2009 Porsche 997

[T Bone]

Originally Posted by Sticky

Oh, right, torque down low doesn't matter because all anyone in a performance car does is sit at redline. All around driveability is important and you have to GET to the freaking higher revs. Do you have to put a BMW fanboy spin on everything?

The total displacement is lower yet it makes more torque than the v8, ridiculously impressive. Better mileage and less emissions too but hey, porsche doesn't innovate right?

What matters for performance cars is the power to weight ratio and power under the curve (the whole thing, not just the part that looks best to you).

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.

[footie]

Originally Posted by T Bone

After 30+ years of basically the same car, it is an ancient platform.

It's Porsche's own insecurity that has meant we have had the 911 for so many years. They believe that without the 911 their customer base would move else where, it's not the design that people are buying into it the fact that the 911 is the top of the Porsche tree and it's that model which people aspire to. If the 911 was mid-engined and still sitting at the top of the tree then everyone would be wanting it instead. The layout has nothing to do with it.

Originally Posted by T Bone

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.

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.

The importance of torque is the pick up from low revs, try accelerating in a S2000 from 1500rpm in 4th and you will see what I mean, you need torque to get to the higher revs and without it you have a race engine, totally impractical on the road and in everyday life but a hoot on the track when the gearbox is setup correctly to take advantage of that very narrow power band.

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.

[swamp2]

Originally Posted by Sticky

Uhhhhhhhh no your uhhh no direct injection allows higher compression more safely on a naturally aspirated motor than it does without. Charge cooling due to fuel evaporation in a direct injection engine typically allows for an increased compression ratio.

DI INDIRECTLY ALLOWS for a higher compression, sure, it does not PROVIDE it as you stated. Splitting hairs a bit perhaps.

Originally Posted by Sticky

I am looking at the same graph as you, the torque falls off, the power no longer rises but does not drop along with the torque due to the increase in revs.

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.

[footie]

Originally Posted by swamp2

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.

swamp,

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.

[swamp2]

Originally Posted by footie

swamp,

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.

OK we are splitting hairs. I said NOTICEABLE not LARGE or SIGNIFICANT. Always pay attention to my diction, I use it carefully unlike yourself. But the fact remains it drops and drops over a fairly significant range of 1000 rpm. My examination of the curve tells me that the dip below 280 kw is either as big or slightly larger than its peak above it. This gives me the figure of a drop to 276 kW. No idea how you could read that at 279 (ok, yeah I forgot your math handicap...)

Either way it is a very different character than the M3 in the very upper rpm range.

[lucid]

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...

[devo]

I think some of these arguments are just for the sake of arguing.

[ruff]

Originally Posted by devo

I think some of these arguments are just for the sake of arguing.

Keeps interest up and forum traffic high about subjects that frankly take dedicated individuals to beat to death.

[footie]

Originally Posted by swamp2

OK we are splitting hairs. I said NOTICEABLE not LARGE or SIGNIFICANT. Always pay attention to my diction, I use it carefully unlike yourself. But the fact remains it drops and drops over a fairly significant range of 1000 rpm. My examination of the curve tells me that the dip below 280 kw is either as big or slightly larger than its peak above it. This gives me the figure of a drop to 276 kW. No idea how you could read that at 279 (ok, yeah I forgot your math handicap...)

Either way it is a very different character than the M3 in the very upper rpm range.

Even if you are correct about it's power dropping to 276Kw that is still a drop of 10hp, no biggie in my eyes. I bet if the M3 engine was allowed to rev a little higher, say 8800rpm I would say it would have lost a lot more than the 10hp that the 997CS is losing.

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.

[T Bone]

Originally Posted by footie

It's Porsche's own insecurity that has meant we have had the 911 for so many years.

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.

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.

[footie]

Originally Posted by T Bone

If a person wants to acceleration from 20 to 100 mph in 3rd gear, they are lazy idiots.

No old friend, on the road that real world driving and real power.

[T Bone]

Originally Posted by footie

No old friend, on the road that real world driving and real power.

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).

[bruce.augenstein@comcast.]

Originally Posted by T Bone

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).

With respect, I would challenge this idea.

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

[swamp2]

Originally Posted by shift@red

well apparantly Porsche AND Ferrari see torque in the same way , since if you you look at the link below, youll see the ferrari f430 and 430 scuderia power and tq curves are nearly IDENTICAL to that of the 911s.

http://www.motortrend.com/roadtests/.../photo_13.html

Please give me some of what you are smoking. The curves are not the same sizes, not the same shapes, do not have the same peaks at the same rpms, nothing.

Originally Posted by footie

Even if you are correct about it's power dropping to 276Kw that is still a drop of 10hp, no biggie in my eyes. I bet if the M3 engine was allowed to rev a little higher, say 8800rpm I would say it would have lost a lot more than the 10hp that the 997CS is losing.

Sure it would drop, who is to say how much Point is that you do not need any rpms beyond the current redline to get maximum performance from the engine.

Originally Posted by footie

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.

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).

[swamp2]

Originally Posted by ruff

Keeps interest up and forum traffic high about subjects that frankly take dedicated individuals to beat to death.

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.

[lucid]

Originally Posted by swamp2

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.

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.

[T Bone]

Originally Posted by bruce.augenstein@comcast.

With respect, I would challenge this idea.

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

This was from the old turbo days but the principle is still applicable....

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.

[Sticky]

Originally Posted by T Bone

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).

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.

[footie]

Originally Posted by T Bone

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).

I can't recall any engines letting go at low revs but can recall some doing it at the redline. But there again it was only bend valves, bust piston, bend con-rod and damaged block.

Though on a brighter note.................the head gasket was OK.

[bruce.augenstein@comcast.]

Originally Posted by T Bone

This was from the old turbo days but the principle is still applicable....

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.

This is completely incorrect. The burn rate of the fuel/air mixture is very nearly a constant, regardless of the density of the charge. Furthermore, the normal "squish" method of inducing light-speed combustion via charge swirl is unaffected by rpm.

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.

[T Bone]

Originally Posted by bruce.augenstein@comcast.

This is completely incorrect. The burn rate of the fuel/air mixture is very nearly a constant, regardless of the density of the charge. Furthermore, the normal "squish" method of inducing light-speed combustion via charge swirl is unaffected by rpm.

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.

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.

Originally Posted by Sticky

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.

In only one area of stress around the headgasket, yes.

[footie]

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.