New Mazda 'WIDE' (15B) Rotary 2007
#226
Originally Posted by Deslock
Additionally, power *is* more important than engine torque since you can make a lot of wheel torque without a lot of engine torque, but you can't make a lot of wheel torque without a lot of power (except when you're at very low vehicle speeds).
The performance of a car is related to having torque and HP ratings appropriate to many of the properties that define it...you seem to be ignoring some of the limitations of engineering in modern vehicles.
Power is not more important.
#227
WWFSMD?
Join Date: Jul 2003
Location: Massachusetts, USA
Posts: 597
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by hedgecore
Your statement seems to be made from a somewhat limited viewpoint.
The performance of a car is related to having torque and HP ratings appropriate to many of the properties that define it...you seem to be ignoring some of the limitations of engineering in modern vehicles.
Power is not more important.
The performance of a car is related to having torque and HP ratings appropriate to many of the properties that define it...you seem to be ignoring some of the limitations of engineering in modern vehicles.
Power is not more important.
Can you elaborate? Also, was there something in my other post that you disagreed with?
As I indicated before, at low vehicle speeds high engine torque is desirable. That situation is precisely due to engineering limitations (with gearing, etc). There are other times when extra engine torque can be convenient (say, if you don't like downshifting to pass). And some people like the predictability of a flat torque curve. But in general power is the more important attribute when it comes to acceleration.
#228
I think he is trying to say that a "torque" motor may be more desireable than a RPM motor, depending on the application, because of the side effects of each approach.
ie, heavy trucks tend to make HP with big torque, because who wants a short-lived, blazing hot, screaming engine cranking a granny gear at 10,000 RPM's?
Likewise, hardly anyone on a sport bike wants a fat heavy slug of a low-RPM diesel. It could make a bike move fast, but the benefits don't outweigh the costs--for this application. Even a slight weight increase here will have big effects on performance.
Of course, all of these are things outside the purely mathematical definitions of torque, RPM, and HP--they are "things which are usually associated with torque (or RPM ), on current design otto cycle engines". But then again, if someone invents a cheap turbine with good throttle response, every semi would use them, regardless of their gazillion-RPM redline. Likewise, if someone invents a torque monster the size of a cuisinart (quasiturbine, anyone?), plenty of sport bikes will use them. If you're just looking at performance numbers though--whether acceleration, top speed, or towing capacity--HP is what matters (assuming otherwise identical cars).
ie, heavy trucks tend to make HP with big torque, because who wants a short-lived, blazing hot, screaming engine cranking a granny gear at 10,000 RPM's?
Likewise, hardly anyone on a sport bike wants a fat heavy slug of a low-RPM diesel. It could make a bike move fast, but the benefits don't outweigh the costs--for this application. Even a slight weight increase here will have big effects on performance.
Of course, all of these are things outside the purely mathematical definitions of torque, RPM, and HP--they are "things which are usually associated with torque (or RPM ), on current design otto cycle engines". But then again, if someone invents a cheap turbine with good throttle response, every semi would use them, regardless of their gazillion-RPM redline. Likewise, if someone invents a torque monster the size of a cuisinart (quasiturbine, anyone?), plenty of sport bikes will use them. If you're just looking at performance numbers though--whether acceleration, top speed, or towing capacity--HP is what matters (assuming otherwise identical cars).
Last edited by BaronVonBigmeat; 11-11-2005 at 01:14 PM.
#229
Bummed, but bring on OU!
Originally Posted by Deslock
Below is your entire post:
Even in this context, you would've been more accurate had you written "Apply x torque at some angular speed and you get power".
Even in this context, you would've been more accurate had you written "Apply x torque at some angular speed and you get power".
Originally Posted by Deslock
Additionally, power *is* more important than engine torque since you can make a lot of wheel torque without a lot of engine torque, but you can't make a lot of wheel torque without a lot of power (except when you're at very low vehicle speeds).
#230
WWFSMD?
Join Date: Jul 2003
Location: Massachusetts, USA
Posts: 597
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by therm8
Power cannot make torque. Power is work with respect to time. You cannot cause work (moving the car) in this case without the torque. Power is basically how much work the engine, and therefore the wheels, causes via the tires in a given amount of time (through torque). An engine that produces zero torque, cannot produce power.
Originally Posted by Deslock
...power *is* more important than engine torque since you can make a lot of wheel torque without a lot of engine torque, but you can't make a lot of wheel torque without a lot of power (except when you're at very low vehicle speeds).
Case in point, two otherwise identical cars travel at 60 MPH. The one making 400 ftlbs at 3000 RPM has less wheel torque than the one making 300 ftlbs at 5000 RPM.
Case in point, two otherwise identical cars travel at 60 MPH. The one making 400 ftlbs at 3000 RPM has less wheel torque than the one making 300 ftlbs at 5000 RPM.
#231
WWFSMD?
Join Date: Jul 2003
Location: Massachusetts, USA
Posts: 597
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by BaronVonBigmeat
I think he is trying to say that a "torque" motor may be more desireable than a RPM motor, depending on the application, because of the side effects of each approach.
#232
Originally Posted by Deslock
Your post is written in an eloquent style, but I can't figure out what it's actually trying to say. Then again, reading comprehension was never my strong point...
Can you elaborate? Also, was there something in my other post that you disagreed with?
As I indicated before, at low vehicle speeds high engine torque is desirable. That situation is precisely due to engineering limitations (with gearing, etc). There are other times when extra engine torque can be convenient (say, if you don't like downshifting to pass). And some people like the predictability of a flat torque curve. But in general power is the more important attribute when it comes to acceleration.
Can you elaborate? Also, was there something in my other post that you disagreed with?
As I indicated before, at low vehicle speeds high engine torque is desirable. That situation is precisely due to engineering limitations (with gearing, etc). There are other times when extra engine torque can be convenient (say, if you don't like downshifting to pass). And some people like the predictability of a flat torque curve. But in general power is the more important attribute when it comes to acceleration.
A well designed car will have an adequate and balanced amount of both based on it's design...
P.S. I'm not trying to be a dick...i'm genuinely curious...how well versed are you in physics?
#233
Bummed, but bring on OU!
Originally Posted by Deslock
None of that contradicts what I wrote:
#234
Originally Posted by therm8
Your points are all based on gearing, which is used to make better use of torque output to provide more work per time...
"Your points are all based on gearing, which is used to make better use of power output to provide more torque or RPM's..."
* That's why quoting torque numbers (or RPM numbers, if you're a ricer) just doesn't tell a complete story of what an engine's capable of. Wow, you have an engine with 500 ft.-lbs. of torque. Surely it will tow more weight and go faster than the car with 400 ft.-lbs? Well...we don't know. We just don't have enough information (namely, RPM's). It's sort of like assuming that the guy with lean muscular legs will win the footrace, without considering his lung capacity, for example.
If only there were an engineering number that we could use...something that factors in torque, but also RPM's too...then we could really make a fair comparison between two engines!
Last edited by BaronVonBigmeat; 11-11-2005 at 03:25 PM.
#235
Originally Posted by hedgecore
My point is that you seem to be ignoring the assumptions of current technology...you're high HP, low torque motor works well, but there are limitations to how many gears can be efficiently implemented into a vehicle...in any 4-7speed transmission on a car engineered to pass crash tests and sold to consumers, torque is a desirable variable in determining a cars performance...
Also high spinning engines weigh less, which is great but unfortunately most costumers don't care about curbweight (nor do car manufacturers for that matter).
Also if car manufacturers would introduce a low end hp number instead of torque (eg. 100 HP at 3000 rpm) and would talk about linear hp curve instead of flat torque curves, there weren't all these endless torque hp threads.
#236
Originally Posted by globi
I doubt it's just because of gearing. The reason why cars with more low-end power are desirable is because, they are more driveable, less noisy and more efficient (less frictional losses).
Also high spinning engines weigh less, which is great but unfortunately most costumers don't care about curbweight (nor do car manufacturers for that matter).
Also if car manufacturers would introduce a low end hp number instead of torque (eg. 100 HP at 3000 rpm) and would talk about linear hp curve instead of flat torque curves, there weren't all these endless torque hp threads.
Also high spinning engines weigh less, which is great but unfortunately most costumers don't care about curbweight (nor do car manufacturers for that matter).
Also if car manufacturers would introduce a low end hp number instead of torque (eg. 100 HP at 3000 rpm) and would talk about linear hp curve instead of flat torque curves, there weren't all these endless torque hp threads.
Agreed, it's all about the engines output pattern...a simple way of putting it comes in the shape of the curve and the total area under the curve.
Bottom line, a quest for only high HP numbers isn't the right quest.
#237
Originally Posted by globi
I doubt it's just because of gearing. The reason why cars with more low-end power are desirable is because, they are more driveable, less noisy and more efficient (less frictional losses).
Also high spinning engines weigh less, which is great but unfortunately most costumers don't care about curbweight (nor do car manufacturers for that matter).
Also if car manufacturers would introduce a low end hp number instead of torque (eg. 100 HP at 3000 rpm) and would talk about linear hp curve instead of flat torque curves, there weren't all these endless torque hp threads.
Also high spinning engines weigh less, which is great but unfortunately most costumers don't care about curbweight (nor do car manufacturers for that matter).
Also if car manufacturers would introduce a low end hp number instead of torque (eg. 100 HP at 3000 rpm) and would talk about linear hp curve instead of flat torque curves, there weren't all these endless torque hp threads.
But, we're stuck with 6 speeds and huge shifting costs...hence the need to reach for a proper balance of HP and torque behavior from an engine.
Last edited by hedgecore; 11-11-2005 at 03:43 PM.
#238
Originally Posted by hedgecore
On Gearing...my point was that if we could easily and efficiently devolop transmission with lots of gears and a good way of selecting them, then a high HP motor with little torque would be appropriate.
The only way to get rid of gears is by having an engine with a flat power curve.
And of course there are gearboxes with lots of gears:
http://cvt.com.sapo.pt/performances/CVT_vs_MT_calc.htm
There should be a semi manual CVT that allows you to operate it at max power or max economy or anything in between. Substitute the stick with a lever (that can be moved from max power to max economy).
Last edited by globi; 11-11-2005 at 03:53 PM.
#239
Originally Posted by globi
Actually you don't need more gears with a high end power engine than with low end power engine. In fact most cars with Diesel engines have a very narrow usable power bands. The RX-8 on the other hand has a huge usable power band. Of course in order to get somewhere you need to operate the engine at max power as well. But it doesn't really matter whether max power is at 2000 rpm or 9000 rpm as far as gearing is concerned.
The only way to get rid of gears is by having an engine with a flat power curve.
And of course there are gearboxes with lots of gears:
http://cvt.com.sapo.pt/performances/CVT_vs_MT_calc.htm
There should be a semi manual CVT that allows you to operate it at max power or max economy or anything in between. Substitute the stick with a lever (that can be moved from max power to max economy).
The only way to get rid of gears is by having an engine with a flat power curve.
And of course there are gearboxes with lots of gears:
http://cvt.com.sapo.pt/performances/CVT_vs_MT_calc.htm
There should be a semi manual CVT that allows you to operate it at max power or max economy or anything in between. Substitute the stick with a lever (that can be moved from max power to max economy).
"space aged"...wow, i feel like an info-mercial, haha
#240
Originally Posted by globi
Actually you don't need more gears with a high end power engine than with low end power engine. In fact most cars with Diesel engines have a very narrow usable power bands. The RX-8 on the other hand has a huge usable power band. Of course in order to get somewhere you need to operate the engine at max power as well. But it doesn't really matter whether max power is at 2000 rpm or 9000 rpm as far as gearing is concerned.
You're talking about high end vs low end.
I mentioned a high hp, low torque engine.
#241
CVTs are also a marketing issue. Many people wouldn't want to drive a sports car at a constant rpm.
Maybe if the FIA hadn't banned it in 1994 it would be more popular.
Maybe if the FIA hadn't banned it in 1994 it would be more popular.
In 1993, the Williams-Renault VDT FW15C - Experimental CVT set-up by Van Doorne Transmissie (VDT) on the championship-winning car bridged the gap to the late-sixties F3 and FJ efforts by DAF. The CVT paired to a Renault V10 constantly revving at its peak led to spectacular test times by David Coulthard, after which CVT was quickly and silently banned from Grand Prix racing by the FIA in 1994, after the worryingly fast test times by Williams.
#242
Registered User
Join Date: May 2003
Location: Hell in the desert
Posts: 445
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by globi
CVTs are also a marketing issue. Many people wouldn't want to drive a sports car at a constant rpm.
Maybe if the FIA hadn't banned it in 1994 it would be more popular.
Maybe if the FIA hadn't banned it in 1994 it would be more popular.
#243
Administrator
Originally Posted by globi
There should be a semi manual CVT that allows you to operate it at max power or max economy or anything in between. Substitute the stick with a lever (that can be moved from max power to max economy).
there are currently CVTs with selectable ratios
#244
Originally Posted by zoom44
there are currently CVTs with selectable ratios
#246
Bummed, but bring on OU!
Originally Posted by hedgecore
CVT isn't an efficient replacement in performance vehicles...won't be for quite awhile...perhaps with new manufacturing techniques and space aged materials. But yes, when they come we'll see a whole new range of performance engine behavior.
http://www.andersoncvt.com/howitworks.html
#247
Originally Posted by therm8
check this cvt out: Seems to overcome alot of the inefficiency problems.
http://www.andersoncvt.com/howitworks.html
http://www.andersoncvt.com/howitworks.html
BTW, someone mentioned that consumers wouldn't be thrilled by transmissions that do not have discreet gears...
Personally, i get a much bigger feeling of excitement from a snowmobile's acceleration than i have from any car(maybe ferarri's, but that's more about the whole experience). I think a CVT in a sports car would totally blow away most enthusiasts idea of what they think fun is!
Again though, i hear SMG's are still getting a bad rap from "car people"...that's kind of sad. If SMG's, which are clearly better performers than standard transmissions can't win people over, how will CVT's?
#248
Int'l Man of Mystery
Join Date: Jan 2004
Location: Central Florida
Posts: 3,651
Likes: 0
Received 0 Likes
on
0 Posts
Easy... some people just don't care about the "on-paper" benefits and more about the Overal driving experience. I hate SMG, auto, etc. Boring, feel disconnected from the car.... the driving experience. Like the Lexus IS 350 vs BMW 330is... on paper the Lexus looks like a winner, but once you get behind the wheel... the difference is stark.
#250
Originally Posted by globi
As I said SMGs and CVTs might not be accepted by everybody, but they wouldn't be used in racing if they were just better on paper.
However, now after learning how it feels, knowing what to expect and realizing the benefits(shifts much faster than even a pro driver) i'm dissapointed more manu's don't offer it as an option. It actually doesn't disconnect you from the car...it immerses you more deeply into it!