Vintage Porsche race cars, list/show your details

[Cory M]

I've seen 33 rear bars listed at 427lb but never measured myself. I'm running stiffer coilovers as are most of the cars running out here. Point is if I were "cajun" I would try out a stiffer rear rate with the existing 23 front bars before buying something softer for the front.

[KTL]

Elephant Racing now offers 36mm rear bars for those needing max stiffness back there.

[Dave at Pelican Parts]

Torsion bar spring force goes up with the fourth power of the diameter. The 33s should be about 25% (just over 28%) stiffer than the 31s, so somewhere up near 450 lb/in. (Assuming the wheel rate is 350 lb/in. for the 31s.)

--DD

[winders]

Originally Posted by Jnikic

WGI's outer loop is an 88-90mph corner in my car and I lift the wheel considerably there. I don't know that you can ever rid of it with these chassis, but I have to believe keeping the tire in contact with the ground as much as possible can only help ...

Yes, keeping the front inside tire on the ground as much possible is a good thing. The problem is that it can be hard to accomplish when setting up the chassis balance the way you want.

The reason the front inside tire lifts off the ground is that the front roll stiffness is greater than the rear. If you stiffen the rear or soften the front, the tire won't lift in the air as much. But, you now have reduced understeer or added oversteer.

The bottom line is that if you have the chassis balance the way you like, there is nothing you can do besides adding more grip at the rear or less at the front.

[Jnikic]

Originally Posted by winders

The reason the front inside tire lifts off the ground is that the front roll stiffness is greater than the rear. If you stiffen the front or soften the rear, the tire won't lift in the air as much. But, you now have reduced understeer or added oversteer.

Can you explain this further - wouldn't stiffening the front or softening the rear only make the roll stiffness differential worse? Isn't it the opposite - soften front, stiffen rear?


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[1970 911]

Weight is a big factor in deciding what torsion bar is right. My car is right around 2000. I use 21 front and 28 rear. I've used that setup for 20 years and it's perfect. Originally I used a 23 in the front and at 120 mph my car would jump 10 feet on the straight away off a bump. So I went down to a 21 in the front and it's perfect.

[Fubawu]

Originally Posted by 1970 911

Weight is a big factor in deciding what torsion bar is right. My car is right around 2000. I use 21 front and 28 rear. I've used that setup for 20 years and it's perfect. Originally I used a 23 in the front and at 120 mph my car would jump 10 feet on the straight away off a bump. So I went down to a 21 in the front and it's perfect.

you should read earlier posts in this thread on this topic ...I run a similar set up and I also debated weight is the key factor for a "perfect" set up. Some think I am wrong etc..
That being said I am going to try a 31 rear bar for next season.. I guess in the long run feel is subjective but lap times are not. Curious to see and hoping a 31mm bar helps.

[Flieger]

Originally Posted by Jnikic

Can you explain this further - wouldn't stiffening the front or softening the rear only make the roll stiffness differential worse? Isn't it the opposite - soften front, stiffen rear?


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You are correct. The earlier statement was backwards. Stiffen the rear to reduce front wheel lift.

[winders]

That's what I get for writing when I am tired. The first sentence in the second paragraph is correct. I just swapped ends (ha ha) in the second sentence. Of course stiffening the front reduces oversteer and makes the lifting worse. If you add more grip at rear, you would need to stiffen the rear to maintain chassis balance, not soften it. At least I got that part right!

[Fubawu]

1969 911S Le Mans and rally history is up for auction next month!

https://www.youtube.com/watch?v=HMadYY5JQmA&x-yt-ts=1422411861&x-yt-cl=84924572#t=43

[tips]

extremely happy

[Fubawu]

Congrats tips, give us some of the details

[tips]

hmm time 1:21 on a 2.55 km track against modern watercooled 911s. Car did well, im so happy. Now I also know which areas I can improve on.

Thanks

[Fubawu]

Tips we need more info on the car

[Roonieb]

[KTL]

Awesome cars Roonieb. You do know that your white car is not a longhood?

[VZ935]

Vintage muscle is a 1969 Camaro that left the factory with a 427 cu inch motor and M22 "rock crusher" gear box.

The car sitting next to it is a 78 935 with 3.00 liter flat fan motor with upside down box and titanium axles.







Same car with the ex Loos and Akin 930 770 0911 at Daytona. I don't own the black 935 anymore



Restored this one with the help of Hayden and the guys at WEVO and Brumos.
It is a 1976 934 coverted to a full 935 in 1980 by Chuck Gaa of GAACO. 3.2 twin turbo, flat fan with kugelfisher mech inj. , upside down box with ti axles.

[Fubawu]

wow guys! those are some nice additions to list!!

[tips]

ooooo wow

Originally Posted by Fubawu

Tips we need more info on the car

nothing special just an SC

[Fubawu]

Here is a video of my first time driving my 71S around the 8:15 mark the GT3 Cups enter
the picture!

https://www.youtube.com/watch?v=TDeSaloUQn0