More 240z Suspension Questions

[Mike Mackaman]

Use the spring that gives you an unsprung weight you like. I personally like zero, but they don't make that spring in the rate I want so I run the shortest that will work.

Mike

[Tom Donnelly]

Use the spring that gives you an unsprung weight you like. I personally like zero, but they don't make that spring in the rate I want so I run the shortest that will work.

Mike

Bingo! That's what I was thinking but I guess I wasn't saying it right. Although, is a spring unsprung weight? But lighter is better, correct?

[joeg]

I said the same thing, Tom.

"Free length" is the length of the spring--shorter is lighter; it's just a matter of mass.

[Tom Donnelly]

I said the same thing, Tom.

"Free length" is the length of the spring--shorter is lighter; it's just a matter of mass.

Ok, cool. I didn't catch that. Sometimes you just gotta spell it out for me.

Thanks to all three of you.

Oh, and Robinson Racing has a spring tester. So I guess I'll be heading up there soon.

[pballance]

Ok Tom, I checked my notes and you should shoot for shock travel, for Bilstein, 2 3/4" - 3" bump and 2 1/2"-2 3/4" rebound. So roughly 5 1/2" total travel.

I did assemble my suspension and check travel and wound up getting 10" springs. That sounds long but I now have plenty of adjustment and when I re did the coilovers I changed the upper hat and put in camber plates. Needed the longer springs to make it work out right.

Of course, if we are at the point of weighing springs for their "unsprung" weight then I assume we have a 10/10ths build and that the driver will notice the difference.

In my car, I know that isn't the case. The driver is doing good to show up.

[Tom Donnelly]

Thanks Paul.

I finally scraped the rust off in enough places and found the weight markings on the springs.

375 front (hyperco) 300 rear (carrera).

I was thinking of testing with 350f/275r and 375f/275r and then 375f/300r like it is now. Keith ran 400/350 at one point but that was with RR shocks. He won the ARRC with Bilstein's and 350/285. I dunno who makes 285 lb springs, maybe Carrera did at one point.

Thanks again to all who posted.

Tom

[TomL]

Paul-

Sorry, but I don't understand your point about choosing your spring length to "center your shock travel". Once you choose your shock brand and length, and decide on your ride height, the shock "center" is going to be wherever it ends up, based on the shock length and the dimensions of your specific car. Seems to me that no matter what length spring you use, the shock rod will end up in the exactly the same place relative to the shock body, unless you change the ride height. The only thing that will change is how high the lower spring mount sits. Or am I missing something? I realize you want to not end up with the shock near either end of its travel (particularly compression), but I don't see how spring length enters into the equation, except as it may limit your ability to set the car at the desired ride height.