Adjustable Spring Seat/Perch onto G series Diff

[Esteban]

Hey a quick search only yeilded people putting coilovers on the stock or sometimes strenghtened shock mount... options I'd rather avoid.

I have this picture from a Gazelle I think but I didn't save the source info so I can't credit who owns it...



Now that I have the RN27 G series diff housing the next step is welding mounts onto it... I'm interested if anyone has info on making the spring seat/perch adjustable similar as to how it is here. I reckon it's a very cool idea. I'd probably rather the adjusting seat use the stock upper mount on the vehicle and have the adjustment ring on the lower mount if possible. Ideas?

[EVOSTi]

you could probably buy the coilover sleave kits and weld the sleave to the diff housing and mount the upper hat to the chasis?

[JustenGT8]

I can't really see the point in that setup? The car could only ever be as low as a lowered spring anyways so what are you achieving? All it lets you do is start with a minimum height and adjust up?

A true coilover setup, allow you to adjust the height without compromising spring rates and in some cases even shock travel.

In all honesty use a proper coilover and strengthen the shock mount to take it....or relocate the lower mount if required to improve yopur rear geometry.

Don't be worried about strength....top end drag cars use this exact setup and the weight transfer loads they experience are many time greater than what your RA ever will

Add a watt linkage instead of the panard rod and lengthen the top link arms and you'll have about the best live axle setup tou can have

[LeeRoy]

Linden had that setup in his old AE71 with the adjustable perch on the diff. I'll try and get a pic of it later but afaik he just used normal coilover sleeves and rings and welded them to the diff. However, cause they use a coilover (narrow) spring the upper mount needs to be modified also.

[MWP]

Any reason why you cant run a shock upside down with coilover springs?
That way the spring would be mounted at the bottom and there would not be the spring clearance issue at the top.

[ill-minded]

i've looked into these for xA6x/xZ1x/xT14x/xX7x chassis's.. and even made a few cad piccies.

there was a set on yahoo auctions also, going for about $300-350 or something but im pretty sure they could be made for less. probably the most expensive part would just be machining and making the aluminium perchy bit things.

[wilbo666]

i've looked into these for xA6x/xZ1x/xT14x/xX7x chassis's.. and even made a few cad piccies.

My thoughts are that this doesn't work very well for xA6x etc...

The crap geometry means you really have to use the stock size springs, so that rules out the off the shelf supply which I feel is one of the main benefits of coil overs (Off the shelf springs in various rates...)

Also you need to ditch the factory bump stop mount / top spring seat...

Just my thoughts


Myself I was thinking more about something like the following for the older IRS toyotas...


Cheers
Wilbo

[JustenGT8]

^^^ yup that's much better.

But, what's the drama with a coilover onto the stock shock mount? Even left completely stock i doubt you would have a failure but it certainly wouldn't take much effort to reengineer to be bullet proof? So much simpler

[ViPeR_NiPPleX]

i like the design, but wouldn't be street legal with the rose joints?

i want to redesign the semi trailing arms ideally. Remove the lower spring perch and strengthen the shock mount... can always dream.

Take a look at the e30 bmw crowd for ideas.

[wilbo666]

^^^ yup that's much better.

But, what's the drama with a coilover onto the stock shock mount? Even left completely stock i doubt you would have a failure but it certainly wouldn't take much effort to reengineer to be bullet proof? So much simpler

It has been a while since I looked at it, but I think room for the spring was a bit of an issue in xA6x at least?...



Cheers
Wilbo

[Soarer21]

Well, maybe my eyes are failing me but I see no problem with the original picture posted by Esteban. Coilover springs are available from 140mm long, though the rates are too high for the rear (400lb start) however in 170mm length they begin at 200lb which is getting somewhere close to a good beginning. The car in his picture, we dont know where the actual height is at the seat position they've chosen so saying "it wont ever be lower then a "low spring" isnt the same as being able to achieve a balance across the car with adjustable heights plus the ease of altering rates if required. Cant do that with a low spring. And dumping a car right on the ground without thought will only create a pig to drive anyway so it might well be fine at the achieved height for a good handling car based upon close to factory mountings.
This above setup is in fact what I am "most likely" going to go for in my own RA60 Celica.
Ive seen it a number of times in various cars and I see no reason why it wont work effectively in a celica.
Obviously the best thing is to wander off for a fully customised IRS setup with equal length arms and inboard brakes but who can afford to do that?


*edit* I just saw the brakes on that gazelle and I wonder whose bright idea was it to mount the caliper at the highest possible point on the diff... Not the best idea they've had thats for certain. Only need to look at an F1 car to see where they should be, though that requires special calipers however the lower to the ground they can be and still get bled effectively the better its going to be.

[JustenGT8]

^^^ you need to look again then mate It's one way for sure, but kinda retrictive considering the effort and no real advantage over the stock setup in my book.

[Soarer21]

Can you explain yourself more fully then? What I see is a spring perch with height adjustment (although in image used it's at max low but that's not the way it HAS to be I'm sure). By having that, you can corner weight the car and you have readily available spring rate options. The stock setup isnt corner weight friendly, and spring rate changes, well they're even harder to achieve...

[big_zop]

^^^ you need to look again then mate It's one way for sure, but kinda retrictive considering the effort and no real advantage over the stock setup in my book.

You wouldnt be talking about adjusting them later on? The pic doesnt show what else is in the way or how bad the body is but i cant see it being easy to adjust the spring perch the way it is

[EVOSTi]

custom springs can be made for $120 a pair in whatever size, length and rate you like. why not do this and save the dramas?