Forum for competition engine enthusiasts. RIP Guy Croft 09/11/2020 - This forum will continue both as a source of information and as a memorial to Guy.
hcd wrote:I guess the forces acting on the suspension mounting point could come from any direction - braking, accelerating?? Here's an idea I haven't seen before, I only hope the bulkhead can take the load at that point.
Huw, the reason I was asking is this: I am sure you've seen many strut tower braces that have right and left threaded bolt to adjust the lenght of the unit. If the torque is acting on the strut brace bar, it would act on the length adjusting bolt as well. I am mechanical engineer, but it seems to me that the bolt would twist a lot (or even get loose), neglecting any torsional rigidity improvement. The downside of not having the bolt is that the brace has to be made in place.
Thank you for the link, I am printing the document as we speak...
Guy Croft wrote:Any increase in front-end stiffness (including engine/chassis strut braces -suprisingly, dampers, springs, tyres, tyre pressures, anti-roll bars, joints and bushes, chassis welding) increases the tendency to understeer (car tries to go 'straight on and won't turn corners easily).
That practically means that if I make chassis reinforcements on front, replace suspension rubber bushings for PU ones etc, I will actually expirience even more understeer?
This confuses me a bit, I admit, as I thought that actually making those improvements will keep the front wheels where they are supposed to be. As I said, I was making conclusions just by thinking, and it seemed logical.
What could I do then to improve handling (being just a DIYer in that area)? I am afraid that I might never know if I overdid one or another end...
although some of the mods may not feel much different it is a rather bad thing to work on just 'one end or the other'.
Can have all kinds of unexpected effects on straighline handling, braking and aerodynamic stability too, not just going round corners. Beware.
Ride height alterations via spring settings too can upset corner weights if not equalised front-rear, thus unbalance the handling.
I nearly 'totalled' my 124CSA due to chronic oversteer by changing things after taking 'expert' advice.
Nick.
The macpherson strut is notorious for understeer. Ford brought it to the masses but Fiat perfected it. Its cheap to produce and maintain but it moves about a bit so induces wheel movement and understeer. So if you can stop the wheel moving around by using poly bushes [don't forget strut top mount], it will improve things.Struct bracing will help to cut understeer and wheel movement but it also depends how stiff the rear end is. bracing here between the rear struts can help to balance the car. Progressive front springs can play an important role too, but it all comes down to experimenting.
Dear Frends-spesialy for YUGO
In my place yugo make(1600) fastest times in races-hoby clasa end to make yugo suspension to work is not problem only money to buy right parts,for engine -gearbox muvment to.
Fot front bar on yugo is 21mm Fiat 128 is 19mm ,oll ruber can be change
- I have make from teflon whit steel cc5mm plate on back side to make rigid
later I make samefrom aluminium whit holl 21mm excentar cc10mm forward
-front side,to stop muvment you can make fiksers on bouth side on front bar
weld mig half colar on bar to stop muvment..
For engine mounts we make rigid/metal side mouts ...
for rear we use reinforced rear transverse suspese arm,for leaf springs we use -for race one long spring + spring from camion light cc9,5mm tight cut like long leaf.centar hetght when you put on flor cc10cm
For shock we use bilstein for opel d gr N in catalog have 3 dif. mod.we use med. 290/120 whit 2 some use 3 eibach springs 60mm..
Front end rear strut brace is nesesery....
open site jupiterfiatpower they have some parts....
Regards
Sime
(GC Note: I have written to Sime to try and help with translation on this post.)
My route is becoming clearer (slowly but surely). I wrote an email to Sime (bugarMK), as he seems to have lot of specific Yugo expirience. So I hope we'll be able to go together through my suspension mods list, and see what's good and what's not... Then I will make a post here on that.
I wrote to Powerflex, they replied with two hours. However, they do not have PU items for Fiat 128/Yugo. They might develop them in 2007.
I am just afraid that due to the extent of work that needs to be done, I might be short of time to make it with the standard I want. And this will in turn stop me from doing it at all... :(
What about looking at what Fiat did to improve the front end? The Ritmo/Strada 130TC had reaction rods from the wishbones to the front crossmember to keep the wheels aligned and a sway bar attached to the reaction rods. I think the same setup was used on the 131 Abarth too. The old 128 3p had a similar setup but without the sway bar.
leifa wrote:What about looking at what Fiat did to improve the front end? The Ritmo/Strada 130TC had reaction rods from the wishbones to the front crossmember to keep the wheels aligned and a sway bar attached to the reaction rods.
Leifa, could you please supply some photos of the setup present on 130TC? I'd like to get a picture if this could be fitted to Yugo...
In the meantime, I've also found an article describing how to convert 128 to reaction arms, the setup looks quite similar to 130TC one.
I spoke to Sime, basically he suggested replacing all the bushes with Unibal's. That is not exactly what I would like to do for daily driver. Sime also suggested putting clamps on antiroll bar, to prevent its axial movements through the bushes, which I find reasonable even for the street car.
I wrote to Chris Wittor (UK distributor of Superflex), but have no answer just yet.
Does someone have experience in self-designing and machining of PU bushes?
Thanks, Guy, I got the answer. Next week they will provide further info, and I will post it here.
I made an Autocad drawing of front sway bar carriers. Such a carriers are used extensively in Yugo racing. However, I couldn't get any information on how big the interference (or clearance) should be for PU bushes and parts that are supposed to rotate inside of them. Any tips?
And here one photo of the carrier installed in Bob's Yugo (thanks to Bob and Crank from Yugoforum):
Got the detailed answer from Chris, including picture and dimensions of the bushes. Most probably I am going to purchase the items off them.
Dimensions of the bushes for the suspension arm (wishbone), that Chris Wittor is offering, are:
Stainless steel (SS) inner tube ID: 10mm
SS inner tube length: 43.5mm
PU bush OD: 29mm top of taper, 27mm bottom of taper (two per wishbone)
