Torque vs. Horsepower, AGAIN

I know it's been on here a million times, but I wrote a little something and I want to hear some comments. Thanks. (I might do some editing based on suggestions from another formum. I'll try to post here if that happens.)

(The original host required a password to log in, but the link should work now.)

First let me know if this (http://kevinthenerd.googlepages.com/torque_vs_hp.html) works. (Google hosting.)

If that doesn't work try this (http://www.geocities.com/k_durette/torque_vs_hp/). (Yahoo Geocities with ads.)

the link asked for username and password

the link asked for username and password
Fixed (hopefully).

very good read, the part towards the end refering to hammering nails really hits the nail on the head :naughty: but seriosuly, thats a great way to look at it

a well written piece. I would have added speed vs torque multiplication, just to make it hit home that gear changes have severe disadvantages.....but I'm nit picking

I think you should add another section. Comparing an engine with a big fat torque curve to an engine with a a slimmer torque curve but providing similar power.
In particular showing how average power throughout the rev range is so much more useful than peak power and how a fatter torque curve provides this.

Worked for me!

well written article
now post it in every forum. lol

agreed with kiwi tho on why engines with more torque feel faster than engines with peaky torque curves

anyone who has ridden in a 60s muscle car knows that even if it isnt as fast as the car in the next lane, it feels faster because the power is there throughout the powerband, whereas the vtec screamer in the next lane has the same or more peak power, but cant use it all the time and the average power is lower.

whereas the vtec screamer in the next lane has the same or more peak power, but cant use it all the time and the average power is lower.


Actually the VTEC screamer probably has more usable area under the torque curve.
The first generation B16a made 90% of its torque from 2,200 to 8,200rpm.
Mine used to pull from 30kph and 1,000rpm in 5th gear, all the way to the speed limit cut in at 180kph. With out the speed limiter it would have gone all the way to the rev cut at 242kph.

From there the VTEC engines have only gotten better in thier power delivery.


The longer and flatter the torque curve, the easier an engine is to drive.
The longer and flatter the power curve, the longer it can accelerate in any given gear.
And of course the more area under the graphs for both power and torque, the faster the car will be.

what is usually pictured as the uber-ricer car is a over-sized turbo'd import.....some 2ish liter making 400+ hp.

There is no doubt if you compare that to a 400hp pushrod NA V8, the V8 will win hands down as far as drivability, width of torque curve, etc.

As a general rule (IMO) the best street cars have at least 50% of their rev range within 20% of their peak torque. This goes for torque monster diesels, high strung turbo gas engines, or well built muscle cars. Any time you infringe on that 50% rule, you are compromising the streetability of the vehicle to make a "exobition" rig. Cool dyno charts, but not fun to drive/ride

if you can make the *UPPER* 50% of the rev-range, preferably a high redline engine......the meat of your torque curve, then you have the best of both worlds. Good drivability mated with very effective HP for the engine design

As with all aspects of engine tuning/building.....compromises are the name of the game

Actually the VTEC screamer probably has more usable area under the torque curve.
The first generation B16a made 90% of its torque from 2,200 to 8,200rpm.

That's in a stock engine. Typically, though, a modified small-displacement engine ends up with a short power band in the pursuit of horsepower. It can't make a lot of torque, so to get power it needs speed. With VTEC, you can operate on two different power bands, but you're still limited by displacement and by the maximum speed of the valve train and bottom end.

That's in a stock engine. Typically, though, a modified small-displacement engine ends up with a short power band in the pursuit of horsepower. It can't make a lot of torque, so to get power it needs speed. With VTEC, you can operate on two different power bands, but you're still limited by displacement and by the maximum speed of the valve train and bottom end.


This is true for any sized engine tough, regardless of the displacement.
At the end of the day power and torque will always be relative to displacement, the difference is how each engine makes use of he displacement it has.

Imagine VTEC implemented on a 5L, quad cam V8.
An easy 500hp with the kind of flat power curve that shreds tyres in top gear from a standing start.

hence the popularity of the Lexus DOHC V8 and Cadillac Northstar V8
actually, i believe infinity makes a OHC (either single or dual, im not sure) VVT V8 in the FX-35 and FX-45

all of these are between 3.5 and 4.8 litres and are easily more streetable and reliable than your typical american pushrod engine, while making the same power.




imo, the worst mistake GM ever made was discontinuing the LT5 in corvettes.
i know it was expensive, but it would have been an amazing engine if it had 10 more years of development

alot of manufacturers are making DOHC VVT v8s. nissan/infiniti has at least 2 in production right now, lexus has a couple, bmw, benz, ect, ect. i do like BMW's new v8/v10 that uses 100% variable valve actuation, using no cams (thats right kids).

that article is pretty basic, but is mostly true. but the examples given arent practical to everyday applications. when tuning on a dyno, you dont get to have that same kind of versatility with the drivetrain. but the same lessons apply.

I'd love to build a project car with a Toyota 1UZ-FE.

but theres no VTEC on any v8 out there. too bad because it would be badass.

not VTEC, but VVT, which stands for variable valve timing.
i imagine honda has a trademark on the name VTEC

yeah but vvt and vtec are different. all modern variable valve timing motors are just that. but vtec has variable lift control, something that noone else uses.

yeah but vvt and vtec are different. all modern variable valve timing motors are just that. but vtec has variable lift control, something that noone else uses.

I believe VVTL is toyotas name for variable valve timing and lift.

but vtec has variable lift control, something that noone else uses.

except: Mitsubishi, Toyota, Nissan, Ferrari, Porsche, and BMW.

The technology is now 18 years old in production cars, but it was over 20 years ago it was first introduced on Honda bikes.

It is now a very mainstream technology, and nothing all that different or unique.

all that vanos, vvti, mivec, ect does not have any variable lift control. its only variable intake timing control. or in some cases, both intake and exhaust timing control. BMW's new camless engines have infinitely variable cam timing but no way to alter valve lift. thats what made vtec unique.

all that vanos, vvti, mivec, ect does not have any variable lift control. its only variable intake timing control. or in some cases, both intake and exhaust timing control. BMW's new camless engines have infinitely variable cam timing but no way to alter valve lift. thats what made vtec unique.


You couldn't be more wrong.

Mivec IS VTEC. Honda licensed the technology to Mitsubishi.
Toyota also use VVTi-L = Variable Valve Timing (intelligent) - Lift. Found in the Celica, and Corrola GT.
Vanos is a variable length intake system, not sure why you mention it?
The BMW system is also able to adjust the lift and timing.
Porsche and Ferrari both use a system with a sliding cam that has lobes ramped in 3 directions instead of 2.

In 1989 when the SiR Civic and CRX were released (actualy sept 88) VTEC was pretty unique and very special.
In 1990 the NSX showed it off to the world, and in 1995 all of Honda passanger cars had some form of VTEC fitted.

But 1988 was a long time ago, and other manufacturers have caught up.

i could be more wrong. #1 bmw's camless valvetrain has no way to alter lift in any significant amount. you just cant do that with solenoids. toyota's is JUST TIMING CONTROL. trust me ive done much work on those vvti cars and they have NO ALTERNATE CAM LOBES. just to be 101% sure i went and looked under the valve cover of a blown corolla motor sitting at my shop. sure enough, they have normal cams. only intake cam timing is controlled.

i dont know about mitsubishi, you could be right on that.

toyota's is JUST TIMING CONTROL. trust me ive done much work on those vvti cars and they have NO ALTERNATE CAM LOBES. just to be 101% sure i went and looked under the valve cover of a blown corolla motor sitting at my shop. sure enough, they have normal cams. only intake cam timing is controlled.

Moppie is referring to VVTL. Note the L in the acronym which stands for "Lift".

http://www.toyota.co.nz/ToyotaTechnology/VVT-i/How+VVTL-i+Works.htm

oh ok my mistake. but there are a lot of variable valve timing mechanisms that have no effect on lift.

BMW's Valvetronic: http://www.bmwinformation.com/technology/valvetronic.html

Kind of makes VTEC look very outdated, (it is over 20 years old though).

It even includes a video for those with limited reading comprehension.

vtec has variable lift control, something that noone else uses.

Wrong.

Many other companies have technologies just as good or better than VTEC.

Wrong.

Many other companies have technologies just as good or better than VTEC.

We have just been over that :smokin:

We have just been over that :smokin:

I was concurring.

I see too many people who think VTEC is the only technology of its kind, purely because honda advertises it so much, I think.

I see too many people who think VTEC is the only technology of its kind, purely because honda advertises it so much, I think.

nah....it wasn't the advertising, it was the 15 year old kids that thought their mommies 65hp commuter car was the baddest thing they had ever driven

One of my favorite VTak satires....

http://youtube.com/watch?v=_QFbCBX8wQU

I was concurring.

I see too many people who think VTEC is the only technology of its kind, purely because honda advertises it so much, I think.

What you really mean is the dumb ricers who advertise it soo much.
Just another exmaple of a great product being ruined by a crappy fan club.:grinyes: