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Discussion Starter #1
OK, all measurements are done. Measurement were compared between a set of MK2 GAB shocks (rear adj, front fixed) and AE86 Tokico shocks (all 4 adj). Here's what I've found:

FRONT:

Front strut housings between AE86 and mk2 are identical in dimensions. However, the caliper mounts are spaced farther apart (by alot) on the AE86, so an AE86 front suspension (like TEIN or JIC) would not be a direct swap in affair.

They do have the same mounting, though, so RCA's* for an AE86 will fit the MK2. ********note: after precise measurement by Don L., the mk2 mounting holes are spaced 1/8" further apart (I didn't catch that). So they will NOT work. aarrrggg...the problems with using a tape measurer....I need to get me some precision measuting tools.********

Due to their exact dimensions, AE86 strut inserts fit in the MK2 housing. The extended length is only 3/16" shorter on the AE86. THe strut insert body is 1/16" shorter than the MK2, so an extra half turn of the housing collar will clamp it down just right. The AE86 strut body is slightly narrower than the MK2, so it has a little side to side movement, but as the housing collar starts to tighten on it, it centers it right up. You cannot use the AE86 housing collar as it is different thread pitch.

I compared damping between the two, both on feel (pushing it down) and speed at which the strut returned to extended position, and the non adjustable MK2 GAB strut's damping was equal to the AE86 tokico somewhere between setting 4 and 5.

Another good thing about this is for having short stroke struts. It is common to use AE92 front strut inserts as short stroke shocks for AE86's. The AE92 inserts are 103mm shorter extended than the AE86, and the strut body is 66mm shorter. What you do is put a 66mm spacer inside the strut housing under the shock, put in the AE92 shock, and now you have a 40mm shorter stroke shock. The TRD short stroke kit for the AE86 is just an adjustable AE92 shock with the spacer. This would work perfect on the MK2.


REAR:

OK, rear is not as good news. Rear AE86 shocks were much shorter than the MK2. The AE86 extended length is 2 1/4" shorter than the MK2. Closed, however, the AE86 shock is only 3/4" shorter than the MK2. This would work for someone who is lowering their car 2" or more. Comparing the shock damping between the two, it was pretty much the same all the way through. The 5 setting on the AE86 Tokico shock was equal to the 7 setting on the GAB MK2 shock. 8 on the GAB shock is a drastic increase (1-7 is pretty linear) from the rest. 8 is VERY stiff.

Some investigation will need to be done to see what rear shock would work as stock and short stroke for the rear.



*Note- RCA's are Roll Center Adusters. Roll center refers to the lower control arm's movement, and how it changes camber and toe during suspension compression. When you lower the front, you change the position of the lower control arm. For example, lets say for every inch of travel you get -1 degree extra camber. If, say at stock height you have 0 camber, if you lower your car 1" you now have -1 degree camber at static hieght. Now when you compress the suspension 1 inch, you have -2 camber instead of -1. Same changes apply with toe.

RCA's are basically spacers which go between the strut housing mount (where it mounts to the lower control arm) and the lower control arm. This resets the control arm back to stock position. In effect it gets rid of any negative camber caused by lowering the car, so your camber remains stock. It also reduces bump steer caused by lowering of the car. They make different thicknesses, so you can choose one thats as thick as the amount that you lowered your car.



Hope this information is useful to someone.

Christian
 

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Good work, Christian! :)

When/if I get my hachiroku I will definitely be hitting you up for some advice.
 

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Hey Christian! This is great news! Thanks for the info..it will help me work toward those suspension pieces so much faster! I'll be sure to remember your contribution when the time comes to release these babies =)
 

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Damn fine work. 8)
Ive been wondering about all these things, But I never have the time to do any of the research. Im especially happy to find out the the RCA's fit seeing as how I orderd a pair because they looked like they would fit properly. And if they didnt, I could have always sold them to a AE86 owner.


I love this place!
 

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What do you mean the caliper is spaced farther out on the AE86?

Are you saying that the lower shock mounting point on an AE86 is farther out than the supra(i.e. the control arm is longer?)?
 

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Discussion Starter #6
The caliper mount is part of the strut housing. The holes on which the calipers mount to are spaced farther apart on the ae86 (the caliper may be longer than the mk2?)

HTH

Christian
 

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Nice work. DonL has had luck running older bmw 3 series shocks in the rear. I think they`re a little shorter but not sure.
 

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SupraFiend said:
Nice work. DonL has had luck running older bmw 3 series shocks in the rear. I think they`re a little shorter but not sure.
By "older 3 series," would you happen to mean the E30 series of BMWs? If so... If you can source a rear set of Turner J-stocks from an E30 M3, you'd have a HELL of a rear end right there!
 

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Actually I run Koni Yellow Sport shocks for a E36 BMW in the rear of my autox Supra. They work fine, but I do wish the shocks were a bit shorter in extended length, maybe 2" shorter would be nice. As is, they never bottom. Excellent shock, but I still have to remove them from the car to adjust them. Would be great to have a dial of some type and adjust on the car. Can have Koni rebuild and upgrade to externally adjustable with knob on side but too expensive. BTW, these shocks have more dampening than I can use, usually set about 1 turn from full hard, it has I recall about 2.5 turns total.

Don L.
 

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For those of you who have ordered a set of RCA for the front struts, where can they ordered ? What is a good price and what range of thicknesses do they come in. I'm thinking maybe 1" or 1.5" would be good. 2' or bigger thickness would worry me a bit. I would need much longer bolts and not sure if the RCAs would have the same fitted holes as the stock strut housing. I mean like a counter-sunk hole in the bottom of the strut housing that fits onto the a raised lip on the a-arm. Thanks.
 

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Don L. said:
For those of you who have ordered a set of RCA for the front struts, where can they ordered ? What is a good price and what range of thicknesses do they come in. I'm thinking maybe 1" or 1.5" would be good. 2' or bigger thickness would worry me a bit. I would need much longer bolts and not sure if the RCAs would have the same fitted holes as the stock strut housing. I mean like a counter-sunk hole in the bottom of the strut housing that fits onto the a raised lip on the a-arm. Thanks.
Hi Don,

I don't know the dimensions on these, but the ones from T3 (Gabe Tyler) come highly recommended from several Corolla peeps (by peeps I mean people, not the yellow marshmallow chicks).


RCA link

I'd like to know for sure what these would do for a lowered Mk2 Supra. I cannot picture how much tilt the control arm has to it right now on mine with Eibach springs. I'll try to measure this week.
Either way, they're probably cheap enough to try out, since reselling prob. won't be an issue.

Regards,

Jimi B
 

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thanks Jimi !!

I don't quite understand how much it can help my susp, but I'm trying to read up on the subject. Makes some sense, and if it can cure some of the initial corner entry understeer, then its a pretty cheap mod !

Don
 

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I'd be interested to see if those RCAs would help on my car. I've noticed I get a lot of bump steer after I install the Eibachs. They're a little different than the bump steer kits I've seen in the past where they move the tie rod end down, but I guess the concept is the same.
 

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These RCAs will raise the front wont they?
 

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They would push the lower control arm down to restore the factory tie rod location.
 

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It just seems to me that it would raise it since we are effectively increasing the length of the strut, wich was reduced with a lowering spring.

Can somembody explain why this would not happen?
 

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The distance between the spindle and strut top are the same before and after. The block mounts under the strut between the knuckle arm and strut. Basically it just move the control arm down. The only way to change the ride height of the MkII is to move the spring perch or change the spring.
 

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After reading the manual and looking at my front susp (lowered with coilovers) I am convinced that RCAs would be a useful part. Ordered a set from Toysport for the AE86 Corolla and shipment was only 2 days. Nice service. The RCAs are 30mm high and measuring my susp arm, that would put them about level to the ground again. Problem is they don't fit the car. Although the body dimensions of the RCAs are good, the hole diameters and inset sleeve are correct for the Supra, I noticed the center to center distance from the two mounting holes are off. The AE86 uses a
3 & 3/8" distance center to center. Supra is 3 & 1/2" . With the inset metal sleeve I can't just machine the holes out, so I'll use these examples and try to find a source to make the RCAs. I'm waiting to hear back from
T-Toys as they sound like a possible place for custom work. Toysport was closer but I don't think they machine.

Don L.
 

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Discussion Starter #19
Don,

Sorry about that. It looked to me it was dead on. Unfortunately I didn't have precise tools to measure everything.

What is T-Toys? Is that the techno toy tuning?

Christian
 

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Yes, Techno Toy. Haven't heard back from them yet. No problem though Christian, plenty of AE86 drivers in club to pass these off to. It's actually very handy to have this set to show machine shops what I need. Other than the spacing of the holes, everything else is right on. Toysport sent my kit with the equiv of metric grade 5 bolts, so I'll be looking for a supplier of metric equiv to grade 8 locally.

Don
 
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