Saturday, July 10, 2010 - 03:31 pm, by: Ben Lipman(Ben12a)
In the pic above, the measurement for the left hand 'leg' is 245mm to the outside centre of the bush, or 237 to the centre of the bush.
The right hand leg outside centre length is 247.5mm or 239mm to the bush centre.
Using pythagoras theorem/right angle triangle rule(or what ever it was called, C2= A2 + B2 ) and the outside measurements I come up with: 117.47mm for the base of the triangle formed by left leg 122.60 for the base of the triangle formed by right leg. Therefore it is offset approx 5.1mm to the front on each arm. So swapping the arms left to right will move the upper ball joint rearwards 10.2mm (if my maths is correct). I have no idea what angle that translates to as i done have the measurement between upper and lower ball joints.
Tuesday, July 13, 2010 - 08:31 am, by: Damian Ware(Frozenpod)
Your math is correct.
10.2mm would be noticeable also not sure what angle that relates to.
My thoughts are swapping the arms left to right might allow the alignment to be optimised for camber not worring about how much caster you have as there will be most likely be more than enough.
Did you have any other thoughts for possible alternative OEM arms?
Ben Lipman Goo Roo NT Soarer TT manual, plus TT track car
Tuesday, July 13, 2010 - 05:12 pm, by: Ben Lipman(Ben12a)
To be honest Damien, I have been snowed under with work and some other issues (we need to move house)
If I find anything I'll certainly post up the information. I don't mind sharing. The more Soarer/supra's on the track the more people will be exploring the boundaries and finding new ways to improve.
On Toymods someone has suggested Mazda FD3S Rx-7 arms as they look very similar. The only thing for it is to go to a yard and poke around. You never know- there might be a Hilux or a Delica that has the perfect arm just waiting to be discovered. When I was younger we found all sorts of parts in the most unlikely places that could be made to fit. (Holden SU carb into a Mini, Hilux diff into an Rx, 626 gearbox into Rx-7 etc)
Otherwise some of the other similar age Toyotas appear to have pressed steel upper arms of an appropriate shape. If one of those fit then they would be much simpler to modify being steel.
Tuesday, July 13, 2010 - 11:05 pm, by: Damian Ware(Frozenpod)
No worries I was just thinking of ideas ie RX-7.
The RX-7 upper front arms from memory are very similar but I think they are very small it has been a long time since I have seen them but they would certainly be worth checking out.
Ben Lipman Goo Roo NT Soarer TT manual, plus TT track car
Wednesday, July 14, 2010 - 08:30 pm, by: Ben Lipman(Ben12a)
Whilst out running this morning, I dreampt up another idea. It may have been done before.
Instead of a straight cut and shut, cut the ball join end and have the inboard end manufactured up to accept the ball joint in a sliding adjustment like the Ikeya formula arms.
Either start from scratch or modify the original arms as described earlier in the thread (plating etc.) The slider would be secured by through bolts to regain some strength.
Of course it could be a •••• idea. Maybe I was dehydrated. It was hot.
Monday, July 19, 2010 - 07:52 pm, by: Ben Lipman(Ben12a)
Or just suck it up and buy the bloody Ikeya arms.
It has been an interesting exercise so far though. When I get settled into the new house I still plan to hit the wreckers with the spare upper arms and have a look.
The Soarer isn't old enough to have a strong DIY following, or more to the point was not around back when no one had the internet and the ability to buy off the shelf solutions. Look at the cars people modified pre 1990s and you will find all manner of inter breeding and so on. People adapted entire steering/braking/suspension systems from one model to another, and everyone had been to a wrecker with a tape measure and steel ruler to search for things that might work.
Just look at Toymods...
Phil Gibson Goo Roo WA '91 UZZ31 track bunky, '94 blk/blk UZZ31
Saturday, July 24, 2010 - 09:46 pm, by: Phil Gibson(Sciflyer)
Z20s (and presumably A70s) have very similar or possibly identical upper arms - i would start there - see if you can get someone on Toymods to measure up thiers.
Celsiors and Aristos have a very different front suspension setup, they type where the upper arms are above wheel height - i doubt they would be any use
And yes Ikeya does both upper and lower arms, in fact i remember reading you cannot (or shouldnt) fit only the lower arms, if you get them you need to buy the uppers as well. Presumably the reverse doesnt apply as Damien Smith is running the uppers only with no issues
Tuesday, August 10, 2010 - 06:09 pm, by: Damian Ware(Frozenpod)
About 15 years ago whilst racing RC I did some suspension geometry math as back then the RC cars suspension designs were not great.
We used to modify them mix and match parts from different cars to get improved designs.
When moving house I found some of the info with one of my older cars, this car had possible caster adjustment up to 12 deg. The only settings which worked was between 4-8 deg which was much higher than every other RC car I have used. After seeing it again I remembered why it had such high caster, which was due to the large kingpin angle.
I have attached a graph dynamic camber with steering angle. Relative to kingpin and caster. Note kingpin angle introduces positive camber as the wheel is turned.
This graph has appoximately soarer suspension geometry kingpin 9 deg Caster 5 deg.
Showing full 90 deg arc and zoomed in for 30 deg approximately the actual usable area 30 deg.
Most likely the best suspension geometry modification that could be made to a soarer would be to reduce the kingpin angle which could only be done by replacing the front uprights and upper arms.
If anyone is interested in the math I am happy to post the calculation details or send through the spreadsheet which can have values adjusted to see what dynamically changes through the steering arc.
Previous
Closed: New threads not accepted on this page
) 
Upload
Upload
