Superstrut Suspension, ST202 - ST205 suspention Options

[celi94]

In Europe we also have celica's with Superstrut Suspension.
Thats wy i'm sharing this information!


The ST205 GT-Four uses a system of front suspension design unique to Toyota. It moves away from the MacPherson strut used on all other Celicas and is much more complex. This system is used on the GT-Four, some Japanese spec Corollas and the higher spec Japanese fwd Celicas (SSII and SSIII). It was available in Europe on the Carina GTi and was an option on the ST202 (thanks Dirk for the info).

My understanding of the system is that the geometry does not give the same camber and castor changes during cornering that occur with MacPherson strut. Is it better? Well, it is different. There are reliability problems if maintenance isn't kept up, TTE had continual problems and I believe they swapped the rally cars back to MacPherson strut.

A brief description of MacPherson strut is in order. The Toyota system uses a lower A arm with rubber bushings front and rear. This has only one degree of motion (ie. it rotates on the bushings). At the outer point of the A arm is a balljoint which connects to the steering knuckle and allows for rotation (steering) and pivot (shock compression). The steering knuckle is rigidly bolted to the bottom of the strut. The whole strut turns when steering, twisting in the roller bearing in the top mount. Fairly simple and cheap, used by most manufacturers.

So what is Superstrut suspension? It is a hybrid between normal MacPherson strut and a multilink setup. One of the requirements of the design brief was that the system would fit existing suspension mount locations. Therefore the system can be fitted into export Celicas as well as the Japanese lower spec SSI! The late production cars even share the same subframe.

The photo below shows the lower part of the system. This consists of a front and rear lower arm, connected (by rodends) to a connector plate. The rear arm has a rubber bushing at the inner end (the only rubber bushing at the front except swaybar D-bushings), the front arm has a balljoint. This system allows the arms to pivot as the suspension turns.



The steering knuckle is quite different to that of the MacPherson strut cars. It bolts securely to the connector plate joining the lower arms (see photo below). The top end connects to the strut part way up using a balljoint (see red arrow in left picture and upper arrow in right picture below. The strut mounts to the body in the normal way, but the lower end is secured to the front lower arm using another pivoting arm visible at the right in the photo above. This arm is near vertical in the photos, it is actually about 150mm long and pivots at each end.



The photo of the assembled suspension below shows that the strut rotates minimally when steering ( the same amount as the front lower arm as it is rigidly connected). The steering knuckle moves instead. While the outboard strut moves rearwards slightly when the car turns in (turning left in the photo), it can be seen that the hub moves forward. But because of the strut movement the actual movement at the wheel is minimised.

The second photo shows the mounting points for the lower arms on the subframe.



All the info from: gtfour.supras.org.nz

[BonzaiCelica]

would it of been possible for toyota to put double wishbone an all 6th gen celica except for the GT-4's? I kinda envy the fact that civic and integras have double wishbone and we dont. Shoot stupid toyota still didnt decide to put double wishbone on the 7th gen as well.

would it of been a convenient thing for toyota to put superstrut on the rear suspension, or double wishbone on the rear would of been a better choice for the 6th gen's

[Edophus]

would it of been possible for toyota to put double wishbone an all 6th gen celica except for the GT-4's? I kinda envy the fact that civic and integras have double wishbone and we dont. Shoot stupid toyota still didnt decide to put double wishbone on the 7th gen as well.

would it of been a convenient thing for toyota to put superstrut on the rear suspension, or double wishbone on the rear would of been a better choice for the 6th gen's

superstrut is essentially double wishbone in effect, i dont think the fact that the gen 6 is just a trailing arm at the rear is to much of a problem really it will have more bearing on tyre wear than much else i would think, it still has toe control etc through the bushes so isnt that crude, also this is why i'd never poly bush the rear end, a gen 7 with superstrut has the equivelant of double wishbone all round . For superstrut on the rear i dont really see much benefit because the biggest benefits of superstrut come from things like the reduced scrub radius, although it would give better camber control. For what its worth i much prefered the front end on my ss3 with superstrut to the honda's i've driven, the hondas didnt feel as tight and solid as the celica did, the honda maybe felt a bit more nimble in the slow stuff, but the celica was sooooo stable through the high speed stuff, both felt different but one wasnt better than the other.

never one to miss an oppertunity heres a couple pics that illustrate how composed a superstrut car is in the corners, first is behind a teg who was holding me up for a few laps, similar tyres but unsure of the rest of there setup but i could have pushed up the inside of a him, but we were not allowed to overtake except for the straights , the celica looks a bit more composed than the teg here, obviously different setups etc and drivers make it a loose comparison at best but shows there really isnt all that much between them. The second pic just shows how happy the back end was to sit just out a little, the front end had immense levels of grip, zero understeer and just a nice angle with the rear drifting just a little.




This post has been edited by Edophus: Mar 19, 2010 - 8:32 AM