jatmon

not really finding much by way of front lower control arms that have solid bushings, is there such a thing? looking to road race an rx8 and would like to make all of the control arms have solid type bearings/bushings. i have done this with other race cars in the past and been happy with the results, just not seeing this for the rx8? is there a reason this doesn't appear to be a common thing?

Loki

iTrader: (1)

The arms are already aluminium, so you wont make them lighter, but you can replace the bushings in the stock LCAs with poly or solid. Its bit of a pain - mostly because with age stock bushings and camber bolts seize up, but can be done. From personal road race experience, poly replacements arent really worth the effort. Offset camber bolts/bushings might help, it depends what the rest of your suspension is like.

You could check Miata NC parts, perhaps someone makes something closer to your needs, its a more popular platform, and the NC is basically a shrunk RX8 in most ways that matter.

Id strongly suggest upgrading the engine mounts to poly though. The driveline moves around too much for racing.

jatmon

i was thinking more of the bind in the rubber bushings. i can install solids, was really kind of wondering about trying to make/obtain a spherical bearing for the rear bushing on the lca. am i overthinking this?

dannobre

iTrader: (3)

Mazdaspeed ( Speedsource) used to make an adjustable spherical bearing for the front arm mount. It is the one with the most rotational movement.

They are not available anymore.

There were some aftermarket ones but AFAIK they aren't made anymore either.

Urethane bushings are not an improvement over stock as they are actually.more compliant and move around more

There is a company that used to make cr/mo arms. I think they were in the UK? Haven't seen anything about them for years either.

Loki

iTrader: (1)

It depends on the rest of your suspension, but if you're near stock movement range, I don't expect problems. Definitely not out of the gate, maybe drive it and see?

What cars are you used to? This is after all a thoroughbred, not a family sedan.

TeamRX8

iTrader: (25)

you can’t install solids because they need multi-motion for alignment changes (front one) and rotation (rear one)

but if you have a lot of miles on them then you need to start off with a new OE pair since the upright/spindle ball joint isn’t replaceable

then you have to replace those bushings with these:

https://www.rhdjapan.com/super-now-f...rx-8-se3p.html

https://www.rhdjapan.com/super-now-f...rx-8-se3p.html


and possibly the lower shock mount bushings if you want those too:

https://www.rhdjapan.com/super-now-f...rx-8-se3p.html
.

CaymanRotary

Team, was going to replace all suspension bushings. Is this a complete list?

jatmon

that is what i was looking for. for the arms that swing in only one plane, in the past for circle track racing a mustang, i have made my own bushings with delrin plastic and a stainless steel inner sleeve with pretty good result. for road racing is this a bad idea?

TeamRX8

iTrader: (25)

Again, you cannot use solid bushings in the lower front CA. Same for all the rear CA. All those need multiple-motion type bushings, which are either going to be spherical bearing/heim joints or rubber/poly that allow multi-motion through material compliance. Trying to use solid bushings there is going to result in the suspension binding up; the opposite of what it should be doing. Only the upper front CA can use the solid type you’re referring too.

It’s not a Mustang; it’s an RX8. Try to get your head wrapped around that first, and how to use a search engine second is probably the next best advice I can provide to you.

Super Now is probably the best for the front bushings, the rear spherical type arms though are offered by multiple companies and are lower cost to buy than converting OE arms. Some of the OE bushings are bonded rather than pressed, which makes replacing them a pain. So just buy the aftermarket arms in the rear is my recommendation.

There’s one rear bushing in the rear spindle/uprights that has to be pressed out/in. Super Now offers that one too (spherical bearing type) on the same website I linked to previously.

Have fun ...

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jatmon

my apologies, i am interchanging (incorrectly) the terms spherical and solid. i understand they need to be spherical due to the geometry of travel. is there enough performance advantage to going with spherical bearings rather than oe type bushings? or is it effort and money wasted?

jatmon

is there enough of a performance gain to justify the expense of the spherical bearings in the control arms?

Loki

iTrader: (1)

Let me put it like this: there are folks on this board with laptime records in their class without spherical bearings. Offset front camber bushings - yes, but AFAIK stock everything else. Take all the front camber you can get. Maybe they'll chime in here.

The spherical stuff is not worth the expense to most people. The effects of something like this are hard to measure without a race team budget, but that's sort of the point. Let's say you shave 0.1s off your laptime with it (which is the upper bound of what I would expect). Will it have been worth it? You can shave a lot more with other mods for the same money. That's why I keep asking what other mods you have, suspensions work as a system. Rigidity in one place moves loads to another.

I don't know how it is on Mustangs, may it's a bigger deal, but around here this is not a thing.

Classing rules also matter: the 8 doesn't do well in highly modified classes because the return on engine mods is very low, so it's not in most people's interest to go all out on mods.

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jatmon

thanks loki, that is exactly the kind of advice i was needing. i completely understand the need to know what other mods have done/intend to do, and i suppose i should disclose my whole plan but i find that people usually get sidetracked from the original question if you tell them you intend to gut an rx8 till it is stupid light, build a cage in such a way as to bring back its structural integrity, make a honda engine fit to the mazda trans and then go enduro racing. questions never get answered that way. instead there are replys that range from "thats not legal" to "thats the dumbest $#1+ i ever heard". i am a student of racing. i am not a good student. i really appreciate you taking the time to answer my question. i have the ability to fabricate this stuff, maybe i will at a later date.

dannobre

iTrader: (3)

I have the Speedsource delrin/ss upper and the speedsource lower with the stock rear bushing. I installed it to get the extra camber. I didn't do it expecting more performance. If anything they are a PIA because they have to be cleaned and lubricated a lot to keep them working

Personally if you don't need the camber they are not a big improvement in any regard