Weight?

[Ole Petter]

I have some thoughts on weights on Porsche 911's...
Myself, I am becoming more and more obcessed with the thought of ripping out everything that doesn't add to the driving experience. As headers contra heater-boxes... So I have no heat in my car at all. But the weight is down, and the engine seems to flow just soooo much better, even sounding better as a bonus. So I am happy!

What triggered my desire to write here, is the weight of the newer, water-cooled 911 models. I had a chat with a 996 owner who had been astounded by putting his car on a scale which said 1580 kg driver and a full load of gasoline. He had a cage and leight-weight sport-seats. He thought the 1380 kg that Porsche had claimed was with a full load og gas and driver...

I had the nerve to tell him that the Porsche dry weight claims hardly covered coolant.

What I then came to think of is - does a 997 S really have to weigh (test-weight dry by a German Auto Magazine) 1485 kg? Does a Porsche really need all this weight? And what makes all this weight?

Does any of that weight add fun? Or just convenience? What remains of the old cars soul, "the light feel" "the tuneability in corners" "the rawness"?

And more so, if a 997 could have a weight of under 1300 kg, maybe 1250 kg?, then I would outrun just about everyting on the road. (I, for one have a creeping sensation that just about every car-maker worth mentioning these days have cars with acceleration figures of under 5 seconds... In the seventies and eighties this was mega-fast! Today a Cayenne Turbo S hits 60 in under 5,5 seconds, BMW M3/5/6 4,9 sec, the new Audi R8 4,6 sec, Mercedes has several models in Europe at last that are stupendously accelerative). Does Porsche have to rethink what is essential to a sports-car? I know that ALL the new Porsches are fabulous cars, don't misunderstand me, but what of the future? A 3.2 Carrera is not much slower to 60 than the new cars... But those numbers told another story 25 years ago! Not many cars had a chance...

I, like many of the old-school Porsche-owners have a different approach than - add weight with every model-change opportunity?!?

Or am I all wrong here? I say: "Fight the fat!"

[aftermath]

I think safety features, crumple zone technology ,etc adds to weight and therefore newer cars are heavier, period.

[burgermeister]

Also ride, noise isolation, wheelbase, creature comforts ... minimize all of it, and you get an Elise. Never driven one, but it doesn't look like a good daily driver to me.
They will sell you a pretty light GT3-whatever if you have the cash. But most folks who buy newer Porsches want a luxury car that still has pretentions. At least in these parts, new Porsches appear exclusively owned by the pre-bluehair / hat set.

[jester911]

Think about all the things in a modern car that used to either be manual or not there at all. 18 way power seats with heaters. Defrost mirrors. Wipers everywhere. Navigation systems. Computerized everything. Airbags in every crevice. With so many gadgets that need motors and wiring or both the car can do nothing but get heavier. That is the stuff that sells cars. The problem is to offset the weight they have to increase the engine size.

My car weighs 2500 lbs. and I wish it weighed 500 less.

[Trotskyite]

Increasing engine size is fine with me, but the weight issue is out of control. The size alone is striking. Park a 997 next to a longhood, they are worlds apart. We are not alone though, A new mustang next to an old fastback is the most obvious example. If one thing can be said about the elise family, is that Lotus designed a car that can pass federal regulations and still weigh a fraction of what a 911 does for a fraction of the price. It can be done, but there is too much money invested in the tooling etc. of their current lines. We can only hope the Cayman has a corporate benefactor that wants to put out some cool club sport models.

[Deschodt]

Is there any chance that the new CAFE standards passed yesterday might help ? If every manufacturer must reach 35 mpg (or are there exceptions for sports cars), maybe Porsche will start looking into reducing weight ? Because I doubt they can achieve 35 mpg with the current flat 6s ! (I get 23 at best)

[TargaFlorio]

It's a vicious cycle: You add more power to a car and now you need bigger brakes (more weight), bigger radiators (more weight) etc. All this slows you down so you have to add more power which leads you do add bigger brakes which adds more weight... then you realize that that the suspension can't handle the increased weight so you beef up the suspension (more weight)... then you need to pass the latest crash tests, so you beef up the chassis (more weight)... then you realize with all the weight that's been added, performance went down... well that's no good because the new model can't be slower than last years model... so you add more power... now you need to add bigger brakes (more weight)... a bigger radiator (more weight)...

Welcome to the 21st Century!

Cheers,
n.
_
http://nicolashunziker.com

[RWebb]

yes, it is a vicious cycle.

but re "the weight they have to increase the engine size."
- I am not so sure that is true. As the air cooled engine expanded in size, little additional wt. was added to the core engine. The wt. gain was mainly in the induction and exhaust systems and part of that was for emissions and noise. There are threads on this here.

Also, what is the wt. of a modern 996 or 997 motor? My bet is that better materials and technology have allowed substantial hp gains with only minimal wt. gains over - say an early 964 motor (which has the heavy induction and exhaust systems).

Certainly the gear box has gotten much heavier despite P AG's attempts to reduce wt. there. For example, the 1995 993 trans. weighed the same as the previous 5 speed in the 964 at 145.5 lbs (with oil). Excl. April 1994, p. 77. Gearbox casings are thin wall, pressure cast Al; the pinion shaft is gun-drilled, and the ring gear forging has pockets to reduce wt. – P AG said all these were firsts for a production road car.

I expect that one result of the new fuel economy law just passed by Congress is that we will a lot more light wt. design features in future cars - and they will get a lot cheaper.

[GrantG]

Originally Posted by RWebb

yes, it is a vicious cycle.

but re "the weight they have to increase the engine size."
- I am not so sure that is true. As the air cooled engine expanded in size, little additional wt. was added to the core engine. The wt. gain was mainly in the induction and exhaust systems and part of that was for emissions and noise.

The weight of the aluminum 3.0 and larger engine blocks are considerably heavier than the 2.7L and smaller magnesium cases...

[RWebb]

yes, there is a bump in wt. then, but it is not all that large compared with the total wt. of the motor.

Aichle - 911 Engines - gives 441 lbs. (2.7L Mg CIS motor) vs. 462 (SC, 1980-82), an increase of 21 lbs. -- only 4.7% in total motor wt. to get a MUCH stronger case.

[Ole Petter]

I agree completely to Targa Florio...

It makes me kind of sad, cos Porsche traditionally has been able to build sportscars with lower weight than the competition and made do with smaller engines too. Nowadays this is no longer true...

And then there is the "new" trend, everything that is new is supposedly better than anything that has come before. And every year there is someting "new" that is added to the options-list as a "must have", be it ESP, brake assistance or sun-visors with lighted mirrors...

But does these things make for a better drive? I think not. A sportscar shouldn't need add-ons. It should have a right in itself, me thinks.

[GrantG]

Originally Posted by RWebb

yes, there is a bump in wt. then, but it is not all that large compared with the total wt. of the motor.

Aichle - 911 Engines - gives 441 lbs. (2.7L Mg CIS motor) vs. 462 (SC, 1980-82), an increase of 21 lbs. -- only 4.7% in total motor wt. to get a MUCH stronger case.

I am VERY surprised to hear that. I was recently quoted more than 100 lb penalty for upgrading from 2.7 Mag MFI to 3.2 Alu Carbs by a very reputable source. Is the 3.2 any heavier than the 3.0? What about the CIS?

[TargaFlorio]

Using light-weight materials like Aluminum isn't always an advantage. The problem with Aluminum is that it's not the strongest material so by the time you make your design strong enough you've had to use "more of it".

Take the all aluminum Audi S8 (alu panels on alu space frame) it weighs in at 4276 lbs...

Aluminum is great on light-weight cars; a light car benefits from an alu suspension because the suspension doesn't have to be that strong. Compared to a heavy car an aluminum suspension might work against you: By the time the suspension is strong enough to handle the weight, it's not that light any more, no matter which material it's made of.

Colin Chapman had it right when he said to 'add lightness"

Cheers,
n.
_
http://nicolashunziker.com

[eR1c]

"Fight the fat!"

YES! Agreed!
I am seriously considering getting a 73 911 to restore and convert to an RS clone... one thing that I think i'll be obsessed with maybe even more than getting power out of the engine is the weight of the car.

[GrantG]

Originally Posted by TargaFlorio

Take the all aluminum Audi S8 (alu panels on alu space frame) it weighs in at 4276 lbs...

Yeah, but compare that weight to an S Class Benz (Steel)...

[TargaFlorio]

The 2008 Merc S550 weighs in at 4465 lbs... so it's 200lbs heavier...
Let's assume that the S8 and S550 are somewhat identical cars, by using Aluminum, Audi managed to save 4% of weight on a 4500lbs car. Yes, it's 200 lbs lighter but at that weight who cares?
I know this isn't an accurate comparison. One car has a bigger engine, V10 vs V8, then again the other car has a bigger gearbox, 4wd vs 2wd etc. but my point still remains the same: A 5 passenger car (a sporty one at that) shouldn't weigh in at around 4500 lbs.


Cheers,
http://nicolashunziker.com

[RWebb]

Originally Posted by GrantG

I am VERY surprised to hear that. I was recently quoted more than 100 lb penalty for upgrading from 2.7 Mag MFI to 3.2 Alu Carbs by a very reputable source. Is the 3.2 any heavier than the 3.0? What about the CIS?

A 3.2L _is_ heavier but - again - it is mostly in the induction and exhaust. Check my database for info. Another Pelican is kindly hosting it - download the *.xls file and tab thru it.
http://www.penaltykicker.com/911/data/
(BTW, your car is in the *.doc table)

It does sound like something odd is going on with the 100 lbs. quote.

[Lukesportsman]

Yeah, I was thinking more in the range of 60lbs but I'll be happier if nearer 40lbs. I've heard 100lbs if you swap OEM 2.7MFI for OEM 3.0 CIS air filter to muffler. The cases just aren't that heavy....period. The crank gets a little bigger and if you go from a 901 to a larger trans then often the flywheel gets larger. P&C's are minimal and air doesn't weigh much in the holes.

I can't believe with as many engine builders we have on here that we can't get a good data base. So many engines get shipped that you'd think Henry, Steve or others would virtually have a data base from shipping weights minus similar crating.

[Lukesportsman]

By the way, I have racing scales that are certified and accurate to a pound. I'll make sure that the next opportunity I have I'll weigh the 2.7 versus 3.0 and difference in weight of the car and get them posted on Pelican. I'll also document the corner weight changes simply be swapping engines. It's going from MFI to ITB's so induction is almost a wash and from early HE's to headers so there might be a few pounds in its favor, but same M&K muffler will be behind each. This will only be a singel data point, but will give us some "hard" numbers to play with in the future.

[911pcars]

This link hasn't been mentioned recently. This might help with some weight calcs.

http://www.early911sregistry.org/jCalzia.html

Sherwood