I thought that if you had more torque at lower rpms you had a broader powerband of high rpm.
Surely torque means something - horsepower is a function of torque.
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I thought that if you had more torque at lower rpms you had a broader powerband of high rpm.
Surely torque means something - horsepower is a function of torque.
[QUOTE=Kitdy;786012]I thought that if you had more torque at lower rpms you had a broader powerband of high rpm.
Surely torque means something - horsepower is a function of torque.[/QUOTE]
Torque = rotational force = force along a lever arm, which = force times lever arm.
In other words, how much force does it take to get moving.
[QUOTE=Kitdy;786012]I thought that if you had more torque at lower rpms you had a broader powerband of high rpm.
Surely torque means something - horsepower is a function of torque.[/QUOTE]
Rear wheel torque at ANY drive wheel speed is dictated solely by engine HP, as determined by the selected gear ratio.
The links I posted make that quite clear.
The only real argument for "torque" in high performance applications is that a very "torquey" engine can provide a flatter power curve and therefore fewer gear ratios and fewer gear changes.
In practice that argument is generally moot, since high rpm, low torque, high HP engine are generally lighter (e.g. Acura V6 vs. a 1969 Cadillac pushrod V8) and can use lighter driveline components due to their lower torque output. The resulting weight savings translates to a lighter car, which in turn offsets the flatter power curve advantage.
That's how that low torque (and quite heavy) BMW convertible manages to run with the "legendary" 1970 GM "muscle cars" in the link I posted.
What the American Lemans series and you'll see this in practice The torque monster Audis (roughly 800 FT-LB of torque feom their big turbo diesels) racing in P1 often times can't shake the high revving, low torque P2 cars (e.g. Penske Porsche).
One must consider all variables (HP, gearing, vehicle weight, etc.) in order to appreciate the big picture.
High torque, low revving engines are beneficial in heavy duty applications involving high loads and long miles (e.g. 18 wheelers). That torque also helps "coming off the line" in that scenario, since dumping the clutch in a loaded down 18 wheeler would produce broken parts and expensive repairs. High torque can also allow for easier throttle modulation during very low speed driving (e.g. rock crawling off road), although modern throttle controls (electronic) can compensate for that to a large degree.
[QUOTE=kingofthering;786018]Torque = rotational force = force along a lever arm, which = force times lever arm.
In other words, how much force does it take to get moving.[/QUOTE]
Even that isn't entirely true, since one can simply "dump the clutch" (or torque brake an automatic) in a high HP, low torque powered car (e.g. formula 1) and burn huge slicks for a hundred feet or more from a dead stop.
The engine is only part of the equation; well suited gearing and a talented driver are two others.
[QUOTE=harddrivin1le;786038]Rear wheel torque at ANY drive wheel speed is dictated solely by engine HP, as determined by the selected gear ratio.[/QUOTE]
I understand.
I also understand that engine hp is a function of torque and rpm.
If you have high torque at low rpms, then it serves to reason that you will have higher hp at lower rpms and thus more wheel torque - which means higher wheel torque across the revband.
[QUOTE=Kitdy;786044]
If you have high torque at low rpms, then it serves to reason that you will have higher hp at lower rpms and thus more wheel torque - which means higher wheel torque across the revband.[/QUOTE]
You are ignoring the huge importance of transmissions and gears, as explained here:
[url]http://i218.photobucket.com/albums/cc136/harddrivin1le_album/HPTORQUEEXAMPLE.jpg?t=1203626480[/url]
You are also ignoring the weight advantage enjoyed by lower torque, higher revving engines, which generally results in a vehicle with a superior power to weight ratio vs. "the same car" fitted with a torque monster engine of the same peak power output.
My 2007 Acura 212 CID V6 TL Type S automatic weighs 3,680 pounds and will break the front tires (235/45-17) loose with virtually no effort from a dead stop. Peak engine torque is just 256 FT-LB at a high 5,000 RPM.
That's moot, since the car produces 286 certified SAE NET HP and Acura specifies a transmission with well suited gearing.
[QUOTE=harddrivin1le;786047]You are ignoring the huge importance of transmissions and gears, as explained here:
[url]http://i218.photobucket.com/albums/cc136/harddrivin1le_album/HPTORQUEEXAMPLE.jpg?t=1203626480[/url]
You are also ignoring the weight advantage enjoyed by lower torque, higher revving engines, which generally results in a vehicle with a superior power to weight ratio.
My Acura 212 CID V6 TL Type S automatic weighs 3,680 pounds and will break the front tires (235/45-17) loose with virtually no effort from a dead stop. Peak engine torque is just 256 FT-LB at a high 5,000 RPM.[/QUOTE]
I'm not ignoring that at all. I'm not even saying that torquey engines are better.
I'm just trying to say that engines with high torque output have higher low rev horsepower.
[QUOTE=Kitdy;786054]I'm not ignoring that at all. I'm not even saying that torquey engines are better.
I'm just trying to say that engines with high torque output have higher low rev horsepower.[/QUOTE]
Yes, they have higher low rev horsepower. You are correct in that.
But it's essentially moot once transmissions are included in the system, as is the case with virtually every car ever built.
And the high torque engine generally adds a weight penalty, which adversely impacts total vehicle performance.
I have had "torquey" cars (e.g. my '86 and '88 5.0 Mustangs - 285 FT-LB and 300 FT-LB Net, respectively) and I have had "torqueless" cars (e.g. my '06 Honda Accord - just 211 FT-LB of torque and virtually identical in weight to the Mustangs).
That real world experience backed the physics - the Accord (244 HP vs. 200 HP /225 HP) was the faster car - as long as it was properly driven. The Mustangs "felt" stronger in around town, low rpm chugging, but that feeling proved false once the hammers were dropped and the cars were properly shifted.
[QUOTE=harddrivin1le;786059]Yes, they have higher low rev horsepower. You are correct in that.
But it's essentially moot once transmissions are included in the system, as is the case with virtually every car ever built.[/QUOTE]
In first gear going off the line where a bulk of 0-100km/h acceleration is done I can see the benefit of a high torque engine - it may be heavier, but the tradeoff is something I am not sure about exactly.
'
Even with transmissions though, accelerating through the gears, it seems as though it would be helpful to have a lot of torque.
Furthermore, there are certain engines, such as the LSx engines that have high torque and are relatively lightweight.
I'm gonna look for the new M3's enigne weight in comparison with the LS7s.
[QUOTE=Kitdy;786063]
Even with transmissions though, accelerating through the gears, it seems as though it would be helpful to have a lot of torque.
[/QUOTE]
[QUOTE=Kitdy;786063]
I'm gonna look for the new M3's enigne weight in comparison with the LS7s.[/QUOTE]
It weighs 445 pounds, which is roughly 30 pounds lighter than the LS7: [url=http://www.germancarzone.com/3-series/19994-detail-m3s-v8-engine.html]In detail: M3's V8 engine - German Car Zone[/url]
And it only makes [COLOR="Red"]295 FT-LB of torque[/COLOR] (in a [COLOR="Red"]3,600 pound car[/COLOR]). But it makes 414 HP, is appropriately geared and therefore runs [COLOR="Red"]0 - 60 MPH in 4.3 seconds[/COLOR] and does the [COLOR="Red"]1/4 mile in 12.8 @ 113 MPH[/COLOR] (source: CAR AND DRIVER).
[COLOR="Red"]That's virtually identical to this 2005 LS2 (400 HP/[B][I]400 FT-LB [/I][/B]of torque) Corvette that is 320 pounds LIGHTER!!!!![/COLOR]
[url=http://www.caranddriver.com/reviews/comparison_test/coupes/almost_supercars_comparison_test+page-5.html]Almost Supercars - Comparison Test / Coupes / Comparison Test / Reviews / Car and Driver - Car And Driver[/url]
Why are you trying to fight the laws of physics? "Big Torque" by itself means nothing. Power to weight (and gearing) means everything - at least for the purpose of this discussion.
[QUOTE=harddrivin1le;785910]Saying it won't make it so and neither will the words of another ignorant person - particularly when the opposite can be readily proven by real world examples and some basic physics.
This BMW M3, for example, is very comparable to the Buick in terms of both ACTUAL power (333 NET HP) and weight (3,838 pounds curb) and is therefore very comparable in terms of acceleration (1/4 mile 13.7 @ 104 MPH) - despite the fact that it produces a mere 262 FT-LB of torque. [I][U]The BMW is actually FASTER than the '70 Olds W30 and the '70 Pontiac GTO 455!
[/U][/I]
[url=http://www.caranddriver.com/reviews/hot_lists/high_performance/sports_car_central/bmw_m3_convertible_short_take_road_test+page-2.html]BMW M3 Convertible - Short Take Road Test / Sports Car Central / High Performance / Hot Lists / Reviews / Car and Driver - Car And Driver[/url]
You should recognize this, since you posted the very same image (from "Hot Cars" magazine) not all that long ago in another thread when attempting to prove how incredibly fast those cars were.
The reason that is so is explained here for the benefit of those who are able to read and comprehend some basic math:
[url]http://i218.photobucket.com/albums/cc136/harddrivin1le_album/HPTORQUEEXAMPLE.jpg?t=1203626480[/url]
[url=http://www.v8914.com/Horsepower-v-torque.htm]Horsepower v torque[/url]
[url=http://www.yawpower.com/tqvshp.html]Yaw Power Products / Where Performance Meets Technology[/url]
[url]http://www.mustangsandmore.com/ubb/DanJonesTorqueVsHP.html[/url]
[url=http://www.mazda6tech.com/index.php?option=com_content&task=view&id=9&Itemid=52]Mazda6Tech - Horsepower, Torque, and Gearing[/url]
[url=http://www.houseofthud.com/cartech/torqueversushorsepower.htm]Yet another guide to Torque versus Horsepower versus Acceleration[/url][/QUOTE]
Just think how much modern tires would have helped the E.T.s on those 1970 muscle cars.
And don't give me any "tires don't make much difference" baloney!
An article on street racing back in the the '60s involved a '60s muscle car with the stock '60s tires. I think it was a '69 Plymouth GTX 440 with 4.10 gears. They author said it beat all the other cars he raced [I]except those which were running slicks[/I]. He also said that the owners of muscle cars running stock tires were having just as much a problem of getting them to hook (get traction) as he was.
Here is a portion of another street race (again, back in the '60s):
The car was another '69 Plymouth GTX with 440...
"We make the first U-turn and go right back in line next to a '75 Firebird. The car sounds healthy enough. The Bird does about 15 short burnouts. Not to be outdone much less taken out of the hole, we counter with another long smokey one and back up to the starting line.
The Bird cuts loose with two horrendous smokies and it's my turn to wait while he chirps and hops all over the place. One of us is going to have to break the ice so we sit there and wait for the Bird to finish getting even with us.
We both break. Just as we thought, he grabs two lengths on us [B]while we sit there burning rubber[/B]. But as soon as the X hooks, it is search and destroy time. We march past the Bird at half track, like let's hear it for mid-range."
The Firebird took him out of the hole because he did the last burnout and his tires had better traction than the GTX, of which the tires had cooled considerably waiting for the Firebird to stage.
[QUOTE=Fleet 500;786088]Just think how much modern tires would have helped the E.T.s on those 1970 muscle cars..[/QUOTE]
Essentially irrelevant in terms of TRAP SPEED, which dictates ET potential. You'd already know that if you didn't have a learning disability, since I've already explained it as least 20 times to you.
[COLOR="Red"][B]THE ET-TO-TRAP SPEED RATIOS OF THOSE 1970 GM "muscle" CARS ARE FULLY IN LINE WITH THOSE OF MODERN CARS, INDICATING THAT TRACTION WAS COMPARABLE.[/B][/COLOR]
Plus, many of the muscle cars were fitted with SLICKS for magazine tests.[I] One test you posted said the slicks made their Hemi test car BOG due to its lack of torque.;)[/I]
This BONE STOCK 426 Hemi tester was fitted with 9" wide drag racing slicks; it also had a limited slip diff. - as did every street hemi car - and a 4.56 axle ratio!!!!. That 6 cylinder, 3830 pound BMW M3 is still essentially as fast as that "mighty hemi" and the new V8 version (with just 295 FT-LB of torque) would simply eat it alive:
[img]http://i218.photobucket.com/albums/cc136/harddrivin1le_album/HEMI323vs456rev.jpg?t=1203649439[/img]
Oh, brother!
1960s slicks, like the ones you post in the Hemi test, are NOTHING like modern slicks! I've even heard that the best radial tires today were as good, if not even better, than some of the '60s slicks!
The G.M. test cars were not running slicks; why you post an irrelevant Hemi test is beyond me.
And AGGGGGGGGAIN with old VS new? Don't you ever change that record?!?
Are you really going to claim that the '60s muscle cars running stock tires had no traction problems? HAH!
[QUOTE=Fleet 500;786095]Oh, brother!
1960s slicks, like the ones you post in the Hemi test, are NOTHING like modern slicks! I've even heard that the best radial tires today were as good, if not even better, than some of the '60s slicks!
The G.M. test cars were not running slicks; why you post an irrelevant Hemi test is beyond me.
And AGGGGGGGGAIN with old VS new? Don't you ever change that record?!?
Are you really going to claim that the '60s muscle cars running stock tires had no traction problems? HAH![/QUOTE]
I posted many examples of "stock" muscle cars fitted with "modern radials" on the other thread (e.g. 428 BLOATBRA JET Mustangs, 427 Yenko Camaros, etc.. They made virtually no difference relative to the original road test data.
You'd know that by now if you weren't [edited].
Here is the Yenko yet again - fitted with beefy "modern radials." It ran 0 - 60 MPH in 5.8 seconds and ran the 1/4 mile in 13.7 @ 107 MPH - WITH HEADERS AND A MODERN EXHAUST SYSTEM!!!!
[url=http://www.sportcompactcarweb.com/features/0307scc_1969_yenko_camaro/index.html]1969 Yenko Camaro 2 Fast 2 Furious Sport Compact Car[/url]
And if the old slicks sucked then why did they have enough grip to make the mighty hemi BOG in that road test you posted?:confused:
[COLOR="Red"][B][I]YOU HAVE YET TO POST A SINGLE SHRED OF EMPIRICAL DATA PROVING THAT "MODERN RADIALS" YIELD A SIGNIFICANT IMPROVEMENT IN MUSCLE CAR PERFORMANCE, RELATIVE TO THE OEM "WIDE OVAL" BIAS PLIES THAT WERE USED IN THE LATER YEARS (e.g. '69 - '71).[/I][/B][/COLOR]
In most cases, the tires of the era were fully adequate for the low powered engines and the limited slip differentials to which they were connected in the various "magazine cars."
P.S. Modern 2WD performance cars have traction problems, too. You'd know that if you'd ever driven one.
Are you serious? Those 9-inch slicks in the '60s are actually skinnier than some of the modern radial tires! I see wider radials tires at the weekly car gathering!
And you really think that Yenkos only run 13.7s? LOL!!!!!!! Did the driver forget to shift out of 2nd gear?
If someone wanted to run your car (or if you had a '60s muscle car) at a track and you had a choice of using '60s bias plies or modern radials, what would you pick?