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andyowl
Sr. Member
Posts: 456
New exhaust "straight through" - good sound!
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« Reply #78 on: July 28, 2009, 09:37:40 am » |
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For the moment I have decided to concentrate on improving the suspension. Looking at the professional pictures taken at the Longcross Sprint (a "National B" status event 10 days ago) see... http://www.rallygallery.com/2009_SCORPION2.aspx?Page=12...it is clear that Baggy Joe is rolling far too much. More power is needed but the ability to go round corners quickly is just as important and I think more power should come after going around corners quickly, if I have to set priorities! Possible changes include: - Lowered suspension (I have made some progress on the leftside rear, more work needed. Front should be easier) - Stiffer anti roll bars, front and rear (we already have the 19mm rear ARB) - stiffer suspension bushes all round (change to Superflex/Proflex Polyurethane bushes) - adjustable shock absorbers (although I don't think the rolling is caused by poor shock absorbers) - wider wheels and tyres (I bought 7J x 15" rims from a forum member last week) - or wheel spacers and the existing wheels and tyres (which already feel superb with good control and powerful braking) If you have any thoughts or experience on any of the above please let me know. Especially alternative anti roll bar supliers. I have found EPM Ltd in UK who can make "special" ARBs. Andy
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Back in business for fun!
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Spyros
Sr. Member
Posts: 325
I'm a real donkey!
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« Reply #79 on: July 28, 2009, 10:47:42 pm » |
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2 additional things for the suspension.
a) Front antiroll bar still. After June 78, another shape of the end of the torsion bar is adopted and this allowed shorter vertical links (7mm) without interference. It is possible to reshape the ends andthen play with the lenght of the vertical links. I cannot say what the effect will be, nor if you need shorters or longers links. The lenght is determined by a piece of tube.
b) Torsion bars. No need to look at the rear. Your bagheera being a serie 2 has slightly ticker rear torsion bar than the serie 1 But, if the rears are Bagheera specifics, thefront where shared with other models of Simca. First, within the Bagheera range, the diameter was higher on the serie 1 ( 17,5 mm versus 17,2) But if you then expand the range, if I'm not wrong, the suspension is identical to the simca 1100. (not the later 130X models) Then there were other models 1100 & Rancho had 18 mm diameters torsion bar. But even better, there was ( hope to find this...) a heavy duty suspension for the 1100, with 20,3 mm diameter torsion bar.
My hypothesis is that the torsion bar has more effect than the shock absorbers.
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Anders Dinsen
Administrator
YaBB God
Posts: 3188
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« Reply #84 on: August 02, 2009, 03:18:30 pm » |
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Interesting photos, Andy.
Rather than two anti roll bars, how about cutting a metal plate with threaded holes in different places, and welding this on the trailing arms? With your adjustable length joints, you will then be able to move the attachment point upper joint on the trailing arm, thereby adjusting the effect of the anti roll bar.
This is just a random idea, and I don't know if it will give you the stiffness you need, but I'm afraid the double arms will be too much... after all, you probably don't need much more grip at the front to cure your bit of understeer.
/Anders
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1982 Talbot Matra Murena 2.2 prep 142 2017 BMW i3 "Charged Professional" 94Ah
Used to own: 2001 Renault Matra Grand Espace "The Race" V6 24v 1997 Renault Matra Espace 2.0 8V 1987 Renault Matra Espace J11 2.2
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Anders Dinsen
Administrator
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« Reply #88 on: August 02, 2009, 09:57:44 pm » |
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I'm a beginner here and I have not yet read my new book on suspension design for competition cars. Are you saying that adding stiffness at the back will increase rear grip to the point that we will produce more understeer at the front? Not a good idea!
No, it's the other way 'round. Adding stiffness at the rear roll bar increases grip at the front. But you only want it to a certain point - since stiffening the rear roll bar will transfer load from the rear to the front, you will loose a little grip on the rear. In the extreme case, the unloaded rear wheel will loose contact with the road, which - unless you have a limited slip differential - is a bad thing in a rear wheel drive car. @Spyros: No longer links won't change anything. If I could mount ARB#2 forward of the vacuum tube and extend the horizontal side arms backwards to reach the vertical links that would give me some more stiffness but not double the stiffness. Comment??
No, since it will still act on the same place on the trailing arm, the effect of the anti roll bar on the wheels will be the same. You have to move the connection point on the trailing arm forward to reduce the effect. . Move it towards the rear, and you'll increase it. /Anders
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1982 Talbot Matra Murena 2.2 prep 142 2017 BMW i3 "Charged Professional" 94Ah
Used to own: 2001 Renault Matra Grand Espace "The Race" V6 24v 1997 Renault Matra Espace 2.0 8V 1987 Renault Matra Espace J11 2.2
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