Couple of ?'s on 510 springs

[grannyknot]

I have ordered 2 split collar clamps for the stock 510 struts,  does lowering the perches  by 1.5" lower the front end by 1.5" or is it less?

Until I can afford the coil over kit that I want I thought I would cut the rear springs so I could get the car on the road in the mean time, this is my guesstimate on where I think I should cut to lower the rear 1.5"

Any advice?

 

[datzenmike]

1.5" is about as far as I would go down. And I strongly advise that the strut springs be increased in spring rate (stiffer) Lowering puts the lowest part under the car at risk of bottoming out on the pavement. And don't kid yourself it will... no matter how carefully you drive something will always surprise you. Stock springs can be trimmed in the mean time and this will stiffen them. A little careful measurement of your spring and some multiply and dividing and you can work out how much to cut off. Remember once cut you can't put it back. I would suggest starting with low at 175 and see how you like the ride. If you want to go stiffer you can trim a little more. Then buy coil overs in the rate you liked. I'm old and I like 150 on my 710 but either side of 200 seems the average for most 510  owners.

 

Measure the wire thickness (accurately) and the diameter of the coil (outside to outside, again accurately) and the number of coils not touching each other. In other words, coils that can move. I already know the 510 uses 90 lb./in. coils. Get those measurements and post them and I can use a simple formula to work out how much to cut the spring down for the rate you want. Easy enough and costs nothing. Accuracy is important. 

 

Cutting a spring to lower the rear ride height assumes that the ride height AND the stiffness will end up being what you want... almost never happens. As spring is removed  the stiffness increases. You might  end up with impossibly stiff uncomfortable ride and still need to trim more to get lower. It could go the other way and you get to the ride height you want but the spring is still too soft. Cutting to lower is a bad idea.

 

I  would get the front spring rate sorted out first then tackle the rears.

 

BTW you do know that the rear springs are cantilevered and to get a 175 rate at the wheel your spring has to be 665 lb/in. 

[banzai510(hainz)]

just remember lowering the perch could hit the tire or rim if you get the wrong offset wheel. example a 15x7+25mm

 

On my 510 I have 510 struts I had the new perch welded at the same spot for my coil overs but went with a 7 inch spring turned all the way down instead of the common 8 inch spring.

I wanted it low in front.

[demo243]

6 minutes ago, banzai510(hainz) said:

just remember lowering the perch could hit the tire or rim if you get the wrong offset wheel. example a 15x7+25mm

 

On my 510 I have 510 struts I had the new perch welded at the same spot for my coil overs but went with a 7 inch spring turned all the way down instead of the common 8 inch spring.

I wanted it low in front.

Tire dependent too - 

Im running a 15x7 +25 with a 10mm spacer and 205/50r15s. The clamp I am using to hold up the threaded sleeve, and the sleeve clear fine, but im going to have to bump all the way to a 6" spring to get enough clearance for the spring perch. Going to run some helper springs to keep everything tensioned moving forward on droop. 

[banzai510(hainz)]

demo

I am running 195 45  15 Nexen  tires up from to clear much as possible so I don't hit the strut.  same 15x7 +25mm Rota RB

[grannyknot]

Well, lots to think about.

The rear spring is 11.625" tall,

9 coils not touching,

4.125" in dia.,

The wire is .567" thick.

 

 The wheels I want to use are 14"x6.5" ET? the tire sizes I think will do the job are 186/65r14 or 195/60r14 and I have found there are still a few companies carrying tires made in the sizes

I think the design of the wheels are called turbines.

Thanks

 

[yenpit]

Dropping the stock spring perch is VERY wheel/tire dependent!  I did this years ago on a budget build 510.  I only considered how much I wanted the front to drop, I did NOT consider the wheel/tire.  I got LUCKY!!  I was running stock 14in 240z-280z steelies with 60 series tires.  Once done I had approximately 1/4 inch of clearance between the tire & the outer lip of the spring perch, but at least using a clamp (not welded), you can always move it up!

 

Keep in mind that coilovers are small diameter, so there is not as much potential issue with the top of the tire hitting a spring perch, especially if using production Datsun/Nissan wheels..

 

I think I only cut off 1/2 of a coil & liked the stance.  Ride quality was fine.  The more coils you cut, the stiffer the spring will be in the end............