S13 Suspension in an Ae86 - Bad for low impact crashes (Bent Rails)

[Matt]

Hi Guys,

I have heard a couple of people lately who have ran the S13 suspension setup in their ae86's have what could be considered a low impact hit come out of it with a bent chassis rail.

Has anyone else experienced bent rails from something which should have only required a wheel alignment to sort it out?

This has got me thinking about the setup, and given the geometry of it and how difficult it is to dial in correctly to start with that it is not worth it.

Cheers
Matt

[fantapants]

the only change i can see that would alter the loads of the impact on the chassis is the longer lca.

where was the chassis damage located? infront of th crossmember or behind? what kind of impact??

and its hardly difficult or brain straining to set it up correctly...

[meadan]

It could have something to do with s13 suspension componenets being stronger, which then trasnfer more load to the vehicle chassis.

Although, most ae86s which have a hit will come out with a bent rail. The simplicity of the front end design doesnt really give much front impact protection.

The s13 front end doesnt really change much geometry which would have an effect on the front end. But the longer control arms, heavier/stronger knuckles, stronger tie rod ends etc "COULD" have an effect. Without decent testing or analysing I would say its pretty negligible.

Also, weve done some low speed crash testing on new models at work. Youd be surprised at what breaks, 10km/h is enough to do some damage...

Big heavy wheels, chinese bolts and cheap suspension components would probably be more of a worry in all honestly.

[fantapants]

what he said

[Golberg]

IMHO - AE86's will often easily bend rails in a minor front end accident. The rails stick out so far from the radiator support so it takes very little. E7's on the other hand don't have protruding rails = win.

[ae8zn6]

Not all of these came from traditional front end hits, I know one of the incidents that Matt is talking about came from a wheel hitting a ditch whilst sideways

[maxhag]

^^ As mentioned above, my case was very suprising....

My rail copped somewhat a side on impact on a ripple strip outer edge, while the wheel was at full lock.
All S13 suspension appears to be undamaged, all taken off TWICE and checked

Obvious damage was that the wheel was sitting 20mm in the guard, with very little neg camber...

The affected rail has been bent inward (toward motor) at the firewall. Also, the rail is twisted ie, cross member bolts are no longer "vertical" (inward at bottom/LCA mount side)...

Motor is out, yet to have it professionally looked at....

[fantapants]

might have something to do with the s13 "wobble" at full lock? if the hit was at the right time and everything loaded up nicely, the force would translate very directly back to the crossmember....

[meadan]

^What he said

I think it all just goes back to the s13 gear being stronger than the toyota stuff.

A ball joint, control arm, steering arms and suspension are pretty much consumables in a crash scenario if you dont want to damage the chassis. If these bits can all of a sudden take the force of an impact, it has to be transferred to the next weakest place...the front rail. Theres no high strength steel in an ae86, so bend that shit back and keep on driving

[Skylar]

Yeah, I agree. It's just strength of components rather than some weird binding geometry created by running s13 stuff. Beef up the chassis or run weaker control arms.

Run some SPL roll centre correction LCAs and bump steer correction tie rod ends set at half inch drop IIRC. They'll be the first things to snap in a hit.