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07-11-2008, 09:04 AM | #89 | |
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I don't mind putting around in low rpms when i get groceries or try to look cool in a 997 Cab. But for performance cars, it is the area under the curve for the last 3000 rpm that matters. After 30+ years of basically the same car, it is an ancient platform. BTW, torque is a function of the bore and stroke, valvetrain, intake lengths.... It is a design decision of where to deliver torque in the RPM band. You make torque like its the best thing.....the only thing that matters is power which is a function of torque and RPM. BTW, my M6 has way more torque than BMW's F1 engine.....this is the argument that you are making....i.e. it makes no sense.
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07-11-2008, 11:26 AM | #90 | ||
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It surprises me how many intelligent people feel that torque low down has no bearing or purpose in a normal hi-performance production engine and feels that it's sole purpose is to ferry the kids to school and collect the groceries. The problem with a lot of you is that you haven't experienced real torque and power together, sure the M6 is getting closer than most to this but when compared to either a Z06 or RS6 engine it's still a one trick pony, either the Z06 or RS6 could be left in 3rd gear and lap pretty close to an all-out attacking lap using all of the gears, why anyone would want to do that is beyond me but the point is that such an exercise would service a great purpose on the road. You guys in the States talk about a gear that offers great acceleration from walking speed until triple figures as the 'money gear', well you only get that with torque. |
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07-11-2008, 11:37 AM | #91 | |
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Well we are looking at different graphs. The power curve reaches a peak at 6500 rpm and then clearly and noticeably drops off all the way to redline. |
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07-11-2008, 11:45 AM | #92 | |
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Your definition of noticeable drop off most be different to mine, I see a peak at 6500rpm @ 283Kw (385hp) and slowly drop to an incredibly low 279Kw (379.5hp). Holy f--k that's one hell of a drop off in power towards the redline. |
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07-11-2008, 05:08 PM | #93 | |
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Either way it is a very different character than the M3 in the very upper rpm range. |
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07-11-2008, 05:23 PM | #94 |
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I must say that it is a blast to be consistently driving in the last 2500 rpms or so in the M3. The car just keeps on going and going. Rpm lights on the wheel would be really nice IMO. I hit the limiter in 2nd a couple of times last weekend in a specific turn where you can't see the tach because of the positioning of the steering wheel at that turn. Plus, who wants to be staring down at the tach when you've got other things to pay attention. At any rate, it's really amazing how the car keeps on going. I am sure the top end will be even more impressive in the CSL...
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07-11-2008, 06:06 PM | #96 |
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07-11-2008, 06:13 PM | #97 | |
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Maybe I was wrong in picking you up on the statement that the power drop was NOTICEABLE, it's just in my opinion the word is used to describe something worthy of notice and a 2.66% drop over almost 1000revs isn't that NOTICEABLE in the grand scheme of things. What is NOTICEABLE is the fact that a 3.8L six cylinder engine can produce 20Nm of torque more than a 4.0L vee eight, very impressive. |
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07-11-2008, 06:43 PM | #98 | |
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Agree Porsche has no balls, risk adverse to the detriment of innovation. The V10 from the M6 would make the Z06 a faster car in acceleration. The weight of the car is the secret to the Z06's success...the weight is impressive. If a person wants to acceleration from 20 to 100 mph in 3rd gear, they are lazy idiots.
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07-11-2008, 07:10 PM | #100 | |
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People don't realize high load, low rpm (i.e. stepping on the gas in low rpms) is really bad on engines. This leads to premature head gasket failure. So get off your butts and shift before you step on it. (this is why I don't care about low end torque).
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07-11-2008, 08:32 PM | #101 | |
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Would you get as specific as you can about how stepping on the gas at lower rpm causes head gasket failure, or any other problem? Bruce |
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07-11-2008, 08:44 PM | #102 | ||
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Yup, already agreed with that. This is mostly DI, I'd guess and why I so wished the M3 would have got it as well (and criticized heavily when it didn't). |
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07-11-2008, 08:46 PM | #103 |
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Accuracy and details are important to me for one (many others here as well). Sorry if you don't see the importance of such things.
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07-11-2008, 09:06 PM | #104 |
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Yeah, I agree with Swamp on this one. I think this is a discussion worth having even if the differences are small. It's good to talk about what torque curves look like on top.
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07-11-2008, 09:12 PM | #105 | |
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When you ignite a cylinder charge with the most available torque, i.e. as much fuel and air as you can cram in by stomping on the throttle, the detonation and explosion is dispersed over a much longer period of time. With lower RPMs, the piston is moving much slower and hence the explosion takes much longer to disperse its energy. This energy then pushes the weakest link, i.e. the headbolts / head gaskets. From a practical standpoint, the old 944 Turbo motors were pretty bad for blowing headgaskets for this reason. Again, be in the right gear when you want to sauce it.......it is less stressful on the engine.
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07-12-2008, 02:36 AM | #106 |
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Are you really trying to say accelerating at low revs stresses an engine more than being at redline? Seriously, come on now, this is just getting absurd.
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07-12-2008, 05:34 AM | #107 | |
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Though on a brighter note.................the head gasket was OK. |
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07-12-2008, 07:58 AM | #108 | |
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Secondly, you're not going to have very high cylinder pressures at low rpm no matter what you do, since the engine is optimized for cylinder filling at a higher rpm by cam timing and intake design. Lastly, subjecting engine internals to pressure at 1200 rpm (meaning 10 times a second) is arguably less problematic than subjecting those same cylinders to higher pressure at, say 3600 rpm (30 times a second), at the torque peak of that engine (whatever that engine may be). The old 944 motors did blow headgaskets, but they were democratic about it, meaning they blew just as often at the track (against the Vettes) as they did everywhere else. That was just bad engineering, and had nothing to do with rpm. Bruce PS - This is akin to the old argument about "lugging", which is supposedly bad for your engine. It pretty much isn't, though - unless you or someone else can come up with something new in terms of argument. |
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07-12-2008, 08:21 AM | #109 | |
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Ha! I don't think we will agree here but I will make my point one more time. Under load, particularly with FI, the explosion is disperse over a longer period of time because of the low rpms putting more stress on the components. In only one area of stress around the headgasket, yes.
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07-12-2008, 08:27 AM | #110 |
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TB,
Find me another example of this apart form the 944Turbo. As Bruce said a design fault at best, I have had numerous turbo models and I haven't heard of head gaskets being a problem before this. The stresses at high rev are far more problematic to engines than at low revs, think of the weight the piston is at 8000rpm compared to 1500rpm and you will know what I mean. Sorry TB but you are beating a die horse on this one and no one is coming to your defence. |
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