[Garrett]

Originally Posted by Saintor

Completely FALSE. HP is what matter for acceleration. You can have a big engine with top torque figures that will be slow as hell. Not its definition, but HP shows how quickly an engine will change RPM under load.

????

A car will accelerate almost identical to it's torque curve, the higher the delta (or it's point on the curve) the faster it will ACCELERATE. *nuttshell*

Thats why I can start from a red light in 3rd gear with my Vete because of the predigious amounts of low-end torque. It's makes driving a car and rowing the gears easier when you have a low-end car. It has GRUNT !!

[Garrett]

Originally Posted by 3aficionado

mapezzul, great info. Wish you would have put paragraphs in to make it easier to read.

HERE ; if you would like to read the whole article. It was a Corvette enthusiest the wrote it ...!

[3aficionado]

Great post Garrett.

I have a few concerns with the new engine. Hopefully the knowledgeable few on this board can elaborate on why my concerns should/should not be warranted.

1.) Reliability. I expect the engine to be a solid performer like all BMW engines. In the outside chance of problems during first year production will the US consumers have experienced technicians to fix the problems? The US BMW techs will only have classroom experience for whatever could occur. Europeans have been maintaining turbos diesels for years. I’ve experienced the lack of qualified technicians with Mercedes and worry BMW in the US could have the same issue in the first year or two.

2.) Perception. The average US consumer has a perception of a turbo engine as being unreliable in the long term. Could this high priced turbo not hold its value due to a US biased perception of turbo engine longevity?

[NaTuReB0Y]

if you don't want the turbocharged 335i....then wait for the M3 4.4L V8 425hp.....

[EnI]

Garrett, your posts are great. I like your thinking.

[mapezzul]

Originally Posted by Garrett

HERE ; if you would like to read the whole article. It was a Corvette enthusiest the wrote it ...!

You got it... i hate putting links on sites since I had gotten yelled at prior! But that was not where I actually got it from.... interesting, I had gotten it off another forum. You found the original apparently. I did not even see the charts/stuff in the middle, nice work! So can we link from here??? I posted some stuff about the Direct Injection on the other thread here about the EPA and how they don't meet the requirements so if I find the link again I was wondering of I could go back and add it?? Thanks!

[JazzEKline]

Originally Posted by Saintor

BMW has also variable timing. Most people won't agree with you as qualifying the Subaru 2.5GT as "a below average turbo".

Once again you are right. BMW does have Variable timing but you were not compairing BMW to Honda. You compaired Subaru to Honda. In that case the Subaru does not have the same engine technology as the Honda. The two engines aren't even the same layout. One is a V6 the other is a horizontally opposed boxter 4. So as I said before it is not a fair comapirson.

As far as a Subaru 2.5 turbo being below average...I stand by my claim. If you want ask people to name a car with a good turbocharged engine. I doubt SUBARU 2.5GT is going to be at the top of the list.

[Saintor]

Originally Posted by Garrett

????

A car will accelerate almost identical to it's torque curve, the higher the delta (or it's point on the curve) the faster it will ACCELERATE. *nuttshell*

No, no, no, no.

Ever tried a 1.8T? 100% of torque at 1600rpm. I can tell you that at 1600rpm, this engine has no trust and not much happens under 2500-3000much

Power is what ultimately will determine acceleration, at any speed.

[Garrett]

Originally Posted by 3aficionado

Great post Garrett.

I have a few concerns with the new engine. Hopefully the knowledgeable few on this board can elaborate on why my concerns should/should not be warranted.

1.) Reliability. I expect the engine to be a solid performer like all BMW engines. In the outside chance of problems during first year production will the US consumers have experienced technicians to fix the problems? The US BMW techs will only have classroom experience for whatever could occur. Europeans have been maintaining turbos diesels for years. I’ve experienced the lack of qualified technicians with Mercedes and worry BMW in the US could have the same issue in the first year or two.

2.) Perception. The average US consumer has a perception of a turbo engine as being unreliable in the long term. Could this high priced turbo not hold its value due to a US biased perception of turbo engine longevity?

BMW builds reliable engines and you really don't have to worry about the "tech" works because your car will be warrentied for 7 years... plenty of time for your concerns to dwindle.

Longevity really isn't an issue either. This engine uses low boost, most of thr performance comes from the fuel delivery and ignition... it doesn't rely too heavily on the turbo's like some engines. It's still a 3.0 liter inline six w/ added tech.

The use of Bi-turbos is even better from a reliability standpoint and even a breakdown standpoint.

[Garrett]

Originally Posted by Saintor

No, no, no, no.

Ever tried a 1.8T? 100% of torque at 1600rpm. I can tell you that at 1600rpm, this engine has no trust and not much happens under 2500-3000much

Power is what ultimately will determine acceleration, at any speed.

... ....

Oh boy... here we go.

Saintor, sorry to burst your bubble but I don't think you have a firm grasp of what torque is or does.

You cannot argue a fact based only on an experience you had with a very "peaky" 1.8 liter engine. There are several links to get you started here in this post, i suggest you read them and try to understand them. It takes a long time to completly understand torque. That article was written from a drag-strip mentality but you can pick bits and pieces as for how toque adds to the feel of a bigger engine because of the GRUNT they produce.


You know the feel of you getting thrown back in your seat when a turbo kicks in ...? Thats torque. If you find the powerband charts (HP & Tq) and look at it you will see that EXACTLy when you notice yourself being thrown back in your seat (boosts kicks in) is the same time to TORQUE raises in the HP/Tq charts.

What car are you talking about with the 1.8l turbo ..? I can easily show you how wrong you are.



-Garrett

[Saintor]

Originally Posted by Garrett

... ....

Oh boy... here we go.

Saintor, sorry to burst your bubble but I don't think you have a firm grasp of what torque is or does.

You cannot argue a fact based only on an experience you had with a very "peaky" 1.8 liter engine. There are several links to get you started here in this post, i suggest you read them and try to understand them. It takes a long time to completly understand torque. That article was written from a drag-strip mentality but you can pick bits and pieces as for how toque adds to the feel of a bigger engine because of the GRUNT they produce.


You feel like your getting thrown back in your seat when a turbo kicks in ...? If you find the powerband charts (HP & Tq) and look at it you will see that EXACTLy when you notice yourself being thrown back in your seat (boosts kicks in) is the same time to TORQUE raises in the HP/Tq charts.

What car are you talking about with the 1.8l turbo ..? I can easily show you how wrong you are.

-Garrett

No, I am not wrong. You are.

Don't believe one site because you'll get another one that says the contrary on this subject.

Fact is that an engine pulls quicker on peak HP over all gears, NOT on peak torque.

If you have an engine with the following specs, 200HP at 5400rpm and 200lbs.ft at 3500rpm. According your logic, you would have to shift to keep an average close on 3500rpm.

I can tell you right away that the guy shifting at redline, will get you easily, no context. Because he is optimising the average RPM close to the 5400rpm - at peak HP.

As for understanding torque, I am a registered professional mechanic engineer, thank you.

It is not for nothing that in track races, tech people focus ONLY on HP figures, much much less on torque. Not a mistake.

Get it.

[ward]

all you hp and torque arguers are both correct and both wrong

hp is a function of torque, no torque=no HP

you can't have one without the other

[akhbhaat]

Lots of confusion and misinformation here.

In a nutshell: torque is the physical force that actually drives the car. Horsepower is a function of torque; i.e. how fast the engine is applying a given amount of torque. You'll notice that horsepower generally scales with engine RPM; the faster the engine turns, the faster it works.

Something you need to understand is that the definition of power is "how fast work can be done," and horsepower is essentially an arbitrary figure used to give a frame of reference (33,000 ft-lbs per minute).

Horsepower measures cumulative work over time, aka "power"; torque is the raw force actually being applied (i.e. the "work").

Torque and engine rpm is usually measured with each turn of the crankshaft. Obviously, the crankshaft is turning half as fast at 3000 rpm as it is at 6000 rpm, meaning it does half as much work over a given period of time (say one second) at 3000 rpm as it does at 6000 rpm. Another way of looking at is this: an engine with a completely flat torque curve, making 100 ft-lbs at all RPMs, is doing more work over time at 5000 or 6000 rpm than it is at 3000 rpm. This also means that an engine making 100 ft-lbs of torque at 6000 rpm is doing the same amount of work over time as an engine making 200 ft-lbs at 3000 rpm. Though the raw physical force (torque) exerted through the crankshaft is half as much in the 6000 rpm engine, it's being applied at twice the rate so the cumulative work done over time is the same (~114 hp in both situations). Obviously, the more torque an engine puts through the crankshaft at a given RPM, the more horsepower it makes at that rpm.

Simply put: the ideal car engine makes a boatload of torque regardless of engine rpm, and can rev to really high speeds (6000+ rpm). You can't really say that one is "more important" than the other, since they're dependant upon one another.

You can use this formula:

(Tq x engine speed rpm) / 5252

To get horsepower.

Once you understand the relationship between horsepower and torque, you can begin to understand why a gasoline engine making 180 ft-lbs at 6000 rpm accelerates a car faster than a diesel engine with 280 ft-lbs at 3000 rpm.

[Robin_NL]

Take a look at 2005 F1 engines. 850/900BHP @ 17/18/19000rpm and maybe 350Nm of torque @ 8000(or something)

Engines:3 litre V10.

But OK, it's a matter of both things, you need REVS to achieve performance.

To accellerate in 3rd from almost standstill for a sprint is nonsense

To accellerate at the max you need to go to 6600rpm in my 330i, not to 2500/3500.

But I understand Garret as well.

Cheers

Robin

[imageWIS]

Originally Posted by GregA

Than buy a 1001HP Bugatti Veyron.

Think quality, not quantity.

Funny, cus the Veyron is probably the best-made car in the world (materials and workmanship).

Although you don’t get a trunk, but you do get to go 0-60 in 2.5 seconds…

Jon.

[Robin_NL]

Originally Posted by imageWIS

Funny, cus the Veyron is probably the best-made car in the world (materials and workmanship).

Although you don’t get a trunk, but you do get to go 0-60 in 2.5 seconds…

Jon.

For the money I think the Porsche Carrera GT is much better but who am I


According to Jeremy Clarkson the New Rolls Royce Phantom is the best car in the world. Stevie Wonder has one too. So it must be quite alright then

[ward]

stevie wonder really shouldn't be driving

[Steved]

I posted on another forum answering questions as to why diesel engines with more torque than horsepower tend not to accelerate as fast as petrol engines with more horsepower than torque. If you fancy a read then let me know and I'll post it.

Otherwise read the following link and all will be explained. I can answer any questions if needs be.

http://vettenet.org/torquehp.html

p.s. try and remember that all engines pull based on torque. There's no such thing as power, it's just a product of torque times revs. A powerful engine will be the one that maintains more of it's torque at higher rpm, so the ideal situation is to have a very flat spread of torque that is then multiplied at the driven wheels by gearing.

Acceleration follows the torque curve but an engine will be working at it's best (highest rate of work) when near the power peak. This is the point at which the rate of decline of the torque curve can no longer be compensated for by higher revs and is also why a car is geared to reach its maximum speed at its peak power.

[imageWIS]

Originally Posted by Robin Hood

For the money I think the Porsche Carrera GT is much better but who am I


According to Jeremy Clarkson the New Rolls Royce Phantom is the best car in the world. Stevie Wonder has one too. So it must be quite alright then

HUH? During the 05’ Top Gear awards the best car in the world was the Veyron! (it also was close to winning the award for gas guzzler at 4 mpg).

Anyways, if you can buy a Veryron, you can most certainly also afford a Carrera GT.

Jon.

[imageWIS]

Originally Posted by 3aficionado

Great post Garrett.

I have a few concerns with the new engine. Hopefully the knowledgeable few on this board can elaborate on why my concerns should/should not be warranted.

1.) Reliability. I expect the engine to be a solid performer like all BMW engines. In the outside chance of problems during first year production will the US consumers have experienced technicians to fix the problems? The US BMW techs will only have classroom experience for whatever could occur. Europeans have been maintaining turbos diesels for years. I’ve experienced the lack of qualified technicians with Mercedes and worry BMW in the US could have the same issue in the first year or two.

2.) Perception. The average US consumer has a perception of a turbo engine as being unreliable in the long term. Could this high priced turbo not hold its value due to a US biased perception of turbo engine longevity?

I disagree with your thoughts regarding #2. Turbo’s are not perceived as relatively bad in the U.S. it just really depends as to which Turbo car you are referring. No one will state that the 911 Turbo has low resale value or that is unreliable in the long term, quite the contrary. At the same time, American car manufacturers have always used Superchargers, which may lead to a perceived bias, which is built into the American automotive psyche. As well, the Supercharger came long before Turbocharging even existed, thus it has a longer track record. But, even nowadays you see that the ‘Supercharger King’, Mercedes-Benz is installing bi-Turbo power plants in its cars, especially at the higher end.

Jon.

[hector]

[QUOTE=Garrett]????

A car will accelerate almost identical to it's torque curve, the higher the delta (or it's point on the curve) the faster it will ACCELERATE. *nuttshell*

QUOTE]
in a given gear that is correct, but if the torque is made at higher rpm(which means the engine is making more hp), for a given vehicle speed you will be able to be in a lower gear which increases the torque multiplication at the rear wheels, and it is rear wheel torque that accelerates the vehicle.

[Bimmerista]

And to spoil the party but get back on topic

I believe that the turbo (as well as the DI) is required for increasing Hp due to the fact that the N series of engines have reached the limit of displacement enhancements through simple bore and stroke increases, which means that adds ons such as valvatronic, DI, turbos, will replace the ilack of physical ncreases in actual displacement.