Real Fiero Tech

The above swaybar endlink image is actually part of a set of images I took for scanning. The 3D model looks like this when sharing space with the new knuckle.
I've been bouncing back and forth between integrated and bolt-on steering arms. Since clearing the swaybar at full lock requires reworking the steering arm I'm going to do another design iteration with a bolt-on arm and see how things look. I would really like to be able to swap out the stock style arm for a clevis to use a rod end with but if I end up making these for others I don't want to force that decision.

I like the idea of the bolt on steering arm, it adds an additional tuning point that you can use to improve the car.

You can keep the one piece design and the production process you'd envisioned by keeping the arm straight, but moving it outboard. The outer tie rod boss would then be a projection in the inboard direction from the "flat" steering arm. Incrementally heavier? Yes, but it solves both the packaging and production difficulties.

The Dark Side of Will wrote: ↑Sat Dec 10, 2022 1:41 pm You can keep the one piece design and the production process you'd envisioned by keeping the arm straight, but moving it outboard. The outer tie rod boss would then be a projection in the inboard direction from the "flat" steering arm. Incrementally heavier? Yes, but it solves both the packaging and production difficulties.

Yep fixing the clearance with the one piece design was no big deal. I did something along those lines. I've finished the designs for one-piece and modular (bolt-on steering arm) knuckles. However, there are a few different paths I am pursuing before I pull the trigger on metal parts.

I'm working on a symmetrical design (same knuckle left and right) that uses a bolt on arm. The symmetrical design means less setup cost for manufacturing and fewer expensive parts to keep as spares.

I also picked up a C8 Corvette knuckle and hub and found that the 4-bolt pattern of the C8 hub is a lot better fit than the 3-bolt C5/C6/C7/Camaro within the tight packaging of the Fiero's knuckle geometry. The hub is beefed up even compared to the C7 and Camaro. Only $85 new from GM. The hub-to-brake offset and caliper lug spacing on the C8 is the same as the C7/Camaro, so there won't be any change to the brake package.

Successfully test fit the C8-based knuckle! Same part can be used on left and right sides, just a different steering arm. I have arm designs for rod ends (with adjustable bump steer) and a stock taper-style arm which you can see here.

Outer tie rod and UBJ are for a C4 Corvette. The outer tie rod fits on the stock Fiero inner. The C4 UBJ shares the same bolt pattern as a K5208 upper ball joint but has a longer stud taper to work better with an aluminum upright. Lower ball joint is K6145 with a steel taper adapter sleeve to increase the surface area bearing on the lower ball joint boss. K6145 style BJs are available with various stud lengths as a geometry tuning aid.

Hopefully will have some metal parts before spring.

Series8217 wrote: ↑Sun Dec 25, 2022 6:55 pm
Outer tie rod and UBJ are for a C4 Corvette. The outer tie rod fits on the stock Fiero inner. The C4 UBJ shares the same bolt pattern as a K5208 upper ball joint but has a longer stud taper to work better with an aluminum upright. Lower ball joint is K6145 with a steel taper adapter sleeve to increase the surface area bearing on the lower ball joint boss. K6145 style BJs are available with various stud lengths as a geometry tuning aid.

Good finds on all!

Is the K6145 the one we were talking about recently (I think we were talking about recently... Can't find the convo now...) that does not fit the factory lower arm?

I had occasionally been mildly frustrated by trying to package a 3 bolt bearing flange. Is the rectangular pattern oriented vertically like that on the Corvette knuckle?

Series8217 wrote: ↑Sun Dec 25, 2022 6:55 pm Hopefully will have some metal parts before spring.

I've tried this Chinese place for machined-from-billet parts that should normally be cast (lots of chips), and these guys are dirt cheap and reasonably quick:
https://www.sh-proto.com/

Not sure I would trust them with regards to ultra-precise things such as precision fits (a part with a press-fit bearing slid in once), or ball-joint sockets, but you could leave extra material and plan to rework sensitive areas.

Depends of course on how much money you're willing to spend so that things run smoothly the first time...

The Dark Side of Will wrote: ↑Mon Dec 26, 2022 5:40 pm

Series8217 wrote: ↑Sun Dec 25, 2022 6:55 pm
Outer tie rod and UBJ are for a C4 Corvette. The outer tie rod fits on the stock Fiero inner. The C4 UBJ shares the same bolt pattern as a K5208 upper ball joint but has a longer stud taper to work better with an aluminum upright. Lower ball joint is K6145 with a steel taper adapter sleeve to increase the surface area bearing on the lower ball joint boss. K6145 style BJs are available with various stud lengths as a geometry tuning aid.

Good finds on all!

Is the K6145 the one we were talking about recently (I think we were talking about recently... Can't find the convo now...) that does not fit the factory lower arm?

Yeah the K6145 is a press in style but larger OD than the Fiero ball joint. 1210-109 here: https://www.qa1.net/assets/uploads/docu ... ess-In.pdf

I had occasionally been mildly frustrated by trying to package a 3 bolt bearing flange. Is the rectangular pattern oriented vertically like that on the Corvette knuckle?

Yep I am using the same pattern orientation as the C8 knuckle. The bolt pattern nicely straddles the upper and lower ball joint bosses.

The 3 bolt C5/C6/C7 bearing is a problem for the Fiero knuckle because one of the bolt heads wants to go straight through the LBJ boss.

Speedtech ran into the same problem with their forged AFX knuckles (C7 bearing) since they wanted a symmetrical design to save on tooling costs. Their solution was to drill a hole in the wheel hub flange and install the bottom fastener from the hub side. So you have to keep specially modified hubs around for spares. Not a huge downside but it's not really elegant.

In my earlier design I rotated the pattern and came up with a workable layout but it necessitates a handed design and one of the bolt heads wants to share space with the swaybar endlink at full lock.

I'm working on finalizing the bolt-on steering arm then I will send out some RFQs.

pmbrunelle wrote: ↑Wed Dec 28, 2022 4:27 pm

Series8217 wrote: ↑Sun Dec 25, 2022 6:55 pm Hopefully will have some metal parts before spring.

I've tried this Chinese place for machined-from-billet parts that should normally be cast (lots of chips), and these guys are dirt cheap and reasonably quick:
https://www.sh-proto.com/

Not sure I would trust them with regards to ultra-precise things such as precision fits (a part with a press-fit bearing slid in once), or ball-joint sockets, but you could leave extra material and plan to rework sensitive areas.

Depends of course on how much money you're willing to spend so that things run smoothly the first time...

Thanks for the recommendation, I'll check them out!

I do plan to leave the ball joint tapers oversize so I can ream them to final dimensions myself at least for the first run. There isn't much else with tight tolerances other than mounting faces being flat and parallel.

Series8217 wrote: ↑Wed Dec 28, 2022 7:30 pm
I do plan to leave the ball joint tapers oversize

I hope you mean undersize!

The Dark Side of Will wrote: ↑Wed Dec 28, 2022 7:56 pm

Series8217 wrote: ↑Wed Dec 28, 2022 7:30 pm
I do plan to leave the ball joint tapers oversize

I hope you mean undersize!

Yep. More material in the hole

Series8217 wrote: ↑Sat Dec 31, 2022 1:47 am

The Dark Side of Will wrote: ↑Wed Dec 28, 2022 7:56 pm

Series8217 wrote: ↑Wed Dec 28, 2022 7:30 pm
I do plan to leave the ball joint tapers oversize

I hope you mean undersize!

Yep. More material in the hole

I have that conversation about bottom bearing inserts with someone about once a year. There are oversize and there are undersize and they are not the same

This is a K6145 mount ring set on top of the 88 Fiero lower control arm for reference. Looks like it wouldn't be a big deal to cut the end of the stock control arm nose with a hole saw to drop one of these in and weld it.

Speedway Motors part number 910-34820

OD is about 60 mm (1 3/8 in)

Not to hijack Steven's work on the front 88 hubs and if this needs a new thread for the Rears I'm happy to transfer

Nevertheless we have a new LS4 / Fiero swap vendor I came across (well fb forcibly notified me) named 2P or Pickard Performance. Several products for 84-88 suspensions on top of his LS4 work. He's recently started mounting Sky/Solstice 30 spline hubs to our rear uprights. See pics below. I like the idea as they may be a bolt in replacement for my cobbled together Cobalt turbo axles resplined with G6 cages and fiero outer stubs but....

• Not sure of the offset change yet, although it looks minimal if not more inboard than the OEM or 2025K hubs

• I'm a bit leery of the cast iron integrity of the pressed in and then redrilled sky/solstice mounting holes just outside OEM locations. (thoughts on this solution)

• 5x110 isn't the most common bolt pattern

• GM/ACDELCO Sky/Solstice hubs manufactured for only 2 years. Although probably stronger than the cavalier 2025K hubs, they already go for quite the premium at 2-300$ each.

draven wrote: ↑Fri Apr 14, 2023 9:56 am Not to hijack Steven's work on the front 88 hubs and if this needs a new thread for the Rears I'm happy to transfer

Nevertheless we have a new LS4 / Fiero swap vendor I came across (well fb forcibly notified me) named 2P or Pickard Performance. Several products for 84-88 suspensions on top of his LS4 work. He's recently started mounting Sky/Solstice 30 spline hubs to our rear uprights. See pics below. I like the idea as they may be a bolt in replacement for my cobbled together Cobalt turbo axles resplined with G6 cages and fiero outer stubs but....

• Not sure of the offset change yet, although it looks minimal if not more inboard than the OEM or 2025K hubs

• I'm a bit leery of the cast iron integrity of the pressed in and then redrilled sky/solstice mounting holes just outside OEM locations. (thoughts on this solution)

• 5x110 isn't the most common bolt pattern

• GM/ACDELCO Sky/Solstice hubs manufactured for only 2 years. Although probably stronger than the cavalier 2025K hubs, they already go for quite the premium at 2-300$ each.

Yeah, he's the guy that got Moroso to produce the LS4 oil pan that mounts the starter. He showed the prototypes either on Old Europe or FaceBalk or both... I and others told him that was a terrible location for the drain plug, but it's the same in production. So he takes advice as well as Rodney. At least he followed through and got an expensive limited market part produced.

Yeah, the Solstice bearings are dumb.

The Dark Side of Will wrote: ↑Fri Apr 14, 2023 8:29 pm Yeah, he's the guy that got Moroso to produce the LS4 oil pan that mounts the starter. He showed the prototypes either on Old Europe or FaceBalk or both... I and others told him that was a terrible location for the drain plug, but it's the same in production. So he takes advice as well as Rodney. At least he followed through and got an expensive limited market part produced.

you're thinking of LS4king (Brandon Furches?) he's a different person than Pickardt/2P's, unless there's more than one LS4 pan.

99% sure pickardt performance is not the ls4 oil pan guy.

Moroso oil pan was done by a guy building monte carlos and mating them to 4t80s.

I actually had the same idea when I had my ls4 and found his oil pan by accident while researching options.

Things are getting real...

The first prototype billet uprights for the 88 Fiero have arrived.

Feature highlights:

Massive wheel bearing strength upgrade as well as stronger ball joints. Inexpensive 4 pot Brembos (Camaro6, C7, and C8 Corvette), 5x120 bolt pattern for wheels (BMW fitment with hubcentric rings). Brake rotor size options from 12.6 inches up to 15.5 carbon ceramic with no adapters required other than rotor centering rings for some options. Bump steer is fully adjustable using spacers. Ackerman can be adjusted by changing the bolt-on steering arm.

Who finally made the uprights?

Would you recommend that vendor?