its peak
> operating rpm range. With less gears, you have to wind it out beyond the
> engines peak hp range or risk shifting back in well below the engines peak
> torque range. Theorhetically, your best fuel consumption will occur if you
> shift out at your engines peak hp range and back in at peak torqure range.
> RPM above or below that window is wasting fuel.
>
>> BTW did I notice that the 05 GC has a different engine with less
>> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
>
> It's about time! However, there is nothing wrong with the 4.0 if you can
> deal with it's fuel consumption... they last forever.
>
>> I like my Jeep but I also like the looks (and specs) on the Infinity FX.
>> I don't do any offroading with my jeep. The Infinity looks like a brute
>> road handling machine. 20 inch tires and 280 hp is pretty impressive. The
>> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
>> Jeep & a boat) for that kinda $$.
>
> If you're not off-roading then the FX line is a pretty cool way to go.
> Personally, I don't think I would want a GC for off-roading anyway... I'd
> rather have an old Cherokee or Wrangler for the dirt and a 300C for the
> ashphalt.
>
> I hope I haven't further confused you,
> -Brian
>
>
Many thanks!!!!
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Cherokee-Ltd" <nospam@home.com> wrote in message
news:a8ydnUjagN0zJkTcRVn-rw@rogers.com...
> "Brian Foster" <brianfoster@houston.rr.com> wrote in message
> news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
>> Thanks for the insight. So the infinity uses "newer" technology if I
>> understand you right?
>
> Absolutely. The 4.0 design is a cast iron push rod engine that dates back
> several decades. It's seen improvements over the years with fuel injection
> and computer controls but the basic design is prehistoric. There are so
> many wear areas (timing chain, lifters, pushrods, rockers) that the DOHC
> (dual overhead cam) design eliminates (or reduces in the case of the
> timing chain).
>
>> The other responses almost all dealt with low RPM tourque in the old
>> fashioned Jeep Engine VS the newer design infinity power plant. The lower
>> end tourque is preferable with a Jeep type vehicle than the additional HP
>> at higher RPM?
>
> It depends what the engine is designed for. In the most basic way of
> thinking, lower RPM produces more torque to initiate movement - higher RPM
> is where horsepower is calculated. This statement is not completely
> accurate but it might help you a bit. Think of an 18 wheeler. It uses a
> 12-14 litre diesel engine that might put out 400 hp at 1500 rpm. That same
> engine will also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0
> litre 900 hp F1 engine in that truck... rev it up to 17000 rpm and dump
> the clutch... hey, where did the clutch go?
>
> Now, to make matters even more confusing. Torque is a twisting force
> measureable by a dynomometer. Horsepower is a calculation derived from
> torque (RPMxTORQUE/5252). To base engine performance strictly on
> horsepower, you have to consider it's ability to create RPM. How does this
> apply to the 3.5L/4.0L comparison? Lets exagerate for the sake of
> explanation.
>
> The 4.0 with a larger displacement has to push heavier pistons up and
> down, turn a hug crankshaft that's proably a foot longer than the V6
> counterpart which in turn drives a lunky timing chain to spin a massive
> camshaft. Wow, lot of work so far but it's okay, the 4.0 has the torque to
> do it. Now, the cam shaft converts the rotery motion back into reciprical
> motion and has to push those 12 heavy lifters up and down all day. The
> lifters in turn push the pushrods up to the rockers which pivot and push
> the valve down into the combustion chamber.
>
> The advantage with the 3.5 is;
> Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
> chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
> valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
> twice as many valves but they are much lighter than the 4.0 valves and are
> able to move quicker. A major restiction on a 2 valve engine is the valves
> floating (not returning to their seats fast enough). The way to avoid this
> is with a heavier valve spring. The trouble with a heavier valve spring is
> that it takes more energy to open the valve.
>
>> Perhaps another stupid question, but couldn't gearing (transmission) take
>> advantage of the higher HP at higher RPM without sacrificing tourque?
>
> Absolutly... but.... when you play with ratios you either get better take
> off or better top speed, not both. You may have noticed that most new
> vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
> speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
> autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the
> newer transmissions are able to better keep the engine in its peak
> operating rpm range. With less gears, you have to wind it out beyond the
> engines peak hp range or risk shifting back in well below the engines peak
> torque range. Theorhetically, your best fuel consumption will occur if you
> shift out at your engines peak hp range and back in at peak torqure range.
> RPM above or below that window is wasting fuel.
>
>> BTW did I notice that the 05 GC has a different engine with less
>> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
>
> It's about time! However, there is nothing wrong with the 4.0 if you can
> deal with it's fuel consumption... they last forever.
>
>> I like my Jeep but I also like the looks (and specs) on the Infinity FX.
>> I don't do any offroading with my jeep. The Infinity looks like a brute
>> road handling machine. 20 inch tires and 280 hp is pretty impressive. The
>> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
>> Jeep & a boat) for that kinda $$.
>
> If you're not off-roading then the FX line is a pretty cool way to go.
> Personally, I don't think I would want a GC for off-roading anyway... I'd
> rather have an old Cherokee or Wrangler for the dirt and a 300C for the
> ashphalt.
>
> I hope I haven't further confused you,
> -Brian
>
>
Many thanks!!!!
Guest
Posts: n/a
Re: New at this, trying to understand horse power
"Cherokee-Ltd" <nospam@home.com> wrote in message
news:a8ydnUjagN0zJkTcRVn-rw@rogers.com...
> "Brian Foster" <brianfoster@houston.rr.com> wrote in message
> news:sBcCd.39362$3v5.16593@fe2.texas.rr.com...
>> Thanks for the insight. So the infinity uses "newer" technology if I
>> understand you right?
>
> Absolutely. The 4.0 design is a cast iron push rod engine that dates back
> several decades. It's seen improvements over the years with fuel injection
> and computer controls but the basic design is prehistoric. There are so
> many wear areas (timing chain, lifters, pushrods, rockers) that the DOHC
> (dual overhead cam) design eliminates (or reduces in the case of the
> timing chain).
>
>> The other responses almost all dealt with low RPM tourque in the old
>> fashioned Jeep Engine VS the newer design infinity power plant. The lower
>> end tourque is preferable with a Jeep type vehicle than the additional HP
>> at higher RPM?
>
> It depends what the engine is designed for. In the most basic way of
> thinking, lower RPM produces more torque to initiate movement - higher RPM
> is where horsepower is calculated. This statement is not completely
> accurate but it might help you a bit. Think of an 18 wheeler. It uses a
> 12-14 litre diesel engine that might put out 400 hp at 1500 rpm. That same
> engine will also produce 1000+ ftlb torque at 1100 rpm. Now lets put a 3.0
> litre 900 hp F1 engine in that truck... rev it up to 17000 rpm and dump
> the clutch... hey, where did the clutch go?
>
> Now, to make matters even more confusing. Torque is a twisting force
> measureable by a dynomometer. Horsepower is a calculation derived from
> torque (RPMxTORQUE/5252). To base engine performance strictly on
> horsepower, you have to consider it's ability to create RPM. How does this
> apply to the 3.5L/4.0L comparison? Lets exagerate for the sake of
> explanation.
>
> The 4.0 with a larger displacement has to push heavier pistons up and
> down, turn a hug crankshaft that's proably a foot longer than the V6
> counterpart which in turn drives a lunky timing chain to spin a massive
> camshaft. Wow, lot of work so far but it's okay, the 4.0 has the torque to
> do it. Now, the cam shaft converts the rotery motion back into reciprical
> motion and has to push those 12 heavy lifters up and down all day. The
> lifters in turn push the pushrods up to the rockers which pivot and push
> the valve down into the combustion chamber.
>
> The advantage with the 3.5 is;
> Smaller pistons, smaller crankshaft, rubber timing belt vs. steel timing
> chain, no lifters, no pushrods, no rockers, 2 small camshafts, lighter
> valves. Every moving part in the valvetrain absorbs energy. The 3.5 has
> twice as many valves but they are much lighter than the 4.0 valves and are
> able to move quicker. A major restiction on a 2 valve engine is the valves
> floating (not returning to their seats fast enough). The way to avoid this
> is with a heavier valve spring. The trouble with a heavier valve spring is
> that it takes more energy to open the valve.
>
>> Perhaps another stupid question, but couldn't gearing (transmission) take
>> advantage of the higher HP at higher RPM without sacrificing tourque?
>
> Absolutly... but.... when you play with ratios you either get better take
> off or better top speed, not both. You may have noticed that most new
> vehicles these days are equipped with 5,6 and 7-speed manuals or 4 and 5
> speed automatics. Gone are the days of the 2-speed powerglide, 3 speed
> autos, 3,4 speed manuals. Like a truck (9-18 speed transmissions), the
> newer transmissions are able to better keep the engine in its peak
> operating rpm range. With less gears, you have to wind it out beyond the
> engines peak hp range or risk shifting back in well below the engines peak
> torque range. Theorhetically, your best fuel consumption will occur if you
> shift out at your engines peak hp range and back in at peak torqure range.
> RPM above or below that window is wasting fuel.
>
>> BTW did I notice that the 05 GC has a different engine with less
>> displacement than before? Something like 3.5 or 3.7 to the old 4.0.
>
> It's about time! However, there is nothing wrong with the 4.0 if you can
> deal with it's fuel consumption... they last forever.
>
>> I like my Jeep but I also like the looks (and specs) on the Infinity FX.
>> I don't do any offroading with my jeep. The Infinity looks like a brute
>> road handling machine. 20 inch tires and 280 hp is pretty impressive. The
>> pricetag is in the mid to high 30s and you can buy a lot of Jeep (or a
>> Jeep & a boat) for that kinda $$.
>
> If you're not off-roading then the FX line is a pretty cool way to go.
> Personally, I don't think I would want a GC for off-roading anyway... I'd
> rather have an old Cherokee or Wrangler for the dirt and a 300C for the
> ashphalt.
>
> I hope I haven't further confused you,
> -Brian
>
>
Many thanks!!!!