what springs to use

[angelmanuel]

guys,

 

i have a 1979 B310/210 that i will be upgrading to 280ZX fron struts. the question is: what springs to use? i know some friends have told me that cutting the factory springs is not a big deal, but i still have doubts about doing that.

 

are there any springs out there that fit my car but are shorter? the B310/210 springs are about 2" shorter than the 280ZX springs, so i would have to cut those 2 inches plus a little more to lower the car where i want it.

 

any ideas?

[datzenmike]

ZX springs are way, way, way to wide to ever fit up into the B-210's strut tower.

It would be a good idea to get some measurements on your stock springs and work out the spring rate. Cutting a spring shortens it but also stiffens it... less number of coils to absorb the weight. Adding stiffness is always good when lowering a car as there is less chance of bottoming it out and the factory springs are a compromise between performance/handling and family comfort. That said by the time you get the car low enough the spring rate may be so high it's impossible to drive in it.

What I did was remove the lower spring mount... the one welded to the strut tube. Grind away the weld so it is smooth. Put the free to move spring mount and spring back on the strut tube and use a split collar to clamp below it. Now the mount and spring can be moved up or down similar to a coil over.




If you find the spring too soft, jack the car up loosen the split collar, slide the spring down and trim some coil off and put back and try it.

 

Measure the width of the wire the coil is made from.  (usually around 1/2")

Measure the outside diameter of the coil. (usually around 4-5")

Number of active coils (a picture of the coil would help)

 

From this, the spring rate can be worked out and this way you can tell in advance how much the rate will increase for every coil or part coil removed. My 710 worked out to about 100 pounds per inch. About a coil and a half increased it by 50% and I liked it and left it there.

 

A 2" split collar will support 6,000 pounds or 3 tons! That's easily 3 B-210 on each strut so it will hold. They are about $25 a pair. So if you have a few tools and an angle grinder you can lower and stiffen your front end when installing zx struts for under $30..
.

[izzo]

IIRC. You need to use the b210 spring perches, springs, top hats, and maybe inserts. Bust out your grinder and welder and get crackin, yo....

 

Dont have a welder? Use collars instead.

[angelmanuel]

i had thought about that, however i thought that having the spring perch too low would cause the tire to rub it. i had a fellow member weld some perches into the 280zx struts. just getting the stock B310 spring to the same size as a 280ZX springs will take 2-3 coils out of them, i am worried about them being too stiff and/or bottoming out.

 

by the way, the stock rate is 94.

[datzenmike]

94 sounds about right. 510 are 89 (or so) Maxima goons/zx are 150, my 710 goon was 100. If replacing with zx struts they will already be shorter than the B-210 so B-210 inserts won't do. You can measure the depth of the B-210 strut tube from the threads down inside to the bottom (I have no idea what that is) but the 280zx is 376mm so some conclusions can be drawn as to how much lower it will sit. 

 

If you do measure your strut depth will you let me know what you get?

[angelmanuel]

the depth of strut tube measured 17.25in/438.15mm. i have found the following measurements for the inserts:

 

B310 front insert:   extended 24.22in/615.19mm compressed 17.81in/452.37mm length of travel 6.41in/162.81mm

 

280ZX front insert: extended 21.36in/542.54mm compressed 15.65in/397.51mm length of travel 5.71in/145.03mm

 

i also measured the springs for both cars and the B310 springs are 2.5in/63.5mm longer than the 280ZX springs.

 

i don't know if all these numbers can help you help me, but any help will be greatly appreciated. by the way, i don't think it makes a huge difference, but you keep refering to my car as a B210, when in reality it is a B310.

[Zeusimo]

I Ised MK5 Rear Springs

The Stock Springrate Is 250

But I Had To Cut A Coil Off To Make Them Fit Onto The 610 Perches

[angelmanuel]

the B310 perches are probably a lot smaller than the 610 perches.

[angelmanuel]

anybody know the spring rate for a 99 sentra? i found a couple of rear springs for that car and they are about 3 inches shorter than the B310's and fit the perches almost perfectly.

[datzenmike]

Sorry B-310.

 

The length of the spring isn't what determined the height the car will sit at. It's the spring rate. A higher spring rate will support and hold up more weight that a lighter one. Rear springs generally don't have to support a motor and trans axle and are 'lighter'.

 

You can work the spring rate out yourself... it's easy. But you need to make a couple of measurements on those springs. You need the..

 

Width of the wire.

Diameter across the width of the coil. Outer diameter is fine as long as you say what it is. 

Number of coils.

 

From this the rate can be mathematically worked out.