the front is high with new ST springs+KYB shocks

[BuDavid]

I don't know what to say, I just put the car down on the road and I was surprized that the car looks like a boat! it was really too high in the front and lowered at the back which is normal as I guess..

here are the new stuff I have under the car:

1-brand new ST springs.

2-new KYB gas shocks.

3-new control arm bushings.

my friend told me that with gas struts it is normal to lift the car so much in the firs few days and then it'll drop a little with time.. I was totally sure of placing the front springs in the front which have 9 turns and the rear have 8 turns! please don't tell me that I'm wrong!:dead:

I suspect a nother thing, when I tightened the control arm bushings I put a plat form under each front wheel to compress the spring a bit so I'll position the sleeve in closer angle to the normal angle while the car is dropped on road ( I think the compression of the spring wasn't enough so the bushing now is forcing the arm back to higher position?).. do I need to loosen the nut/bolt of the bushings and bounce the car while it is on the ground and tighten it again? I mean that the bushings might make some torque to lift the car in the front..

Note: the car is a bit lower after roding for an hour! I don't know weather if that lowering will proceed or not..

I'm so confused right now.. I'll just attach a picture and give me some opinions please.. and please tell me it is correct that the front have 9 turns and the rear have 8:hurt:

thank you guys..

[jmortensen]

Looks to me like the springs are backwards. Sorry. I don't know about 9 turns vs 8 turns, but since the struts have the same amount of travel and the cars tend to ride a little high in the nose as they come stock, it seems that you want the shorter spring in the front.

Your friend is wrong about the struts. As long as they hold their gas charge (should be damn near forever) they will add a little bit of ride height to the car.

When you first set a car down off of a lift or a jack the control arms can't move because the tires are effectively pinched under the car. Rolling the car back and forth just a couple feet will settle the suspension and allow the control arms to move back to their normal position. If you drove it around, you've already gotten all of the settling that you're going to get.

[Carl Beck]

...... snipped....cjb....

I'm so confused right now.. I'll just attach a picture and give me some opinions please.. and please tell me it is correct that the front have 9 turns and the rear have 8:hurt:

thank you guys..

Hello Mohammed:

I do not have any specifications for the aftermarket "ST" springs, so I can not answer your question directly.

I can however tell you that the OEM/Stock springs for the 240 have:

Front Springs 10 Coils

Rear Springs 10.65 Coils

Right Front Spring Free Length = 15.2 inches (386mm)

Left Front Spring Free Length = 14.7 inches (373.5mm)

Rear Springs Free Length = 14.5 inch (369mm)

So the free length of the OEM/Stock Front Springs is longer than the rear.

The Rear Springs have more coils, in a shorter distance... so their spring rate is greater than the front.

The Spring Rates for the OEM/Stock Springs are:

Front = 83 lbs/in. (1.48 kg/mm)

Rear = 103.6 lbs/in. (1.85 kg/mm)

I agree with John - almost everyone I've heard from reports that the new gas shocks, being sold for the 240-Z's will raise the ride height of the car between .75 and 1.25 inches. I believe that this is an issue we need to take up with KYB and others...

Looking at the picture you provided - the front of the car looks about right to me - but the rear is sagging. With a stock 240-Z, with stock wheels/tires - you can normally place three to four of your fingers, with your hand held vertically - between the top of the tire and the wheel arch.

Stock Ride Height for the 240-Z, if you measure from the bottom of the rocker panel to the pavement - is 8.00 to 8.25 inches. Measured at the notch in the pinch weld seam, where the car's jack is supposed to be placed... Note - measure to the bottom or underside of the rocker panel... not to the pinch weld seam that sticks down below the bottom of the rocker panel.

Wheel/tire size can increase or decrease ride height... so you have to take the effect of larger or smaller diameter tires/wheels into account - when using the 8 / 8.25 inch measurement.

Remember that the 240-Z's were Sports/GT's... with all independent suspension. Lots of ground clearance, lots of spring/shock travel. In stock form they aren't supposed to be sitting on the ground..

Note Picture of Stock 240-Z below - see the ground clearance in front.... see the tire/wheel arch clearance in the front.

FWIW,

Carl

[Carl Beck]

Oops...for got the Picture...

Carl

[ktm]

Carl, I just put in Tokico HP shocks and springs and my front end dropped. So much so that I can not fit my jack under the cross-member anymore.

[rtaylor]

If I may hijack a question. If I only install KYB struts w/o putting on new springs, will that also increase the front end height?

[Arne]

If I may hijack a question. If I only install KYB struts w/o putting on new springs, will that also increase the front end height?

Probably, Randy. My guess from stuff I've heard from others and previous experience on other cars leads me to expect probably a 1/2" ride height increase.

Problem is, the only way to avoid that is to find non-gas struts, which is darn near impossible these days. KYBs are lower pressure than Tokicos, so the increase in height should be less.

[Carl Beck]

Carl, I just put in Tokico HP shocks and springs and my front end dropped. So much so that I can not fit my jack under the cross-member anymore.

Hi Bo:

Do you have the spec.'s on the Tokico springs?

Free Length

Number of coils

Wire diameter

What wheel/tire combo are you running?

Would be interesting to see what it takes to drop the front end with their shocks.

thanks,

Carl B.

[240ZGL]

I'm going Konis on all corners. Just got the fronts today. Rears should be no problem to find. I know there big bucks.

[Carl Beck]

If I may hijack a question. If I only install KYB struts w/o putting on new springs, will that also increase the front end height?

Hi Randy:

With the older KYB gas pressure shocks, no one reported, nor did I notice any increase in ride height when they were installed. However it "seems" that the newer KYB GT-2's as well as the Tokico's do result in an increase in ride height if only the shocks are changed.

The OEM front springs in the 240-Z are rated at about 83lbs/in.. and the load on the front strut is about 562lbs to 602lbs. So a high pressure gas shock that had a positive pressure of 83 lbs.. would unload the spring and lift the car 1 inch.

If they are installed with aftermarket springs - that have a shorter Free Length to begin with, and which have a higher spring rate - the effect would not be as great. If the after-market springs have a spring rate of say 125 lbs./in. then lifting 83 lbs off the load, would result in about a 1/2 inch increase in ride height... ( but the shorter springs would hide that effect to an extent).

The original gas filled shocks... used an inert gas (nitrogen) to reduce foaming in the oil in the shock when the shock was pumped rapidly. However they had a very low positive pressure. From what I've read and been told by people who are supposed to know - the new Gas Pressure Shocks do have a very high positive pressure.

The Racing Shop that measured the spring rates for me (on the OEM and re-production springs), told me that the cars they more normally deal with - like Camero's/Firebirds.. high pressure shocks can have a positive pressure as high as 100 lbs.

I guess we'll have to get a couple of the newer KYB's and Tokico's and actually measure the amount of upward force they produce. Then take the matter up with the manufacturers...

FWIW,

Carl B.

[Carl Beck]

Looks to me like the springs are backwards. Sorry. I don't know about 9 turns vs 8 turns, but since the struts have the same amount of travel and the cars tend to ride a little high in the nose as they come stock, it seems that you want the shorter spring in the front.

...snipped...

Hi Jon:

Think about that.......(hint - spring rates)...

FWIW,

Carl B.

[jmortensen]

Hi Jon:

Think about that.......(hint - spring rates)...

You're ASSuming that the springs are the same length. If the springs were the same length, then yes, the one with less coils would be stiffer, and one would expect that the stiffer spring would go in the rear. But we don't know that to be true. Regardless, looks like the springs are switched front to rear to me.