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Re: Leaf springs

PostPosted: Tue Jan 28, 2014 5:18 pm
by 1300gt
Cheers wayovermyhead,

I should have added further, that I'm also looking for something to eliminate rear tramp. As a previous grumpy pinto mk1 i had which i used King springs used to tramp all over the place (koni sports shock, but no lowering blocks, and only 185 road tyres).
So without having to resort to tramp rods I was looking to see if there was an easier fix. Which these springs seem to be.
As its a weekend/road rally/casual track car which ill probably use some decent tyres I'm looking for something a bit better than i had before. The Zetec I'm hoping to have around the 200hp mark on itb's.

I didn't realise these ones you were talking about are from King.
Thanks again for your help and the help from this thread. Lots of knowledgable people!

Re: Leaf springs

PostPosted: Tue Jan 28, 2014 5:59 pm
by Danny M
How did you have the Koni's adgusted

Re: Leaf springs

PostPosted: Tue Jan 28, 2014 6:07 pm
by 1300gt
They were a multi leaf (3-4 from memory) and lowered about 2" with no blocks. And obviously not with an extra rebound leaf like others have mentioned here. Poly bushed at the front with rubber at the rear.
Shocks were yellow Koni sport which we tried stiffening them up, but this did make the ride quiet firm and rougher per uneven surfaces. Im assuming the shocks only offered a compression adjustment (no rebound as thats the spring).
Thats all i can recall, was a quiet a few years back.
So you can see why id like to get something to work a bit better.

Re: Leaf springs

PostPosted: Tue Jan 28, 2014 6:16 pm
by Danny M
Regular Koni's only have rebound adjustment but it does have some effect on bump as a side effect
In their softest setting Koni's are still far too stiff in the rebound as they're a twin tube shock with very small foot valves and pistons so they are more prone to tramping as they're trying to hold the wheel off the ground

Re: Leaf springs

PostPosted: Tue Jan 28, 2014 6:41 pm
by 1300gt
Cheers Danny,

Im a bit confused as to rebound and being at its softest. Can you confirm something for me so I'm not getting confused..
When we talk about rebound, I'm assuming its about rebound dampening settings which are usually positive or negative.
So the more rebound dampening the slower the shock allows the spring to return. The less dampening the faster the rebound will be. Which the leaf spring is doing the rebounding.
So these shocks are a fixed compression are they. How are they made firmer or softer? When they are just adjusting rebound which would just be faster or slower?

I have new Bilstien shocks which a few have said are good. I didn't get the Grp1 shocks but the one slightly softer.

Re: Leaf springs

PostPosted: Tue Jan 28, 2014 8:51 pm
by Danny M
First of all consider the "shock" as a damper which is more accurate.
Yes if you increase the rebound rate it will slow the rate at which the spring will return to "installed" ride height. If the rate is too high the tyre loses contact with the road. Koni's by design are a twin tube damper in that the shaft and piston run up and down inside a thinner second tube inside the main housing and the piston pushes oil down through the foot valve into the outer cavity which acts as a reservoir. When the piston moves up in rebound it then pulls the oil back up through the foot valve into the inner cavity tube. Because of the diameter of the tube the actual amount which passes through the foot valve is quite small with the valve and it's bleed holes being restrictive. In the past we've played with them on a shock dyno and we resorted to literally drilled holes in the foot to allow it to draw as much oil as possible and we could not get near a mono tube like a Bilstein.
When you adjust a Koni you push the shaft down and it locates two tags on the piston into slots in the foot valve and the foot valve is adjusted changing the rate in which fluid in moved through foot valve adjusting mainly rebound
With the Bilstein the softer set are the ones to have

Re: Leaf springs

PostPosted: Fri Jan 31, 2014 8:45 pm
by 1300gt
Makes sense regarding the Koni.
So how much difference is there in regards to axle tramp by using Bilsteins instead?
And just read you made some mk1 springs? do you have any idea how low these are from standard(ish) or how much travel/mm they leave until hitting bump stops on chassis rails etc..?