Raising Front Ride Height S7

[theduck]

I presume you have to adjust the collars on the spax coilovers, but how do you do it? And which way to you adjust them, up or down the shock body?

 

I've set the front wheels to have negative front camber and the ride height seems to have dropped quite a bit in the process!

[Snapperpaul]

You compress the spring more to raise

However once you get to the end of the shock travel you will then only compress the spring

Bottom wishbone is usually level when at rest

[theduck]

That's good news as from memory the collar is at the bottom currently, so spring as full open as possible. Gives me plenty of adjustment. How I do actually adjust the collars though? Presume I need a special tool?

[Guest Alan_builder]

Snapperpaul is not wrong. Adjusting the spring length will alter the ride height.However it will also change the car's ride characteristics.Let me try and explain.Springs are sold as Lbs/ins compression. I can't remember the exact spring rate for the S7 but it will probably be higher than 170lbs/ins and lower than 270lns/ins. Lets take a figure of of 200lbs/ins. This means for the first inch of compression it takes 200lbs and for the next inch another 200lbs being a total of 400lbs and for a 3 inch a total of 600lbs. Your car is a fixed weight, the dampers are asymmetric Up and Down, so they are different rates. Even if the dampers are adjustable they don't always adjust both up and down rates. So basically one tunes the suspension by the nuts on the coilovers additionally you need to keep the active stroke within the range of the shock absorbers so they don't bottom or top out and finally often the angle at which of the coilovers is not best set to adjust ride height, the S7 is a prime example.I ask why you have set the front wheels to have negative front camber? Our cars with double wishbones tend not to have much negative front camber unless you are an ultimate racer and then I would have expected you to know how to adjust the height via the front springs ect.The S7 has one wishbone and the lower is a track control arm originally with a roll bar but lots are modified to have a rear strut as the roll bar proved to stiff for the S7. Both of these configurations perform close to double wish bones.Any way you should look at what you have done and just how much negative front camber you have dialed in. Adjusting the wishbone top ball joint also lengthens the leaver and I think that will lower your car. So now you need to make the same length change to the spring rocker arm, rather than adjust the spring.Does you top wishbone and track control arm get further apart as you travel out from the car side? It should by 15 to 20 degrees. Sorry if this post covers other reply but a funeral interrupted my reply.As you have done some work on the front suspension

 

And that is what the full editor did when it would not save in normal mode!

[Snapperpaul]

If your shock is not fully open turning the collar upwards will increase ride height

If you are at full open then turning the collar will give a pre load to the spring

 

Im Not exactly wrong Alan

But you are indeed long winded

[Guest Ian & Carole]

I don't know!!............. all those years I spent raising and lowering the rally car suspension using the spring saddles from tarmac and then to forests settings.

Can only asume my results were, after all, down to my driving skills and not the set up of my cars.

[theduck]

I set negative camber as that is what's suggested on, I think, dave Andrews site. If the figures on there are not correct then what front camber, toe and castor should I be setting?

 

I understand basics of how this all works, just never put it I to practice!

[Guest Alan_builder]

I don't know!!............. all those years I spent raising and lowering the rally car suspension using the spring saddles from tarmac and then to forests settings.

Can only asume my results were, after all, down to my driving skills and not the set up of my cars.

 

Was that a McPherson strut you were adjusting?

[Guest Alan_builder]

I set negative camber as that is what's suggested on, I think, dave Andrews site. If the figures on there are not correct then what front camber, toe and castor should I be setting?

 

I understand basics of how this all works, just never put it I to practice!

 

Please re-read Daves article. He starts with the camber, then changes the whole set up, ditches the roll bar, but doesn't come back to caster. I have not played with an S7 setup, in fact having a 2b/4 it took me a long time to gather why the S7 was so bad and 2B/04 so good with the roll bar. Its the McPherson's and the weight which make the difference.

 

After fitting tie bars the car is essentially a double wishbone as I said earlier. Properly constructed double wishbones don't seem to run 2 degree of camber in my experience, 0.5 yes. As I said well designed double wish bone systems are designed to keep the tyre in constant contact with the road while cornering.

Again take a look at the first drawing in Camber. it clearly shows the wishbones wider at the body than at the top and bottom ball joints, that with create the camber changes Dave is talking about.

[theduck]

Alan I am still running the front arb, and intended to do so until after IVA when I would look to carry out the tie bar conversion.

 

So what should I be running now? Are the figures I have gathered from daves articles correct? Between 1 and 2 degrees negative camber, 4 to 8 degrees negative castor and stock toe?

[Guest Alan_builder]

As far as IVA goes it matters not.

 

The IVA tester measures the car width, track and wheelbase length. These numbers are used later but I need to think what for. Changing camber and caster will alter these by a minute amount.

 

Negative Caster promotes steering self centering, which the IVA man will test when he checks the front brakes lock up prior to the rears. If you scrub your tires out in 10 miles he will not care as he wont be there to care.

 

Get your ride height back go to 0 camber 4 to 8 caster and standard toe as you say. The priority is to pass IVA in your build not set up a racing car.

 

Please PM me and tell me about the receipts you have for the car.

[theduck]

Thanks Alan, will go with those settings then.

 

Will pm you now.