Dorkiphus.net - Rear torsion bar question

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Quote:

Originally Posted by OldTee (Post 317052)

Using the formula example leaves me confused. Stock for the sc at 1400kg (wt from the book) and a 24.1mm standard bar gives a angle of 38-39 degrees. I measured 29.5 plus 1.6 degrees at the sill giving 31.1 degrees. Some 7 degrees or so different.

The formula says for a 28mm bar should be 25-26 degrees, plus 1.6 degrees for the sill leaving 26.6 to 27.6 degrees for the new 28mm bar.

I would think the formula would be much closer than I got for stock.

The book swing of 13 degrees seems to be a lot.

To answer a question you may have, the measurement is the spring plate, at the top, with the shock off, plate unattached from the banana arm and the the bottom stop removed from the cover.

Have at me gang.

ARF

When I did the rear torsion bars on my car it was through a bit of trial and error at the start. I didn't change the angle at all at the start just to see what it looked like.. It turned the car into a rally style bug. :) The clearance at the rear wheel went from under the fender by and inch to 8 inches below it. So 13 degrees may sounds like a lot, but it's a huge difference in spring rates by going to a large bar.

Quote:

Originally Posted by OldTee (Post 317052)

If you are after Euro height (which I think is a bit too high) the angle should be 24-25 degrees. Like I said, I went with just lower than Euro, not quite race (which would require more than 2 degrees of camber to not rub your fender through) Where are you getting the 1.6 degrees for the sill from?

Quote:

Originally Posted by tdatk (Post 317057)

About mid way on the sill on the silver plate. Measured it on the ground then on the lift. There was a .5 or so difference between on the ground and in the air.

My main question is: if I am measuring 29.5 plus sill of 1.6 what should I set this bar too. Not 18.1???????.

ARF

Quote:

Originally Posted by OldTee (Post 317059)

John,
Your overthinking this. Raise the car on the lift , you already disconnected the SP and shock/bolt, remove the 24mm t-bar and Install the 28mm t-bar and go with 24 degrees as read on the indicator sitting on the top of the spring plate (see my pic on pg 1) thats it for Euro ride height. Now if it's too high you have around 1/2 " adjustment from the eccentric bolt on the SP to fine tune if you set in in the middle adjustment. Like I said, I went with 23 degrees and that is as low as I'm comfortable with and no rubbing.
Tim

Trial and error time. I am going to go with 20 degrees. See what happens.

ARF

Quote:

Originally Posted by OldTee (Post 317063)

Trial and error time. I am going to go with 20 degrees. See what happens.

ARF

Yo Yo Yo...... It's gonna be slammed....:lol:

My slightly lightened race car with 33 mm T-bars reads 15-16 degrees for "race height" and 17-18 degrees for "Euro height". What a difference a thick bar makes. Will be starting that process tonight, so thanks all for posting this.

Quote:

Originally Posted by Dr K (Post 317078)

What a difference a thick bar makes.

Do your patients often notice?

John use the calculator. Add or subtract the sill angle from the spring plate angle.