I need some info re spring rate and have problem with front scrub on indy r. Also powder coating cracking on upper front wishbones . Notice movement on top of suspension under heavy braking. Running 7in fronts with dunlop stickey tyres for hillclimbs.Car 280 bhp +seq box and on double adjustable shocks. I suspect I will have to modify top wishbones as I fear weld fracture. Any opinions.
Hey Ajw,
I'm not totally clued up with regards to suspension setup on these, but is this chassis running the inboard or outboard front shock setup?
(i'm guessing outboard)
C.
Its running inboard .
If you look closely youll see some movement in the cycle wings when braking and slow speeds too...
Are you not always going to get some rotational movement between the uppers and lowers when braking?
I guess you will always get some, unless every thing is 100% rigid.
On the MK indy it's quite large as the upper wishbone flexes more than is probably desirable due to it's U shaped design; I would think this
is minimised on the R with it's new triangular upper bone design (but you still get some bending under breaking because the apex of the triangle
is not near the ball joint, and the upper ball joint is far from ideal as well being a tie rod end under bending...)?
Most locost based designs are similar in this respect; you have a tie rod ball joint in bending under breaking; this will try and bend the upper
wishbone.
Cheers
Dan
I think alot of the movement is due to the bushes in the wishbones compressing too.
Hi
On the few off the Indy R's i have had to sort out what we found to be problems are. 12mm bolts through 1/2" bushing and mounting brackets.
Spring poundage wise you will have problems with selection untill you have made sure the dampers are valved right at low - medium speed as spring
change was masked by wrongly valved dampers. And also you have got to check that there is no air in them.
Geometry wise check out the amount off camber gain in roll, Or rather the amount off camber LOSS. That will give you an idea as to what will be needed
to gain better front end grip.
Cheers Matt
The suspension on my car is totally rose jointed and has triangle top wishbones. The issue of flexing came to notice at Kirkstown last week end. The car tops 130 mph with the present gearing and we were topping out three times per lap. I had a call from MK and discussed strengtening webs/straps on uppers. Car is on 350 lb front inboard springs and 300 lb rears
Hi
Is that the single shear pivot mounting point or from the chassis brackets themselves. The was the chassis wishbone mounts that where breaking on
Ian's car.
Also does the car still feel soft on the 350Lb fronts. That is way OTT for the application. Mk where recommending higher and higher poundage on the
front to a number off customers who all discovered that it was air in the Dampers. Once bled they where back on 250Lb - 275Lb iirc. Although they had
the single adjustable which could be mounted the right way up where as the double adjustables can not.
The weak spot seems the weld joint at outer uppers where tube from rear of wishbone is welded. We intend to either replace pipe with higher quality
or make new uppers. Lot of flex under braking ,you can see wings moving.I am told the front springs are 350 and rears 300. Its on double adj shocks
with front valves to the top ( protech boss said no problem when I spoke to him at Autosport show. I am running the height under the chassis at 100mm
measured from box section down. We cannot keep speed through corners as quick a our pals westfield hyabusa and he is 3% faster . Maybe I should chuck
out duratec and go bike route!. We had considered using a powertec v8 next year but no if suspension cannot take pressure
AJW
Ireland
Hi,
I ve sent U2U. Too many Mk lovers sending thier comments to me. LOL
Cheers Matt
quote:
Originally posted by procomp
Hi,
I ve sent U2U. Too many Mk lovers sending thier comments to me. LOL
Cheers Matt
The problem seems in the geometry and will spend next sat resetting
1.5/2deg negative
2/4 castor
350 lb fronts
300 rears
Will try 50 lb less on springs
will look at new roll bar setup ( has anyone got photo of latest blade system)
Have a hillclimb in south co kilkenny coming up and need to be ready
Car was third in kirkstown to a radical and TMS300 (v6 mountune) but cannot get times quicker to a westfield with a 1.4 modified (extreme Engines)
hyabusa .He can carry the speed through the corners
Alex
Kilkenny
Ireland