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Discussion Starter #1 (Edited)
Cap'n 2JZ's 1985 Toyota Supra
Suspension Build Thread



So I decided that the best route for me as a rear suspension installation was to create something on my own. I wanted adjustability for my own preference and funcionality for when I buy my 16" wheels (I'm still running the stock 14") so I can adjust the fender gap easily. I also have intentions to use this car for lapping day events when I finish it. Many said that this adjustable rear suspension would not work, but here is the write up to prove its potential, not only that, Megan racing is developing the exact same type of suspension right now, the thread came up after I started working on this idea, great minds think alike I guess. My version cost me about 52$ a rear spring (about 150 shipped) (From George at Raptor Racing, thanks again G!!!) and about 60$ shipped for the spring spacers. So were talking about $210 for this rear set up, really not bad at all.

I have to send out a BIG thank you to George from Raptor Racing, for most of these parts I got from him. Thanks a lot George, you have no idea how much I appreciate what you do!


Important info

Calculating spring rate, and spring compressed height.

Cap'n 2jz

09-10-2008, 07:29 PM

lets try this again. I've based my measurements off of the stock springs, in the soso condition they were in, add a tiny bit a sag for the years)

(Stock Spring Rates)
(FRONT: 250 LBS)
(REAR: 150 LBS)

So if I take a #400 Spring

considering the distribution to be about 60/40 ---> (57/43)

Weight: 2800
Front: 1600 lbs
Rear: 1200 lbs

so then I take 1200/2= 600 lbs per wheel in the rear.

600/400= 1.5 inch of drop from the spring.


brings the fender height to 23 inches with a 60 profile tire (much too low to be usable without the spacer)

Cap'n 2jz
10-16-2008, 06:26 PM

The lowest spring rate on a 5.5 inch round by 9.5 inch tall spring is 400 pounds. In reality I took a front spring and am putting it in the back.

The stock MK2 rear suspenion measures 14 inchs uncompressed and 9.5-10 inches when compressed, giving it a rate of 150 pounds. The springs I bought are 400 pounds, they are 9.5 inches tall and compress to 8 inches which makes the car way too low, then you add in that spacer and adjust your height.



The Rear Suspension

Eibach 400 lbs circle track springs with Threaded Collars


To start these are the parts I used. I ordered Eibach 400 lbs circle track racing springs, 5.5 inches wide by, 9.5 inches tall.

model #: 0950.550.0400



Now you cant just slap these in because it will drop the back end way too much, which makes the car front rake and look really bad. I put them on to let them settle in so I could decide how I was going to install the spacers. The springs dropped the car 1 inch initally, then once they settled the car droped another 1.5 inchs, making it 2.5 inches in all, which slammed the car way too much in the back. So then once the springs settled I removed them and I went onto stage 2, welding in the threaded collar.


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Spring spacer

SS-85500-A

Here are the adjustable spring spacers that I bought from a circle track racing magazine.



http://www.daymotorsports.com/product/352/SPRING-SPACERS




Modding the Lower Control Arm to install the Collars

Modding the lower table to use the spring spacers. I had to cut off the top of the spring bottom mount because it would have let the spring spacer sit too high, I cut off around the mount and slapped in the spring spacer, I'm in the process of welding it in now, but here is the procedure.

Remove spring (easy if you do it MY way) screw spring compressors, they just dont fit in there. Unbolt the shock and remove it off its mount, that makes the table move down another inch or 2, then jam a 10" long solid screwdriver and or crow bar under the spring and pry it up out of its cup, then jam the crow bar under there and force the spring up onto the mount, force it about half way across the table and then stick your foot in there and kick it out, works like a charm, took 10 minutes on each side. So many people tell me that its hard to remove them, they just dont have the right technique lol :crossjerk Also remove the rubber cushion that sits against the body of the car, its way too thick and doesnt leave very much room for adjustability under stock height if you run with it. I cut some cusions out of 1/8 inch thick rubber sheet and installed them on the top and bottom of the spring as cushioning.







I used a die grinder to cut off the top of the table where the spring sits, this was long and gay, but its possible.





Then grind the surface flat (its not done yet in that picture, Ill update later) try and make the spacer sit in paralell with the table, this is important or else when the car sit the spring spacer will hit the bump stop when it levels out, watch out for this.










Before you weld in that spring spacer, you cannot overlook this. By cutting off the upper part of the table you no longer have a contact surface for the bump stop, so what I'm going to do is I'm going to weld a piece of angle bar onto the table in the place of the portion I removed. The idea of this is to give a place that the bump stop can contact if the suspenion compresses that far (I doubt it with the stiffness of those springs) but even still, you dont want your wheel ramming the inner fender if you hit a bit divit. I would also replace the stock bump stops with a pointy type model so that there is no interference with the threaded collar.


Problem Solved






Installing the spacers on the a-arm














Front Suspension

Ground Control (Eibach springs) 500 lbs adjustable coil over sleeve kit


For the front I bought a set of ground control coilovers, (Eibach) 500 pounds for the front. The install was really easy, took like 30 minutes on each side.








So here is the final result, something not too low and adjustable for the fitment of bigger wheels.



Front



Rear



Nose



Tail








Camber Mod (COMPLETE)

I bought Dave2JZGTEs rear weld in camber kit. I've dropped and dissassembled the rear subframe and am currently in the process of buying new bushings and cleaning and preparing the tables for cutting and welding. My progress so far...

grinding off filth and painting

before





after









ok, so here it is, camber mod done, new poly bushings --> All thanks to RAPTOR RACING, thanks a lot George!!!!!










right before the poly sub-frame bushings










Addco sway bars








Future Plans (need money)

I've been doing my research about sway bars, and I've come to this decision about my car. The front I'm going with an addco bar and a white line adjustable rear. Why?

All can be explained here. A very good read if your unsure about your sway bar choice.

http://forums.celicasupra.com/showthread.php?t=28735&highlight=whiteline

UPDATE: I would have ideally like to run the white-line in the back, but I was able to get in on the last group buy of the addcos so I picked them up as a set instead. I'm very happy with the performance of the addcos all-together, one day I will pick up a white-line and test the differences for myself, because the addco is very solid the way it is IMO.

If you lazy I'll sum it up very quickly. The addco comes out to be stiffer than the whiteline, except for the whitelines highest setting in the front. The rear addco is too stiff and often results with an over steer issue. The whiteline bar, is adjustable, and you can set it to your driving preference, soft to stiff, under-steer to over-steer.

A few resources to a healthy suspension build. Every one of these threads is a fantastic resource and insight into building your suspension properly.

Supralee

http://forums.celicasupra.com/showthread.php?t=30123&highlight=addco

Carlos Brown

http://forums.celicasupra.com/showpost.php?p=542906&postcount=82
see thread for more details
http://forums.celicasupra.com/showthread.php?t=39419&page=9

SupraWes

http://forums.celicasupra.com/showthread.php?t=11146
 

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If you disconnect the half shaft, the springs just about fall out. What locks the rear spring spacer to keep it from adjusting on it's own? How do you adjust once in the car and under load, I don't see any provision for aid in turning the spacer to adjust it, do you just jack the car up and take the load off?
 

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Discussion Starter #3
it wont adjust on its own, the weight of the car will never allow it, and besides that, its not like a macpherson in the front that turns with the steering, the rear is always stationary. And yes to adjust the height all you have to do is unload the suspension and turn the sleevles, exactly like coil overs.
 

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I knew it would work, why would I do it if I wasnt sure lol
 

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the a-arm is hollow underneath, I'll grab a picture of that tommorow.

the springs are 5.5 inches in diameter x 9.5 inches tall . The spring spacers are 5.5 inch and I got them from day motor sports. model 8550A

http://www.daymotorsports.com/product/352/SPRING-SPACERS

I got the springs from George, he ordered them from Eibach for me.
 

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no dude its really sporty and not too harsh at all, the car handles like a beast
 

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Well after searching I am looking at the

Front:
935 Coil over kit for the front which has 450 pound front springs (depends on if its adjustable)

Rear:
Adjustable perches and ~350 (give or take) but most likely 11" tall springs (because of lighter spring rate).

Then I will have adjustability in front and rear so if when wheels or tires or both change i can get to the height I want.

Should give quite a bit better handling than stock (combined with my custom front and rear strut/shock tower bars) but still be streetable since its my daily.

and not to big of a hit on my wallet, cause thats always nice too.
 

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I dont think the 11" tall springs are going to give you enough drop to be able to fit the adjustable spring spacer, I looked at that as an option. The corner weight of our cars stock is about 600 lbs on each rear wheel, so if you look at that spring rate 350 lbs, that means it takes 350 lbs to compress the spring 1 inch. 600/300= 1.7 So with those springs you would see the spring compress to be 9.3 inchs tall (11-1.7) which would roughly put you at stock right height. .2 of an inch drop to be exact. ( I measured the stock springs compression by measuring the spring under compression under the car to see if my math was working, the STOCK spring is ~ 9.5-10 inches tall compressed )that would not let you put in the spring spacers. The springs I have have a 400 rate but they are shorter, 9.5 inches tall and when you calculate the spring rate 600/400= you get 1.5 inches of spring compression with the weight of the car, putting the spring at 8.5 inches tall and 2-2.5 inches of drop on the rear end. Then you fit the spring spacer in the place of the cut a-arm. This gives you a possibility of a maximum drop of 2 inches all the way to 3 inch monster truck style over stock.

This is also the reason I chose a 500 rate for the front, the variation between the stock spring rates was 100 lbs. The lowest spring rate I could get for a 9.5 inch tall 5.5 inch wide spring was 400 lbs. I made a rule of thumb to start out with the back, and then organize for the front. I did this to make sure it wouldnt throw the balance off the car, you cant have the rates too close either, like 400/400.

(front was 250, rear was 150)
 

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like any other method, the table drops in the same way, the lower you go the more negative camber you get.
 

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I took the car out for the "test" tonight. It passed with flying colors, I am very impressed, I'm so satisfied that I'll go to sleep knowing it worked first shot lol. The car sticks to the road, its unreal. The suspension gets gitty when your on bumpy roads, or like the old-paved country roads that we tried out tonight. This is when you know what spring rate you've chosen, but on smooth asphault its a dream, such a smooth ride. hit me up with any questions or comments if you might have them.

I got a ticket tonight testing it out too lol, its a really hilarious ticket. In french she wrote "conducteur d'un vehicule a fait crisser ses pneus sans nessite sur un chemin public" translation --> driver of a vehicle that was un-caringly spinning his tires for no reason on a public street. (at 1:30 in the morning I might add) I was about to rip it and saw some jeep liberty a good distance behind me, I'm like "good no cops" yeah well they drive libertys around here now. Anyways it was a chick and she comes up and goes, yeah I'm pulling you over for your "crissment de pneus", and your car smells" I was like, "thanks, and yeah me and my buddy are just testing out the car after the job we finished tonight" She goes "yeah ok, give me your papers". Some giggles later she comes back with a 52$ ticket and calls me "dear" in french. Here you go dear, how thoughtful!! me and my buddy were dying, all for the cause. :thumbsup: We continued on our quest to where we were going to test it too, lol we amused ourselves some more before going home.
 

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the a-arm is hollow underneath, I'll grab a picture of that tommorow.

the springs are 5.5 inches in diameter x 9.5 inches tall . The spring spacers are 5.5 inch and I got them from day motor sports. model 8550A

http://www.daymotorsports.com/product/352/SPRING-SPACERS

I got the springs from George, he ordered them from Eibach for me.

from the specs of the part number you ordered this adjustable spacer should work with eibach and st springs as well. prolly will raise the rear to stock ride height with it all the way down which is what id like for the rear. if need be i can cut a 1/2 coil off my rear st's which will stiffen them up a lil as well. i think ill be buying a set of these spacers once i finish payin pops back for the loan to get my truck. lol. thanks for the writeup.
 
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