Porsche 944T brakes on VW 1303S

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TZepeSH
Posts: 237
Joined: Wed Nov 03, 2004 1:55 am

Re: Porsche 944T brakes on VW 1303S

Post by TZepeSH » Tue Jul 24, 2018 2:01 am

My torque bar is more of a copy of the CSP system.
https://www.csp-shop.de/technik/pdf/deeng/20917.pdf
https://lh5.googleusercontent.com/-IpMX ... G_9646.JPG

Thanks for the info on studs removal, I was considering heat because aluminum expands more than steel and I thought it would make removal easier. Good point with the wheel nut on, not to damage threads. Big hammer it shall be.

Bruce2
Posts: 6852
Joined: Sat Oct 13, 2001 3:01 am

Re: Porsche 944T brakes on VW 1303S

Post by Bruce2 » Sat Jul 28, 2018 3:18 am

I presume you copied that description from the Mendeola site.
Ol'fogasaurus wrote:
Mon Jul 23, 2018 10:18 am
Mendola's 'stiffy'.jpg
.... transfers some of the load to the torsion housing
Nope. This is a fantasy. The extra bar does nothing.
Ol'fogasaurus wrote:
Mon Jul 23, 2018 10:18 am
reducing some of it from the spreader bar that would normally pass everything directly into the shock towers
Here's how the 3 bar setup works.
We all know that when you accelerate forward, the rear ends of the frame horns want to bend down. Newton tells us this happens. When the rear wheel rotates ccw (as viewed from the driver's side), the engine and trans unit wants to rotate cw. This is what pushes the frame horns down.
Install two diagonal links from the rear trans bracket up to the top shock tower, then when the frame horns are pushed down, these two links will try to pull the top of the shock tower down and towards the center of the car. In other words, the two diagonal links are purely in tension.
If you just had those two links, they wouldn't stop the frame horns from bending down. Instead the downward motion of the frame horns will just pull the two shock towers together. Here's where the third cross bar goes. Once it's installed from one shock tower to the other, it will be in compression when you accelerate away.
The result of these three bars is that the tops of the shock towers will see forces pulling straight down. This is not a problem because the vertical section of the shock tower is HUGE, so it won't be bending. There will be a torsional load on the torsion housing's tubes. But since they are very large in diameter and very thick walled, there will be virtually no movement of them too.
These types of links are either in tension or compression when they are working.
Now consider the two extra links in the "stiffy" setup. Which way is the force acting on the links? There's no force pulling the top of the shock tower away from the trailing arm's pivot point. Also, there're no forces pushing the top of the shock tower towards the trailing arm's pivots. Since there are no forces in tension or compression on those links, they aren't doing anything!

Comment on the Bugpack setup in your photo:
This is just a bunch of scrap metal. Don't waste your money on it, it was designed by an incompetent dummy with no engineering comprehension whatsoever.
As the two diagonal links pull down, they just bend the cross link since they are attached not at the end. Since the cross link will be in compression, this will help bend it more. To demonstrate this, take a drinking straw and stand it up on a table. Put your finger on it's end and apply force towards the table. In other words put it in compression. It can take quite a bit, right? Now while applying that load, also push on it's side a tiny amount. How much compression can it take now?

Look at the CSP 3 bar setup. This is designed properly. The downlinks are in tension and the cross link in compression with no side load at all.

Ol'fogasaurus
Posts: 14031
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Location: Just north of Seattle

Re: Porsche 944T brakes on VW 1303S

Post by Ol'fogasaurus » Sat Jul 28, 2018 9:57 am

Bruce, as usual you are looking at what I say in a very bias manner. Some of what you say is true and some only half true you have to lean to look at things in a wider "cause and affect view" not linear. Remember "the dance of death" that the frame horns can do... depending on what the cause is.

Lee

Bruce2
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Joined: Sat Oct 13, 2001 3:01 am

Re: Porsche 944T brakes on VW 1303S

Post by Bruce2 » Sat Jul 28, 2018 12:22 pm

As usual, you assume every post that disagrees with you to be a personal attack.
Ol'fogasaurus wrote:
Sat Jul 28, 2018 9:57 am
Bruce, as usual you are looking at what I say in a very bias manner.
Re-read the first line of my previous post. My reply is based on what I assume to be the claims of Mendeola.
Ol'fogasaurus wrote:
Sat Jul 28, 2018 9:57 am
and some only half true
Like what?

Ol'fogasaurus
Posts: 14031
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: Porsche 944T brakes on VW 1303S

Post by Ol'fogasaurus » Sat Jul 28, 2018 1:35 pm

Bruce, I am in a lot of pain from the surgery so I don't want to get into a spitting contest here as I probably wouldn't be nice.

It is one thing for a car to sit in the garage and the weight of the engine, being cantilevered to the end of the trans mounts does induce some hanging motion. But consider what happens on the road going over speed bumps, holes, turtles and other things. The mounts can: bounce up and down, side to side, go in a circle or even figure 8.

Racing and off-roading can excerbate these things to the point of failure.

Also remember that the torsion assy is an assy so things that happen to the assy stay in the assy unless there is a direct path for the loading to go in a different direction; e.g., a path of escape. Also look at the shape of the trans mounts/Pickle Forks... they are formed that way (remember what strengths a tube has and doen't have and the straight section used to cure some of it) to fix certain problems ithen there is the stiffening flanges that need to be welded closed as the spot welds don't really do a good job.

The soft stock styled trans mounts also help some things happen that you don't want.

The 2 connections to the pan are known to be not the strongest so you want to help them out too.

The stock trailing arm pivot is not what one thinks it is (pictures for some other time).

This is about as much sitting as I can do but maybe there is a clue in there.

Lee

Bruce2
Posts: 6852
Joined: Sat Oct 13, 2001 3:01 am

Re: Porsche 944T brakes on VW 1303S

Post by Bruce2 » Mon Aug 06, 2018 1:01 am

So your argument is that there's a whole bunch of voodoo going on that you don't understand, and that you think I'm wrong but you can't explain why.
Got it.

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