Corner weights early cars

[lasseknoppel]

For You who have not seen them in the flesh, original Porsche front bumper weights for improved road holding capacities. Imagine Porsche, so concerned with low weight, actually producing these things. THEY ARE HEAVY!! They even put spare part numbers for all to see!

Lasse

[Gearbox]

I understand that they weigh 50 pounds a piece. One of those "opps, we goofed" engineering snafus that looked good on paper and caused Porsche to take a band aide approach after the first cars were produced when they found it to be too light up front to allow the car to turn at speed. I'd hold it up there with the 72 outside oil filler cap and the 2.7 engine.

[210bhp]

Lasse

I've been looking for a pair of these for my car but shipping this weight FROM ANYWHERE has always been the issue.

Regards
Mike

[daepp]

When did they quit using these? Are they present on a 72 T, or just an S?

[72tii]

I installed a pair of these in my '68 911 a couple of months ago and was amazed at the difference. I know it's counterintuitive to add weight to a sports car, but these really make a difference in cross-wind stability and on turn-in, at least on the street. Maybe on the track, the car would handle better without them- I don't know. I haven't had it on the track yet.

[ttweed]

I understand that they weigh 50 pounds a piece.

I have a pair in my garage and they are 25 lbs. each, 50 lbs. total for the pair. IMHO, the factory put these in to raise the polar moment as a CYA move to save drivers who don't know about TTO, or how to correct for it, from themselves. I took mine out a long time ago and haven't ever wanted them back. I'm pretty sure they never put them in the race or rally cars where the driver was expected to have a clue.

When they lengthened the wheelbase in '69, they were no longer considered necessary, although they did put the two batteries up front in boxes to help with weight distribution in the later cars.

TT

[denson]

You have to love that.

Funny story is that my 63 356S cab felt light in the front (sorry, I brought up a 356). A few weeks later I bought an optima battery with the cloning enclosure. I installed it and was about to discard the old regular cell battery and it dawned on me. Keep this battery next to the new optima and dead center to the vehicle. After wrapping it in a towel and placing an acid mat below, I installed it. Went for a ride and was a bit taken back that it cornered better (less understeer, could that be possible?) and felt more stable in straight line.

Mike Kuhn, I agree 100%.

Go figure. I guess it comes down to whatever it takes.

John

[lasseknoppel]

I think they may have been needed in the mid-sixties when You ran on Michelin X or something like that. On modern tyres and on-the-spot wheel adjustment a SWB runs just fine, even on three wheels with inner front in the air. All 911 Porsches are very sensitive to incorrect angels and funny corner wheights, they should be very very correct. Try that and a good not too heavy tyre and be amazed what a 40-year old piece of German engineering can do!

Lasse

[Gearbox]

IMHO, the factory put these in to raise the polar moment as a CYA move to save drivers who don't know about TTO, or how to correct for it, from themselves. I took mine out a long time ago and haven't ever wanted them back. I'm pretty sure they never put them in the race or rally cars where the driver was expected to have a clue.
TT

I couldn't disagree more, TTO, or Terminal Throttle Oversteer, happens when you lift off throttle in a turn thus transfering weight to the front tires, making your rear tires light and the front heavy. This results in the rear tires sliding out and the front tires gripping harder in the turn spinning the car out as both ends are now going seperate directions. Additional weight in the front would just make things worse in regards to TTO. The weights were to overcome a massive under steer in the SWB cars. While you want some under steer in all production cars and especially for novice drivers on the race track which gives them much more confidence than a oversteering car (which has a higher tendency to spin out), the SWB 911 had so much under steer you could not turn in fast at all. So the likelyhood of inducing TTO was highly unlikely as the car just wanted wanted to drive straight off the track in a fast turn, not spin as in TTO. In fact, it was Porsche's racing program who came up with the weights to correct the handling of the car which eventually made it into the production cars. Corner weights is extremely important in race car set up, and the suspension of the SWB was very limited and could not be adjusted to move enough weight forward. The weights are an intregal part of the car if you want to make it handle and corner fast, put them back in, Porsche's period race cars had them, your SWB 911 should too.

[kenikh]

These were a band aid fix to a poorly designed front suspension in the SWBs; this is well documented. If you upgrade some front end componentry to LWB parts (which parts escape me), you can have fantastic handling and lighter weight. These should be in the the junk pile or left to the Q-tip crowd.