gttman
|
| posted on 31/12/06 at 12:04 PM |
|
|
quote:
Originally posted by Lippoman
If you measure only the torque you do not know anything about the power of an engine. You also need to know the rpm.
Strange as this is exactly what I said.... so what exactly are you disagreeing with?
'Power' is simply a calculation of the torque an engine produces at a given RPM's.
[Edited on 31/12/06 by gttman]
Andygtt
Please redefine your limits
|
|
|
|
|
gttman
|
| posted on 31/12/06 at 12:26 PM |
|
|
Maybe I should point out that I am not saying having a high torque figure is more important than having a high Power figure...... Its entirelly down
to application.
On my GTT I hope to get more BHP than Torque... but this mystical power increase is only acheived by moving the torque curve high up the RPM.
Andygtt
Please redefine your limits
|
|
|
Lippoman
|
| posted on 31/12/06 at 02:41 PM |
|
|
If torque was a figure of the power you would not need to know any other variable to calculate it.
Power can be transformed into any torque by use of gearing, but a double the power engine gives double the torque at the wheels at the same road
speed, even if the shaft torque is equal (or less).
The powerband is what makes the engine usable, power (the area under the power/rpm-curve) tells us how fast it will be; shaft torque is of less
importance, that is mainly needed to design the transmission.
The only torque that is really of interest is the wheel torque and that can be derived from power.
|
|
|
Bob C
|
| posted on 31/12/06 at 04:50 PM |
|
|
If you hang a 100lb weight on a tree branch, 1 foot out from the trunk - you are applying 100ft lbs of torque to the joint of branch and trunk.
That's a healthy amount of torque!
And the power level is.........??? zero
As a motor drives designer I need to have a very clear "physics textbook" understanding of these physical quantities, which is why I tend
to squirm a bit when "pub talk" type statements are made by folk with a different understanding!!! But we are all free to say, believe and
understand whatever we want so happy new year to everyone ;^)
Bob
|
|
|
gttman
|
| posted on 31/12/06 at 05:31 PM |
|
|
Sorry but You need to read what I said, I know that Torque AND rpm are used to calculate power and I never said anything different.
If you have no torque you also have no power...
If as engine experts you can demostrate that and engine with a flat 100ftlb from 1000-7000rpm redline can be more powerful than an engine with a flat
120ftlb over exactly the same range, then you will have proved me wrong.
Andygtt
Please redefine your limits
|
|
|
bike_power
|
| posted on 31/12/06 at 10:25 PM |
|
|
quote:
Originally posted by G.Man
quote:
Originally posted by gttman
Hang on, he just pointed out that you could buy the ZX14.... he certainly didn't start saying it was the be all and end all, just ended
defending from people saying how unsuitable it is just because they prefer the busa or R1.
And I think it was the ZX14 that was said to have more torque than the Busa not the ZX12.
And if all things were equal the car with more torque over the same rev range WILL be faster... torque is the measure of power of the engine.
Thanks Andy, I was beginning to think I was mad, love the look of your GT car btw..
I would also like to say, that an RV8 engined 7, or even a decent cossie turbo, with a sequential box, will give a bike engined car a good run for its
money, however, the weight will slow it in the corners, and THAT'S the reason we build bike engined cars..
[Edited on 29/12/06 by G.Man]
I didn't claim the ZX14 was great - you did G Man, you pointed out that they were cheap and they were great, different from the ZX12 and without
half the problems of the old engine. (page 2)
---> YOU SAID: "The fact of the matter is that there is no better motor out there to run stock in a BEC"
So you are mad, or simply have no memory or you say stuff that's got no foundation in truth so forget it very easily.
---> You did it again on page 4: "The zx12r also makes more torque than the BUSA so it isn't all RPM based anyway... "
You need to remember the bullshit you come out with so you don't trip yourself up.
Show me a Rover V8 engined 7 with about 200 lb ft (double a busa) and the same weight as a busa powered 7 and the busa powered car will be faster.
You only have to go to any track day to find out. It's not just about torque, there is a whole lot more to it . . . and no, weight isn't
the only answer either.
G-man, you simply quote bullshit figures and ignore fact and information quoted by people who obviously understand things far better than you (the
post from Bob C) , you even deny saying things you said only a couple of pages ago, how have you managed to complete your car and get it on the road
?
I thought you might have had something interesting to say but you sound like a shandy drinking pub bullshitter  
|
|
|
birt
|
| posted on 1/1/07 at 02:58 AM |
|
|
Aye Aey Aey, Cccalm down Cccalm down (as a curly haired Scouser with a dodgy tash once said).
Some of you know that I have now moved to Oz and as I am sat at home bored on new years day I thought I would check out the good ol’ Locostbuilders
site.
I suppose I'm not surprised to see that the same old arguments are still taking place! It just needs someone to drop it in here that bike engine
aren't as good as car engines anyway and all hell is gonna break loose! Ha ha.
Ignoring driveability and concentrating on balls out performance, do we all agree on the following points?
Engine torque is an important factor in making a car go quickly but is meaningless unless combined with speed.
Quoting a peak torque value alone is an unsuitable indication of performance.
All that really matters for sheer performance is the POWER at the wheels over a given (useable) rpm range.
An engine that produces more torque over a similar rpm range will produce more power in a similarly geared installation.
If you use an R1, Busa, ZX12R or ZZR14 your car will go like stink and the parameter most likely to affect you track times is your ability as a
driver.
As for me, I am doing a ZX10R conversion to get me through tough Aussie Design Rules emissions so I will keep you all posted on my progress.
Anybody else on here done a ZX10R yet?
Marc
|
|
|
gttman
|
| posted on 1/1/07 at 09:12 AM |
|
|
quote:
Originally posted by bike_power
Show me a Rover V8 engined 7 with about 200 lb ft (double a busa) and the same weight as a busa powered 7 and the busa powered car will be faster.
You only have to go to any track day to find out. It's not just about torque, there is a whole lot more to it . . . and no, weight isn't
the only answer either.
This is only because a 7 type can't take the torque of a Rover V8 but can handle a busa.... build a car that can harness the torque better and
it would be a different story.
Andygtt
Please redefine your limits
|
|
|
Lippoman
|
| posted on 1/1/07 at 10:56 AM |
|
|
Gttman
If you take only torque you have a figure that tells "nothing" about the engines power, if you mix in the rpm's, you're not
talking torque anymore, you're talking power.
Torque has nothing to do with time, it is a static measure (lbsft or Nm). As soon as you enter a "per second" or "per minute"
(or per any other unit of time) into the equation you convert it into power.
|
|
|
G.Man
|
| posted on 1/1/07 at 12:39 PM |
|
|
quote:
Originally posted by bike_power
quote:
Originally posted by G.Man
quote:
Originally posted by gttman
Hang on, he just pointed out that you could buy the ZX14.... he certainly didn't start saying it was the be all and end all, just ended
defending from people saying how unsuitable it is just because they prefer the busa or R1.
And I think it was the ZX14 that was said to have more torque than the Busa not the ZX12.
And if all things were equal the car with more torque over the same rev range WILL be faster... torque is the measure of power of the engine.
Thanks Andy, I was beginning to think I was mad, love the look of your GT car btw..
I would also like to say, that an RV8 engined 7, or even a decent cossie turbo, with a sequential box, will give a bike engined car a good run for its
money, however, the weight will slow it in the corners, and THAT'S the reason we build bike engined cars..
[Edited on 29/12/06 by G.Man]
I didn't claim the ZX14 was great - you did G Man, you pointed out that they were cheap and they were great, different from the ZX12 and without
half the problems of the old engine. (page 2)
---> YOU SAID: "The fact of the matter is that there is no better motor out there to run stock in a BEC"
So you are mad, or simply have no memory or you say stuff that's got no foundation in truth so forget it very easily.
---> You did it again on page 4: "The zx12r also makes more torque than the BUSA so it isn't all RPM based anyway... "
You need to remember the bullshit you come out with so you don't trip yourself up.
Show me a Rover V8 engined 7 with about 200 lb ft (double a busa) and the same weight as a busa powered 7 and the busa powered car will be faster.
You only have to go to any track day to find out. It's not just about torque, there is a whole lot more to it . . . and no, weight isn't
the only answer either.
G-man, you simply quote bullshit figures and ignore fact and information quoted by people who obviously understand things far better than you (the
post from Bob C) , you even deny saying things you said only a couple of pages ago, how have you managed to complete your car and get it on the road
?
I thought you might have had something interesting to say but you sound like a shandy drinking pub bullshitter
I have quoted the torque figures for the Busa and zx12r at higher rpm's, making more torque doesnt always mean peak torque, its about the range
of torque.. A high peak torque figure is useless if the curve peaks and troughs just as fast...
Just shows you can look at numbers and not understand them...
I compared with the zx12r as you were once again spouting bollox about faults with the zx14r which were just regurgitated zx12r problems... hence why
I brought in the comparison...
I did not deny anything with regard to BobC's post, I should have said, torque gives acceleration, but I said equals instead... you are that
dumb you dont even know the difference..
I still stand by the comment the zx14 is the best motor to run stock in a BEC, you have a difference of opinion... baaaaa
If you have evidence that I am wrong then post it...
[Edited on 1/1/07 by G.Man]
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
|
|
|
gttman
|
| posted on 1/1/07 at 02:35 PM |
|
|
quote:
Originally posted by Lippoman
If you take only torque you have a figure that tells "nothing" about the engines power, if you mix in the rpm's, you're not
talking torque anymore, you're talking power.
Torque has nothing to do with time, it is a static measure (lbsft or Nm). As soon as you enter a "per second" or "per minute"
(or per any other unit of time) into the equation you convert it into power.
I may be ignorant in your eyes but I know that it is torque at different rpms that is MEASURED to calculate power.
I also know that the higher the measured torque at each rpm increment the higher the power....
Therefore IMO the engines measured torque throughout the rpm range is very important regarding the engines performance.
Andygtt
Please redefine your limits
|
|
|
bike_power
|
| posted on 1/1/07 at 08:23 PM |
|
|
quote:
Originally posted by G.Man
I compared with the zx12r as you were once again spouting bollox about faults with the zx14r which were just regurgitated zx12r problems... hence why
I brought in the comparison...
I did not deny anything with regard to BobC's post, I should have said, torque gives acceleration, but I said equals instead... you are that
dumb you dont even know the difference..
I still stand by the comment the zx14 is the best motor to run stock in a BEC, you have a difference of opinion... baaaaa
Right . . . one by one this time
I didn't say the ZX14 had any faults - this is the point, we don't know yet ! I didn't regurgitate anything about the ZX12,
you're the only person claiming the ZX12 has any faults. What faults are they, out of interest ?
You said: "I should have said torque gives acceleration . . ." - NO IT DOESN'T.
Torque is a twisting effect. It's a measure of how hard the engine can twist the propshaft. Think about 100 lb ft - that's a 50lb weight
hung off a 2ft bar. If you really think about that it means jack poo as far as acceleration is concerned. It might roll your car forward but
it's not going to do much else is it regardless of how peaky or flat the graph may be on paper.
Heck, my legs can apply more than that by jumping on the bar. It's only when you start to consider the other factors such as power, which is
the work the engine is able to do, that it becomes clearer. Why does a S1 Elise 120bhp accelerate less fast than a S1 Elise 160 ? The peak torque is
almost identicle, the torque curves are very similar but the power is different - it's the power that makes the differentce, not the torque.
Have a look at these:
Standard S1 Elise 120bhp
http://www.dyno-plot.co.uk/dyno/dynoplot/109/Lotus-Elise.htm
Elise 160
http://www.dyno-plot.co.uk/dyno/dynoplot/50/Lotus-Elise.htm
These are both stock cars as far as I can see, both S1 Elises. The 160 accelerates much faster than the 120bhp engine - 1.2s quicker to 60 according
to a Lotus friend and on a track the additional power is worth 2-3 seconds or more a lap, depending on circuit.
The torque figures for both engines are very similar. The 160bhp car does not have any more torqure than the 120bhp car, in fact, it develops
it's torque much higher up the rev range and the 120bhp engine has what would usually be referred to as a smoother and more useful spread of
torque.
So why is the 160 car faster if it has no more torque than the 120 car ? The top end of the 160 has been improved by better breathing - the power the
engine makes is increased by the fact that it can gulp more air at higher rpm. This is why it's faster - it can do more work, not because it
has more torque because you can see that it doesn't. Even if you look at the area under the graph you can see that where the 160 gains at the
top end it looses out at the bottom end.
This is also why a Rover V8 with 210 lb ft is slower than a Hayabysa with 105 lb ft of torque. Rover has much greater area under the graph, hell, the
Rover probably makes more torque at fast idle than the Hayabusa but on a track, the busa will beat it. Same way the Elise 160 will beat an Elise
120.
If you want the detailed maths behind it you'll need to speak to an engine designer.
If you think the ZX14 is the best engine to use stock, in a BEC then you obviously base that statement on the same assumptions you base your
"torque=acceleration" assertion on. You've no idea.
|
|
|
bike_power
|
| posted on 1/1/07 at 08:30 PM |
|
|
quote:
Originally posted by gttman
quote:
Originally posted by bike_power
Show me a Rover V8 engined 7 with about 200 lb ft (double a busa) and the same weight as a busa powered 7 and the busa powered car will be faster.
You only have to go to any track day to find out. It's not just about torque, there is a whole lot more to it . . . and no, weight isn't
the only answer either.
This is only because a 7 type can't take the torque of a Rover V8 but can handle a busa.... build a car that can harness the torque better and
it would be a different story.
Not sure I understand you ? Take two Fury's, one Hayabusa and one Rover V8 with 200ish lb ft of torque - same brakes, same weight, same Sierra
diffs etc. Only difference is the power of the engines and the fact that Rover has double the torque of the busa.
What I am saying is that the busa will be faster round a circuit, or in a straight line or in any other measure you care to come up with. I know this
is the case, this is what happened when people first started putting bike engines in cars.
If the V8 is making more power than the busa then of courtse it will be faster but then the V8 will also have more than 200 lb ft of torque.
|
|
|
bike_power
|
| posted on 1/1/07 at 08:33 PM |
|
|
quote:
Originally posted by Lippoman
If you take only torque you have a figure that tells "nothing" about the engines power, if you mix in the rpm's, you're not
talking torque anymore, you're talking power.
Torque has nothing to do with time, it is a static measure (lbsft or Nm). As soon as you enter a "per second" or "per minute"
(or per any other unit of time) into the equation you convert it into power.
Thanks, that's what I was trying to say !
Hence why a bike engine is usually more powerful than (for example) a Rover V8, more rpm, more air, more work done, more power == faster car all else
being equal.
|
|
|
gttman
|
| posted on 1/1/07 at 09:30 PM |
|
|
quote:
Originally posted by bike_power
What I am saying is that the busa will be faster round a circuit, or in a straight line or in any other measure you care to come up with. I know this
is the case, this is what happened when people first started putting bike engines in cars.
If the V8 is making more power than the busa then of courtse it will be faster but then the V8 will also have more than 200 lb ft of torque.
Ok that last paragraph explains what you mean... I though you were suggesting that a V8 could never beat a Busa.
I've actually officially raced (0-100-0) Busa engined cars (radical and westfield) with slightly better BHP/ton than the kit I had which had a
SBC V8 (did a mag featured world record attempt)... and back to back on the same day they were 1second slower to 100mph than my car and would have
been more if it wasn't for the terrible gearchange in my car (took 0.4 seconds).
This is why I find it strange (and bite) when people claim BEC are unbeatable..... but then again for the money I think they are... which is why
I'm also building one.
Andygtt
Please redefine your limits
|
|
|
Lippoman
|
| posted on 1/1/07 at 10:35 PM |
|
|
Gttman
This "debate" over torque vs power has been raging through most of the motor fora I visit and I may have a tendency to preach.
I know that torque is used to calculate power, this is because it is simple to measure torque. If there was a simple way to directly measure power,
I'm certain the dynos would use this instead.
If I have offended you in any way, I offer my most sincere apologies...
|
|
|
G.Man
|
| posted on 1/1/07 at 11:06 PM |
|
|
What you fail to identify is that 2 engines of the same peak BHP, say a cosworth 2 litre and a mildly tuned BUSA..
In a vehicle of the same weight, using these engines, the Cosworth would be faster..
A cosworth engine will make an escort fly, because it has the torque to move the weight quickly...
Use a BUSA engine of 200bhp in an escort, and the busa engine wont be anywhere near as fast....
Yes you can increase BHP by raising rpm, but you cannot raise torque without increasing the amount of fuel and air burned in each cylinder...
So its the force on the wheel (leverage aka torque) that provides the increase in the rpm of the wheel against resistance... ie acceleration...
The lack of torque in a bike is overcome by using the primary reduction as a torque multiplier...
If you wanted to see the difference torque makes, you would have to remove the bike engine from its box and therefore the primary reduction, and then
see ..
Thankfully, we can tell much more easily, compare the performance of a BUSA to a ZX14 or a ZX12
Busa vs zx12 the early torque of the busa gives it a lead from standing start, zx12 narrows the gap at higher rpm, but the busa is still faster, as
its torque is higher than the zx12's which has higher rpm related horsepower...
ZX14 vs Busa... ZX14 pulls away early and the Busa never catches it... due to higher torque and higher bhp....
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
|
|
|
Lippoman
|
| posted on 2/1/07 at 06:24 AM |
|
|
Rpm
To quote "'Allo, 'allo":
"Listen very carefully, I will only say this once."
The powerband is what separates the Cossy from the 'Busa. If you can get the engine to stay at its peak by using gear shifts the higher power
will translate into higher force=better acceleration. That is why "peaky" engines usually are accompanied by multiple speed gearboxes or
(ideally) CVTs. Why do you think FIA outlawed CVTs in F1? The acceleration and hence the speeds would have been maximised by allowing the engines to
stay at peak power at all times.
If shaft torque was "the thing" that gave acceleration, then you would change gears as soon as the torque curve passes its peak.
If you have an engine that delivers x power at a certain (road) speed and another that delivers 1,5x power at the same speed, the more powerful engine
will have 1,5x the force to accelerate. Regardless of which engine has the higher shaft torque.
Rpms is one way that you can get more air and more fuel to burn in the same time and that translates into higher torque at the wheels using correct
transmission.
|
|
|
G.Man
|
| posted on 2/1/07 at 08:47 AM |
|
|
I give up, you win, an engine with more torque and more bhp, is not as good as Busa..
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
|
|
|
gttman
|
| posted on 2/1/07 at 09:38 AM |
|
|
quote:
Originally posted by Lippoman
This "debate" over torque vs power has been raging through most of the motor fora I visit and I may have a tendency to preach.
I know that torque is used to calculate power, this is because it is simple to measure torque. If there was a simple way to directly measure power,
I'm certain the dynos would use this instead.
If I have offended you in any way, I offer my most sincere apologies...
Not at all, I was just frustated as I feel I am being miss quoted.
I think the point you are making is that in a rotational application like an engine it is technically incorrect to quote Torque figures.... whilst
that may be the case, fact is it is only the torque that can be measured and thus everyone refers to it.
Andygtt
Please redefine your limits
|
|
|
Lippoman
|
| posted on 2/1/07 at 06:37 PM |
|
|
G.Man
I did not state that a 'busa was better than a Cossie, you stated they were equal in terms of peak power. So what really sets them apart then is
the powerband.
A well built turboengine generally has the best of several worlds, having loads of mid range as well as top end power, making it easy to stay within
the powerband. But the cost of building and maintaining a high power turboengine is not for every budget.
Stating that the weight of the Cossie with sequential transmission would be equal to a 'busa engined is a bit of twisting the world to suit ones
taste, the BEC builder should be ashamed if he couldn't bring it way lower on the scales. And if you the take costs into consideration, then its
really time to wake up and smell the coffee (as long as you keep the BEC fairly stock)...
I stated that the engine with the higher power will outperform the other regardless of shaft torque with the correct transmission, so how did you come
up with the above sentence?
I favor BECs of any flavor due to their inherent lack of weight when compared to car engines, the lack of low range torque is something I'll
have to learn to live with. I'm also infatuated to the screaming sound of an engine passing 10 krpm, and sequential gearboxes.
My remarks were made in general terms and I used the 'busa and Cossie as references only as they already had been brought up.
|
|
|
G.Man
|
| posted on 2/1/07 at 07:39 PM |
|
|
Lippoman
I got fed up of discussing it, because people keep completely ignoring what I post...
Yes the busa has same or similar BHP, but if it hasnt got the torque to shift a heavier weight in the first place its gonna be no good in a FORD
ESCORT...
Yes, in our application the car is light enough that the lower torque isnt so much of an issue...
I used the escort in my above example, I could have used a cosworth sierra, remove the cossie engine and slap in a busa... lets see how the car goes
then....
To accelerate a car you need ft/lb's...
Try this... get your vehicle to its peak torque rpm in 1st gear and floor it, then try it at peak horsepower..
The car will accelerate much faster at its peak torque than it will at peak bhp...
Drag racers know that an increase in torque will result in a reduction in ET, and an increase in BHP with no change to torque will result in a peak
speed and slower ET....
Its the difference between torque and power...
Ideally you want as much torque as possible maintained for as wide an rpm band as possible, that give you your work rate... horsepower...
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
|
|
|
bike_power
|
| posted on 2/1/07 at 10:54 PM |
|
|
quote:
Originally posted by G.Man
I got fed up of discussing it, because people keep completely ignoring what I post...
bike_power: : Mrs G-Boy
  
|
|
|
G.Man
|
| posted on 2/1/07 at 11:07 PM |
|
|
bike_power, may I ask you what your experience is?
you post anonymously and dont appear tobe building anything, so what exactly are your "qualifications"
I mean you patronise in the extreme, read the bits you choose and interpret them in a twisted manner to make your arguments seem stronger..
Then you post a number of pathetic cartoons to try and belittle me..
So come on, I have openly stated my experience here, so give me yours...
or are you just a troll that completely ignores the original posts to start some trouble?
PS we are on page 2 now if you know how to tweak your forums views...
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
|
|
|
bike_power
|
| posted on 3/1/07 at 10:01 PM |
|
|
quote:
Originally posted by G.Man
bike_power, may I ask you what your experience is?
you post anonymously and dont appear tobe building anything, so what exactly are your "qualifications"
I mean you patronise in the extreme, read the bits you choose and interpret them in a twisted manner to make your arguments seem stronger..
Then you post a number of pathetic cartoons to try and belittle me..
So come on, I have openly stated my experience here, so give me yours...
or are you just a troll that completely ignores the original posts to start some trouble?
PS we are on page 2 now if you know how to tweak your forums views...
Give up, it's you who have not read a single word that other people have posted and you've even changed what you post to suit the wind -
you even contradict yourself and forget what you've said but still want me to explain further. It's not going to happen.
You've not read what I've posted already so why would I post anyting else ?
The cartoons are from Pistonheads and they're not cartoons, they are emoticons. They are very common and I didn't create them. Have a
look at www.pistonheads.com - it's a good site.
The bangs head on wall emoticon represents the feeling you get when, for example, you're having a battle of wits against an unarmed man.
The punching emoticon represents, well, you can guess that surely ?
Don't get so would up, it's all a laugh, have fun. A ZX12 doesn't have enough torque to get wound up over does it
I'll have to torque to my Doctor about this
Oh dear, time for bed
|
|
|
