Suspension type comparisons

[gnosez]

I have driven my 240 with 3 different suspension set-ups (stock, progressive, coilovers). I drove it 3000 miles home after I bought it with stock and I what could be considered worn out shocks and springs. Then I did the poly, larger sway bar (frt and rear), new shock and progressive springs change-over. That lasted a year and t he car now has coil-overs, adjustable shocks, T/C kit, camber plates, adjustable delrin control arm bushings. Each time the ride got better (IMHO). So where can I go from here and what should I expect for that effort and expense?

[johnc]

You can go which ever direction you want. First figure out your intended use, how much money you have, what level of comfort and handling you want, etc.

[gnosez]

Just the person I hoped would reply...I think the only thing I haven't done to the suspension is make the caster adjustable, installed quick steering knuckles, or put in the tubular control arms that Ross and others sell. I use the car for three things: 1) as a spirited road car that sees 10,000 miles a summer, 2) an AX car, and, 3) 3-4 track events a season (NHIS, Limerock, Summit Point, etc.). What I'm interested in is two-fold: what changes can I make and what will I gain if I do so. At this point money is not being considered, the quality of the ride and it's responsiveness is.

[260DET]

The stock 240 body/chassis is not particularly rigid so the more you improve the suspension the more that rigidity aspect becomes relevant as to further improvement.

[gnosez]

No doubt it would. I have added front and rear strut tower bars and a roll bar. There is also an "L" bracket plate welded to the frame where the front sway bar is located as it was beginning to crack the spot welds. I'm still interested in finding out what the next suspension tweek should be and what it will give me in return.

[johnc]

I think you have the basics in place. Now its a matter of testing and tuning spring rates, anti-roll bar sizes, shock adjustments, and alignment settings. My suggestions:

 

Spring rates: 175 front 200 rear

Anti-roll bars: 1" front 3/4 or 5/8" rear

Shock settings: 1 or 2 front 3 or 4 rear

 

Alignment

 

Front

 

Camber: 1.5 negative

Caster: much as you can get - try for 6 degrees positive

Toe: 0 or 1/4" out

Ride height: 6" measured at the bolt holding the bottom of the front fender on the car

 

Rear

 

Camber: 1 degree negative

Toe: 0 or 1/16" in if you can adjust it with offset bushings

Ride height: 6.50" measured at the end of the rocker panel

 

If I had a performance street Z this is where I would set things.

[gnosez]

I'm running 1" front 3/4 rear sway bars, 200# front/225# rear, camber is -2 front and -1 rear, caster is +4, ride is set at 5 3/4 front and 6 rear (street) 5 1/4 all around track, and shocks are set at 3 front and 2 rear. How user friendly is an Ackerman steering set-up? I might go to 250# rear and move the 225s up front for the NHIS and Limerock locations (big dips-oh, my).

[260DET]

Any particular reason for recommending toe OUT for the front, John? As you would know, the rule is that toe out tends to cause frontal instability. I believe that some toe out however may help reduce turn in understeer.

[Drax240z]

Yup, front toe out will reduce turn in understeer. John, I'd love ot hear more!