Front Ride Height Adjustment

[99boxster559]

Hi all,

I am looking for some technical adivice on changing the front ride height of my 82SC. PO had lowered the car and although it looks good, the car is clearly lower on the drivers front side than the passenger. The tire will sometimes rub the inner fender peeling off flakes of tire which is not ideal.

How much height can one get from turning the adjustment screw?
More importantly how does one adjust height with the torsion bars?
Does the whole TB need to come out and be reindexed or can you reindex just the cap?

How can one tell with the car on the lift if your indexing the right way "higher" rather than lower with the suspension at full droop?

[smadsen]

I sympathize with your desire for a simple, easy, quick, and cheap fix. Those options are seldom available on a 40/50 y/o car. I'd recommend verifying both torsion bars are in good condition (like not broken). Then I'd take down the threaded adjusters and give them a good cleaning.

Cars with the big rubber bumpers had certain Federal U.S. ride height parameters to meet back in the day. This was done with, among other things, big steel 1/2" thick washers on top of the strut tower. Removing those effectively lower the car to what was called "Euro ride height." My advice is don't lower the car to Euro ride height without first removing these spacers. Others may have a different opinion but it doesn't make sense to raise ride height with the spacers and then try to lower if by re-indexing the T-Bars.

To put it back together, put the adjusters in the middle of their travel. Then index both T-bars at the angle the nearly correct side was, or index it up one click to raise it as a starting point. Put the car down, maybe drive around the block, and run it up on a level floor and start measuring ride height. The anal among us might put enough redi-crete in the drivers seat to simulate a driver, and a half tank of gas.

Also, always put the T-Bars back in the way they came out. They've been twisting a certain direction all their lives. Now is not the time to reverse the twist. When you get close, dial in your ride height with the screws.

Also you can level your garage floor with linoleum squares to get level so your measurement are the same side-to-side. If you go to all this trouble, now is a good time to zero the rack, center the steering wheel, and re-set your toe-in.

Good luck!

[Schulisco]

Increasing the ride height is some of the easiest tasks on a G body 911 from our host:
https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/55-Lowering_the_911/55-Lowering_the_911.htm

I couldn't find a single video showing only that task. But there are plenty of videos talking lowering and making over the adjustment of the riding gear on a 911. Instead of lowering you increase the ride height by turning the screws the other way...pretty that simple.
Brief intro:
https://youtu.be/8VXnBxrqriE?t=154

Playlist from KlassikATS about 911 suspension:
https://www.youtube.com/playlist?list=PLkWFofpgz2Og6nqijrJAFz7MB_vVCU9Vp
Very good explanation of a proper suspension adjustment:
https://www.youtube.com/watch?v=sflOzTfxOQA (pt2, pt1 also available in the channel)

Always give the car a full wheel alignment afterwards incl. weight distribution on all 4 corners which is key on these cars. Probably it makes sense to do other jobs on the ride gear as well before...

Here in the tech spec book from Porsche you get all the required numbers: https://porschecarshistory.com/wp-content/old/Techspec/03/911-all-78-81.pdf
From 1981-1983 pretty much nothing big changed any more.

It seems that you're new to these cars. There's a bunch of reading I always warmly recommend to get a better technical understanding of these cars because they're a bit special than other cars:
https://www.amazon.com/-/en/dp/1845849558
https://www.amazon.com/Porsche-Service-Manual-1978-1979/dp/0837617057
https://www.amazon.com/-/en/dp/0760308535/ (online https://www.pelicanparts.com/cat/r_911m)
There are many more but these are precious to every 911 newbie ...

How much height can one get from turning the adjustment screw?

On the front much more than on the rear, if your car already has the adjustable rear sway arms which I suppose should be the case on a SC ...it's probably enough to solve your issue.

More importantly how does one adjust height with the torsion bars?

Torsion bars can be remained when adjusting the height.

Does the whole TB need to come out and be reindexed or can you reindex just the cap?

Only on the rear and depending on the height you want to achieve. See above.

How can one tell with the car on the lift if your indexing the right way "higher" rather than lower with the suspension at full droop?

There are angle numbers given in the tech spec book, mainly the setting is primarily adjusted on counting teeth of the spring bars & control arms and fine-tuning then standing on the ground.

Thomas

[Bill Verburg]

Originally Posted by Schulisco

I.......
Here in the tech spec book from Porsche you get all the required numbers: https://porschecarshistory.com/wp-content/old/Techspec/03/911-all-78-81.pdf
...
Thomas

That's a great archive!!!

They wouldn't happen to have the '74 and '75 Techspec booklets?

[Schulisco]

Originally Posted by Bill Verburg

That's a great archive!!!

They wouldn't happen to have the '74 and '75 Techspec booklets?

There are, but I didn't found them yet on the net, you can purchase them by our host or on Porsche itself. Compare the prices. These tiny "books" are pretty pricey...

update: Bill, I found only this, does this help you?
https://porschecarshistory.com/wp-content/old/Techspec/01/911-all-72-73.pdf

Thomas

[99boxster559]

Originally Posted by Schulisco

Increasing the ride height is some of the easiest tasks on a G body 911 from our host:
https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/55-Lowering_the_911/55-Lowering_the_911.htm

I couldn't find a single video showing only that task. But there are plenty of videos talking lowering and making over the adjustment of the riding gear on a 911. Instead of lowering you increase the ride height by turning the screws the other way...pretty that simple.
Brief intro:
https://youtu.be/8VXnBxrqriE?t=154

Playlist from KlassikATS about 911 suspension:
https://www.youtube.com/playlist?list=PLkWFofpgz2Og6nqijrJAFz7MB_vVCU9Vp
Very good explanation of a proper suspension adjustment:
https://www.youtube.com/watch?v=sflOzTfxOQA (pt2, pt1 also available in the channel)

Always give the car a full wheel alignment afterwards incl. weight distribution on all 4 corners which is key on these cars. Probably it makes sense to do other jobs on the ride gear as well before...

Here in the tech spec book from Porsche you get all the required numbers: https://porschecarshistory.com/wp-content/old/Techspec/03/911-all-78-81.pdf
From 1981-1983 pretty much nothing big changed any more.

It seems that you're new to these cars. There's a bunch of reading I always warmly recommend to get a better technical understanding of these cars because they're a bit special than other cars:
https://www.amazon.com/-/en/dp/1845849558
https://www.amazon.com/Porsche-Service-Manual-1978-1979/dp/0837617057
https://www.amazon.com/-/en/dp/0760308535/ (online https://www.pelicanparts.com/cat/r_911m)
There are many more but these are precious to every 911 newbie ...


On the front much more than on the rear, if your car already has the adjustable rear sway arms which I suppose should be the case on a SC ...it's probably enough to solve your issue.


Torsion bars can be remained when adjusting the height.


Only on the rear and depending on the height you want to achieve. See above.


There are angle numbers given in the tech spec book, mainly the setting is primarily adjusted on counting teeth of the spring bars & control arms and fine-tuning then standing on the ground.

Thomas

Thomas,
thanks for the in depth response. I have the bentley manual and watched through all YT videos on the matter but none of them explain how much range can be achieved through using the screw or the removal of the TB cap and what that does.

I also should be more descriptive on the problem. The car as it sits now measuring from TB center to wheel center is telling me that the car is about 2.5 inches lower than even euro spec so the car needs to go up in height. The rear is set dead on at euro spec and the front is lower which gives the car a front slanted rake.

[Schulisco]

I would try to lift it as much as possible whithout dismantling the front axle. Then you can see what you can achieve that way. Count the rotations and denote them, but you already said that the car is different high on both sides. If it's that low, you probably won't reach all the way back on euro spec height but it's worth a try.

This is the only screw you have to turn on car's left and right:

Source: https://www.youtube.com/watch?v=8VXnBxrqriE&t=154s

Remember that you change the camber on the front when setting the car higher, this *must* be checked and readjusted by minimum for sure afterwards. Second are the corner weights. You can check the camber with a simple digital angle meter or even a smartphone app ;-)

Thomas

[Schulisco]

This is how the height is adjusted as suggested by Porsche:



Taken from the tech spec booklet...link above...

Some people control the height by measuring from the fender to the center of the wheel hub. I don't have any numbers for that currently, but they're also available on the net.

There are no numbers iirc on how much height you gain per rotation of the screw. Its mostly individual to the car I guess, depending on the tires, pressure, weight of the car, gas tank level etc. All in all you have to raise it step by step. Or the other way - lift it on a post lift, turn the screws on max, so you can put car back on the ground and then you're able to lift it by a car jack, and then go down step by step... or when you can get on a workshop pit - or a 4 post workshop lift - is ideal for this job...

Thomas

[icarp]

Easy fender height numbers are 25 1/8" front and 24 5/8" rear , from the edge of the lip to the ground . First make sure the car is on VERY LEVEL GROUND , then measure.
this is a good starting point , the 911 car is sensitive to 1/16" in ride height , so keep testing .
Every time you change the front ride height you MUST RESET THE FRONT TOE !!!!!
0 TOE is what the factory specs allow for .10 +_ .10 that means 0 is in spec
I like 0 in the rear as well

any 911 sc loves this set up

Ian

[99boxster559]

Tried to achieve the ride height by adjusting the screw but it wouldnt lift to the height I needed. So I pulled the TB cap moved it one notch up and set the adjustment screw till the drivers side was even with the passenger. Took for a good bumpy ride on snowy roads to get the suspension settled and now sitting all even!

Will have to wait for spring to drive across town to the local Audi dealership where I can use their alignment rack.

Thank you all for the help and suggestions, turns out it was a 5 minute job to move the TB cap and was of no fuss.

[$yncro]

Awesome! Now time for turbo tie rods.

[icarp]

check the toe at this point, for every height change there is a toe change .

Ian

[Schulisco]

Glad to hear that you succeeded!

Also check the wheel loads on all 4 corners!!

And we want to see pictures...

[99boxster559]

classic guards red G body. Running like a top now thanks to Thomas's helpful input, fired right up when it was 15 degrees out!

[icarp]

Originally Posted by icarp

check the toe at this point, for every height change there is a toe change .

Ian

OP, do you understand the advise that has been shared here ?

If you changed the ride height .030" your toe has changed as well.
If the toe was correct it is now incorrect . Period no way around it .

You do not have to follow my advise , I just posting this for others
that may read this post .

Ian

[99boxster559]

OP, do you understand the advise that has been shared here ?

If you changed the ride height .030" your toe has changed as well.
If the toe was correct it is now incorrect . Period no way around it .

You do not have to follow my advise , I just posting this for others
that may read this post .

Ian[/QUOTE]

Hi Ian, yes I understand that the toe changes as ride height changes. I will certainly align toe, caster, and camber when I can get the car to an alignment rack.

[PeteKz]

I think some numbers are off. If you change the ride height .030", that is so small that the extra burger you ate for lunch will compress the suspension as much! You could not even measure the toe change for that small of a ride height change.

A good question consists of: how much does the toe change for a given front ride height change, while holding the other factors constant? That is, with the stock suspension and steering geometry not changed. I might go see if I can measure the actual toe change for a 1" change in front ride height. Has anyone else done that and posted the numbers? And no, I'm not looking for the steering and suspension geometry diagrams that Bill V has posted several times in other threads. I mean actual measurements.

My starting hypothesis is that the change in toe for a 1"/25mm ride height change is within the specification tolerance for toe angle. Otherwise, I would think that bump steer, even at specified ride height, would be very noticeable.