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03-23-2007, 02:42 PM | #23 |
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03-23-2007, 11:37 PM | #25 | |
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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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2 things:
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03-24-2007, 05:15 AM | #27 | |
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Prediction vs. expectation
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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.
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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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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:
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:
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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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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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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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
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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Hopefully next time we get to discuss an interesting topic on the same page. |
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