Torque

[Carfreak9922]

I have a question if the m3 has less torque than the 335i wouldnt that make the 335i a close competitior?

dumb question...

just wondering

http://www.bmwusa.com/Standard/Conte...e/default.aspx

[ihyln]

hmm.. which icon to use...

or or... no wrong forum icon. This will have to do:

[armyav8tor]

Originally Posted by Carfreak9922

dumb question...

You said it yourself. Torque is for towing, HP is for racing.

[sg///M3]

Originally Posted by armyav8tor

You said it yourself. Torque is for towing, HP is for racing.

I always thought torque was for acceleration and HP determines top speed.

[Davinhci]

not again

[Manny212]

lol i love these threads...ok i'll keep it simple. Yes, the 335 has more torque but less HP. But the M3's max torque is in effect from like the 3k rpm range until redline and reaches max hp at 8400 rpm. The 335 redlines somewhere around 7k i believe and produces less engine speed. I've had a few drinks and that's all i can say. M3 in the end is faster against a stock 335

[Keto]

Originally Posted by Carfreak9922

dumb question...

I just watched the end of Zoolander and this post makes Zoolander look smart.

[Hammer]

dont mind the flame...

afaik you have the acceleration, as mentioned earlier in this topic, by torquere for at a longer powerband in the m3 than in the 335.

Just the peak-torqure is higher but the m3 revs with nearly the same torque from 4-8k rpm and when you downshift you keep in this torque-band

i m not sure about this, maybe swamp or another Pro may help here

[southlight]

I can't remember how many times this topic has been discussed. Just search for it.

A short summary: Due to the differing transmission ratios the M3 provides more torque at the wheels than the 335 once the rpm is over 1500 rpm. Lucid made some great charts/graphs based on his calculation showing this:







/thread


Best regards, south

[hakaida442]

Originally Posted by Carfreak9922

I have a question if the m3 has less torque than the 335i wouldnt that make the 335i a close competitior?

dumb question...

just wondering

http://www.bmwusa.com/Standard/Conte...e/default.aspx

[adamr]

hey what you guys had for supper last night?

[footie]

The reality is that BMW themselves admit the M3 is quicker in the in-gear acceleration in 4th gear.

4th 50-75mph
M3 = 4.9s vs 335i = 5.2s

I think the preception of speed is with the 335i because of the surge of torque when the turbos spool up against the smoother increase of torque that the M3 has. It part of the reasons why I enjoy turbo engines, you get all the thrill without the speed.

[rai]

Originally Posted by sg///M3

I always thought torque was for acceleration and HP determines top speed.

dear lord.

F1 cars have ~800hp but less TQ than many street cars. Guess that would mean F1 cars are slow (right?).

You have to figure gearing and TQ at the wheels. If a F1 engine turns 19,000 a minute it is using the TQ more often. It's why HP is a function of TQ AND RPM.

The power a Formula One engine produces is generated by operating at a very high rotational speed, up to 20,000 revolutions per minute (RPM). This contrasts with road car engines of a similar size which operate safely at typically less than 7,000 rpm. However, the torque (turning force at a given speed) of a Formula One engine is not much higher than a conventional petrol engine. For example, the 2006 2.4 litre Toyota RVX-06 V8 engine produces (740 bhp) at 19,000 rpm and outputs 274 N·m (202 ft·lbf) of torque

[J08M3]

Originally Posted by rai

dear lord.

F1 cars have ~800hp but less TQ than many street cars. Guess that would mean F1 cars are slow (right?).

You have to figure gearing and TQ at the wheels. If a F1 engine turns 19,000 a minute it is using the TQ more often. It's why HP is a function of TQ AND RPM.

Exactly, HP is a function of TQ

[bruce.augenstein@comcast.]

Originally Posted by Carfreak9922

I have a question if the m3 has less torque than the 335i wouldnt that make the 335i a close competitior?

dumb question...

just wondering

http://www.bmwusa.com/Standard/Conte...e/default.aspx

Behind the wheel, the 335i does indeed feel a bit livelier than the M3 in everyday driving, and in fact it probably really is livelier. This point has been debated at great length in these pages, both with and without rancor, but the primary point is, as footie has said, "you get all the thrill without the speed" in the turbo car. To the driver, the 335i feels effortless, since you can give it gas at low rpm in a higher gear and the car will pull very hard without the sturm and drang associated with high revs. By contrast, the M3 will actually be quicker from pretty much any speed to any other speed, but because of its gearing, you will always be looking at greater revs, and the associated feel to the driver of greater effort.

In regard to horsepower vs torque, quite simply horsepower rules. Take any two cars that weigh the same, and in a side-by-side acceleration contest, the car with more horsepower at any given point will be accelerating harder than the car with less horsepower. Torque and gearing simply don't matter at all. In fact, horsepower is kind of a simple shorthand in that context. You can do all that computing of torque at the drive wheels if you like, but you'll find that more power equals more torque at the drive wheels, pure and simple.

I've used an example of a waterwheel generating some 2600 pound feet of torque - at 12 rpm. If you hooked that waterwheel to the drive wheels of a car, that car would jump from zero to 12 rpm of the drive wheels very quickly. But since 12 rpm of the drive wheels is equivalent to about one mph, what if you wanted to go faster?

Well, you'd have to gear it up. If you wanted to go 60 mph you'd need to gear the waterwheel up by 60 times - thus netting you about 43 pound feet of torque at the drive wheels. 43 foot pounds of forward thrust in a car weighing thousands of pounds just isn't enough to get the job done. In fact, it almost certainly isn't enough to overcome wind and rolling resistance at that speed. If you do the math (horsepower equals torque times rpm over 5252), you'll find that the waterwheel is only making about 6 horsepower.

The solution would be to speed the waterwheel up. Using a convenient flood (and assuming the waterwheel wouldn't fly apart), what if we could speed the water wheel up to, say, 120 rpm, while making the same amount of torque?

Well, the car would then be going 12 mph. Gearing it up to go 60 mph would now reduce the drive wheel torque to about 520 pound feet. That's still not a lot, but it's plenty to keep the car rolling at 60, and you could probably still accelerate at that speed. Doing the math shows, TA DA!, about 60 horsepower - so you can see that raising the rpm by a factor of ten gives you an increase in power by a factor of ten.

In fact, that's the horsepower story. It's torque at rpm. Raising the rpm at which torque is delivered gives you more power by a like amount - and more power gives you a greater ability to accelerate, period.

Bruce

Edit: PS - For a more complete explanation of power vs torque, go here, in note 31.

[rzm3]

HP = torque x rotational speed (both have be in correct units of course)

HP does determine top speed. However, because most road car engines rev to 7000-8000 rpm, a car that has higher HP would usually have higher torque as well.

Yes 335 does have higher torque (300ft lb vs. 295ft lb), but you need to think percentage, which is only 1.67%. And the M3 has much higher torque at wheel.

[J08M3]

Originally Posted by bruce.augenstein@comcast.

In regard to horsepower vs torque, quite simply horsepower rules. Take any two cars that weigh the same, and in a side-by-side acceleration contest, the car with more horsepower at any given point will be accelerating harder than the car with less horsepower. Torque and gearing simply don't matter at all. In fact, horsepower is kind of a simple shorthand in that context. You can do all that computing of torque at the drive wheels if you like, but you'll find that more power equals more torque at the drive wheels, pure and simple.

For the street I totally disagree with you. Reason being it's not very practical to be at a high RPM all the time while driving around town. In fact I almost find it impossible in city driving to get much over 6,000 RPM in my M3. If I didn't have any torque/not making any power below that this car would be ridiculous to have as a street driven car.

[bruce.augenstein@comcast.]

Originally Posted by J08M3

For the street I totally disagree with you. Reason being it's not very practical to be at a high RPM all the time while driving around town. In fact I almost find it impossible in city driving to get much over 6,000 RPM in my M3. If I didn't have any torque/not making any power below that this car would be ridiculous to have as a street driven car.

You say you "totally disagree", but you can't since it's simple physics I'm talking about. As for keeping your M3 above 6000 rpm, there's no need. The more aggressive gearing of the M3 means it'll be making more power than the 335, even in street driving. As lucid has pointed out (and he's quoted in this string), the M3 has the torque-at-the-drive-wheels advantage even in everyday types of driving.

Bruce

[Artz 330]

Originally Posted by J08M3

For the street I totally disagree with you. Reason being it's not very practical to be at a high RPM all the time while driving around town. In fact I almost find it impossible in city driving to get much over 6,000 RPM in my M3. If I didn't have any torque/not making any power below that this car would be ridiculous to have as a street driven car.

for example: an S2000 below 6,000

[lucid]

Originally Posted by Artz 330

for example: an S2000 below 6,000

I don't get this. Are you saying the S2000 doesn't make power until 6000 rms and all of a sudden it makes a ton of power (apart from the fact that power will increase almost linearly with engine speed for a relatively flat torque curve)? That can only happen if you have a reaaally skewed torque curve, where torque itself climbs significantly with rpms. The S2000 actually has a pretty flat torque curve. It does start to breathe better after 6000 rpms, but that's only a 10% or so increase in engine torque. My point is all engines will make more power at higher engine speeds until they run into breathing/combustion problems--unless they have really uneven torque output over the rev range--and that's by definition.

I would be very interested in knowing how the torque curve of the BMW ALMS V8 looks like by the way. Anyone aware of any data on that (I'm sure it's not out there)? Any guesses Bruce? Apparently, it's redline won't be higher than the stock V8, but it does produce an "estimated" peak 485 hp and peak 376 ft x lb.

[J08M3]

Originally Posted by bruce.augenstein@comcast.

You say you "totally disagree", but you can't since it's simple physics I'm talking about. As for keeping your M3 above 6000 rpm, there's no need. The more aggressive gearing of the M3 means it'll be making more power than the 335, even in street driving. As lucid has pointed out (and he's quoted in this string), the M3 has the torque-at-the-drive-wheels advantage even in everyday types of driving.

Bruce

exactly, there is no need because it makes enough torque. You can get a car to move with very little torque if geared correctly, the engine would be screaming though and not practical to drive around town.

[BMW-videos.com]

I don't get it. Are some of us trying to say torque isn't too important? How about when you're coming out of a sharp turn? If I recall correctly, the AUDI R10 is destroying the competition in lemans because of all the torque its twin turbo diesels produce. if you can hook, low rpm torque will catapult you out of corners. IMO, f1 cars have so little torque because there engine displacement is so highly limited. To make the horsepower and torque they have to rev to 19,000rpm plus period or else they wouldn't make the power. I'm sure if they weren't so liter limited you could have F1 cars that could run endurance races (since current engines will not withstand extremely long durations). What would an f1 car with a 7 liter engine and almost seamlessly fast shifting be like? I think if useable that torque will fling them out of corners at dangerous speeds. I think torque is underestimated.