Kenku

Well, some time on and I'm back at it. A few chunks of the whole project now.

First off, I need a mockup wheel to figure out stuff like tire fitment. So I modified a correct looking wheel model to be... close enough for my purposes.



Second off, one of the big limits of the FB in racing is the lack of genuinely good dampers available. There's stuff kinda good available if you're clever but nothing world class without cutting someone a big check. I'm not even going into the couple Taiwanese coilover options that are available because they're not going to do the job.

So screw that.

General idea is to do like KW and some other competition dampers do and have an inverted monotube with linear ball bearing guidance to eliminate stiction. This is even easier because one of the Bilstein strut sizes is 40mm OD, and a 40mm OD hard chromed tube works great in linear bearings. The problem is the Bilstein adjustable shafts are hard for random people to get and the shock piston options that I want to use aren't available for Bilstein.

So I ordered some surplus parts to reverse engineer and made a thing.





So that's a Penske style Linear/Digressive piston, to take a Penske adjustable shaft without modifications, and fit in a Bilstein strut body. Still have to design the head seal thing to put the Penske dimension seals in the Bilstein strut but that's not hard. What'll be more interesting is making the shaft adjusters work in a way that's accessible even with the limitations of FB style knuckles.

Next up though is going to be redoing my floating rear hubs - in short I don't like a lot of the limited wall thicknesses in places so I did a lot of digging and found a different bearing that will give me a lot more room.

peejay

If you are as much a fan of easily replaceable wear items as I am, I have compiled a small list of 4x100 hubs that use sealed or otherwise preloaded bearings.

so you can use Miata front hubs or Civic EG rear hubs if you make a 28mm diameter spindle shaft. Or you could use BG-esque Escort rear hubs if you want a 30mm shaft.

I compiled this list while looking for a hub/bearing set that used a 35mm shaft so I could use a complete Volvo 740 front suspension, which hides the rack in the subframe and uses 35mm spindle preloaded cartridge bearings, in my RX-3, with 4x100 wheels, since somehow I habe a bunch of 13x7 and 13x9 wheels from Miata autocrossers liquidating their old wheels.

What I did find was that Contour/Mystique/Cougar used a 4x4.25 hub with a 35mm spindle, which actually meshes well with my vision of making a Japanese MkII Escort with the car, since all UK Fords were 4x4.25. Although if Brexit thoroughly craters the pound, I might be able to afford to just import an Escort to begin with. I'm already seeing my "UK rally shops wish list" getting cheaper and cheaper.

But then I still have all these 4x100 wheels. I might be able to bung Escort hubs on small-bearing FB struts.

j9fd3s

iTrader: (3)

https://www.opticatonline.com

if you pick wheel hubs as a part type, and it helps to pick a brand, like moog, you can search 4x100 wheel hubs.

the miata hubs are cheap and available, but they are not strong enough. also the bearing isn't enough for a miata with sticky tires, even if you repack them out of the box, the chinese ones last a weekend, and the OE Japanese ones might go half a season.

plenty of other choices though

peejay

*clicks*

peejay

Cannot stress enough how awesome that site is, if you like to hack-engineer like me.

Searching master cylinders now... 3/4 inch dual stage master cylinder with attached reservoir? BAM, here's a bunch of part numbers. First hit I clicked was for an '05-'10 G35/M35/M45. Manual brakes here I come.

Kenku

Details not done yet... like, need to get an axle nut to reverse engineer. But built enough room for the rear spindles to go from 0 to 3 degrees of camber without issue. Radial slicks really need the camber.

It would be nice if I could build around parts store stuff but there's some limitations. In the rear, I'm building the drive flange around Wide 5 bolt on units - there's companies that do crowned axles for them, or on a more highfalutin option, Winters makes replaceable CV joint ball drive ones. The bearings and seals are off the shelf industrial stuff though.

In the front, SCCA says the bearing carrier can't be modified, so stock FB style spindle... with all sorts of stuff cut and welded to the forging.

If I had my druthers I'd just use an MR2 Spyder knuckle and bearing but instead I have to create something that would have no real performance difference but takes lots of work to make. Oh well, rules are rules.

j9fd3s

iTrader: (3)

we use it to help catalog parts, but the new site lets you pick by attribute, which is in the PIES data. mmm pie

Kenku

Got some quotes to get most of the machining done (the pistons take some operations I'm probably going to have to diy) at $42 apiece for the shock pistons! I may have to spring for that.

... and lowest quote on the hubs do far is $600ish. At that price I'll lathe them myself.

j9fd3s

iTrader: (3)

this is why its worth a look to see if there is something off the shelf, it will be cheaper, and replaceable when you hit something

Kenku

Like I said before... the fronts there might be if I wasn't constrained by rules requiring the Mazda spindle. The rears as illustrated are completely oddball compared to OEM automotive practice due to the need to have the snout large enough diameter to accommodate a drive axle whose axis isn't in-line with the bore. Those bearings are 50mm ID.

If I wanted to take a big weight hit I'd go to Howe 2" 5x5 stuff, but then good wheels get expensive too. If I were allowed to screw with the axle housing more I could essentially use Miata hubs and axles (or Honda or whatever) inside an axle housing big enough to contain the CV joints. If I didn't care about the camber I could just redrill the stock axles.

Doing shrunken Howe style hubs as illustrated means there's only 2 completely custom machined items (aluminum hub and bolt-on spindle) per rear corner, and honestly of those two only the spindle is really hard to do. The alternative is cutting Race Products in Aussieland a check, but they want around $3k US and I don't particularly want to think about getting replacements from overseas.

Kenku

Well, why not an update?


Illustrated at 2.5 degrees of camber; again the ball on the end of the axle is just because I don't want to model splines on something I'm buying anyway. Everything fits in CAD, I've got a hunk of billet, time to get to work.