[GI] Poly bushings: Making a Comeback in Feb 09'!!!

[onlytrueromeo]

I'm a fan of blue

Royal purple would work though, most people wouldn't see them, and if they did they'd already see alot of random colors on the bottom of my car - cherry bomb, S/S Muffler, Red AWR Mounts, etc...haha

Maybe I should put a rainbow sticker on my car...


...or not.

[marcdh]

purple suits me nicely! I vote with both hands in the air

Edit: Forgot to say, any hardware to go with I'm all for, I hate putting a new part in with old rusty bolts

[MazdaManiacMx3]

I am in for whatever suspension components you can come up with,
color doesnt matter to me , red would be fine , but I would prefer whatever hardware there is to be SS if possible . I hate rusty parts ..

Kris -

[wytbishop]

I will get the highest quality hardware I can. I feel the same way about reusing onld hardware and rust and stuff. It will however add to the cost of the kit.

I will make hardware optional.

[wytbishop]

I am also investigating larger diameter sway bars. I figure I'm there right.

[MazdaManiacMx3]

That would also be something I'm interested in, just wondering when do you think these items will be available , I would like some kind of time frame to decide whether to put the car back together and take it out of the garage or leave it in and wait for the parts .. I'm really looking for every possible bushing I can replace as well , my plan is to disassemble the suspension components and have them sandblasted and powdercoated while off , I am already in the process of undercoating the whole car now .
Kris -

[wytbishop]

I don't know what the lead time will be from the manufacturer of the bushings. I will be able to submit my drawings to them for quotation by the 22nd of Aug. at the latest.

Once a price is established (hopefully by Aug 29) I will post it in this thread and wait to receive consent from Jeff to start the group buy which may take another week or so (Sept 5). I anticipate ordering between 6 and 10 sets. At that point I will probably have an idea from the manufacturer as to how long it will take them to produce the parts, but I expect it to take in the order of one month. I will take receipt of the parts (first week in October) and perform some quality control which will likely take a few days. If, in that time your payment has been received, your parts will be mailed forthwith.

I think in the best case scenario parts could be at your door by mid October however I cannot estimate manufacturing time accurately at this point. To be conservative, I would suggest you not expect to have your bushings until November.

THIS IS JUST AN ESTIMATE. I DO NOT HAVE ALL THE INFORMATION NECESSARY TO MAKE AN ACCURATE PREDICTION ON DELIVERY TIMES AT THIS POINT.

Sway Bar End Links: I am going to purchase a set of AWR endlinks next month and check the fitment. I have made a few calls and I don't think I can make them myself for the price they are selling the Probe/MX6 ones at. If the fit is good I will report that to the forum. If they are not suitable I will price out a set myself. Count on $200 + Shipping for these if I have to make them. They're easy to make but the parts are expensive unless you're buying 500+ quantity.

Large Diameter Sway Bars:I currently do business with a company which does custom bending and heat treating. I would like to have 25mm front and 22mm rear bars, but I will have to figure out the cost of labour, as well as how to accurately mass produce such a complex bend. I have access to cheap material for them, but I don't have enough information to determine if this idea is cost effective yet. Also with the change in diameter of the bars, new brackets would have to be fab'd and there would probably be drilling/tapping to mount them.

Hope that clears it up a bit for everyone.

[wytbishop]

First Inventor pics...just for fun...





Modeling the existing bushings is very straightforward. I'm trying to identify ways to improve them. I'm working on the grease issue, but I think ultimately to make them greaseable you would have to modify your suspension parts with grease zirks.

More to come.

[fowljesse]

Greaseable would be great! Mine are not, and they've been creaking for a couple months, because I'm too lazy to get under there, and take it all apart. What a great name "Zirk".
I want sway bars!!

[wytbishop]

Greaseable is going to be tough. I have a plan to make it possible with banjo bolts and extra machining but it will not be cheap and I don't think anyone will want to pay the extra cost.

[onlytrueromeo]

Yeah I can understand how that would be tough...us there something else we can do to prevent the squeaking? Poly against metal directly is prone to noise, if you can get grease in there, great but it won't last long and you have to take the whole thing apart to get grease there...

Which part will squeak the most, the outer part that goes into the suspension, or the part where the bolt goes through? What about if we were to fashion some sort of rubber "boot" over the ends, and used the bolt that would normally go through to hold it in place, that way we could grease the inside of the boot and keep that pressed against the poly bushings, keeping dirt out and grease in?

[wytbishop]

I have been doing a lot of reading about lubrication and noise and here is what I have found so far...

1) The harder the bushing, the more noise it makes. A comfortable Shore A70 poly bushing when properly installed will likely last the life of the car without noise. As the bushings get more and more firm, it becomes harder and harder to eliminate noise.

2)Using a grease zirk (a fitting on the housing of the bushing to allow grease to be injected periodically) is not recommended and should not be required.

3) Polyurethane cannot be impregnated with graphite (or any other lubricating additive) as the graphite would either be totally engulfed by the urethane making it useless or the graphite would prevent the urethane from binding during the curing phase of manufacturing because...it's a slippery lubricant...der.

4) Most people are lubricating their bushings with the wrong lubricant (a petroleum based grease) and after a while it either washes away or actually reacts with the poly bushing accelerating breakdown and causing noise. Polyurethane requires a very special type of grease. This grease is very sticky and thick and it should only be necessary to apply at installation.

5) It's not very expensive and I will be adding a healthy amount to each order of bushings I sell.

According to my reading this is the solution to the squeeking bushings.

[onlytrueromeo]

Sweet...yeah I read that about the grease too...makes sense not to use petroleum grease - most plastics don't like it, or anything but metal, because, well, they're derived from hydrocarbons...

If I only have to take them apart and grease once a year, great. If, like you say, they should last the life the bushing, even better. So is 70A what you are going with? Or were we looking more for 80+?

I like learning about this stuff

[wytbishop]

I think 70 is very close to stock firmness, maybe slightly harder. I think most people want to go a little stiffer than that, so I will make 80 an option. I think I will go with 70 because I'm not looking for super stiff suspension. I might also fill a second set of control arms with stiffer ones in case I ever want to do any time attack racing in the future.

Really it's up to you all. If you want 90A I should be able to get them for you. I'll have to check with the manufacturer, but I don't see that being a problem.

As for the squeaking issue, I have an idea. The SuperPro TTL bushings have a knurled inner surface. I'm not sure how they accomplish that, but it does a couple of things. First it reduces the amount of surface contact between the bushing and the sleeve by creating a bunch of raised points instead of a large perfectly smooth flat surface to mate to the steel sleeve. Second it creates a small space for some lubricant to be trapped between the bushing and the sleeve. I think over time though that the knurl would wear down and you'd basically have a flat surface again and most of the lube would get squished out. I was thinking about creating a long thin spiraling groove on the inner surface of the bushing that goes several times around the diameter but isn't very deep. This would allow some lube to be distributed all around the sleeve but not allow the bushing to deform a lot under load.

In theory that would work, but it might be too difficult to cast.

It would look like this...or thereabouts...

[wytbishop]

Ok so I did some more thinking and I have refined my plan. I think the way to definitely stop the squeaking issue for absolute certain is to make sure that a healthy amount of the (correct type) grease is effectively trapped in the space between the sleeve and the bushing. SuperPro uses a light knurl on the inner surface of the bushing to try to accomplish this, but I think it will eventually wear to a basically flat surface causing the problem to reassert itself. I suggested a groove to hold the grease, but I don't think that's good enough. So I came up with this...



This is a cross-sectional view of the large outer bushing of the rear TTL. I have drawn a series of grooves, about 0.025" deep which create a tight criss cross pattern on the surface which will be in contact with the steel sleeve. There is still plenty of contact area for the bushing so there is no problem with deformation of the bushing material, but there is a fair amount of grease trapped in there and these grooves are not going to wear out. Ever. So there will always be a reservoir of lube in contact with the steel sleeve, hopefully preventing it from squeaking. I may incorporate this on the outer surface as well.

Anyway, I'm just trying to keep you all up to speed with the ideas I'm working on and I encourage you to ask any questions or offer any input you have. Your ideas give me lots of ideas. You often think of things that I don't think of.