mk e wrote:
A little off the engine subject....I'm remembering that the 87/88 fieros got better front suspension after the chevette they lifted it from went out of production in 86. Do I have that right? Or was it only the GT that got updates? Have you done any additional suspension work?, sorry if you said and I missed it.
What kind of timeline have you got in your head for this build? Fall? Spring?
I'm thinking I can get it running by the fall.
The Fiero team developed a bespoke suspension during the Fiero's development. GM's bean counters said no, and the team had to pull the Chevette's front suspension for the front and the Citation's front suspension for the rear.
For 1988 production only, the car finally got the suspension that was originally designed for it, which is MUCH better than the '84-'87 suspension.
The '84-'87 suspension has pro-dive, huge scrub radius and tiny brakes up front. 9 3/8 x 3/8 solid rotors... At least GM put aluminum calipers on the Fiero, but since they used the same mold as the iron calipers, the aluminum calipers were flexible and soft. The rear suspension had anti-dive when it was in the front of a Citation, but that turned into pro-squat when they moved it right into the back of a Fiero without geometric changes. It ended up with bump-steer due to the fixed inner tie rod end location. Also, the tiny 5x100 hub cartridges in that system can't take much hard use.
The '88 fixed the pro-dive, has much better alignment adjustments, has a great scrub radius and light effort for manual steering. Both front ends are short/long A-arm. The '88's got 10 1/2 x 3/4 vented rotors all around. Both rear ends are strut, but the '84-'87 has an A-arm and toe link, while the '88 has parallel lateral links and a trailing link. While the roll center is not adjustable from the factory, modifying the system to raise the rear roll center is not difficult and is a phenomenal improvement to a system that's already pretty good. Camber at both ends can be adjusted to ~ -1.75 degrees without any mods. Installing rod end lateral links is also really easy and results in a good improvement in path accuracy and camber control with zero negative effects on ride or NVH.
I think that if the '88 GT/Formula had been the Fiero that debuted in '84, the Fiero would have been in production a LOT longer and might even still be part of GM's model portfolio.
The '88's only weakness are the '88-Fiero-only front hubs. They're reasonably tough, but they're small OD have a shallower flange offset than any other hub, so there's nothing that can be swapped in. I have geometric data on the knuckle, and just need to get enough other things out of the way to CAD up a knuckle that will accept C5/6/7 Corvette front bearings. With the Corvettte wheels offsets, packaging the '88 knuckle with the same scrub radius as stock actually results in a LARGER hub flange to kingpin axis offset, which makes the new one easier to package than the original.
The Northstar car is an '87, but I also have a stock V6 '88.
The '87 ("The Mule") has spherical bearing rear control arm pivots, rear hub end components from a Pontiac 6000 with larger hubs, brakes and outer CV joints (27 spline), Koni struts and coil overs, 11" front brakes, UHMW PE front suspension bushings, Koni front shocks and an anti-dive mod in the front suspension that works wonders.
Coming soon:
Rear: fabricated rear knuckles to accept C7 Corvette rear hubs with 33 spline CV joints, raised rear roll center, improved toe link geometry, 12 3/16 brakes, hot rod drum-in-hat parking brake, strut clamp extension plates to fit 18x11 rear wheels.
Front: spherical bearing lower control arm pivots, fully adjustable upper control arms, aluminum lowering spindles with aluminum hubs, 12 3/16" brakes and 17x9 wheels
Eventually:
Rear: Custom valved Bilstein inverted struts, custom fabbed subframe
Front: Custom wide-track control arms to use the same fabbed knuckles as the I'm developing for the '88; coil overs on custom valved Bilsteins.