Why Is The 928 So Heavy?

[EIPtuningR32]

i know how almost everything is aluminum on these cars and i began wondering, besides the V8, what it is that weighs this car down to something around a mear 350lbs? also, my insurance company says that this car weights 2200lbs.......

[Danglerb]

My recycle center has scales, so I weighed my US 83, with gas, without me, at 3280 lbs IIRC.

Well its a "bit" wacky, but near as I can tell Porsche did some crazy expensive things to keep weight down, but also put in stuff like the huge group 49 battery and a 23.5 gal fuel tank. Aluminum and magnesium parts in the same car as the heavy power seats. I think its a safe bet that nothing is otherwise than Porsche intended, no surprises, just how to deliver a car that does what the 928 does at a price low enough for people to buy them.

I can't explain why the motor is as heavy as it is, but some engine likely could.

OTOH look at what a stripped track car weighs and one can easily make the argument that luxury items are behind the weight.

[EIPtuningR32]

Originally Posted by Danglerb

My recycle center has scales, so I weighed my US 83, with gas, without me, at 3280 lbs IIRC.

Well its a "bit" wacky, but near as I can tell Porsche did some crazy expensive things to keep weight down, but also put in stuff like the huge group 49 battery and a 23.5 gal fuel tank. Aluminum and magnesium parts in the same car as the heavy power seats. I think its a safe bet that nothing is otherwise than Porsche intended, no surprises, just how to deliver a car that does what the 928 does at a price low enough for people to buy them.

I can't explain why the motor is as heavy as it is, but some engine likely could.

OTOH look at what a stripped track car weighs and one can easily make the argument that luxury items are behind the weight.

quite true, its just from looking it over, it looks like they used SUPER light materials but still ended with a suburban like (weight) product.lol.

[Mrmerlin]

For the record the car is made from galvanized steel, the doors, fenders and hood are aluminum.
The 928 is a heavy car because it was designed that way,.
Most GT cars are built like this so they will offer a solid platform, and provide a quiet ride, at the same time offering advanced crash protection.
Things that add weight are all of the hi quality parts that were designed for the car, the front suspension pieces for example very strong, the seats, the best you can buy when they were made, not many cars that were manufactured at that time were built as strong nor could do as much performance wise as the 928 was designed for.
If we had autobahns here its a sure bet that most owners would be fitting new tires every few years as 150MPH isnt a time to find out that your tire s went bad, or had dry rot cracks in them.
Just a few thoughts........

[928forlife]

The early cars are really not that heavy.

But like Mr. Merlin said it is the high quality parts, those super thick lower front suspension pieces. the whole weissach rear suspension is masive and built to last, and of course the long heavy torque tube and its heavy tunnel.

Then you have the engine which is very large because they opened it up to 90 degrees to fit it in that low space and the tranny.

The good thing is most of the weight is very very low and evenly distributed making the 928 extremely solid at high speed.

I like those heavy solid pieces, gives the car its great feel.

[diverdan]

Its still lighter than the 4200 Maserati which is also a sweet ride.

diverdan

[Normy]

One of the reasons that the alloy engine weighs 560 pounds [same as a cast iron chevy] is the enormous bore spacing of 122 mm. This is approximately the same as a 7.2 liter Chrysler big block [440 Dodge]. My guess is that they did this so as to have the ability to enlarge/modify the engine later for racing.

As to the rest of the car, they were probably concerned about crash-worthiness, and they needed to appeal to large American drivers. They didn't have the sophisticated CAD/CAM software that is available today that would have pared down the weight without sacrificing strength or size.

N

[EIPtuningR32]

Originally Posted by Normy

One of the reasons that the alloy engine weighs 560 pounds [same as a cast iron chevy] is the enormous bore spacing of 122 mm. This is approximately the same as a 7.2 liter Chrysler big block [440 Dodge]. My guess is that they did this so as to have the ability to enlarge/modify the engine later for racing.

As to the rest of the car, they were probably concerned about crash-worthiness, and they needed to appeal to large American drivers. They didn't have the sophisticated CAD/CAM software that is available today that would have pared down the weight without sacrificing strength or size.

N

soooo.... now that you shined a new light into my eyes, whats the dealio on boring and stroking one of these bad girls?

[Mrmerlin]

in the long run you will save cash by either super charging/turboing the engine Boring and sleeving is very expensive

[petri]

The weight of the car is relative: 928 was relatively heavy to its time companios, which really didn't compare with it, because 928 offered so much more complete modern thinking of the GT car than any other car in teh market. But if you compare it with Ferrari 550 and up, Maser 3200Gt and up, Aston Vanquish and up etc., cars equipped with equal functions, it turns out to be lightweight. It was just a modern Grand Tourismo car born 20 years before its time. Yes, race 928 can be very lightweight, when you drop all luxus and extra safety issues away.

[Normy]

Originally Posted by EIPtuningR32

soooo.... now that you shined a new light into my eyes, whats the dealio on boring and stroking one of these bad girls?

Talk to Hacker-Pschorr about that one. He knows some guys in Wisconsin that are REMOVING the aluminum cylinder bores completely and replacing them with huge steel liners. There is a group that is selling 5.5 and 7.0 liter steel liner engines- I think that Tim Murphy has something to do with it.

Boring and stroking this engine is an EXPENSIVE proposition: I talked to Susan at Devek one day, and she told me that typically, to take an '87 and later block [earlier: not possible] from 5.0 liters to 6.4 liters costs about $20,000! Devek, of course, did perfect work, but I suspect you won't find a cheaper deal.

It is far easier to mount a blower on the engine- typically $8000 when all is said and done. Just make sure your compression is low enough. Burned pistons have a horrible taste...

N

[Danglerb]

Weight isn't that much of a factor once your 100+ mph, my guess is that none of the weight saving measures on the 928 were due to total weight, just hitting the magic 50/50 balance.