[FS] Polyurethane Bushings

[wytbishop]

I wanted to post up about something that Mark (mooneggs) and I were talking about the other day.

Looking way back at some threads from the old days with the OG mx-3 crew specifically Luc St. Pierre who was the founder of SRD performance, and what they had to say about the different suspension mods they had done is very interesting. I'm going to do some more research, but the immediate impression Mark and I got from them was that the softness of the rear bushings was pretty crucial to the performance of the rear suspension.

I'm going to do a bunch of reading and I think I'm probably going to advise that 90 and possibly even 80A bushings for the rear of the car may not be adviseable. That doesn't mean I won't sell you all whatever you want, but I feel I have to take steps to try to give you the best information possible.

I'll get back to you all on this later this week, but I want you all to give it some thought.

Thanks,
Charlie

[onlytrueromeo]

I don't have a problem changing the rears to 70 if it will help performance! Anything is better than the preload I have now!

Glad to see you guys are tryin to make the product the best that it can be!

[fowljesse]

That's what I've been saying all along.
I don't know if you read my skateboard kingpin analogy...
I've even thought of ways to make it even more active for ridiculously tight cornering.
However, with other suspension upgrades, and good tires, the 70A will give alot. I'm only concerned about bump-stop, which could be critical at those G's. I understand, though, that Poly has a more exponentially increasing resistance compared to rubber.
I'm really looking forward to testing it out!

[mx-3_4evr]

^ I listened to you because it actually makes sense. I actually ordered 70 duro for the whole rear end since there is barely any weight in the rear

[Mooneggs]

Originally I had considered getting 2 different durometers but as I was under my car again today looking around I don't think I would want any one part of that rear suspension geometry to give any more than any other part.... so I will be getting all the same durometer... probably 70 since OEM was 65 (or so)... I know what my suspension feels like now in the rear and it's 17 years old LOL so I can't wait to see what a brand mx-3 felt like brand spankin new

[tehbrookzorz]

I'll give this some thought.

[hppwdn]

I may switch my laterals to 70, but I'm keeping the trailing links on 90 since I primarily drag and I want them to prevent squating.

What would be the deadline to decide by if we need to change durometers?

[onlytrueromeo]

Yeah, I know that I want a stiff front to reduce wheel hop as much as possible without too greatly affecting the ride quality. If the lateral links need to be softer, so be it...I noticed when replacing the rear strut that not only the lateral link bushings moved when "twisting" the wheel but the trailing arm bushing was the primary bushing to reduce top/bottom flexure of the wheel. The lateral links prevented more of the horizonal plane movement. (I don't think I'm explaining this well...hopefully I can take pictures when I replace my last strut to explain)

Also, this is assuming I'm not confusing parts...the trailing arms are the ones that bolt to the frame towards the middle of the car (run along sides of car), while the lateral links are the ones that run side to side. It's late and I'm too tired to post pictures, so forgive me if I am wrong!

[wytbishop]

Here is a point which I find very telling. The front lateral link is the one that the Anti-Sway bar links to. The rear lateral link is the one with the very large bushing on the spindle end which we presume contributes to the active steering of the rear end.

MazdaSpeed offers suspension arms with 30% stiffer bushings but they only offer the Trailing Arms and the front Lateral Links. I inquired once if they could get the MSP rear lateral links as well and was told that MSP never made them...only the trailing arms and fronts. It seems to me that Mazdaspeed never offered a stiffer bushed rear lateral link most likely because a stiffer bushing would reduce the activeness of the rear suspension/steering. I can't say that that is the case for sure, but it makes a lot of sense.

I have more reading to do.

[onlytrueromeo]

I will try to take pictures/videos of the bushings as I move the rear suspension components.

[wytbishop]

I have spoken to the manufacturer of the molds and the first test mold should be done this week. A test bushing will be poured to check the shrinkage and be sure that final size is within tolerance. Assuming all is good, the remaining molds will be cut right away. I will then receive a sample "kit" for test fitting and if it's all good we're on our way to the poly supplier.

I need everyone to confirm the hardness of their bushings at this time please. Based on reading I have done lately I have added this note to the GB top post...

***NOTE REGARDING HARDNESS***
I HAVE DONE MUCH READING REGARDING THE HARDNESS OF THE REAR END BUSHINGS AND ITS AFFECT ON THE HANDLING OF THE CAR. IT IS MY STRONG RECOMENDATION THAT BUSHINGS HARDER THEN 80A NOT BE USED IN THE LATERAL LINKS. HARDER COMPOUNDS IN THE FRONT END AND TRAILING ARMS SHOULD NOT CREATE ADVERSE HANDLING CONDITIONS, HOWEVER HARD LATERAL LINK BUSHINGS WILL PROBABLY NEGATE THE ACTIVE STEERING INTENDED IN THE DESIGN OF THE SUSPENSION AND MAY EVEN CAUSE BINDING IN THE SUSPENSION. 70A HARDNESS IS RECOMMENDED FOR THE LATERAL LINKS.

ULTIMATELY, THE DECISION IS YOURS AND I DISCLAIM ANY LIABILITY BASED ON THE SELECTION OF BUSHING HARDNESS AND ITS AFFECT ON YOUR CAR'S HANDLING.

I am happy to discuss this with you all. There is still time to place new orders for those who are late to the party.

PLEASE CONFIRM YOUR BUSHINGS' HARDNESS

[onlytrueromeo]

I would like 80A on everything except lateral links, please change them to 70 as recommended, unless 65 is available!

[kast2L]

I would like 80A on everything except lateral links, please change them to 70 as recommended, unless 65 is available!

^ 80 on the rest except lateral links and ill keep the 70a

[hppwdn]

I'll join the trend. Switch my laterals to 70A and leave my trailing links at 90A. My suspension is overly stiff already, a little 70A in the lateral links should do it some good.

[Flyer]

Lateral links to 70A, everything else at 90A

That's what I've been saying all along.
I don't know if you read my skateboard kingpin analogy...
I've even thought of ways to make it even more active for ridiculously tight cornering.
However, with other suspension upgrades, and good tires, the 70A will give alot. I'm only concerned about bump-stop, which could be critical at those G's. I understand, though, that Poly has a more exponentially increasing resistance compared to rubber.
I'm really looking forward to testing it out!

In other words, it fowljesse does not break these, nothing can