Real Fiero Tech

I'm glad to see this getting updated!

Ditto! It's great to see progress on this.

It's also great to see guys going this hard on a Fiero with the intent to RACE rather than make it fit a rebody.

Here is a couple shots on the front tie ins for the A pillar bars.

I can take better pictures tomorrow, but they attach the forward frame rails to the new 2x4 rockers.

I started to do the work front hub upgrade.
The machined seal adapters:

They will be a press on ring so to the freezer with the spindles:

and the shimmed front bearings:

I am using 4340 USA made tubing for the shims.
3/4" .030 wall at .75 length for the front bearing shim. and 1.75 .125 wall machined to 1.470 ID and .500 length to press on the Fiero Spindle base (1.499 OD)

Tomorrow I need to figure out how I will get the needed radius/chamfer in the inner bearing to clear the radius on the spindle.
My lathe chuck is not small enough to grab the ID of the Inner race, Plus I think the steel will be to hard to machine myself...

What hubs?
The bearings don't need to be pressed into the spindle

It is the Early Small GM Drum Hub (also known as the corvair hub)
the pressing will be for the adapter for the seal, as the new hub uses much larger seals. (1.75 vs 1.5 sealing surface.)

I did some more front hub work.
Front rotors are off a C4. They are take off's from a 13" brake C4 front end with black painted, "Corvette" embossed, PBR calipers, which to me tells me this would be a Grand Sport front I think...

these cost around 37$ for economy Centric rotors and 51$ for premium Centric rotors at Rock Auto
Anyways here is the original rotor:


Now, the GM small car drum hubs have an overall diameter of around 6.13"
and the C4 hub is around 5.87" OD, obviously we are comparing steel and cast iron construction of the hubs, so I wont be plainly turning down the hubs to match, but they are rusty and need cleanup regardless.

I am pretty much maxing out by 8x14 Lathe's capabilities on this. I have a bit more to go, I want to remove all the parts of the hub that are flaking off, and bring the overall diameter closer to 6", and also place a healthy chamfer to clear the ridge-radius inside the C4 rotors.

I don't want to make these hubs very weak either. If you search on some pro-touring sites, there are known failures on using these front hubs for autocross. But, that is on a very heavy car with very wide front tires. I don't think this car will have the same front tire corner load. I will run through some calcs this week to see how different the side loads it would be at a 1.5G turn in a 3600lb 50/50 car vs a 2600lb 50/50 car.
But as you can see, I still haven't completely removed enough metal along the periphery to completely clean the edge, so I am not too worried about reducing the overall strength.

I just need to squeeze a but more tool travel out of my lathe to finish this job and the hubs will fit in my rotors and I will have cheap 13" brakes on this car.

As part of the hub swap, I have also had to bring in the inner bearing stop .125" to match the Fiero bearing spacing.

All the hub failures I've seen (Miata, S2000, Fiero) are fatigue cracks that form around here:


On the cars that are subject to these failures, the racers replace the hubs at least once per season as preventive maintenance.

A big fat fillet right there is probably a great idea.

If you look close you can see there is an undercut on the face of the flange,The backside has a generous radius leading to the flange.
I did have to shave about .005" off the hub to get the Vette rotor to slide over the pilot. I will modify one of my tools to cut a radius into the pilot at the flange surface where my clearance cut ends.

http://www.pro-touring.com/threads/6990 ... ub-failure
the one documented failure I have seen.
The billet Kore3 replacement units:
http://kore3.com/proddetail.php?prod=10075

I thought I remember seeing a cheap replacement casting drum hub that has failed as well... Cant seem to find it again...

Documentation showing Drum Hub cross reference to Chevelle, Chevy II and Camaro hubs, for people looking to replicate the swap known as the Corvair hub swap, I'll refer to it as the GM short spindle swap:
http://corvaircenter.com/phorum/read.php?1,657804

Some stuff that was done today:

I never liked that the boxing of the cross-member wasn't complete across the bottom.
So, with the use of CAD... (that's Cardboard Aided Design for those techies out there)
I cut the trapezoid out of some 16GA scrap steel.

And I wanted to use my dimple die set since I've had it for six months and haven't even messed with it yet.

And here it is all welded in:

Good enough for the girls I date.

I'm working on the same for the rear control arms, since they leave a lot to be desired structurally:



Don't mind all the parts from an unrelated tire studding endeavor, it's a shared shop space.

And the Prothane bushings were finally installed in control arms, after the adventure many moths ago installing them into new sleeves (which differed enough from the factory sleeves to need modifications). And the front control arms got some sweet paint using leftover primer and engine enamel.

FieroWanaBe1 wrote:http://www.pro-touring.com/threads/6990 ... ub-failure
the one documented failure I have seen.
The billet Kore3 replacement units:
http://kore3.com/proddetail.php?prod=10075

I thought I remember seeing a cheap replacement casting drum hub that has failed as well... Cant seem to find it again...

FieroWanaBe1 wrote:Documentation showing Drum Hub cross reference to Chevelle, Chevy II and Camaro hubs, for people looking to replicate the swap known as the Corvair hub swap, I'll refer to it as the GM short spindle swap:
http://corvaircenter.com/phorum/read.php?1,657804

Cool. Interesting info!

http://wilwood.com/Hubs/HubProd.aspx?itemno=270-7037
Wilwood does make a hub too that could work in this application.

I went nuts with my plasma table and the 1" dimple die.
The fist control-arm went pretty half-hazardly, I tried to line the holes with the holes in the control arm.

The second I had only enough scrap to make the brace 2 pieces, so I just eye-balled an even spread.


I painted them with a some old left over gold wheel paint from who knows when. (A teaser for the livery spoof)

That's a lot of boxing.

I've never heard of the control arms or cross member failing...

Boxing should keep things from flexing which is a good thing.

My intent is to reduce flexing using 275 tires.

I have bent a rear lower in a low speed collision.
The front lowers are have a lot of metal in them, so adding weight just didn't seem appropriate.
The front upper could be twisted easily in my hands.

The boxing is purely, objectively for my peace of mind.

I am using 18Ga for the boxing, I haven't added too much weight, especially to the front subframe. I see why they boxed it near the mounts for the steering rack, I just wanted to see the whole length boxed, to help stiffen it up a small amount.

Does anyone have a recommendation on what brand water pump to buy?
The one I pulled out had an Iron Impeller, and it worked great for street driving with the 4 speed (and at 75mph on the interstate).
OE one is 92$ on rock auto, it looks just like the one I pulled of.
Gates is 13$, and has a stamped impeller.
There is a Bosch for $18, iron impeller shown. I wonder who (and where) really made it for them.
Is going OE really worth it or will one of the parts store brands get me a truly equivalent pump?
The photo listing for Cardone shows an Iron Impeller too, but I worry about sealing integrity on these cheapies...

I have always used cheap water pumps on my pushrod swaps. I have always just verified it has the metal impellar instead of plastic when picking them up