Ride height just doesnt look right...

[Richard Burns]

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.

[mickey356]

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.

[rolls 912]

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.

[rattlsnak]

Originally Posted by rolls 912

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.

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.

[agrimmitt]

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!
Cheer and good luck!
Art

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

[DRACO A5OG]

+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

[450knotOffice]

Originally Posted by rattlsnak

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.

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.

[rolls 912]

Th

[rolls 912]

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.

[DanielDudley]

Yes, well consider tire size.

[javadog]

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

[rolls 912]

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

[javadog]

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

[mickey356]

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.

[mickey356]

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..............

[rolls 912]

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.

[rolls 912]

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

[Fishcop]

Originally Posted by rolls 912

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?

[rolls 912]

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 ?

[SiberianDVM]

Originally Posted by rolls 912

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

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. )