snap oversteer

[SuperBuickGuy]

I know this seems like an odd place to ask this question, but honestly, I think you folks are subject matter experts and could add some insight.

This is all about a FJ40 that I've built with 3 link front and 4 link rear... but the question is kind of a "I need to check the basics before I get into fine-art"

when driving, it seems to want to turn harder right than left. Left seems quite controllable but going right has a vague center to a good initiate the corner, to a feeling like it wants to snap oversteer. On a vehicle with bias ply, 38" tires - it does add a bit of drama that I'd rather not have. Absolutely everything under this is brand new

I know I could live with this, take some camber out and perhaps give it a bit of toe-in.

So the basics, what do I look for in any vehicle that goes from vague steering to oversteer?

at full droop.... 14" of travel, but it's balanced at 4" to the bumpstops at ride height (the front drops down into holes to provide traction... not a desert racer that's almost opposite)

 

[84rzv500r]

i built a 4x4 87 Astro van with a L98 TPI IROC motor/700R4 and a leaf spring set up with a Dana 44 in the front and a corp 14 bolt full floater in the rear.... I used caddy eldo rear calipers and F-250 rotors on the rear and used d52 pads on all 4 corners...

I had a steering linkage just like yours and I had some serious bump steer...

I built and axle truss to pull some more positive camber in the front and found that 1/8" toe worked best..

a Steering dampener was NOT optional

 

[phantomjock]

Not really a fan of the asymmetrical setups like this. Makes design and tweaking a bit of a challenge. There are some suspension analyzers on line you might try - but might be all limited to the "simpler" symmetrical case.

Good Luck. Let us know how you sort it out.

Cheers - Jim

 

[SuperBuickGuy]

I moved the panhard bar up... but it's been raining and I have this stupid thing which interferes (called 'work')




I was afraid I'd have to run a stabilizer (or multiple) but honestly, I don't need it. I'm thinking about hydraulic assist like the C3 has, and that would effectively do the same thing as a damper

what I think I've come to as a conclusion is to be certain about the rear tire pressures - they were uneven - because I have a loc-rite in the back (front too)... and everyone knows what those do if you don't go into a turn in a neutral throttle...

with that said, I love loc rites on the track because they're utterly predictable - I knew when I hit the throttle in my a-body Buick that it was immediate understeer so when coming out of a corner there would be little steering input just increase the throttle position (drove the instructors nuts - which is always a good thing

84 - toe in or out?

 

[SuperBuickGuy]

some pictures of the rest of the suspension

 

[84rzv500r]

IN

 

[rtj]

I had a land cruiser with big bias tires and a cj5 with big radials. The cj was far superior in handling. I attributed it to the radials. Just my limited experience. It was 30 yrs ago, so don't remember the sizes.

 

[SuperBuickGuy]

Radials make a huge difference, more robust, better fuel economy, less rolling resistance and less desire to follow every crack. Bias ply makes it up in lightness and the most fatal of all afflictions itswhatigotitis.

This was a leaf spring vehicle, and so the entire suspension is new to it - but I suspect that whatever ills it would do similar things on a car... I'm still leaning towards tire pressure issues.... but today was wet and I was doing a billion other things so I didn't get out to test the new panhard bar position nor did I do a tire pressure test.