How to make torque at higher RPM...
Teching In
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Originally Posted by Louie83
I can see why you want to make more TQ at higher RPMs than lower; because HP = TQ x RPM / 5250 therefore, you will make more total HP making 300 lb/ft from 4000-7000 RPM than from making 300 lb/ft from 2000-5000 RPM. But how does it help you take advantage of gearing, like that Reher guy was saying? I'm confused on that part.
Car B makes 300 lb/ft at 6000 rpm
Gearing at 80 mph
A - 3.00 Gear for 3000 rpm
B - 6.00 Gear for 6000 rpm
A = 3.00 x 300 lb/ft = 900 lb/ft (Rear Wheel Torque)
B = 6.00 x 300 lb/ft = 1800 lb/ft (Rear Wheel Torque)
Which car will accelerate faster at 80 mph? B
Car B is faster because it can take advantage of more gearing.
Gene
Last edited by Tightwad; May 28, 2006 at 09:39 AM.
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From: virginia
Originally Posted by Tightwad
Car A makes 300 lb/ft at 3000 rpm
Car B makes 300 lb/ft at 6000 rpm
Gearing at 80 mph
A - 3.00 Gear for 3000 rpm
B - 6.00 Gear for 6000 rpm
A = 3.00 x 300 lb/ft = 900 lb/ft (Rear Wheel Torque)
B = 6.00 x 300 lb/ft = 1800 lb/ft (Rear Wheel Torque)
Which car will accelerate faster at 80 mph? B
Car B is faster because it can take advantage of more gearing.
Gene
Car B makes 300 lb/ft at 6000 rpm
Gearing at 80 mph
A - 3.00 Gear for 3000 rpm
B - 6.00 Gear for 6000 rpm
A = 3.00 x 300 lb/ft = 900 lb/ft (Rear Wheel Torque)
B = 6.00 x 300 lb/ft = 1800 lb/ft (Rear Wheel Torque)
Which car will accelerate faster at 80 mph? B
Car B is faster because it can take advantage of more gearing.
Gene
Launching!
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From: cobourg ON
well if both those cars are making 300 ft/lbs at different rps it doesnt matter really. Hp is simply another unit of mesurement and has nuthing to do with what an internal combustion engine creats (TORQUE). if an engine makes 300 ft/lbs at 3000 rpm and another makes 300 ft/lbs at 6000rpm then with gearing you can multip[ly the torque top the wheels, but it will be at different speeds that is all. the unfortunate part of engines is they automatically start to decrease in power (torque) as soon as they hit 5250 as previopusly stated i think. the only way to improve power after is to exponentially add more power by using power adders such as nitrous,blower. as it is a linear equation so making torque up top is a hard thing to do make the best of what you can make and gear the crap out of it to multiply the amount. gearing can only make up for so much before it becomes a detreiment to your goal.
(edit) yes an engine will make peak power in some cases after 5250 but it is being held back sorry to say guys
(edit) yes an engine will make peak power in some cases after 5250 but it is being held back sorry to say guys
Last edited by bifster; Jun 20, 2006 at 09:50 PM.
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Originally Posted by bifster
well if both those cars are making 300 ft/lbs at different rps it doesnt matter really. Hp is simply another unit of mesurement and has nuthing to do with what an internal combustion engine creats (TORQUE). if an engine makes 300 ft/lbs at 3000 rpm and another makes 300 ft/lbs at 6000rpm then with gearing you can multip[ly the torque top the wheels, but it will be at different speeds that is all. the unfortunate part of engines is they automatically start to decrease in power (torque) as soon as they hit 5350 as previopusly stated i think. the only way to improve power after is to exponentially add more power adders (nitrous,blower) as it is a linear equation so making torque up top is a hard thing to do make the best of what you can make and gear the crap oput of it to multiply the amount. gearing can only make up for so much before it becomes a detreiment to your goal.
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From: K-W, Ontario
Originally Posted by bifster
well if both those cars are making 300 ft/lbs at different rps it doesnt matter really. Hp is simply another unit of mesurement and has nuthing to do with what an internal combustion engine creats (TORQUE).
correct the remainder of your post.
It may be typical for a certain engine combination to roll off torque at 5350
RPM, but others may begin to peak at this RPM, or later.
There is nothing linear about making power. I'm sure Erik could elaborate on
the years of school it took to learn the basics about engine building, and even
then I bet he's still finding secrets of how air enters a cylinder.
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From: Wish I was in a boat fishing...
Originally Posted by bifster
well if both those cars are making 300 ft/lbs at different rps it doesnt matter really. Hp is simply another unit of mesurement and has nuthing to do with what an internal combustion engine creats (TORQUE). if an engine makes 300 ft/lbs at 3000 rpm and another makes 300 ft/lbs at 6000rpm then with gearing you can multip[ly the torque top the wheels, but it will be at different speeds that is all. the unfortunate part of engines is they automatically start to decrease in power (torque) as soon as they hit 5350 as previopusly stated i think. the only way to improve power after is to exponentially add more power adders (nitrous,blower) as it is a linear equation so making torque up top is a hard thing to do make the best of what you can make and gear the crap oput of it to multiply the amount. gearing can only make up for so much before it becomes a detreiment to your goal.
Launching!
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From: cobourg ON
hahaha well guy please find me a graph that has huge torque numbers after 5250. most engines street cars build max torque around 35-4500 and it is a known fact that any engine will begin to loose torque shortly after 5250. trust me on this guys I have more then 5 college and university professors that have told me this same thing as well if anyone has taken any physics they should have touched on it at some point depending on area of study sorry. and no im not a crackhead and I have a verry good attendance thanks.
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From: K-W, Ontario
Originally Posted by bifster
hahaha well guy please find me a graph that has huge torque numbers after 5250. most engines street cars build max torque around 35-4500 and it is a known fact that any engine will begin to loose torque shortly after 5250. trust me on this guys I have more then 5 college and university professors that have told me this same thing as well if anyone has taken any physics they should have touched on it at some point depending on area of study sorry. and no im not a crackhead and I have a verry good attendance thanks.
Here's a graph proving all of them wrong:
This engine peaks TORQUE at 6000 RPM. The only thing special about
the number 5252 is that both HP and TQ are equal at this point EVERY time.
Check out the formula...and show your teachers this thread. I'd love to hear
what they have to say about this.
Last edited by Adrenaline_Z; Jun 20, 2006 at 09:55 PM.
Launching!
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From: cobourg ON
do u notice how th ehorse power keeps rising after 5250?? and the torque is dropping anyways? well Hp is known to show how efficient an engine is at making torque. if you have an engine making 300 hp at 2000rpms and another at 6000rpms they will have extremely different power number under the curve I wish ppl would stop thinking engine make HP they dont guys its simple another measurement that is inacurate specially when you change the rpm level.
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From: K-W, Ontario
Do you also notice the TQ curve still climbs between 5252 and 6000 RPM?
I can find other graphs that show torque curves peaking later in the RPM band
as well.
Nobody here is saying engines "make Horsepower". HP is just a unit of measure
like miles, inches, etc.
What we're trying to display is that different engine combinations will make
torque at unique points depending on the needs of the car, track, race class...
and so on.
I can find other graphs that show torque curves peaking later in the RPM band
as well.
Nobody here is saying engines "make Horsepower". HP is just a unit of measure
like miles, inches, etc.
What we're trying to display is that different engine combinations will make
torque at unique points depending on the needs of the car, track, race class...
and so on.
Launching!
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From: cobourg ON
oh ok sorry my bad (bowing head) yes it is verry posible to build engine depending on needs.
I dont mean to anger anyone but it does become increasingly harder after 5250 for an engine to produce torque. and it is almost exponencial when we look at this torque = hp x 5252/rpm and plug in any numbers it will show the relation im triing to show
again sorry for the hyjack i guess but please continue on your post. IM verry interested in these engine combos anyways
sincere apologies
I dont mean to anger anyone but it does become increasingly harder after 5250 for an engine to produce torque. and it is almost exponencial when we look at this torque = hp x 5252/rpm and plug in any numbers it will show the relation im triing to show
again sorry for the hyjack i guess but please continue on your post. IM verry interested in these engine combos anyways
sincere apologies
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Originally Posted by bifster
I have more then 5 college and university professors that have told me this same thing...
Moderator
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From: Raleigh, NC
Originally Posted by allngn_c5
I agree with the last, when you use a supercharger you are eliminating the lag from a turbo. When you turbocharge, you eliminate the s/c'r fall off in high rpms. When you use the 2 together it seems like you would have a$$$$$phalt tearing torque, coupled with tons of horsepower all the way to the rev limiter. Don't know of any LS1's out there that are running supercharged and turbo cars at the same time. Sounds good in theory but does it work.
Also, Turbo lag may be there in theory, but in practice, the power can come on for a Turbocharged vehicle a LOT stronger and faster than some Supercharged applications. The old conventional wisdom about turbos and lag are really only a myth for more modern street/strip turbos.
FormerVendor
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From: Houston, Tx.
Originally Posted by bifster
hahaha well guy please find me a graph that has huge torque numbers after 5250. most engines street cars build max torque around 35-4500 and it is a known fact that any engine will begin to loose torque shortly after 5250. trust me on this guys I have more then 5 college and university professors that have told me this same thing as well if anyone has taken any physics they should have touched on it at some point depending on area of study sorry. and no im not a crackhead and I have a verry good attendance thanks.
At least your learning something now. Any engine will start to lose tq and hp as the airflow drops off to the cylinders as the rpm rises. This will always happen. When this happens in terms of rpm is dependent on the heads and cam and the stroke of the engine in question. You can make peak tq at 2000 rpm or 12000 rpm depending on how the engine is designed. There's no arbitrary rpm limits but rather mechanical and aerodynamic limits.
FWIW most "college and university professors" like "engineers" know little to nothing about the internal combustion engine or how it works. The ones that really do know wouldn't have told you that. Almost everyone I know is an engineer of some type yet more than 90 percent don't know much about what we are talking about. The ones that do and the ones that ARE familiar with the subject are capable of probably a much better understanding of this stuff than the normal Joe Q. Public.
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Originally Posted by racer7088
Any engine will start to lose tq and hp as the airflow drops off to the cylinders as the rpm rises.
Would you like to revise this quote? While it is correct through the words 'airflow drops off'. that is not dependent on 'rpm rises'.
I'm pretty sure most of your NA race engines have much higher volumetric efficiencies when the intake, exhaust, and cam tuning 'come on the cam'. And your forced induction motors may have an even more pronouced preference for higher engine speeds. To the best of my knowledge, all of the big, 1000+hp Supras don't do anything until over 5500 or so.
David
