Pele

iTrader: (28)

Okay, on the rear, which bushings should you replace with rubber? I remember something about them binding and making the car more prone to breaking rear traction...

Anyone have ALL poly bushings on the rear end? What's it like?

Directfreak

iTrader: (2)

I know this doesn't answer your question, but on advice from the local Auto-X'ers, and this board, I replaced everything with poly bushings, except the rear. There I went with OEM Mazda rubber replacements.

Before I took the car off the road for my project, I was much happier than I ever thought possible with the new suspension I had put in.

Wankelguy

82transam

iTrader: (18)

so the upper AND lower control arms in teh back get rubber? where did you guys buy the rubber ones? dealer?

GT1

I've got all Energy poly. in the rear, it greatly improoved the feel and responce of the car. It does step out the rear at limit a bit, but its very predictable and not excessive at all.
The only thing I have noticed is that the car is a bit more sensitive to changes in tire pressure, and a little more caution is needed in the rain.

REVHED

A lot of experienced workshops here recommend poly urethane in the lower control arms and watts link only. Leave the upper bushings alone unless they're completely falling apart. If so, use new rubber.

DriveFast7

iTrader: (1)

IMHO I wouldn't even put poly in the watts link. That thing isn't centrally located and its pivot point is too high up. Geometry all wrong, too high roll center.

The Pro7 racers actually put nylox lock nuts on all the rear arms including watts link. The don't tighten them all the way, leave them just a hair loose to allow the bushings to swivel a lot.

Tell you the truth, you'd be better off replacing the watts with a panhard rod and putting all new rubber bushings in the upper and lower links.

82transam

iTrader: (18)

replacing it with a panhard bar isn't that easy, most of us are looking for purely bolt in stuff.

DriveFast7

iTrader: (1)

But a panhard is more effective!

You can bolt in the Ground Control panhard rod and drive it to the muffler shop. Ask them to weld the bracket onto the axel real good and you're DONE.

jsinrx7

EVERY Bushing in my 79' GS has been replaced with Energy Suspension poly bushings about 2 yrs ago and I coundn't be happier with them. It can get a little tail-happy when you're really on it, but its so predictable, that everyone will think your're a pro! I have heard all of the "downs" of going all poly, but take it from me it is ALL untrue. They dont bind, they dont squeak, and they wont bend your control arms. In fact Energy suspension has different "durometers" (soft/hard) for different parts of the car so they are not all "super hard". If you are gonna go poly, go energy susp. definetly

Kill No Cone

iTrader: (6)

I had a completely stock rear suspension except for springs to lower it. When I was hard in a corner the car would squat, then settle and pop out. If I came in to a corner hot the car would squat, settle, and then slide out often.

Then I put a Panhard bar in and it relives one of the axis of bind related to the watts link, that are inherent in first gen cars. This took a lot of bind out of the rear.

Now when I come into a corner hot there is no point where the rear seems to stop and settle, so the rear end does not pop out like it used to. The Panhard bar made a world of difference.

Recently, I made a deal with a friend to split a set of poly bushings for the lower control arms. Now we both had enough for the bottom control arms.

totallimmortal

what do u guys think about the upper link bushing mod from PB&J racing? it involves drilling symmetrical holes in only the upper bushings to allow them to twist more, reducing binding, and in turn, snap oversteer.

The_7

i went out and had a look at my rear suspension and how about instead of modding the bushings, replace them with poly ones and then replace the nuts on the ends of the links with nylock ones, adjusting them so there isnt any side play but that they can still pivot easily. this way you will have much less binding, but because of the poly bushings you still have a firm suspension.

edit: also the previous post was me also, why does this happen so much? lol

DriveFast7

iTrader: (1)

Carl did a real nice writeup of that. Many SPEC-7 racers were doing that.

I talked to Jim Susko @ G-Force Engineering about this and he said it creates torsional wind up on the axel. I wouldn't do it.

It will reduce some bind but you have to realize those links short length and crummy angle just plain suck. So you're really not accomplishing much.

This mod won't reduce snap oversteer. MY blue rx7 below does not have snap oversteer. It took a Panhard Rod and spherical bearings inthe lower links to make the car more manageable in the turns. This is more of the direction you should go towards if you're serious. Keep in mind heims and sphericals are klunky loud and FIRM.

The tri-link and removing stock upper links was what finally made it handle GOOD and got rid of snap oversteer. I out corner Subaru WRX's with AWD!@!@!@

Otherwise I'd reccomend putting new soft stock rubber bushings in all the links back there and ditch the rear sway bar. It'll feel better but still have crummy stock rear suspension geometry.

Some peoples do this or that and say it handles good on the street but you don't really know how good it handles until you're on a track squealing the tires in every turn all weekend. Then your car's suspension needs become prevalent. I should know, I used to have a thick rear sway bar with poly bushings and first time on the track she snap oversteered so much the instructors said to take it easy. Strange thing was it felt TIGHT on the street. I was shocked when I looped it exiting Turn 4 @ Willow Springs.

The_7

i will definately do the panhard bar and other goodies in the future, but right now im just looking to improve the most i cant without spending alot of money, im not really expecting alot.

Rx7carl

Ok, time to throw the flag here. Read this thread carefully. Both of the guys who did poly in the rear end say basically the same thing. "it still oversteers, but I can control it". My mod is admittedly a band aid, and a cheap one at that. That was its purpose. It's cheap and it works. Do I run that on my racecar? Of course not, I use Jim Suskos setup, but thats not realistic [nor cheap] to run on a streetcar. Yes Brad, Jim's right, axle windup is still there, so is driveshaft plunge, , but most guys will be running stiffer than stock springs if they are making a hot handling streetcar so I dont see that as a big issue. The springs and swaybar will now control roll complaince instead of the bushings binding. The mod I detailed is simple cheap and it works. I have driven stock/ my modded/ and Jims setup. I have experience wiht all of them. It's not a bad setup for a streetcar guys, or I wouldnt have gone thru the trouble to write and host it. Inittab did it and was happy with the results.

Captain Lou

Since we're on suspension,

can anyone recommend some springs?

IM looking for stiffer than stock and preferable does NOT drop the car.

I havent found any yet?

DriveFast7

iTrader: (1)

Mmmmmmmmmm...... well the upper links are certainly still influencing axel movement after their bushings are drilled. The upper links are still vertically locating the axel otherwise it would bounce all over the place. Only way to completely take the upper links out of the equation is to remove them or replace the bushing material with foam... like rollbar padding.
Otherwise all the drilled bushings are doing is letting the link flex a bit before it starts to move up or down. It doesn't take much movement for it to bind.

As for stiff springs, I had 225lb rears in there. Idea was to prevent the rear suspension from moving to the point that it starts to bind. Didn't work like that. I would need 450+ lb front springs to balance out the suspension and that is too stiff for street and on a 1st gen getting close to too stiff for a DOT-R tire. Otherwise the stiff rears just cause oversteer which is what we're trying to get rid of in the first place.

But to each their own. You're right, I wouldn't expect very many street cars to have a tri-link but then again, not many street cars handle as good as they should.

inittab

This reminds me of an idea I had a while back. The ES bushing sets are made of a three piece construction. The outer poly is soft and very compliant while the center core is made of hard poly. What if this center core was drilled out oversized so all the bushing contact was on the outer soft material instead. I wonder if that would help the binding situation. It wouldn't be as soft as roll-bar padding but it should have way more flex than the stock rubber.

wae

I'm at the point on my car where I've just gotten half the rear suspension off the car and I'm probably looking at new bushings for the control arms and Watts link. So, on a related note: If the E.S. poly bushings are a no-no, where can one get the rubber bushings? VB has the Watts link, but as far as the control arms, VB doesn't show them in their catalog, I can't find them on Mazdatrix's site, AutoZone & Advance Auto don't seem to show them in their catalog. The best I can find is a whole new OEM control arm. Granted at about $300-400 for all four, that might be cheaper than having new bushings pressed in and having the old arms powder coated (not necessarily in that order! ).

Rx7carl

Your absolutely right Brad. Like I said, its a band aid, but it is effective and a quite noticeable improvement for a streetcar. A better solution would be some sort of spherical bearing that wouldnt require lubrication and can withstand the harsh environment. Bob, you chime in here and back me up or what?

grantmac

What I'm wondering is if I could modify a Panhard bar to use normal, rubber or poly, bushings and so make it better for a street car? Would it be that much work to keep the heim joints? As in could I just service them with every oil change or what.
Grant

The_7

i went out and had a look at my rear suspension and how about instead of modding the bushings, replace them with poly ones and then replace the nuts on the ends of the links with nylock ones, adjusting them so there isnt any side play but that they can still pivot easily. this way you will have much less binding, but because of the poly bushings you still have a firm suspension.

inittab

hehe..... yes yes... I have done the mod as described on Carl's site. Does my car handle better? Yes! Is there less snap oversteer? Yes! Is it perfect? No, but it's way better than stock. I do recommend this mod to anyone who wants better handling for very little cash. It works!

DriveFast7

iTrader: (1)

Okey dokey Carl. I'd have to drive it before I'd agree it's noticeable improvement but I'll take your word since you do autox and IT7. sounds like inittab agrees it works.

Using a threaded length rubber or poly bushing would be a good idea like grantmac said. Or even have it use a front control arm type bushing. Put zerk fitting on it to lube it. whatever the bushing material, it would need to have adjustable length so you can centrally locate the axel laterally. car-to-car variations/bent frames would require it.

I have seen street cars with the ground control panhard rod using it's heim joints. I'd reccomend cleaning them with WD-40 once a week and you'd be looking at replacing them once a year. I wonder if they could be protected with a soft flexible rubber sleeve. Is it simply a matter of wrapping the heim joint with 1/8" thick sheet of rubber available @ Ace Hardware for $2.99???