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gatouille
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Front suspensions almost like real racecars...

Post by gatouille »

We all know suspension kit from intrax, RSR ....
Very nice adjustable springs... but a little expensive when your target is just trackdays.

We use 2 cheap ways to make the front suspensions stiffer, first is very cheap and very efficient but not ajustable.
1) Buy 2 springs 10 euros each one !
Photos shows Bilstein but it works 10 time better with Koni :
Image

Many choice there
http://www.geiss.fr/fr/produits/documents/RESSORTS.pdf
I have CXF4-089 321 N/mm

You need 2 parts machined which will do "guide" for springs
Image

This one is usefull to but do nothing when braking,
Image

Little and cheap springs do the same work than the RSR BAR even when you are braking

And the second way is....

Later thank you
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gatouille
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Re: Front suspensions almost like real racecars...

Post by gatouille »

2) How to move a standard koni to a coilover
Best results if you tune the internal hydraulic of koni of course.
This part with a koni and you have a adjustable coilover suspension !
Image

A standard spring like STAC diam 160 mm

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killaz
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Re: Front suspensions almost like real racecars...

Post by killaz »

And You end up with extremely short travel and really high bind position?
I would skip this kind of suspension mod.
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Re: Front suspensions almost like real racecars...

Post by Maurizio »

I use a similar setup for my daily driver, but with a 55 N/mm spring (35 N/mm backside springs and uprated front anti roll bar).
Image
Which I myself find the perfect setup for, (on normal street tires) in the wet (=daily driver).

To me 321 N/mm sounds seriously stiff even for a racer... (Binding of that spring is the last you have to worry about :lol: )
The tracks you drive on must be very smooth, billiard table like.
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75evo
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Re: Front suspensions almost like real racecars...

Post by 75evo »

I have helper springs too. But very lightweight, about 120lb/in or something like that. The springs were meant for a mountain bike. I have 27mm torsion bars but found out the rate was too low. But the thought of taking them out gave me nightmares!
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Re: Front suspensions almost like real racecars...

Post by Duk »

Something to keep in mind is that you are using a very small amount of metal to be a spring. Don't expect them to last very long before they start to loose their rate.

Another approach is to use Bilstein small body dampers. They are 38mm in diameter (the same diameter as the Koni Yellows but use a bigger piston than the Koni's because they are a single tube damper). The Bilstein's also have a circlip grove machined into them and there are threaded spring sleeve/seats available and it all works with 1 7/8" springs with plenty of different rates and a few different lengths (8, 10 and 12 inch).
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Re: Front suspensions almost like real racecars...

Post by killaz »

It can be done with 50mm body and 2,25 ID springs too, they just need fabrication of sleeves..

Image
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Re: Front suspensions almost like real racecars...

Post by gatouille »

Thank you for your answer, I plan to do the same for road use Maurizio on my GTV6.

I know that sounds not logical Killaz 75evo and Maurizio, believe me or not these springs do a very good job.
Look this video, my friend Gtvpp (camera inside) has these springs for years , and with only an ALfetta 2 liters 142,4 hp he's not often ridiculous .

Look in Dijon track, last year, he's got springs and me (9919 VB 63) not yet, we met both troubles with motor and had less than 120 hp
My motor is a stock but every parts brand new twin saprk engine (143,1 hp when wind is behind me :mrgreen: )
http://www.youtube.com/watch?v=0U5NlpaHXkA

Of course it would be better with working INSIDE the shock absorber Koni to make them stiffer , this is something I plan to do .
Target of this topic was only to show with few euros you can make efficient suspensions not the best of course. 20 euros 2 springs, and 4 littls parts in aluminium as guide of springs.
I will make a topic of the opening KONI and tuning them.
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Re: Front suspensions almost like real racecars...

Post by Duk »

gatouille wrote: Of course it would be better with working INSIDE the shock absorber Koni to make them stiffer , this is something I plan to do .
Target of this topic was only to show with few euros you can make efficient suspensions not the best of course. 20 euros 2 springs, and 4 littls parts in aluminium as guide of springs.
I will make a topic of the opening KONI and tuning them.
Why would you want to make the Koni stiffer? You can't use damper bump valving to replace a whole heap of lacking spring rate :? .
I like what you've done, it's a well priced reasonable compromise fix for lack of spring rates and I'm interested to see how you go about opening the Koni's and playing with the valving, but more bump valving is not what they need (typically).
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Re: Front suspensions almost like real racecars...

Post by Mats »

All Konis I have ever seen for the 116 chassis have about the same low speed bump damping as a stock shock. Really not enough for anything. High speed bump is about rock hard though and that is waaaay to much, the other way around would be much better (but still bad). ;)

Compensating a too low bump damping with a spring is the wrong way to go, the other way around is also the wrong way to go. Konis off the shelf for a 116 car is always the wrong way to go if you want to go fast on a racetrack. :P
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