Suspension: Springs

[genericwood]

Dean, spacing the spring will just raise the ride height. It will have no affect on the spring rate.

Erik

[George Willet]

Dean, the aluminum spacer is just that, a spacer. Its useage will raise the ride height of the car, (generally 3 times the thickness of the spacer in the front, equal in the rear).

What changes a springs rate, the amount of force to compress, is to do one of several things, make it: with a thicker wire; more or less coils; or to cut off some of the coils.

Did this answer your question and clear it up for you?

[60sRacer]

Adding a spacer won't change the spring rate - that's in the spring parameters. The spacer will change the ride height, and is how height and corner balance adjustments are made. (Unless you have adjustable coil-over spings such as those sold by Alfaholics).

If you want to change a spring rate, you have to cut off portions of coils, then compensate for the shorter spring - which then lowers the car - by adding spacers.

Robert

[turbolarespider]

Ok, here's a question...

What is the motion ratio of the shock (damper)?

If one could figure a way to build up the body shock mount, then theoretically, one could save a lot of weight by going with a coil over and dropping the spring pan + that massive spring.

Theoretically.

Eric

ps- this recent revival has been very educating. Really.

pss- george- what is the W/D rear spring rate, the yellow ones? That's one you missed on your chart. Just gotta know....

[George Willet]

Quote:

PSSs

[60sRacer]

Quote:

Originally Posted by turbolarespider .....one could save a lot of weight by going with a coil over and dropping the spring pan + that massive spring.....

[vintage prep]

I bet Jack Beck knows something about progressive springs on an Alfa

One could easely build a cambered rear axle of the "floating" type. Axle housings and shafts are available for up to 1.5 degree +- and tow in too. Unfortunately it's all stock-car type stuff so it's a bit big for Alfa's. Smaller version floater with neg. camber and some toe in might be one of the last (as yet unused) tricks left in the bag for a hot Alfa track car.

Also, 12 years ago Felix had coilovers in front with 450 lb springs (course the motion rate was way different than stock). I made my own A-arms and reworked the chassis for the coil mounts. Worked well but I couldn't afford to race at that time, just used Felix on the street. The next owner of Felix had to remove them for the 2.5 TransAm series.

Not sure if this was cleared up but when you consider spring rate motion ratio on a A-arm suspension, it's the distance from pivot to tire center that counts, not the outer ball joint.

Hope I havn't annoyed anyone, I was way late to this thread.

[davbert]

Eric

here u go... just plan on reinforcing the shock towers. lower rod end spacer brings up roll center too. great looking set up


according to alan... 200lbs rear

if you want i'll sell you my set with the bilsteins too

Quote:

Originally Posted by turbolarespider Ok, here's a question... What is the motion ratio of the shock (damper)? If one could figure a way to build up the body shock mount, then theoretically, one could save a lot of weight by going with a coil over and dropping the spring pan + that massive spring. Theoretically. Eric ps- this recent revival has been very educating. Really. pss- george- what is the W/D rear spring rate, the yellow ones? That's one you missed on your chart. Just gotta know....

[George Willet]

I hate to disallusion you, but that spacer on top of the arm doesn't change the pivot point. Changing pivot points changes geometry.

And it looks from the lower picture that the coil over is mounted on the inner of the ball joint bolts. Not to the spacer.

The spacer might be there to change negative camber angle, and widen the track.

[genericwood]

George, I didn't post the picture. But I have seen it before. While the spacer doesn't change the pickup point, it allows the outer pickup point to be moved to the bottom of the upright with a rod end. In effect, this lowers the outer ball joint position by over 2 inches for a given ride height. With this type of set up. You can dramatically lower the car and still keep the roll center above ground if you choose.

Erik

[vintage prep]

Raising the roll center also allows one to use a softer sway bar and springs, and reduces the torsional or twisting stress on the fairly weak sheet metal chassis. The Felix car had this trick too, although I did it with special A-arms instead of the adaptor. Notice in the pictures above how small that 2.5" spring is. It's so much more effective when mounted outboard on the lower arm. The weight savings adds up to several pounds per side

[turbolarespider]

In the US, the only real place where that mod is legal is in SCCA's autocrossing Street Mod class. While it would be fun to play with, there's no realistic way to make the power that the class leading boosted M3's are running.

But it is fun to think about.

I always have a good time reading these suspension threads- as they quickly diverge from a simple "what springs should I run" to how the roll centers change and what is good/bad/ugly with the chassis. Very fun to read.

Eric

[George Willet]

Thanks for pointing out what I missed with the use of that aluminum block. I see that the rod end is mounted UNDER the spindle, not on top as the stock ball joint is.

[Alleggerita]

What am I missing here? I cannot see any pictures in this thread. Is this my computer not showing them?

[bryan]

Quote:

Originally Posted by davbert Eric here u go... just plan on reinforcing the shock towers. lower rod end spacer brings up roll center too. great looking set up according to alan... 200lbs rear if you want i'll sell you my set with the bilsteins too