Real Fiero Tech

ok, so there's been lots of discussion on struts both here, and on Old Europe, and I've never seen anyone try using a strut meant for another vehicle except in crazy custom applications. I'm no expert, but it seems to me like many struts could be adapted to the Fiero, the design isn't that crazy. why isn't this avenue more explored? the bolt pattern of the towers seem like a non-issue to me. it's just sheet metal, not hard to drill a new one, for a different hat. the spring perch isn't a big deal either, we cut those off to make coil overs. only thing I can see that would even be close to a big deal would be the lower mount to the knuckle.

am I crazy?

You are not crazy, but there are several things to consider. For example, the Camaros/Mustangs use a rigid lower attachment (so the lower strut/upright hole is round, not slotted), and use a slotted upper mount for camber adjustments - so they are opposite of the Fiero setup). There are other differences (length of upper shaft shank, clearance between base of the strut and the CV, bolt spacing & angle of hole placement on strut/upright flange). I am sure there is a workable solution, but it hasn't been documented as of yet.

Yarmouth Fiero is working on a solution using some aftermarket Camaro struts in his build thread, but hasn't got everything worked out yet.

There is no advantage to other rear struts unless you know the valving is better than what you have -- or if the new struts can be revalved.

well, that was actually a big part of what sparked this thread. I saw your post in the mall on Old Europe looking for Bilstein struts, and it got me thinking, that looking for fiero specific parts limits what we can use drastically. lets face it, 99% of the real world doesn't give 2 shits about a 30 year old plastic car with minimal following. I'm sure there's something else similar enough out there for us to be able to make it work.

Series8217 wrote:There is no advantage to other rear struts unless you know the valving is better than what you have -- or if the new struts can be revalved.

This. The Koni Red struts are still available and can be revalved for whatever springs you want to run, within reason.
If you need to go further than production based struts allow, the Koni Motorsport model 2817 universal strut (and comparable offerings from other MFG's) is fairly easy to incorporate in that level of build. In the case of the Fiero, just weld the "cheeks" of the taco clamp to the steel sleeve at the bottom.

http://www.koniracing.com/2817.cfm



There's also a 2816 that can be used in customer-built strut housings... may have to snag a pair of those for Bad Idea.

ericjon262 wrote:well, that was actually a big part of what sparked this thread. I saw your post in the mall on Old Europe looking for Bilstein struts, and it got me thinking, that looking for fiero specific parts limits what we can use drastically. lets face it, 99% of the real world doesn't give 2 shits about a 30 year old plastic car with minimal following. I'm sure there's something else similar enough out there for us to be able to make it work.

It's relatively straightforward to shorten, retube, re-shaft, rebuild, or make a new housing for any Bilstein strut. The reason I have that post is so I can get some that I don't have to adapt for the Fiero. All Bilstein monotube dampers can be revalved.

I have spent a significant amount of time researching other cars which Bilstein makes struts for, with the goal of finding another one that will fit the Fiero. There was nothing close; they're all too long. I thought I had posted that information on this forum but I guess not. I'll have to find it..

ok, makes enough sense. is there any advantage to the strut being adjusted down on the knuckle instead of up on the strut tower?

Shouldn't make a difference.

The Dark Side of Will wrote:Shouldn't make a difference.

thanks.

There is very limited clearance between the bottom of the strut and the top of the CV boot on a stock Fiero, so take that into consideration.

Monroe to Bilstein strut and strut insert crossreference with dimensions (from the 2007 Monroe catalog):
https://docs.google.com/spreadsheet/ccc ... sp=sharing

The first sheet is strut inserts, the second sheet is struts.

I started with the Monroe catalog since it's the only one I could get dimensions directly from. This means the crossreference guide misses any applications that Monroe does NOT make a strut for!

I was looking today for the cheapest Bilstein struts and happened to find the E30 325iX strut insert, which is apparently much shorter than the normal E30 insert. It's also one of the cheapest 36mm monotube struts that Bilstein has for sale. I would like to get more information on this strut, including the internal geometry of the housing, and the length of the bump stop. With that information we can determine if it will work on a Fiero by using a fabricated strut housing or just clamping the ears directly to the bottom (if it's strong enough), assuming it's short enough.

thanks for posting that.

I have a related question, when it comes to shock placement, if one were to convert the rear suspension to a SLA setup, how would one place the shock/spring in relation to the control arm? my thought process thinks it would be best to have the shock positioned so that it actuates in a plane as close to perpendicular to the control arms as possible(which for the rear of a fiero would most likely require some type of pushrod actuated suspension)

Edit: perpendicular to the roll center of the car would be best wouldn't it?

ericjon262 wrote:thanks for posting that.

I have a related question, when it comes to shock placement, if one were to convert the rear suspension to a SLA setup, how would one place the shock/spring in relation to the control arm? my thought process thinks it would be best to have the shock positioned so that it actuates in a plane as close to perpendicular to the control arms as possible(which for the rear of a fiero would most likely require some type of pushrod actuated suspension)

Edit: perpendicular to the roll center of the car would be best wouldn't it?

That's not really a related question, you might want to start a new topic about converting the rear to SLA, and deciding on the ideal geometry for it

Series8217 wrote: That's not really a related question, you might want to start a new topic about converting the rear to SLA, and deciding on the ideal geometry for it

lol. the more I think about it, the more complicated it gets in my head. I'll start a second thread.

ericjon262 wrote:

Series8217 wrote: That's not really a related question, you might want to start a new topic about converting the rear to SLA, and deciding on the ideal geometry for it

lol. the more I think about it, the more complicated it gets in my head. I'll start a second thread.

Yeah, there are a LOT of considerations.

Series8217 wrote: I was looking today for the cheapest Bilstein struts and happened to find the E30 325iX strut insert, which is apparently much shorter than the normal E30 insert. It's also one of the cheapest 36mm monotube struts that Bilstein has for sale. I would like to get more information on this strut, including the internal geometry of the housing, and the length of the bump stop. With that information we can determine if it will work on a Fiero by using a fabricated strut housing or just clamping the ears directly to the bottom (if it's strong enough), assuming it's short enough.

I'm a regular poster in R3V's 325iX and V8 swap sections... I'll be installing Koni yellows in Bad Idea sometime this year, along with converting the front struts to coil overs.
Evaluating the wall thickness of the insert tubes vs. those of the Fiero Koni struts might give some insight into whether the Fiero taco clamp or something like it could be welded directly onto the BMW insert. The BMW suspension presses the shell into a bore in a forged knuckle, so I don't think the insert could take that, as it's smaller in diameter and the press on combination with the edge of the bore would create a high buckling stress.

on an actual related note, is there a big advantage to installing a spherical bearing in the strut top on our struts? I'm about to make new strut top mounts or mod the ones I have, for my 88 cradle swap, and if it's worthwhile, I'll see what it takes to make it happen.

Yes, there's less deflection of the rubber bushing. I've heard it's noticeable on Fox Mustangs and the like.

However, I remain skeptical of putting spring loads axially into a spherical bearing, although I know that's the common way to do it.

Until you get into very stiff dampers, the spring loads are larger than the damping loads. I don't have time to write up my thoughts right now, but I'll try to circle back here in the next few days.

If I recall correctly, Aurora (or maybe someone else) makes a spherical with high axial load capability for such an application.

Vorshlag uses that or something similar in their camber plate kits, which route both spring and damper loads through the spherical bearing.

Still not sure I think it's a good idea.