What's wrong with my Protech?

[Ted]

I have Protech shocks with normaly harder springs (the kit of SJSportscars). My problem is that at the rear, I can't get a ride height of 160mm. As you can see on the pictures below, the spring is maximum loaded?
Could someone tell me if he see something wrong?
In the kit, they were two sorts of spring, 2 bigger than 2 other. Do the bigger ones go front as they were identified?








On the picture below, spring is not loaded at all, and the "setting nut" (don't know how to name it) is quite hight :

[Rice crispy]

Ted remember twhilst the car is in the air the shock in the last picture will be fully extended as there is no weight from the car compressing it or the spring. I would set the ride height on the ground and then jack it up to check that the spring is not able to move. Not sure which spring is which but the fronts will be harder to compress.

[Ted]

When I tried to set the height, I've rised the car to set the damper easyly. After one test, the height was not enought, so I set it the higher I could, but still not enough.

I've seen that Nitron sells harder springs for rear than for front. I will search informations...

[Ted]

Ted remember twhilst the car is in the air the shock in the last picture will be fully extended as there is no weight from the car compressing it or the spring. I would set the ride height on the ground and then jack it up to check that the spring is not able to move. Not sure which spring is which but the fronts will be harder to compress.

Is it the black nut that sets at the same time ride height and preload of the spring?

[Ted]

Damn, I've asked SJ and he tell me the larger springs go to the rear....

[mikeydude]

Hi...
Just a quick note.... I would highly recommend that you paint the rear suspension arms as they are very prone to corrosion.

[Ted]

It's pissing me of. SJ just sent me an email saying big springs go front, I had already invert 2 springs.
If my springs were correct, well, I can't see where do the problem comes from. I must be missing something....

[steve matthews]

Ted, this is what we did with the Protech.
1. Get the springs in the proper place.
2. Cut a piece of wood for the front measure and the rear measure.
3. Start lifting the collars until the wood clears the frame members.
Count the rings under the collars should match both sides for balance.
4. At this point we used scales and fine tuned the 4 corners by weight.
You could do it by measure and get close. Measure only at a metal surface.
No tub or body panel.
5. 1/2 tank of gas and driver seated for best suspension performance when
adjusting the collars.

It is much more complicated than this but should get you going.

Steve

[Ted]

Ted, this is what we did with the Protech.
1. Get the springs in the proper place.
2. Cut a piece of wood for the front measure and the rear measure.
3. Start lifting the collars until the wood clears the frame members.
Count the rings under the collars should match both sides for balance.
4. At this point we used scales and fine tuned the 4 corners by weight.
You could do it by measure and get close. Measure only at a metal surface.
No tub or body panel.
5. 1/2 tank of gas and driver seated for best suspension performance when
adjusting the collars.

It is much more complicated than this but should get you going.

Steve

But my problem is that with the collar lifted at the maximum, I don't have 160mm under the frame, only 150. With damper with spring on it, off the car I can lift the collar almost at the top only turning it by hand. Seems like spring is to short or not enough hard...

[steve matthews]

On my Fed. car the front collar is almost centered in its travel on the shock
The rear collar is about 3/4 up onto the shock.

Do you have the old springs to match against?

You are 10 mm lower or about 3/8".

Is the problem in the front or the back?

Steve

[Ted]

The problem is on the back. And I have only 150mm maximum under the frame, with collar fully up.
Unfortunatly I don't have anymore old springs :/

[steve matthews]

That 10mm may be the rear alignment adjustment.
Their is a cam lobe that can raise or lower a small amount to get the geometry correct.
Just a thought.
Someone correct me if the above is not true on Ted's car S-2.
When you get it right you will be surprised at how well the car performs.

Steve

[Ted]

If juste seen my wheels are 7Jx16 ET35. The section GD of the Lotus Service Notes says the wheels are 7J16 ET60.
Could it be a source of my problem, because forces applied to the springs are higher as the wheels are 25mm more out?

[Andy_J]

Hi Ted

I don't have much knowldege in the are a of supension, but I can tell you

1 those springs look to short if you can't get the 160mm if ride hight, have you been sold a lowering kit in error or got the springs the wrong way round.
2 The offst of your wheels will not make up the for the differnecin in height, bit the rim size and tyre profile will have an effect if you don't have standard sizes fitted.
3. The cam bot refered to by steve will be fo adjusting amber or toe on the rear suspension not height.

Andy

[Fredjohn]

Ted
I suggest you go back to real basics:

Take off all 4 springs, dismantle the shocks/springs, then measure the UNCOMPRESSED length of each spring: I expect you will have 2 of one length and two of another length.

Publish the lengths on here and also send them to SJ. Someone on here will know if they are the correct lengths or not and SJ/Protech will also be able to check what they have actually sent you.

Hope this helps.

Bon courage mon ami.

John

[Don.Hasi]

on the Lotus layout the longer ones are in the front.