guttedmiata

So the consensus seems to be that Derlin offset bushings in the LCAs don't work well because of binding issues trying to get all the alignments specs in place. The issue is the hardness of the Derlin and it's unwillingness to flex enough.

So why has no one tried offset Poly bushings? Or have they and I just can't find it searching. What are the issues or concerns here? I can make bushings for $50 opposed to $650 for v8 roadster LCAs.

mrmonk7663

iTrader: (9)

This is for the rears...maybe it will help. Super Pro Polyurethane Adjustable Rear Bushing Kit for 90-05 Miata

guttedmiata

Yeah, guess I didn't clarify I was talking about the front. Thanks for the attempt.

NiklasFalk

iTrader: (1)

Moving the lower ball joint 8-10mm outwards (and reinforce the new location, longer bolt...) is easier/cheaper and does not move.

I assume you can (are allowed to) mod things since the V8R arms are on the table.

OGRacing

iTrader: (1)

i got the V8 roadser arms. seam to be expensive but better alternative. as with poly once it's molded you have no adjustment.

guttedmiata

Not sure how it's easier. Sounds like a cobble job actually. We're talking about moving 3 holes 3/8". Bottom mounting hole probably isn't that big of a deal, but the two holes for the horizontal bolt seem like more of a problem as they are right at the edge of the arm. Looks like you'd have weld "tab extensions" onto the arm, fill in the old bolt holes, and then make new holes.
Am I wrong with this? I'd love to see a picture of an arm this has been done to.

I can put a piece of poly bar on the lathe and turn it down in less time I'm sure.

I guess the question I'm searching for, is why is no one doing it?

guttedmiata

???

The adjustment would still be with the cam bolts.

NiklasFalk

iTrader: (1)

You got it, and you need a longer horizontal high grade bolt.
I'll see if I can get by my garage and snap some pictures, I have one spare LCA on the bench.

It's a bit crude job and it will not make things lighter, but we have not seen a failure for years of w2w racing (I think this exact mod it's on 4-5 cars here).
But add 275 slicks and the loads go up.

guttedmiata

Cool. Thanks!

Leafy

iTrader: (1)

Am I the only one here thats surprised you arent on a fully spherical suspension yet?

guttedmiata

Link me the source and mail me a check

Leafy

iTrader: (1)

I can give you the source easy. Coming up with ~$1500 is your problem.

Custom Online CNC Machine Shop | Free CAD Software

https://www.motionindustries.com/pro...ng&numItems=10

guttedmiata

No no no. I said link me the source AND mail me the money. You only did the first part.

NiklasFalk

iTrader: (1)

This LCA have been modded 15mm (5/8").




All new "clamping" surfaces have washers welded, to make it as reasonable as possible.
With the current exchange rates this was a $100 job here (sans tax, per LCA), you should be able to get it made for less.

90civichhb

iTrader: (5)

I think that extending the lower control arms like that is probably one of the cheapest ways I have seen, and it looks fine to me.

With that said, have you had any negative impacts by doing this, like bump steer issues, tie rod issues...ect? What benefits have you received from it, only camber adjustment?

NiklasFalk

iTrader: (1)

Only benefit is more camber and some extra track. I have not checked changes in bumpsteer but don't assume anything different than moving that pivot point by other means (e.g . OEM adjustment).
The motion ratio for springs and rollearn change a little, but springs are plentiful.

Leafy

iTrader: (1)

It shouldnt change bump steer, it only very slightly changes the roll center location. It also very slightly reduces the amount of camber gain.