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      03-23-2007, 02:42 PM   #23
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Originally Posted by ILC32 View Post
In your poll, you predicted the motor would make 430-439, I said 410-419.

Who had unrealistic expectations?

I get it now. If someone disagrees with you, they are whining.
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      03-23-2007, 05:15 PM   #24
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I'll reserve comments on the motor until after I drive the car. That's the true test.
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      03-23-2007, 11:37 PM   #25
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Originally Posted by sdiver68 View Post
some more engines:

AMG 6.3L 438lbs 507HP/465 TQ
GM LS7 (Z06) 458lbs 505HP/475 TQ

IMHO, mass and dimensions versus performance is a much better yardstick than hp/l.
This whole engine comparison winds up confusing me. If the above figures are correct for MUCH larger and torquier engines that are also just as fuel efficient (or more so) as the M3's V8, what is the TRUE point of a high-revving design? Less torque does allow for a lighter weight drivetrain, but then the M3 will still weigh a lot more than a GT3, Z06, etc.

I'd love to see a breakdown of how much lighter the engine, transmission, axles, gears, clutch, etc. etc of BMW's high-revving M3 vs. the Z06's "old school" pushrod 7 liter V8. The immediate 470 lbs ft of torque in a Z06 makes it really fun to drive with friends -- just to whip their head back!

If you compare an F430's 483 HP V8 to a Z06's 505 HP V8, the Z06's V8 makes more torque, more HP, weighs almost the same (based on above numbers), yet gets dramatically better fuel economy (16/26 vs 11/16 for the Ferrari).

If revs cost in gas and in torque and (it seems) don't benefit much in weight., what is the point?
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      03-24-2007, 12:46 AM   #26
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Quote:
Originally Posted by e36jakeo View Post
This whole engine comparison winds up confusing me. If the above figures are correct for MUCH larger and torquier engines that are also just as fuel efficient (or more so) as the M3's V8, what is the TRUE point of a high-revving design? Less torque does allow for a lighter weight drivetrain, but then the M3 will still weigh a lot more than a GT3, Z06, etc.

I'd love to see a breakdown of how much lighter the engine, transmission, axles, gears, clutch, etc. etc of BMW's high-revving M3 vs. the Z06's "old school" pushrod 7 liter V8. The immediate 470 lbs ft of torque in a Z06 makes it really fun to drive with friends -- just to whip their head back!

If you compare an F430's 483 HP V8 to a Z06's 505 HP V8, the Z06's V8 makes more torque, more HP, weighs almost the same (based on above numbers), yet gets dramatically better fuel economy (16/26 vs 11/16 for the Ferrari).

If revs cost in gas and in torque and (it seems) don't benefit much in weight., what is the point?

2 things:
  1. BMW designed the engine to meet displacement requirements
  2. The kick ass drivetrain is connected to a non-sports car chassis, the E92
I realize #2 may be heresy but the 911, Vette, F430 are real sports cars.
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      03-24-2007, 05:15 AM   #27
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Prediction vs. expectation

Quote:
Originally Posted by ILC32 View Post
In your poll, you predicted the motor would make 430-439, I said 410-419.

Who had unrealistic expectations?

I get it now. If someone disagrees with you, they are whining.
Sure I over-predicted, that is totally different than whining about reality once it becomes known, and different than whining about a great success. Whining has nothing to do with disagreeing. Just tell me, are people (not nec. you) whining or not?

This plant is easily capable of the 430 number. I honestly thought we would see about 108 hp/l from this engine. Scott has already said he has seen it dyno at the 426 number we heard a lot about. Secondly it may be a bit under rated. Marketing, not engineering makes the final call on hp specs! Next this plant has to last for some time including a likely CSL. With nothing much other than bumping the redline a few hunderd I'm sure it'll put out 430. All that aside about why I predicted what I did I indeed overestimated what BMW would publish, I guessed and I was wrong, period. Does that direct admission make you happy?.... It's still fun guessing.

Any way you look at it the motor is great, it will suit the car and drivetrain (once they release a damn 7sp ZSG), and it is going to seriously

And I still say to those who are - STOP WHINING.
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      03-24-2007, 05:41 AM   #28
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Weight, mpg, etc.

Quote:
Originally Posted by e36jakeo View Post
This whole engine comparison winds up confusing me. If the above figures are correct for MUCH larger and torquier engines that are also just as fuel efficient (or more so) as the M3's V8, what is the TRUE point of a high-revving design? Less torque does allow for a lighter weight drivetrain, but then the M3 will still weigh a lot more than a GT3, Z06, etc.

I'd love to see a breakdown of how much lighter the engine, transmission, axles, gears, clutch, etc. etc of BMW's high-revving M3 vs. the Z06's "old school" pushrod 7 liter V8. The immediate 470 lbs ft of torque in a Z06 makes it really fun to drive with friends -- just to whip their head back!

If you compare an F430's 483 HP V8 to a Z06's 505 HP V8, the Z06's V8 makes more torque, more HP, weighs almost the same (based on above numbers), yet gets dramatically better fuel economy (16/26 vs 11/16 for the Ferrari).

If revs cost in gas and in torque and (it seems) don't benefit much in weight., what is the point?
MPG in a large displacement engine simply comes from running at extremely low rpms (and tall gears) 4l @ 3k rpm is using more fuel than 8l at 1250 rpm. Purpose of a high revving design is to win a road race (not nec. a drag race). High revs, lower torque = lighest weight engine, drive train and chassis.

You don't see any high displacement torque monster engines winning at elite levels of racing do you?

All that being said the Z06 is a nice package. One way it's engine saves weight by having much less complex/bulky heads and one cam. It will be punished by other drive train components being really strong (heavy) to handle the monster torque. Even with that penalty the Z06 is designed from the ground up to be lightweight sports car and the engineers really achieved something. M3 will also be designed to be light too but it is a 4dr and simply a bigger car. The engine and drive train in this sense will be a bit unmatched to the chassis. The engine and drive train truly belongs in something like a Lotus chassis. Wouln't that be fun....
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      03-24-2007, 09:36 AM   #29
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More comparisons and graphs

Gathered some of the very few Ferrari dynos I could find and converted everything to "apples to apples" for the attached graphs. Maybe I should have added some of the better AMG plants (or Porsche) as well but I am just so disinterested in MB (and Porsche is not very apples to apples since it is not a V8)... I'm happy to share my Excel file if anyone wants to make some other comparos.

Things to note:
-In making the M3 V8 torque curve smoother and getting to peak at lower rpm they absolutely sacrificed some small bit of mid range torque (see purple vs. orange on torque graph). Top end torque does not fall nearly as fast as M5 though.
-M3 V8 >> F360, purely from an engine stand point (exact same displacement). Man was that Ferrari high strung.
-F430 >> M3 and M5 engines. Man does this thing make gobs of torque for per displacement. Not as much as GT3 though.
-M3 V8 probably has a few hundred valauable rpm left past 8400 but look how the F430 torque falls off so slowly at high rpm and hp just seems to keep on going. Definitely some extra performance to be had here if the longevity was not adversely affected.
-The Ferrari data looks so good (almost impossible). But my data did come from engine dyno measurements. Again as per my previous comment that the new M engine is evolutionary rather than revolutionary.
-Ferrari seems to also have very low drive train losses ~12% on peak hp, ~10% on peak torque, M5 is 14/17 respectively.

Comments:
-I used linear scaling to guess engines performance at smaller displacements. I know, not perfect but I don't know an better, easy way.
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      03-24-2007, 03:03 PM   #30
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Quote:
Originally Posted by T Bone View Post
Horsepower is a measure of work. More work the drivetrain can do, the faster you accelerate.


Quote:
Revs are as important as torque in determining the amount of work a drivetrain can do.
Revs determine WHEN an engine produces a certain amount of HP or torque, RPM doesn't determine the actual amount of HP or torque an engine can produce.

Also, the use of the term drivetrain here is not appropriate. Drivetrain as a whole is not just what produces HP and torque, it also transfers engergy. Transmission, driveshaft and diff all are parts of drivetrain.


Quote:
So while you main get 85% of the engines torque low in the power band, you actually want to be pounding through the gears at the higher rpms (while trying to maintain torque).
Read my previous post. I, and BMW never said "85% of torque low in the powerband." It's "the engine delivers 85% of max torque in A RANGE of 6500rpm." With a powerband this wide, you are wasting useful revs and giving up shifting time by using a CR box, which cuts you off quicker than a normally geared box.

And no, I wouldn't want to be pounding through the gears at higher rpms to mantian torque with this engine. Look at the graph, you get less torque after 6500rpm, and in the last 1000rpm you actually get less than 380NM.

Quote:
The flat torque curve is really good for flexibility but when you are tracking / performance driving, revs are critical to extract max performance and a close ratio gear box gives you high revs with relatively constant torque.
A flat torque curve is good for EVERYTHING. For this particular engine, revs are only critical to extract max horsepower. This engine acutally produces most torque between 3500-6500rpm, whereas max HP is produced near redline. Mid range is where you want to be for constant torque, not the top end.

Also, a CR box doesn't give you more revs or make you rev higher. It only limits the length of each gear and drops fewer revs when upshifting. For high-sprung engines like built S52, S50B32 and S54, which don't wake up until 2000rpm to redline, yes, a CR box can keep you in the sweet spot. But the S65 is a different story.
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      03-24-2007, 04:42 PM   #31
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Quote:
Originally Posted by maq View Post




Revs determine WHEN an engine produces a certain amount of HP or torque, RPM doesn't determine the actual amount of HP or torque an engine can produce.

Also, the use of the term drivetrain here is not appropriate. Drivetrain as a whole is not just what produces HP and torque, it also transfers engergy. Transmission, driveshaft and diff all are parts of drivetrain.




Read my previous post. I, and BMW never said "85% of torque low in the powerband." It's "the engine delivers 85% of max torque in A RANGE of 6500rpm." With a powerband this wide, you are wasting useful revs and giving up shifting time by using a CR box, which cuts you off quicker than a normally geared box.

And no, I wouldn't want to be pounding through the gears at higher rpms to mantian torque with this engine. Look at the graph, you get less torque after 6500rpm, and in the last 1000rpm you actually get less than 380NM.



A flat torque curve is good for EVERYTHING. For this particular engine, revs are only critical to extract max horsepower. This engine acutally produces most torque between 3500-6500rpm, whereas max HP is produced near redline. Mid range is where you want to be for constant torque, not the top end.

Also, a CR box doesn't give you more revs or make you rev higher. It only limits the length of each gear and drops fewer revs when upshifting. For high-sprung engines like built S52, S50B32 and S54, which don't wake up until 2000rpm to redline, yes, a CR box can keep you in the sweet spot. But the S65 is a different story.

I would suggest looking at the definition of horsepower and work. RPM is integral in determining a horsepower rating, along with Torque. SAE HP (an arbitrary definition of work created by James Watt BTW), says that revs after 5252 rpm has a great impact on HP.

We don't share a common view of the world or physics so it is pointless to discuss. In my world the sky is blue.

BTW, here is a hint for you RPM = Distance, Torque = Force
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Last edited by T Bone; 03-24-2007 at 05:04 PM.
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      03-24-2007, 08:54 PM   #32
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Quote:
Originally Posted by T Bone View Post
I would suggest looking at the definition of horsepower and work. RPM is integral in determining a horsepower rating, along with Torque. SAE HP (an arbitrary definition of work created by James Watt BTW), says that revs after 5252 rpm has a great impact on HP.

We don't share a common view of the world or physics so it is pointless to discuss. In my world the sky is blue.

BTW, here is a hint for you RPM = Distance, Torque = Force
I give up. I have no idea why you are talking about horsepower vs torque etc, when I didn't even touch that subject. All I was trying to say was more revs ≠ more torque in the case of the S65, which seems to be your opinion.

In my world you don't know a whole lot about engines.
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      03-24-2007, 09:09 PM   #33
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I give up. I have no idea why you are talking about horsepower vs torque etc, when I didn't even touch that subject. All I was trying to say was more revs ≠ more torque in the case of the S65, which seems to be your opinion.

In my world you don't know a whole lot about engines.
What I am trying to say is RPMs are as important as Torque in rating the ability of an engine.

Horsepower is a measure of physics term called Work. The more work an engine can do, the faster it can accelerate the car. Work is Force multiplied by Distance. The Force for an engine is Torque. The Distance variable for an engine is RPM. I.e. the higher the RPM the more distance the engine exerting its torque.

As an example: An engine that generates 500 foot pounds of torque at 3000 RPM is less powerful than an engine that generates 300 foot pounds of torque at 8000 rpm.

HP (SAE) = torque X rpm / 5252
  • Torque Motor: 500 foot pounds X 3000 rpm = 285 HP
  • High Rever: 300 foot pounds X 8000 rpm = 456 HP
BMW's philiosophy is that it is more efficient to make power or work by creating motors that have moderate torque at high RPM rather than big torque at lower RPMs (Mercedes, Chrysler etc).

High RPMs over torque means that BMW can use lighter drivetrain components. This philosophy of design is also why F1 Cars turn 19,000 rpm, generate about 230-250 foot pounds of torque.

Peace out.
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      03-24-2007, 09:57 PM   #34
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Quote:
Originally Posted by T Bone View Post
What I am trying to say is RPMs are as important as Torque in rating the ability of an engine.

Horsepower is a measure of physics term called Work. The more work an engine can do, the faster it can accelerate the car. Work is Force multiplied by Distance. The Force for an engine is Torque. The Distance variable for an engine is RPM. I.e. the higher the RPM the more distance the engine exerting its torque.

As an example: An engine that generates 500 foot pounds of torque at 3000 RPM is less powerful than an engine that generates 300 foot pounds of torque at 8000 rpm.

HP (SAE) = torque X rpm / 5252
  • Torque Motor: 500 foot pounds X 3000 rpm = 285 HP
  • High Rever: 300 foot pounds X 8000 rpm = 456 HP
BMW's philiosophy is that it is more efficient to make power or work by creating motors that have moderate torque at high RPM rather than big torque at lower RPMs (Mercedes, Chrysler etc).

High RPMs over torque means that BMW can use lighter drivetrain components. This philosophy of design is also why F1 Cars turn 19,000 rpm, generate about 230-250 foot pounds of torque.

Peace out.
You see, your argument is torque at higher rpm is good (which I never questioned), my argument is the S65 has LESS torque at higher rpm, thus it does not a close ratio gearbox (which was our original topic).

Hopefully next time we get to discuss an interesting topic on the same page.
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