Horse Power and Torque

[Pro]

holy thread revival batman!

 

[jibbby]

Gotta revive a few these oldies but goodies every now and then.....

 

[gte]

This may have been answer already, but I'll give it my shot (even though it is a thread revival and I didn't re-read the whole thing)


When the 1uz makes more torque then horsepower, it means that engines peak VE is below 5252 rpms. This can be affected by modifications, torque converter and transmission.

An n/a vs fi will definitely have different ratios, forced induction cars almost always create maximum hp 500 to 1000 rpms before redline (with properly sized and properly working components), and on most cars this is after 5252rpms, I would imagine on most f/i 1uz's, the redline would be equal to or higher then 6500rpms anyway.

A supercharged vehicle (there are 3 types of superchargers, will stick with the one most similar to the turbocharger, the centrifugal supercharger) will be different then a turbocharged vehicle. Since a turbochargers boost is not limited by crankshaft revolution speed, it can make much more midrange torque through the midrange area of the rpm cycle ... a turbocharger is also more efficent in compressing the air, then even a centrifugal supercharger.

Hopefully that makes sense ...

For the 4.0 liter, some members dyno with great torque and some dyno with greater hp. Is there an explaination of these outcomes? What does it mean when the dyno shows more torque than HP and what does it mean when HP is greater the torque? Would the NA and FI have different ratios or would a supercharged system be different then a turbo system?

 

[jibbby]

So then Torque ratings on a dyno test can be changed thru the stall rate change of a torque converter and or transmission, differential gearing mod's?

If that is the case then going from a stock SC400/Soarer torque converter stall rate to let's say a stall rate T.C. of 2200 will increase the torque numbers and decrease the whp's numbers on a before and after dyno test.. Is that right? Same as let's say a lower rearend differential gearing change, I would assume...

Same dyno numbers with different curves or different dyno numbers with different curves with those changes?

That was really the most recent question asked on this thread

 

[gte]

The problem with an auto is that it will downshift, but lets say you could lock it in gear and not have it downshift

If the rpms artificially increase from the torque converter slipping, it's not going to be accurate until it locks

If the converter was less efficient, then it would decrease overall numbers

I think I am understanding your question, if not let me know and try asking a different way?

So then Torque ratings on a dyno test can be changed thru the stall rate change of a torque converter and or transmission gearing mod's?

If that is the case then going from a stock SC400/Soarer torque converter stall rate to let's say a stall rate T.C. of 2200 will increase the torque numbers and decrease the whp's numbers on a before and after dyno test.. Is that right? Same as let's say a lower rearend differential gearing change, I would assume...

Same dyno numbers with different curves or different dyno numbers with different curves with those changes?

That was really the most recent question asked on this thread

 

[MikeMan]

well, thats not really true, even if the trans is 1:1 the diff still isnt. and transmission ratios dont take into accont the diffs ratio, i dont think its possable to really get any stock car to spin the wheels at a true 1:1 ratio with the crank. even cars that have really high overdrives the wheels arnt spining faster then the motor. for example the V160's 6th gear ratio is 0.793:1 but the supra diff ratio is still 3somthing:1 so there is some mutiplication, i believe most people dyno in 3rd gear so its even further from 1:1 ive never seen someone try to dyno a mkiv supra in 6th before.
an engine dyno would be true 1:1 becouse the dyno is directly linked to the crank unless there are gears inside it.

Probably the closest you will get to 1:1 on a stock petrol vehicle is a 1993 F Body with its 0.62:1 top gear and 2.73:1 Final drive, but even that supplies a total ratio of 1.69:1

 

[shoryu]

I hope because this thread is relatively recent, I won't get shot in or about my face area for posting in it, but for the question of power and torque peaks, the answer is relatively simple. With a higher power peak than torque peak, what is going on is that the engine can breathe well above 5252 rpms and so the torque doesn't drop off so much after said RPM. This, through the wonderful arena of math, allows for more power to be developed at a higher rpm because the horsepower formula leans indicates 'more torque at higher rpm equals more power' i.e. 'a '95 1UZ makes 234 lb-ft of torque at 5600 rpm, making for the rated power peak of 260 hp. If we could some how make that same 234 lb-ft of torque at, let's say, 7500 rpm (oh goodness) the power peak at that rpm would now be be 334 hp, just from extending the engine's band of efficient breathing.
Now, for the more torque than power, it's the opposite, the engine just doesn't breathe that well over 5252 rpm, limiting the extension of the torque band, thus limiting horsepower. As for different forms of forced induction, all of them will give you more torque than horsepower out of the 1UZ unless you free up the breathing of the engine above 5252 rpm, which I guess is what some of those people from that link in the 7th post did. Mk, well that's my piece and my first post as well.

 

[jibbby]

How does one free up the breathing on an 1uz-fe to increase the horsepower and torque at higher rpm's? I would say Intake, heads, exhaust, and cam mods takes care of the motor... Gearing too has alot to do with higher rpm power when the car is in motion especially if it is equiped with an automatic tranny...Differential gearing and Torque Converter stall rates are big....

 

[cribbj]

Nice articles in AutoSpeed recently on the Torque vs HP debate:

Part 1: http://autospeed.com/cms/A_108647/article.html

Part 2: http://autospeed.com/cms/A_108648/article.html

Unfortunately you need a paid subscription to get past the first page, but subscriptions are cheap and Julian's a good guy.....

 

[340i]

off topic, but, i cant believe imperial measurement is still being used in a developed nation. what a horrendous form of measurement.

 

[Toysrme]

torque will not tell me anything i want to know about a vehicle. torque is static.
horsepower is a function of torque that has been applied over both time & distance.



340i they use it because we rule the earth; not new zealand. <- true LoL!

 

[rms]

off topic, but, i cant believe imperial measurement is still being used in a developed nation. what a horrendous form of measurement.

If it ain't broke, don't fix it.
OZ, NZ, and UK shows what happens when politicians interfere with engineering.

BTW what size are the wheels on your car ??????

 

[Pro]

there's nothing wrong with imperial measurements - it's just that decimal measurements are more refined for more precise work. you can manufacture something a nanometer across, but try tooling a laser cutter for a quarter of one thousandth of an inch...

most of the nuts and bolts on the kingswood are 9/16, 3/8 and a #2 phillips. it's held together for 30odd years - metric equivelant is 14mm and 11mm.

what's the problem?

 

[cribbj]

We all like power, but it's torque that'll get the car launched smoothly.

Supra's are famous for their highend power, but they really need a bit more torque to get themselves away from the stoplights smoothly.

 

[340i]

340i they use it because we rule the earth; not new zealand. <- true LoL!

haha good point. just amagine though, one set of tools, all values are instantly obvious which is bigger/smaller than the next, no need for fractions etc.
i can see however, how the advent of SI units would be just as annoying for someone in a country not using them as the primary unit.

 

[rms]

- it's just that decimal measurements are more refined for more precise work. you can manufacture something a nanometer across, but try tooling a laser cutter for a quarter of one thousandth of an inch

.00025"

Try telling that to Boeing, McDonnell Douglas, NASA, American military etc.

This is really off topic and I wont say any more

 

[camaro68]

Well stated RMS

 

[Pro]

try telling that to half the japanese computer chip producers.

decimal is easier and NASA have been using decimal since the Voyager 1 launch IIRC because CERN refused do deal with imperial.

 

[Pro]

OT now anyway :tongue2:

 

[Toysrme]

This is how the world reads your post:

haha good point. just amagine though, one set of tools, all values are instantly obvious which is bigger/smaller than the next, no need for fractions etc.
i can see however, how the advent of SI units would be just as annoying for someone in a country not using them as the primary unit.

This is how American's read your post:

blah blah blah

The simply truth is that a football field is 100 yards, not 91.44 meters. 91.44 meters = extremely non heterosexual playing field.

http://en.wikipedia.org/wiki/List_of_sports_attendance_figures

As long as NCAA Division 1-A football (highest college division) reigns supreme on that board (37mill in 2006), the US will never go metric. (NFL is 14-17mill normally)