ivangene

I never said drive 70 and 4k rpms...

freeway in my area is 55,.... I said 3rd (4th is fine if you wanna putt around) and in no way is that "driving it hard" its actually the opposite... the motor is spinning and IMO it likes to spin fast rather than tug boat along...I come from VW's and you drive a 40 hp motor kinda rapped out..it is easier on the motor to spin fast then to have large torquing action from low rpm's - you dont have to red line it, just keep it spinning, they love it! - (course top speed is like 70 and you have to have big ones to get a 40 horse that fast!)

DreamCarrera

Bruce, please keep in mind that Quad owns a 993, if I am not mistaken, and they need a top end rebuild after traveling so many miles. I would assume that higher RPMs hasten the need for the rebuild, thus the hesitation for Quad to recommend driving at higher RPMs.

Quadcammer

Um, thats exactly what people said.

What gear are you in at 55-60mph and answer of 3rd or 4th. What kinda revs is that?

Are you killing it? No...are you creating more wear...yup.

Sings? Another bull**** term made up by people with absolutely zero support for their position. You like how your engine sounds at 4k rpm? Great, have at it, but don't delude yourself into thinking that you're doing your engine any favors.

see below

And since when is running at 2500rpm steady speed cruise outside of its operating parameters? This is not some highly tuned race car that idles at 2000rpm. Its a run of a the mill flat 6. It is perfectly fine in 6th gear at 2500rpm on the highway.

These cars are typically rarely used 2nd or 3rd cars. Not to mention production compared to the typical toyota is miniscule. Finally, the majority of owners are not posting on forums. Hence you probably haven't heard much.

So why is it that you compare the driving technique of a 40bhp VW to your 200bhp 911. They are completely different powerplants. Of course you need to spin the **** out of a 40bhp vw, it has no power anywhere. Your 3.2 has plenty of power at "tug boat" rpms of 2500rpms".

Um, there is no fairy dust in your M96. High revs wear out internal combustion engines faster...this is no mystery.

Btw, I don't think comparing the reliability of the M64 to the M96 will turn out in your favor.

Quadcammer

1. It seems like you are focused on carbon build up here. Given the electronic fuel injection and adaptive ecu (as you noted), carbon build up is incredibly minor. Regardless of whether the engine is run at 4000rpm or 2500rpm, the ecu with use the 02 sensor feedback to keep the a/f ratio near stoich. Timing is advanced to get the most complete fuel burn without detonation. Porsche wants to produce good fuel mileage and minimal emissions. These vehicles don't have weber carbs and points ignition...carbon build up is basically a non issue...and even if it was, higher rpm and low load would produce the same result at low rpm and low load. 2500rpm on the highway is more than enough to prevent lugging considering a 996 needs maybe 20bhp to keep its highway speed.

2. i've tuned numerous N/A and forced induction cars, from fuel and timing maps to maf curves. I don't deal with 996s, but I'm familiar with the ecu used by the vehicle. Its not exactly revolutionary. The adaptive fuel trims and timing are used to keep a/f stoich and emissions clean at part throttle. At full throttle, the car reverts back to open loop anyway, which provides commanded fuel and timing maps.

3. The engine sounds the same because it is the same. The sound is provided by the exhaust, the engine block material, the firing order, and several other variables. Whether you regularly run the car hard or not has nothing to do with it.

4. Once again, higher rpm=higher friction=more wear. heres a test for you. Run your hand along concrete at 3" per second back and forth. Then do it at 1 inch per second. Which do you think will result in less skin on your hand?

Once again, running the car at wot to redline is not a big deal. it won't cause instant engine damage or catastrophic failure. But you aren't doing your engine any favors. Furthermore, running at high rpms for no reason simply causes additional engine cycles which will eventually cause shorter life for items like the rings and valve springs.

If you want to do it for fun, go ahead. But this is not a needle bearing 356 motor, 2500rpm is not lugging a god damn thing.

ivangene

OK so maybe we just want to emphisize dont under rev.. i looked at the gear/mph/rpm chart and I guess 3rd is a little high for "cruising" but I think it started as a bit of fun and turned into something more.....

2500 rpm is about minimum for me - yes I tend to run it a little faster as I have not grown up yet and pray I wont be all grown up too soon... - turning my "debate" switch - OFF -

ivangene

IF you use lower pressue the 1 inch a second can create less wear...there is some point where presure and friction and heat and waer have a sweet spot and some area where the percent is not sufficiently differant and some point where its a big frickin deal...

RE carbon build up... I have seen Tips and 6 speed pistons and almost without exception you can tell which is which from across the room.... same motor, same firing order same ECU... differant RPM usage

whoops I thought I was in debate -OFF- mode

Quadcammer

Point is that at 2500, you have enough power to not need significant throttle to keep that speed. The difference in throttle opening to retain speed between 2500 and 4000rpm is maybe 5%. Considering you are already at very light load, the cylinder pressure differences are not really worth discussing.

Ok, so one piston has a very light coating of carbon...so what? This is not exactly going to harm anything.

ivangene

+1 on the RPM's we can put that horse in the ground....

carbon is not one piston, I mean ALL pistons on tips -vs- 6 speeds, they tend to have significantly more carbon build up... and on close to zero clearance motor the added carbon can make contact with the head, so yes, carbon is an issue at some point. It also effects heat disapation to some degree I would suspect. Having the choice to use carboned up pistons or clean tops I doubt you would put the carbon ones in there for some reason or another which is the same as saying you dont think they are as good... maybe not bad, but not as good....so tips run lower rpm's and have more carbon deposits = cant be better = lower rpm cant be better

there I win

BruceP

I appreciate the effort you put into your response, but you're really just making counterclaims rather than making me smarter. So we'll agree to disagree.

I've owned two dozen cars and raced a little. I've also consulted to two car companies. But I'm not a mechanic or an engineer. I can only make calls on the basis of my aggregated observations and what I've learned along the way, just as you are doing. And here's what I think:

- Only an electric motor operates at the same efficiency all the time. Reciprocating engines don't. I drive my diesel tractor differently than I drive my 996, because the engines were built to operate differently. I see no dividend in making a motor do something its designers didn't make a priority of, even i fit can. These guys had a specific 'typical' use in mind when they made decisions about reciprocating parts.
- My confidence about efficiency is based partly on two things: I keep religious track of mileage (I think this is a great indication of how well an engine is running), and I pay close attention to my tailpipes (following an issue with my Dinan Z3).
- This engine doesn't suffer much from wear to reciprocating parts (most don't. I was recently in a limo that had over a million kilometers on it). Whereas it does suffer from lots of things that may - may - be related to engines being used too little and too gently. That's the risk I choose to take.
- I have to disagree that carbon is not an issue, having just spent a few thousand dollars rebuilding the top end of my wife's MINI. It's a long story and not really all that relevant, but believe me. Carbon is not something to dismiss, even in a modern engine.

I don't know why this issue makes you so hostile, but you are absolutely free to use your car as you see fit as far as I'm concerned. Until someone educates me otherwise - that's educates, not berates - I'm going to remain a member of the drive-it-like-you-stole-it tribe, which is pretty large and seems, anecdotally at least, to have pretty trouble free cars.

babylonboots

I feel jilted. My Tip will only go into 5th no matter how fast I go.

wyovino

I just want to say that I agree with everyone on this issue.

seanmcr6

When I drove my C4S across canada...I had the cruise on in 6th doing 115-120KPH. I was getting 7.8L/100Kms through flat, boring Saskatchewan! That's MUCH better than Porsche's own numbers.

Even now...doing long trip on cruise at 120-125....I get under 10L/100Kms...and that's also better than Porsche's number.

I could do pretty close to 600Kms to a tank. The EPA rating for my car says I should only get 441Kms.

City driving....and especially in the winter....my fuel economy SUCKS *****. In the winter I've been getting 300Kms to a tank. The computer tells me I'm getting 18.4L/100Kms. Which is WORST than Porsche's and EPAs numbers.

So in the end, I think it all balances out.

thklinge

I guess I do "inspired" driving, and this winter there has been a lot of "TC OFF"-driving, both around town and elsewhere. I've usually been between 22-23L/100kms.
And 98 unleaded costs 2,56 usd / litre...

BruceP

Oh, sweet jeebus... don't get everybody going on octane.

FWIW, I feel your pain. The price difference between regular and premium in Canada runs about 15 cents a litre, which translates to 57 cents per US gallon. Those guys don't know how lucky they are...

thklinge

Octane is easy: Fill whatever is written in the manual. Porsche says 98 for my 996 so that's what I'm filling. Any more than that without a remap is just as silly as screaming down the highway at 4500 rpm