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What are Torque and Horsepower really?

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stm316

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Post Mon Feb 02, 2015 6:32 pm

Re: What are Torque and Horsepower really?

The 800NM "8Lt" engine would have a painfully long stroke, and thus not rev very high, or respond quickly, so I'd bet it wouldn't be geared to allow mass wheel spin.... but I could be wrong (think Kenworth at 60KM/H)
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Post Tue Feb 03, 2015 7:30 pm

Re: What are Torque and Horsepower really?

Chevy LS7 engine 7.0l 101.6mm stroke, max rev 7000. Max torque =640 nm
Dodge Viper engine 8.4l 100.6mm stroke, max rev 6200. Max torque = 813nm


So, why would a 8 liter engine have PAINFULLY long stroke? And not rev very high? Low responce?
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Post Wed Feb 04, 2015 7:14 am

Re: What are Torque and Horsepower really?

RobtheFiend wrote:Chevy LS7 engine 7.0l 101.6mm stroke, max rev 7000. Max torque =640 nm
Dodge Viper engine 8.4l 100.6mm stroke, max rev 6200. Max torque = 813nm


So, why would a 8 liter engine have PAINFULLY long stroke? And not rev very high? Low responce?


These are pushrod engines and because of that they are inherently limited to lower RPMs than a typical SOHC/DOHC setup UNLESS they are VERY well engineered. These two engines would be in that category, the Vipers V10 doesnt really have a "painfully" long stroke, its bore is actually larger than the stroke 4.055"x3.96" while the LS7 has a bore & stroke of 4.125"x4.00", to me these are engines that are quite "square" and not overly stroked. The main limitation for the LS7 is not due to the stroke but due to: "During GM's reliability testing of this engine in its prototype phase, the LS7 was remarked to have been repeatedly tested to be 8000 rpm capable, although power was not recorded at that rpm level, due to the constraints of the camshaft's hydraulic lifters and the intake manifold ability to flow required air at that engine speed." For the Vipers engine I would say its biggest limitation is also not the stroke but the fact that its engine design dates from the 1960s and is limited by its pushrod configuration.
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Post Fri Mar 13, 2015 8:06 am

Re: What are Torque and Horsepower really?

Daffyflyer wrote:There are a lot of misconceptions around torque and horsepower. If you're still a bit puzzled after Robbo and Stevo's explanation, I suggest a read of this.

http://hooniverse.com/2010/01/14/dont-b ... -it-means/

for newbies the best explain is. Horsepower=Speed and Newton-Meter= acclration
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Post Fri Mar 13, 2015 8:14 am

Re: What are Torque and Horsepower really?

Jakop750 wrote:
Daffyflyer wrote:There are a lot of misconceptions around torque and horsepower. If you're still a bit puzzled after Robbo and Stevo's explanation, I suggest a read of this.

http://hooniverse.com/2010/01/14/dont-b ... -it-means/

for newbies the best explain is. Horsepower=Speed and Newton-Meter= acclration



Errr. No.

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Post Mon Mar 30, 2015 11:41 am

Re: What are Torque and Horsepower really?

I've been away for a full year and people still don't understand HP and torque?

Let me find a wall to bang my head against.
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Post Mon Mar 30, 2015 12:42 pm

Re: What are Torque and Horsepower really?

PhillipM wrote:I've been away for a full year and people still don't understand HP and torque?

Let me find a wall to bang my head against.



But remember, you need lots of torque to successfully knock yourself unconscious. Also welcome back!
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Post Tue Mar 31, 2015 12:52 am

Re: What are Torque and Horsepower really?

Need a lot of horses output to post some of the stuff on torque though....:D
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Post Sun Aug 02, 2015 10:35 am

Re: What are Torque and Horsepower really?

1 more thing about torque I don't think anyone really mentioned. With higher torque numbers you can space gear ratios further apart, so you can 'jump ratios' faster. That (in my understanding) is due to the engine being able to handle that load better then given lower torque engine with same hp.
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Post Wed Aug 12, 2015 10:11 pm

Re: What are Torque and Horsepower really?

Found this quick but interesting and relevant article. On butt dynos, torque, and gearing. http://www.roadandtrack.com/car-culture/features/a25271/fool-your-butt-dyno-for-fun-and-profit/
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Post Tue Sep 22, 2015 3:12 am

Re: What are Torque and Horsepower really?

Arse dyno's, unless very finely calibrated, (lets put it this way, I work with a lot of racers, I trust one of them to give me accurate arse dyno feedback. One) feel the change in acceleration, acceleration squared, effectively. Which is why engines with a broad spread of torque (S2000, RX8), get blasted by idiots on the internet for being torqueless. Because they can't feel a constant surge, they're waiting for a kick that never comes.
To the extent that Honda actually deliberately put a dip in the torque with the S2000 so that when it kicked back in again you got to go VTEC YO!

Engines with inconsistant torque curves that suddenly jump up and drop off (big turbo's, etc), feel fast because the rapid change in the acceleration of the acceleration. Even if they're not.
I can make your car feel a lot faster with the engine mapping even when it's actually going slower by putting ramps in the torque curve - a fact many flight-by-night chipping/remap firms exploit.
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zag

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Post Sun Jan 24, 2016 3:20 pm

Re: What are Torque and Horsepower really?

It's a shame, you completely disregard diesel engines. Which actually put their "power" as the torque they produce rather than HP which is a lot lower than petrol motors, a 2000lb/ft diesel will blow the doors off any petrol motor on the dyno. even though it could be a 1000HP motor.
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Post Mon Jan 25, 2016 7:40 am

Re: What are Torque and Horsepower really?

zag wrote:Which actually put their "power" as the torque they produce rather than HP which is a lot lower than petrol motors

No they don't. Read and look at the various links posted in this thread, you are spewing nonsense.
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Post Wed Jan 27, 2016 10:19 am

Re: What are Torque and Horsepower really?

easy, horsepower is torque times RPM divided by 5252.

I have made a gasoline/petrol engine that has efficiency as good as diesel and a torque curve just as good. Using premium gas.
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isomgmsghs

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Post Wed Jan 27, 2016 11:27 am

Re: What are Torque and Horsepower really?

I also just made a replacement for the factory Cummins 4BT engine, originally 265 TQ at 1600 RPM and 105HP at 2500 RPM.
This gasoline version has 45% more torque at 1600rpm and 140% more HP at 4000RPM. same bore and stroke. nearly same efficiency.
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