i tried 250's in the front of my b210, has a mazda piston engine in it, much heavier than the a12. way to stiff for me, mind i do have 280zx struts and inserts. went back to the 180 pounders, thou i would like to swap in a much stiffer roll bar

^^ Really???? I've got 250's in the front of my truck now and they definately don't feel noticably stiff when driving, in fact I thought about going stiffer :S

I don't know how people can run 225's etc in 1200's with ca18's and the likes, would be way to soft for my liking.

I don't know........ I had 250 pounders in my coupe first and it felt like a car with no suspension! I think the only damping or compression came from the tires! Most of the 510 Vintage race guys run 200-250 up front and the 1600 is a few hundred pounds heavier. I replaced mine with 175 pounders and it's still really firm, but at least it's got some compliance.

JMAC, the 275lbs kings are from the prosport catalogue:

Part # KPS-104-X5K
F-H 180
ID 65
lbs 275
S-H 59

F H = free height
S H = solid height

My streeter struts are based on the B110 /S13 brake conversion with KYB golf /rabbit inserts and the track car struts are based on Stanza struts shortened with koni sport adjustables.

In my case the 250# springs are mated up to shortened B310 struts and KYB GR2 gas strut inserts for the Z-cars. IIRC, the struts had to be shortened ~2" to mate up with the Zed strut cartridges. The valving on the Zed strut carts seems to work well with the 250# springs.

Gary

Hey Benny - your kings springs with 275lb rate - are they just std off the shelf 'sports low' - KDFL-57 ?? Or are they a spring originally for a different car that fit the bill, or are they just something not listed in the std catalogue?

See that's something I want to sort out now that I have a little more time. What strut\shock combo is used in both instances? I was planning on using 200lbs\in springs with my stanza struts but I don't know how short I should cut them. I had some basic shock options form -1 inch to -4 inches but these are all non adjustable gas inserts for heavy cars (1200kg roughly)

I currently run a kings spring 275 lbs 180mm free length spring in my track car and a 5kg/mm generic [280 lb] 180mm free length in my streeter with a tender spring. I would say that its [streeter with 280lbs] just a tad too firm for the street. 4kg /mm [220 lb] would be better

The coil overs in my streeter have a much longer amount of travel when compared to the coliovers in the track car.
I would suggest it is better that the wheel drops into the undulations in the road surface rather than skipping over the top of them on the street. If the tyre is not on the road there is no grip.

500lbs springs in a 1200 would be just plain silly

I use 250pd x (200mm freelength) on my 1200 with a ca18. I'm very happy.

250pd with standard length springs would be good for a v8

As you are going coilovers, you will probably run shorter springs so you can fit wider rubber.
When you run shorter springs, you need much larger rate springs to stop the same weight in the same distance.

Keep all this in mind.