There was a recent post up about the benifits of the tower brace on a Supra chasis(JZA80, JZA70, or MA70). This brought up some questions I have been having with regards to suspension setup on an IRS(independent rear suspension) FR(Front engine, Rear wheel drive) car with loads of power where grip is crucial to all aspects of driving be it road racing, drag racing, autox, drifting, or whatever the particular sport may be.

Common sense dictates that the softer the spring rates on the rear springs and softer the setup with more give, should yield more traction as it allows the suspension to move easier and keep the tires on the ground.

The front would be a good place to stiffen up the suspension but not too much because one does not want to induce understeer(I know it sounds unlikely but hit a turn to hot and see if it doesn't push the front end some)

1) What companies if any offer spring rates that are adjustable at the individual end user level?

2) Where in the suspension should changes be implemented?

3) I have seen sway bars (the round bar that runs from one side of your suspension to the other) that offer many mounting locations. How do each of the different mounting locations change the way the sway bar does its job?

4) Where is the best place to start when working on a custom tailored suspension when on a budget?

5) Though strut braces are useless over the rear of the vehicle, does the extra rigidity cause any changes in the way a vehicle handles? The same thing applies to those floor braces and other chasis braces that fit in the passenger compartment.

Common sense serves you well.

1) Adjustable spring rates? Eh, not going to happen. You want a rate that matches your specific car as best as you can. It's the damper you want to adjust, not the spring. Most companies offer adjustable dampers, but their rates are generally not right for the MKIII.

2) That's a very, very broad question. Take me, for example, I've bought all NEW components. New rear upper balljoints, front uppers, front lowers, sway bars, bushings, endlinks, all new bushings for the entire suspension setup, including front and rear subframe bushings, and steering rack. How far do you want to go?

3) Each different mounting locations puts a different amount of pre-load on the bar, thus, making it stiffer, or softer. Generally, the stiffer you go, the LESS body roll you'll get. However, if you go too stiff, you run the risk of breaking the mounting points, unless you re-enforce them.

4) Custom tailored suspension and budget don't belong in the same sentence. I'm getting custom suspension done by TIP engineering. Tim is a great guy, and really knows his stuff. He has a suspension section over on supramania.com.

5) The strut tower bars don't to anything on our cars, really. Mostly cosmetic. The do-luck floor bar works very well at stiffening the chassis, I also have a hatch bar, and plan on group A style front bracing.

1)On the topic of dampeners, I assume that is what the stock TEMS is controlling. Is that system adequate for spirited weekend driving with possible circuit club track days in the future? With the "firm upgrade" from supras.com?
What about the aftermarket shock absorbers (I want to say Koni but I don't know for sure)that are supposed to work with the factory system, do they provide decent performance when used together?

2)I was a bit vague on this one, my apologies. What I should have said was; for someone wanting to build a complete suspension, where should changes be employed first to gain the most "bang for the buck"?

3)Got it. Thanks for the info.

4)Again I misspoke. For someone wanting to take their time with building a suspension setup, what is the best place to begin, same question as #2 basically

5)Could the same thing be accomplished by adding sheetmetal bracing in key points and having said sheetmetal braces chamferred for weight savings? Stitch welding also along connections between unibody sheetmetal that was only previously spot welded.

1) Yes, the TEMS are the dampers. They leave a lot to be desired if you get into anything competitive. Koni's are really nice, that's what I use currently. The TEMS compatible dampers you're thinking of are Tokiko Illumina II's. They're alright, but I hear that they pop easily, which is bad.

2) Get a good lowering spring, if you're going for auto-x, drift, anything where you want the car stiff, get a linear wound spring. Sway bars make a HUGE difference. Night and Day, in cornering. Probably the best upgrade you can do. Other than that, check all the bushings and make sure they're up to the task, all ball joints, etc...

Most bang for the buck would be springs, dampers, and swaybars.

3) You're welcome.

4) I believe I answered this above? If not, I'll do so tomorrow, it's late and I have work at 8am.

5) Stitch welding is great for chassis rigidity, the addition of sheet metal won't do a WHOLE lot, except add some weight. I'll post pics of the group A cars tomorrow so you can see what I mean, and you'll understand why it's much better than sheet metal.

1) Oh, thats sad. On the topic of dampeners again, Tein makes a remote dampening system, is it worth the extra coinage to have it adjustable? Do you know anything about the system? Could you have it set up in groups, similar to the stock TEMS but with more refined settings, race, firm, comfort, ect?

2) On the bushing note, I know they make them for the Z32 Nissans, do they have needle bearings that can be pressed in in place of the bushings? If so do they provide enough of an advantage over the "Energy Suspension" bushing sets?

5)Is there a way to stiffen the targa/sport top area on the supras that have it? I have heard it causes a lot of chasis flex when the roof is removed and naturally the absence of solid roof and structural components located there would mean more flex over a hardtop even if the roof is installed. Is there a way to do something similar to the old Mercedes Gullwing and strengthen bellow the doors to make up for the inadequacy?

I do believe their is a Targa top brace system out there somewhere. I've only heard of it but would be good idea to ask around and research. I might just be manifesting things in my head again.

If not you should design one and make some cash.

1) Sure is. Honestly, for the cash you'll spend on that TEIN setup, I think you'd be better off with a custom set of coilovers that are corner balanced to your car, like I'm doing. You could probably set that up in groups, but I'm sure it wouldn't be easy.

2) Really the only guy who makes bushings for our cars is Ronnie K. over on SM. ES is going to start making them, supposedly... No needle bearing deals like you asked, though.

5) Yes, the do-luck floor bar helps a lot, and there's a guy over on Supramania that made something called Weezlwings. I believe his name over there is theWeezl. He doesn't make them anymore, but here are pics:

http://www.supramania.com/forums/showthread.php?t=24760

Targa cars already have extra chassis bracing.

Edit: here is information on the Energy Suspension bushings that are supposedly being made: http://www.supramania.com/forums/showthread.php?t=62998

And here's the guy currently making aftermarket poly bushings for our cars:

http://www.supramania.com/forums/showthread.php?t=40079&page=2

1) Yeah I knew they were expensive. I guess for a custom setup you can't beat parts custom matched to your car.

2) I may look into that when I start doing suspension work. The guy on the forum was asking a very fair price for a complete bushing set. (I worked with MKIV suspensions quite a bit a few years ago, Are the MKIII suspension arms also made from aluminum?)

5) I like that chasis/targa brace. It looks kinda like a T-top. It probably wouldn't be hard to make provided one had the tube bender and welder. You know what its made of? Judging by the discoloration I would say steel but it could just be the camera playing tricks. Just bolts in the stock location which is pretty cool. Theres no way to brace the floor for the same effect is there, say about 6 inches or so to surround the passenger foot area or build a brace that could just be stepped over like boxing the floor?

1) Right on.

2) The upper front, and rears are. You can only get the whole assembly if you plan on getting new upper ball joints for front/rear, and it's costly, at: $312.25 EACH, and that's with a 20% discount from my dealership! List price is $472.16 EACH! (and there are FOUR of the uppers!)

Front lower ball joints are $82.74 list, and I got mine for $54.71 each, not bad. Those uppers though, they'll kill you.

5) I have no idea what it's made of. I have a hardtop, so I never really looked into it much at all. As I stated earlier, the do-luck rear floor bar is said to have a significant increase in chassis rigidity for targa cars, other than that, I suppose a harness bar would help, hatch bar, and any triangulation to solid points in the rear. Here are the pics of the Group A cars I mentioned earlier.

Please note, the Group A cars were RACE cars made from the MA70 chassis.

Pics- click to enlarge:

Is the tower braced to the firewall like that from the factory. That looks nice. They came factory like that for group A, stripped down and braced?

I know what you mean on suspension parts. When I did the work on my MKIV the suspension bushings were also only available by getting the entire upper A arm. I dropped 700 bucks just to change 4 bushings.

No, that was all done by the Toyota race team. If you study the pics, the bracing from the strut towers goes straight through the firewall, and connects to the roll cage INSIDE the car. THATS how you brace an MKIII. There were 50 of these cars built, and there are only a few left in existence.

Yeah, I just ordered a bunch of stuff for my rear subframe while it's out and fully disassembled. Not exactly cheap, buy you have to pay to play!

Thats one thing I think I will like about the MKIII over the MKIV. They are just so much cheaper to work on. Now that I think about it I kinda wish that when I bought my NA I would have just waited a little longer and gotten a TT, as it is much easier to find parts and make power, plus they are a better place to start brakes and suspension wise, if I remember the stats correctly.

quote:

Originally posted by Amontgomery:
Common sense dictates that the softer the spring rates on the rear springs and softer the setup with more give, should yield more traction as it allows the suspension to move easier and keep the tires on the ground.

How so? The spring pushes the tire to the ground.The pivot points from the SLA allow the necesary movement to keep the contact patch.

Luckily since we have the best suspsension design from the factory, all we need is better components than mass production. You need not get too stiff. Jeff Gore MA71supraturbo by screen name on a few sites has done extensive suspension work and tested many setups. Try searching for his posts here and other forums for anything not already answered by shaeff. With regards to how a product like HKS hypermax works, or something of the sort.