Ride height just doesnt look right...
 

Hi
I have had all sorts of headaches with getting the alignment / ride height right.

It is a 68 (with a 3.2). It has now been set up per the little spec book but it just doesn't look right. What do you all think?

http://forums.pelicanparts.com/uploa...1322024636.jpg

http://forums.pelicanparts.com/uploa...1322024651.jpg

Thanks

Rolls

I dont know enough to say if that is "off" or not but it wouldnt surprise me if thats how they were shipped in 68.

Well that could be OEM spec height but, even still, I'd say it could use a little dump to balance her out.

Hey Jim

I had the tyres just under the guards which looked great but was a pain to drive + it dialed in too much camber. Problem is with the rear when he pegs it back one notch its then to low....

Costs $500 per adjustment so keen to get it right once and for all.

Question
 

It started life as a 912? And a some point (you) someone dropped a 3.2 into the shell, first I would take it to a good (race) shop and have the car corner balanced and camber check against the added rear weight. It looks like the shop set the torsion bars to handle the increase weight of the motor. How does it handle in a corner and under hard braking. Do you have any tire wear issue's.
Art

Art - bang on. Just finished the 3.2 instal / resto. Had the camber checked - Its correct. I have put turbo rear torsions to handle the rear weight.

Handles like garbage. Can't comment on tyre wear as its only been completed.

Not really a lot of experts in this part of the world - this is my third go at it and im rapidly approaching $1500 thus far and still feel like I m going around in circles.
Do I just adjust until it 'looks right' or is there a specific measurement?
Thanks for responding.

It appears that you have it set up for off road adventures. I love the 3.2 in a "stock: looking 68....great sleeper, but i'd take it to a very good shop to get it set up for handling...........this may divert you from the seemingly stock suspension bits...but then with a 3.2 ....you are already headed down that path.

regards,al

PS: nice looking 68

Okay, Let's do some math, What is the measurements from ground thru center of the wheel to fender lip?

I am not familiar with a circa 68 but is the rear adjustment only at the Torsion bar or do you also have adjustable camber plates for height adjustments?

Please post your measurements, for us state side guys in inches please :D

Jim

Looks pretty much like my 1968 911T German import on the way from the Houston port to Los Angeles in 1971:

http://forums.pelicanparts.com/uploa...1322038224.jpg

Measurements
 

Okay thanks
From fender to ground through hub center is
Front:660mm (25.98inches)
Rear:685mm (26.96inches)
Ground to middle of rear torsion is 320mm

Does anyone know the correct euro height?

Maybe this will help " its a caculator for spring height ,

500.00 a pop for adjustments " and now going
Into the holidays. Ugghhhh. I feel for yu.

Don't stress you"ll get it


911 Spring Plate Angle Calculator

The rear tire looks to small. Is it a 165? Is it the same size as the front?

You could get some nice QuickChange spring plates for the price of one "adjustment".

ELEPHANT RACING QuickChange Spring Plate for Porsche 911/930

Hi there,

IN GENERAL, ground-to-fender lip numbers for an early car such as your '68 would be 25 inches for the front and 24.5 inches for the rear. That sets up the intended forward rake we all know and love as the car is just sitting empty and is, for all intents and purposes, "stock". It also creates the gaps between the tire tops and the fender lips that look correct, but "correct" is quite subjective. Tire size factors into all of this from a looks perspective, so it would be nice to know what size you are using...

Since you installed Turbo (26mm?) rear torsion bars, you can NOT use the '68 tech spec book numbers and expect the desired results. Use those numbers and you will end up high in the rear every time (as you have already found out).

The information in the spec books is presented in such a way that it negates the influence of tire size on the setup. If you think about it, it does make sense to do it that way from a suspension geometry point of view... the stock suspension is designed to work within a certain range of motion regardless of tire size. The way it is presented in the spec books also can be difficult to measure accurately, so that is why many will reference fender lip heights just for ease and a sanity check.

My advice would be to use the angle calculator noted above (assume 60/40, although you are probably a little more tail heavy than that) with a weight in the 2300-2400 lbs range (if you don't have a more accurate weight measurement yet) and try again with what it tells you. I am guessing you did not install adjustable spring plates in the rear? Unfortunately, they would have paid for themselves by now as they certainly help in getting it set correctly the first time in terms of overall ride height. They also are very nice to have for dialing in a good corner balance.

Hope that helps,

Ride height........
 

I have my SC set at 25.5" front and 25" rear. At that height I can run 205x55-16s front tires (7x16 Fuchs) and 245x45-16 rear tires (8x16 Fuchs) without and rubbing issues. Makes the car look slightly raked towards the front. Speaking of the front suspension, you can lower or raise the front via an adjusting screw on the lower arm. Jack up the front of the car to take pressure off the screw and turn with an 8mm (I think) wrench. Hope this helps.

Being the European i am i would lower the car as much as possible

Please stop doing this to me...! Every time I click on a link to ER I end up buying something!:D

lower it to what you think looks/drives good.... it takes time to set these up, once you are happy get an alignment/balanced.

68 and earlier spring blades are different from 69 and later. 68 is last of short wheelbase. spring blades are 1 inch shorter than 69 or later.

Try posting this on the Australian site I am sure you will get someone who can help you out locally.
Regards,
Richard.

Try posting this on the Australian part of this site I am sure that you will get some good local advise.
I think Spence 88 is in Melbourne and he seems to be up with who to contact for this sort of thing.
Good luck,
Richard.

A 68 short wheel base car that had a type 4 in it and now has a 3.2 in it? It handles like garbage?
I'am by no means a suspension expert but I think you need to look at things other than just making it "look right". I'd have to guess that with the wheels and tires alone you're never gonna get that thing to do anything close to what it could have done stock (handling wise) without some major work.
Putting that much more weight into the back of that car is not just a simple engine/power upgrade.
You've got your work cut out for you.
Oh, and I wouldn't bother with any more height adjustments until you do some serious math.

I am sure I am not the first person to put a larger engine in one of these things. I dont think it will be that difficult to get the setup right either. Its not a track car, its a daily driver. Richard - thanks for Spence ref - awaiting a reply.

Since there are a different amount of splines on the inner torsion bars vs the outer splines, moving the inner spline one notch clockwise and the outer spline one notch counter clockwise will give you 1 degree of movement. (or reverse the directions if you need to go in the other direction.) Moving just the outer spline one notch can give you too much movement.

A good shop should be able to re-index the rear torsion bars and or adjust the sway bars (if you have them) also to get it right. It would be interesting as to what size torsion bars that you current have in the back. $1500.00 is high if you not happy and the ride height and handling are not to your liking. But once you get it set (someone should have factory spec's) , I would recheck and re-corner balance the complete suspension. Find a a PCA chapter (ring them up) and go to a couple events where guys are autocrossing or running early Porsche's. You will find someone who loves the "mark" and will help you find a good mechanic!:D
Cheer and good luck!
Art

Read Doug's input for R-Builders> He is a good guy who know his suspension cold!

+1 for your year go with 25F 24.5R

I do my own alignment, I could try to walk you thru it, PM me or Skype me.

Cheers,

Jim

THIS is absolutely CRITICAL to understand. Critical. It sounds like your mechanic may have simply rotated the torsion bar one notch WITHOUT rotating the spring plate one notch in the OTHER direction. By failing to do that, the angle of adjustment would be MUCH more than you'd want for a small amount of ride height change in either direction, hence the seeming inability to be able to adjust the ride height to where you want it.

Here is a quote from a fellow Pelican who responded to a question I had about six and a half years ago when I rebuilt my suspension and had a question about setting rear ride height and how it related to "indexing" the torsion bars:

The inside of the torsion bars have 44 splines, and the rear has 40 splines. Therefore, the math comes out to:

Moving the inner bar one spline:
360/44 = 8.18 degrees

Moving the outer bar one spline:
360/40 = 9 degrees

The difference between the two is .82 degrees, so you're moving both the inner and outer for fine increments (move the inside and outside in separate directions to achieve the .82 degree change). When you pull the bar out of the spline, do so very gently, and slide it to the next notch. In my case, I need to move my car "up" about 3/4 of an inch, so I'll be moving the inner spline counter-clockwise 3 splines, and the outside clockwise 3 splines for a total change of roughly 2.46 degrees.

Please check my math, but I'll double check it in about 15 minutes when I re-index my own rear bars! On my car with 33mm rear torsion bars, roughly 3 degrees seems to move the car about an inch.

Th

Great stuff here gents. Thanks
Jim, I've got an engine instal on another project Overdue so will leave this suspension setup to my mechanic. Sounds like its 25 and 24.5 I go!
On another note, it's always intrigued me how sensitive 911's are to ride height and suspension set up. You really need to know your stuff to get this right. great that some of you share this knowledge - I find this the most challenging of all the components of a resto.

Yes, well consider tire size.

I imagine you kept the stock torsion bars in the front. So, when I hear that you added turbo bars to the rear, which I would expect to be 26mm, I think you went too far there. I probably would have used 24mm.

If the car doesn't have sway bars, I'd look into adding those as well. For a daily driver, I'd stick to sizes that were reasonable.

Good luck,
JR

Jr - yes I'm thinking Santa might need to stuff a sway bar down the chimney. What size would you recommend?

I'd probably use 15mm bars on both ends, assuming you pull the turbo rear torsion bars and use something smaller. I think those are too big for the relatively small increase in weight in the back end, compared to what an early 911 would have had.

Cheers,
JR

Is it me or does it seem odd that all this is being considered AFTER an engine swap?
An engine goes in with little to no knowledge of the how's and what's of the 911 suspension.
I mean no disrespect in any way and I know this isn't a track car but, don't you think you should do some hard research on this BEFORE.
Trust me, I understand your impatience but it'll save you money and give you more enjoyment in the long run if you just sit, take a deep breath and read, read, read.

I was doing some reading the other day and I was reminded of this thread when I read that the weight of a 1974 912E is 2315 lbs and the weight of a 1984 911 Carrera 3.2 2667 lbs.
Thats 352 lbs of difference. I'm sure it's not all motor but ya gotta figure..............

The differential between my car and a 84 Carrera is significant. It s a lot less than 352 lbs. I don't have electric seats, air con, electric windows, gadgets, fancy seats, radios, door trims, center consoles, sound deadener, cruise control, sun roof, spoilers, big wheels, heating unit, large fuel tank etc.

I did consider all of these factors before I commenced the conversion. I already have a stock restored 356 and it bores me to drive - just good to look at. I wanted an efi daily driver in a vintage body. I fully understand that it will never handle as well as a standard 912. The car can be retro fitted back to stock by simply replacing the motor mounts and tacking in a circle where the oil filter lives.

Had my car corner balanced today. Just 3kgs off perfect weight distribution. Very Pleased considering the 3.2 in the back!

How's it looking and handling now?

Update
 

Looks great and it's brilliant to drive. Really flies along - point and shoot. Interesting how the right height can really make it look the part.

Installed the Nurburgring seats as well tonight just to keep me planted. Although its interesting - there's a fair amount of flex in the frame. Did you end up with the ST or the Nurb seats ?

Can you explain that a little more? 3kgs off perfect after the corner balancing? What were the numbers before the corner balancing? From your 1st description, the car handled badly, now it's good, so what were the changes?

(I've got an '84 I'm gradually turning into a track car, so I'm trying to justify the cost of a set of scales. :) )