1988 Fiero track car

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Jalisurr
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1988 Fiero track car

Post by Jalisurr »

Background: I've been doing Time Trials in sport class with a lightly modded 2009 Corvette Z06 for a couple years and I'm getting bored of it. Not the racing, that's always fun, but the car. I want to build something different and interesting. The end goal is to have something around as fast as the corvette, but lighter and simpler (but not cheaper, let's be realistic here).

To that end, I've picked up a 1988 Fiero base 4cyl car. No power anything, no sunroof, perfect starting point. The current plan is to build up phase one over the course of the next year or so and go from there.

Image

Now, the plan:

Drivetrain:
- K20A2 swap - This will give me a nice light compact engine and transmission which are known to be able to make very good power (~200whp NA for the first iteration, ~400whp on a supercharger once the chassis development is more or less done). I have a set of mounts from kfiero on their way: https://www.facebook.com/groups/1086771178323278
- I'll be using the stock RSX-S 6 speed transaxle, adding an LSD
- Custom axles - Honda inner and Fiero outer
- RSX shifter and shift cables are actually around the right length for the car, so use that or an aftermarket RSX shifter like KTuned
- Halltech ECU

Suspension:
- Tubular upper and lower control arms in the front, and links in the rear. Sphericals everywhere.
- Not finalized on coilovers yet, working off Steven's development but I may look at working with a racing coilover manufacturer like Reinharte to develop something for the Fiero, or make something from QA1 work.

Brakes:
- I like WCF's kit to put the Porsche 4 pot Brembos with 2 piece rotors on all 4 corners. Light, race proven, easy to find racing pads.

Interior:
- Building to Max category Time Trials rules
- Roll cage
- Stripped except for dashboard
- Fixed racing buckets (not finalized on brand/model yet)
- AEM or Haltech digital gauge cluster (remove stock gauges completely to simplify engine swap wiring)

I'll try to update as I go, right now I'm just collecting parts, the first step will be the engine going into the car as the old duke is pretty tired. That's not gonna keep me from making it go around the local race track as a baseline though!
1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
Jalisurr
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Re: 1988 Fiero track car

Post by Jalisurr »

Got my first time trial in with the 88 Fiero. My local track is River's Edge road course at Mission Raceway.

Current status:
Stock Iron Duke
Stock suspension
Old all season tires
Stock brakes

Best lap time: 1:36.66. Video of a full time attack session here: https://youtu.be/sZ-YJD3kAIc

For reference, my best lap time with my 2009 Z06 was a 1:14.3, and really fast guys in Porsche GT3RSes are in the 1:10 range.

Overall impressions: the car is very well balanced. Can really control the attitude of the car with the throttle, more so than I could in the Corvette. Everything else is terrible, the suspension is soft, the engine is pathetic. The brakes were totally fine but then I wasn't going very fast. But the balanced feeling of the car has me encouraged that this will be a good platform to build up into something fun.
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Re: 1988 Fiero track car

Post by The Dark Side of Will »

Welcome!

You're off to a great start! Looking forward to seeing your car take shape.

The '88 Fiero has hella potential, but it's hardly ever realized, much less publicized.

How much have you read on this forum?

Tubular upper arms are way more work for less adjustability than some much easier designs to field...
http://www.realfierotech.com/viewtopic.php?f=3&t=17936

You won't be able to significantly undercut the weight of the stock lower arm... and the arms don't contribute a lot to the unsprung weight anyway.

I have some spherical bearing shells to replace Fiero front lower inner bushings.

ETA: I have a LOT of other stuff in the works that I think you'll really like, but didn't want to take over your thread right away! :wink:
Jalisurr
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Re: 1988 Fiero track car

Post by Jalisurr »

The Dark Side of Will wrote: Mon Jun 07, 2021 3:49 pm Welcome!

You're off to a great start! Looking forward to seeing your car take shape.

The '88 Fiero has hella potential, but it's hardly ever realized, much less publicized.

How much have you read on this forum?

Tubular upper arms are way more work for less adjustability than some much easier designs to field...
http://www.realfierotech.com/viewtopic.php?f=3&t=17936

You won't be able to significantly undercut the weight of the stock lower arm... and the arms don't contribute a lot to the unsprung weight anyway.

I have some spherical bearing shells to replace Fiero front lower inner bushings.

ETA: I have a LOT of other stuff in the works that I think you'll really like, but didn't want to take over your thread right away! :wink:
Thanks! You're totally right, when I said tubular arms I was thinking of the adjustable ones like you mentioned in my head for the top. I'd ideally like to convert to a coilover in front for adjustability, I was thinking that a tubular lower might make that easier as well rather than modifying the stock one as some do with the stronger/lower bottom shock mount, but I could be wrong?

I've been reading a fair bit, saw the development of those upper control arms and the rear suspension links, plus Steven's development. I'll be stealing a lot of ideas from him as far as spring rates go etc.

Please if you have ideas of things I could do better, lay them on me. I'm very much in the initial planning phase but I'm excited about the possibilities.
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Re: 1988 Fiero track car

Post by Shaun41178(2) »

Awesome dude. Can't wait to see this car progresses now that you have your baseline
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL

530 whp is greater than 312
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Re: 1988 Fiero track car

Post by The Dark Side of Will »

I was impressed with how light FieroGuru's car ended up... I think he started with a no-option '88.

Anyway... stuff to do to the car:

-Tilton 7.25" dual disk clutch for Honda K series: https://tiltonracing.com/product/honda- ... ssemblies/

-Adjustable UCA for '88's as I already mentioned: http://www.realfierotech.com/viewtopic.php?f=3&t=17936
Both my design and Steven's in that thread

-Shells for spherical bearings in front lower control arms (all model years): http://www.realfierotech.com/viewtopic.php?f=3&t=21745
With you, Eric & Draven, I could find two Old Europe buyers and do a second run of 5 kits.

-Rod-end rear lateral links for the '88 Fiero suspenison: http://www.realfierotech.com/viewtopic.php?f=3&t=2573

-You've already posted in the "Stronger '88 bearing" thread: http://www.realfierotech.com/viewtopic.php?f=3&t=21514
So you've seen my front knuckle design to accept C5/6/7 Corvette hub bearings

-I'm working on a similar product for the rear: http://www.realfierotech.com/viewtopic. ... 61#p159161
The Dark Side of Will wrote: Sun Aug 16, 2020 4:31 pm
Image

Image
An important thing to note about fabbed knuckles is that the strut mount can be moved inboard to make room for WIDE wheels and tires. From measurements, 18x11 *should* fit with 315/30-18 rear tires, as long as the strut can be moved inboard to make room. The '88's can handle even a little more... maybe as much as 18x11.5. That's getting to the point at which a 335/30 would fit.

This would use C6/7 33 spline bearings and the 33 spline outer CV's from large GM FWD cars that *should* plug right onto Fiero axle bars.

For brakes I'm looking at a Wilwood Ultralite HP32 rotors: https://www.wilwood.com/Rotors/RotorPro ... o=160-2900

I've developed a Hot Rod Parking Brake, which you probably don't need at all for Time Attack
http://www.realfierotech.com/viewtopic. ... 53#p157853
http://www.realfierotech.com/viewtopic. ... 60#p157960
http://www.realfierotech.com/viewtopic. ... 88#p158088
http://www.realfierotech.com/viewtopic. ... 93#p158093
http://www.realfierotech.com/viewtopic. ... 42#p158142
http://www.realfierotech.com/viewtopic. ... 33#p158233
However, it is compatible with the relatively small rotor bolt circle in the Wilwood rotors
http://www.realfierotech.com/viewtopic. ... 14#p158314

Basically... I'm designing everything around Corvette hubs and Corvette *compatible* brakes... meaning that a C5/6/7 Corvette brake kit would bolt up. Caliper selection remains open, but I'll probably go with Wilwood. A 2700# Fiero doesn't need as much brake as a 3500# C7.

I infer you've read Steven's thread about front coil-overs: http://www.realfierotech.com/viewtopic.php?f=3&t=17671

Since rear Konis are NLA... Building inverted struts from scratch using Bilstein dampers should not be hard at all from a fabrication standpoint. Steven also said he used a basic shim-stack calculator and it was right-on for his use on his front shocks.

Lots to do!
I'll have my engine in the car in a few weeks, and be able to get back to suspension & brake stuffs.
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Re: 1988 Fiero track car

Post by Jalisurr »

The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm I was impressed with how light FieroGuru's car ended up... I think he started with a no-option '88.
I'm trying to be realistic with weight expectations, given I'll be adding a full cage I expect most of my weight savings by stripping the interior and getting rid of the boat anchor engine will be cancelled out. I'm hoping for below 2600lbs.
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm Anyway... stuff to do to the car:

-Tilton 7.25" dual disk clutch for Honda K series: https://tiltonracing.com/product/honda- ... ssemblies/
Lighter flywheel + clutch are definitely on the list to go in. Not sure which brand I'll go with yet
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -Adjustable UCA for '88's as I already mentioned: http://www.realfierotech.com/viewtopic.php?f=3&t=17936
Both my design and Steven's in that thread
Yep, those look great. Did one of you work with WCF on the adjustable UCA they are selling? They look almost identical
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -Shells for spherical bearings in front lower control arms (all model years): http://www.realfierotech.com/viewtopic.php?f=3&t=21745
With you, Eric & Draven, I could find two Old Europe buyers and do a second run of 5 kits.
Very interesting. What's the advantage of keeping the OEM lower with the rod-end conversion over going to a tubular lower arm?
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -Rod-end rear lateral links for the '88 Fiero suspenison: http://www.realfierotech.com/viewtopic.php?f=3&t=2573
I've seen this one, this is fantastic work and will be on my list for sure
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -You've already posted in the "Stronger '88 bearing" thread: http://www.realfierotech.com/viewtopic.php?f=3&t=21514
So you've seen my front knuckle design to accept C5/6/7 Corvette hub bearings

-I'm working on a similar product for the rear: http://www.realfierotech.com/viewtopic. ... 61#p159161

An important thing to note about fabbed knuckles is that the strut mount can be moved inboard to make room for WIDE wheels and tires. From measurements, 18x11 *should* fit with 315/30-18 rear tires, as long as the strut can be moved inboard to make room. The '88's can handle even a little more... maybe as much as 18x11.5. That's getting to the point at which a 335/30 would fit.
That's a heck of a tire for such a light car - I'm currently planning to run a 275 on a 18x9.5, which is slightly more tire/weight as the 325s on the back of the 3200lb Corvette. I'll probably be running Enkei RPF1s and Nankang CR1s for Time Trials.
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm This would use C6/7 33 spline bearings and the 33 spline outer CV's from large GM FWD cars that *should* plug right onto Fiero axle bars.
This would be great, the C6 gets the SKF Racing bearings that are pretty guaranteed to last on a track in a light Fiero.
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm For brakes I'm looking at a Wilwood Ultralite HP32 rotors: https://www.wilwood.com/Rotors/RotorPro ... o=160-2900

I've developed a Hot Rod Parking Brake, which you probably don't need at all for Time Attack
http://www.realfierotech.com/viewtopic. ... 53#p157853
http://www.realfierotech.com/viewtopic. ... 60#p157960
http://www.realfierotech.com/viewtopic. ... 88#p158088
http://www.realfierotech.com/viewtopic. ... 93#p158093
http://www.realfierotech.com/viewtopic. ... 42#p158142
http://www.realfierotech.com/viewtopic. ... 33#p158233
However, it is compatible with the relatively small rotor bolt circle in the Wilwood rotors
http://www.realfierotech.com/viewtopic. ... 14#p158314

Basically... I'm designing everything around Corvette hubs and Corvette *compatible* brakes... meaning that a C5/6/7 Corvette brake kit would bolt up. Caliper selection remains open, but I'll probably go with Wilwood. A 2700# Fiero doesn't need as much brake as a 3500# C7.
Depends how fast it is! Wilwood calipers are great. I've not had luck with Corvette OEM brakes, I had a C4 ZR1 years ago and ended up bending one of the front calipers open on track, that was pretty great. Even the 6 pot fronts on the Z06 are only JUST good enough for my local track, but it's exceptionally hard on brakes. I expect the Porsche Brembos will probably be sufficient but I wouldn't go smaller than a 13" rotor.

How do you think the weight of your parking brake setup compares to the little spot caliper with bracket like WCF supplies with the Brembo kits? I am supposed to have a parking brake to be street legal here, but it doesn't need to actually work all that well.
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm I infer you've read Steven's thread about front coil-overs: http://www.realfierotech.com/viewtopic.php?f=3&t=17671

Since rear Konis are NLA... Building inverted struts from scratch using Bilstein dampers should not be hard at all from a fabrication standpoint. Steven also said he used a basic shim-stack calculator and it was right-on for his use on his front shocks.

Lots to do!
I'll have my engine in the car in a few weeks, and be able to get back to suspension & brake stuffs.
Which shocks and springs to use is definitely the area I still need to do the most figuring out. Steven's research is fantastically useful on spring and shock rates to look for. I may reach out to some racing suspension makers and see if they would be interested in making something.
1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
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Re: 1988 Fiero track car

Post by Jalisurr »

Couple pics from the baseline Time Attack session:
Image
Image
Image
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Re: 1988 Fiero track car

Post by The Dark Side of Will »

Jalisurr wrote: Tue Jun 08, 2021 1:59 pm
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -Adjustable UCA for '88's as I already mentioned: http://www.realfierotech.com/viewtopic.php?f=3&t=17936
Both my design and Steven's in that thread
Yep, those look great. Did one of you work with WCF on the adjustable UCA they are selling? They look almost identical
WCF's product is Steven's design.
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm -Shells for spherical bearings in front lower control arms (all model years): http://www.realfierotech.com/viewtopic.php?f=3&t=21745
With you, Eric & Draven, I could find two Old Europe buyers and do a second run of 5 kits.
Very interesting. What's the advantage of keeping the OEM lower with the rod-end conversion over going to a tubular lower arm?
There's not a lot of gain in terms of unsprung weight reduction to be had from going to a tubular lower arm. The OE lower arm is structurally efficient, but does need to be modified for coil-overs. Maybe another flavor of adjustability justifies fabbing a new arm, but there are much more cost- and effort-effective ways of pursuing unsprung weight reduction.
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm An important thing to note about fabbed knuckles is that the strut mount can be moved inboard to make room for WIDE wheels and tires. From measurements, 18x11 *should* fit with 315/30-18 rear tires, as long as the strut can be moved inboard to make room. The '88's can handle even a little more... maybe as much as 18x11.5. That's getting to the point at which a 335/30 would fit.
That's a heck of a tire for such a light car - I'm currently planning to run a 275 on a 18x9.5, which is slightly more tire/weight as the 325s on the back of the 3200lb Corvette. I'll probably be running Enkei RPF1s and Nankang CR1s for Time Trials.
Big tires turn the car...
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm
The Dark Side of Will wrote: Mon Jun 07, 2021 8:56 pm For brakes I'm looking at a Wilwood Ultralite HP32 rotors: https://www.wilwood.com/Rotors/RotorPro ... o=160-2900

I've developed a Hot Rod Parking Brake, which you probably don't need at all for Time Attack
http://www.realfierotech.com/viewtopic. ... 53#p157853
http://www.realfierotech.com/viewtopic. ... 60#p157960
http://www.realfierotech.com/viewtopic. ... 88#p158088
http://www.realfierotech.com/viewtopic. ... 93#p158093
http://www.realfierotech.com/viewtopic. ... 42#p158142
http://www.realfierotech.com/viewtopic. ... 33#p158233
However, it is compatible with the relatively small rotor bolt circle in the Wilwood rotors
http://www.realfierotech.com/viewtopic. ... 14#p158314

Basically... I'm designing everything around Corvette hubs and Corvette *compatible* brakes... meaning that a C5/6/7 Corvette brake kit would bolt up. Caliper selection remains open, but I'll probably go with Wilwood. A 2700# Fiero doesn't need as much brake as a 3500# C7.
Depends how fast it is! Wilwood calipers are great. I've not had luck with Corvette OEM brakes, I had a C4 ZR1 years ago and ended up bending one of the front calipers open on track, that was pretty great. Even the 6 pot fronts on the Z06 are only JUST good enough for my local track, but it's exceptionally hard on brakes. I expect the Porsche Brembos will probably be sufficient but I wouldn't go smaller than a 13" rotor.
Brakes are a great place to look for unsprung weight reduction... Going bigger than necessary for the application just adds unsprung weight.
Just remember that C4 was Liiiiiiiiteraly tech from 1980.
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm How do you think the weight of your parking brake setup compares to the little spot caliper with bracket like WCF supplies with the Brembo kits? I am supposed to have a parking brake to be street legal here, but it doesn't need to actually work all that well.
Good question? That's very implementation-specific. I can weigh the prototype this weekend and get back to you.
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm Which shocks and springs to use is definitely the area I still need to do the most figuring out. Steven's research is fantastically useful on spring and shock rates to look for. I may reach out to some racing suspension makers and see if they would be interested in making something.
Steven has picked out a Bilstein inverted strut cartridge that can be adapted, but the housing would have to be fabbed from scratch. It shouldn't be difficult, but needs to be done. With a rebuildable Bilstein cartridge, that unit could be valved by any shop that rebuilds Bilsteins.

I can do the design work on the strut housings.
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Re: 1988 Fiero track car

Post by Jalisurr »

The Dark Side of Will wrote: Tue Jun 08, 2021 2:49 pm
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm Very interesting. What's the advantage of keeping the OEM lower with the rod-end conversion over going to a tubular lower arm?
There's not a lot of gain in terms of unsprung weight reduction to be had from going to a tubular lower arm. The OE lower arm is structurally efficient, but does need to be modified for coil-overs. Maybe another flavor of adjustability justifies fabbing a new arm, but there are much more cost- and effort-effective ways of pursuing unsprung weight reduction.
That makes sense from a weight reduction standpoint. I was more thinking if I'm already going to the work of converting the lower control arm to use coilovers and rod ends, why not just pick up a set of tubular lowers from WCF? Maybe I'm missing something.
The Dark Side of Will wrote: Tue Jun 08, 2021 2:49 pm
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm That's a heck of a tire for such a light car - I'm currently planning to run a 275 on a 18x9.5, which is slightly more tire/weight as the 325s on the back of the 3200lb Corvette. I'll probably be running Enkei RPF1s and Nankang CR1s for Time Trials.
Big tires turn the car...
Oh, yeah, sorry, intonation over text. I was impressed that you would be able to fit so much tire, not trying to say it's not necessary.
The Dark Side of Will wrote: Tue Jun 08, 2021 2:49 pm
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm Depends how fast it is! Wilwood calipers are great. I've not had luck with Corvette OEM brakes, I had a C4 ZR1 years ago and ended up bending one of the front calipers open on track, that was pretty great. Even the 6 pot fronts on the Z06 are only JUST good enough for my local track, but it's exceptionally hard on brakes. I expect the Porsche Brembos will probably be sufficient but I wouldn't go smaller than a 13" rotor.
Brakes are a great place to look for unsprung weight reduction... Going bigger than necessary for the application just adds unsprung weight.
Just remember that C4 was Liiiiiiiiteraly tech from 1980.
Yeah, I have every intention of shelling out for 2 piece rotors to keep the unsprung weight down, but these brakes need to be 100% trustworthy to turn good lap times. I figure if my C6 Z06 has a 14" rotor up front stock (and 13" rear) and I consider it just acceptable but not overkill, then a 13" rotor should be fine on the lighter Fiero going the same speed. I wouldn't be comfortable going smaller than that.
The Dark Side of Will wrote: Tue Jun 08, 2021 2:49 pm
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm Which shocks and springs to use is definitely the area I still need to do the most figuring out. Steven's research is fantastically useful on spring and shock rates to look for. I may reach out to some racing suspension makers and see if they would be interested in making something.
Steven has picked out a Bilstein inverted strut cartridge that can be adapted, but the housing would have to be fabbed from scratch. It shouldn't be difficult, but needs to be done. With a rebuildable Bilstein cartridge, that unit could be valved by any shop that rebuilds Bilsteins.

I can do the design work on the strut housings.
Thanks. Unfortunately a lot of the pictures on that original thread are gone so I feel like I'm trying to piece together what's been done in the past.

See if I have this right:
For the front, you need to modify the lower mount point, and then run a conical spring that goes on the 2.5" spring mount of the coilover, but uses the stock 3.5" top spring mount, is that the final solution? I see some mention of trying to do it a different way to avoid side-loading on the strut but I'm not sure if came of that.

For the rear, you need a strut housing for the cartridge of choice, and then the threaded spring perches. It seems relatively straightforward if you are able to fab the strut housings.

I would ideally like to find something with external adjustability so that I didn't have to revalve shocks to tune the car's handling, which the bilsteins are not. I ran DRM valved Bilsteins on the Z06 but I trust that the development has been basically sorted for that platform so I don't need to be able to easily mess with it myself. It looks like there is a QA1 shock that seems to work well in the front, and Koni may be the solution for the rear. Draven pointed out some good potential parts towards the end of that other thread
1988 Fiero Track Car (In Progress)
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Re: 1988 Fiero track car

Post by The Dark Side of Will »

Jalisurr wrote: Tue Jun 08, 2021 6:36 pm
The Dark Side of Will wrote: Tue Jun 08, 2021 2:49 pm Brakes are a great place to look for unsprung weight reduction... Going bigger than necessary for the application just adds unsprung weight.
Just remember that C4 was Liiiiiiiiteraly tech from 1980.
Yeah, I have every intention of shelling out for 2 piece rotors to keep the unsprung weight down, but these brakes need to be 100% trustworthy to turn good lap times. I figure if my C6 Z06 has a 14" rotor up front stock (and 13" rear) and I consider it just acceptable but not overkill, then a 13" rotor should be fine on the lighter Fiero going the same speed. I wouldn't be comfortable going smaller than that.
What pads were you running? That sounds like you were still on street pads.
Jalisurr wrote: Tue Jun 08, 2021 1:59 pm Thanks. Unfortunately a lot of the pictures on that original thread are gone so I feel like I'm trying to piece together what's been done in the past.

See if I have this right:
For the front, you need to modify the lower mount point, and then run a conical spring that goes on the 2.5" spring mount of the coilover, but uses the stock 3.5" top spring mount, is that the final solution? I see some mention of trying to do it a different way to avoid side-loading on the strut but I'm not sure if came of that.

For the rear, you need a strut housing for the cartridge of choice, and then the threaded spring perches. It seems relatively straightforward if you are able to fab the strut housings.

I would ideally like to find something with external adjustability so that I didn't have to revalve shocks to tune the car's handling, which the bilsteins are not. I ran DRM valved Bilsteins on the Z06 but I trust that the development has been basically sorted for that platform so I don't need to be able to easily mess with it myself. It looks like there is a QA1 shock that seems to work well in the front, and Koni may be the solution for the rear. Draven pointed out some good potential parts towards the end of that other thread
That's basically it up front... However, spring rate selection among the tapered springs is sparse. You may want to fab a new top mount to use conventional coil overs and straight 2.5" springs, which means probably welding it to your cross member. There is no concern with side-loading on the shocks at the front end.

Adjustable shocks are for dual purpose cars. There's a fraction of critical damping for best performance. That fraction and the weights & rates that determine the exact damping force required do not change from one event to the next. F1 cars don't use adjustable shocks...

Edit: WCF lowers are shipped with urethane bushings. If you want sphericals, you'll still have to cut & weld them.
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Re: 1988 Fiero track car

Post by The Dark Side of Will »

Jalisurr wrote: Tue Jun 08, 2021 6:36 pm
Oh, yeah, sorry, intonation over text. I was impressed that you would be able to fit so much tire, not trying to say it's not necessary.
No big deal... I've just heard people spout the idea that tires can be "too big" for autocross or time attack.

285/30's are a great tire for 18x9.5 wheels. I have those on C5 Corvette wheels for the back of my car.

A Fiero likes having the tires in proportion to the weight distribution. A typical Fiero has a 45/55 weight distirbution. Since 45 is 80% of 55, the front tire should be 80% of the rear. So with a 315 rear, the front wants to be 255... so a 255/40-17 is a great pick, since there are a lot of options in that size.

The few aluminum 4 cylinder Fieros that have been built have less rear weight than typical, which actually means they can run wider FRONT tires... because the front/rear split is narrower, and the rear is the limiting end for tire size.
Jalisurr
Posts: 57
Joined: Mon Jun 07, 2021 1:14 pm
Location: Vancouver, BC

Re: 1988 Fiero track car

Post by Jalisurr »

The Dark Side of Will wrote: Tue Jun 08, 2021 8:03 pm
Jalisurr wrote: Tue Jun 08, 2021 6:36 pm Yeah, I have every intention of shelling out for 2 piece rotors to keep the unsprung weight down, but these brakes need to be 100% trustworthy to turn good lap times. I figure if my C6 Z06 has a 14" rotor up front stock (and 13" rear) and I consider it just acceptable but not overkill, then a 13" rotor should be fine on the lighter Fiero going the same speed. I wouldn't be comfortable going smaller than that.
What pads were you running? That sounds like you were still on street pads.
Street pads would have faded within a lap or two. I did one track day on the EBC Yellows that came with the car, had fade and burned through the entire pad in one track day (~90 minutes of track time). Went to powerstop track day pads, those didn't fade but only lasted 2-3 days. Tried G-Loc R10s, those lasted a bit longer but not enough to make up the price difference to the powerstops

My local track is exceptionally hard on brakes. Running at other tracks I haven't had the same sort of issues, but I'll be building for the local one. If I really wanted to optimize for time trials where you only run 2-3 hot laps at once I could probably get away with smaller, but it needs to handle HPDE where you're running 20 minute sessions as well
The Dark Side of Will wrote: Tue Jun 08, 2021 8:03 pm That's basically it up front... However, spring rate selection among the tapered springs is sparse. You may want to fab a new top mount to use conventional coil overs and straight 2.5" springs, which means probably welding it to your cross member. There is no concern with side-loading on the shocks at the front end.

Adjustable shocks are for dual purpose cars. There's a fraction of critical damping for best performance. That fraction and the weights & rates that determine the exact damping force required do not change from one event to the next. F1 cars don't use adjustable shocks...
In a perfect world where I already know what damping rates and balance front/rear I want, yes. F1 teams get to set up their cars with data from the tracks and then dyno the shocks to be precisely where they want them to be. In the corvette I was fine with the custom valved Bilsteins, Doug Rippie Motorsports had done the development on that specific chassis to get the valving dialed in. In the Fiero...less so.
The Dark Side of Will wrote: Tue Jun 08, 2021 8:03 pm Edit: WCF lowers are shipped with urethane bushings. If you want sphericals, you'll still have to cut & weld them.
Hmm, ok. Their site seems to indicate they can do them with urethane or sphericals now https://westcoastfiero.com/products/fro ... -arms-1988 I haven't been in contact with them yet though.
1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
Jalisurr
Posts: 57
Joined: Mon Jun 07, 2021 1:14 pm
Location: Vancouver, BC

Re: 1988 Fiero track car

Post by Jalisurr »

The Dark Side of Will wrote: Tue Jun 08, 2021 9:14 pm
Jalisurr wrote: Tue Jun 08, 2021 6:36 pm
Oh, yeah, sorry, intonation over text. I was impressed that you would be able to fit so much tire, not trying to say it's not necessary.
No big deal... I've just heard people spout the idea that tires can be "too big" for autocross or time attack.

285/30's are a great tire for 18x9.5 wheels. I have those on C5 Corvette wheels for the back of my car.

A Fiero likes having the tires in proportion to the weight distribution. A typical Fiero has a 45/55 weight distirbution. Since 45 is 80% of 55, the front tire should be 80% of the rear. So with a 315 rear, the front wants to be 255... so a 255/40-17 is a great pick, since there are a lot of options in that size.

The few aluminum 4 cylinder Fieros that have been built have less rear weight than typical, which actually means they can run wider FRONT tires... because the front/rear split is narrower, and the rear is the limiting end for tire size.
Nankang does make the CR1 in a 285/30 and a 255/40...hmmm. I was thinking 245/275 but if they fit, why not go wider? I'm hoping with the K20 (about 400lbs including the transmission), I should be closer to 46-47% rear, but that's pure speculation for now.
1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
ericjon262
Posts: 2824
Joined: Mon May 24, 2010 5:34 pm
Location: Aiken, SC

Re: 1988 Fiero track car

Post by ericjon262 »

if I didn't already say it, welcome to the board! I look forward to watching your progress, The K series swap ought to be interesting, definitely a massive step up from the old duke!
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
eHoward
Banned
Posts: 2157
Joined: Tue Aug 31, 2004 2:45 pm

Re: 1988 Fiero track car

Post by eHoward »

Welcome to the forum. Glad to have you here. And great to see one a Fiero on a track!

I had Civic SI with a K24 as a commuter car for a little bit until it was hit while parked in the airport and came back from the body shop in two colors. I woke up the next morning and traded it in on an RS3. It was a blast though. I really enjoyed that K series engine. Best part about the swap is probably going to be that sweet short geared 6 speed transmission with LSD.

Good luck and keep us posted!
Jalisurr
Posts: 57
Joined: Mon Jun 07, 2021 1:14 pm
Location: Vancouver, BC

Re: 1988 Fiero track car

Post by Jalisurr »

Little bit of progress. I've been quite a while researching and gathering parts. Due to various delays (covid, natural disasters, etc etc) I am currently still waiting on engine mounts to start that part, and various suspension components to start that side of things. However, I've grown restless and started working on what I can do right now.

Anyways, on to the updates.

I've started stripping the interior. Console, carpets, trim pieces. The head unit and speakers are out, and in the hole where the head unit was I've fabbed up a basic switch panel with some toggle switches, a clock, 12V outlet and a couple usb ports. At the moment only one toggle switch is wired, it controls the radiator fan. (I also changed the radiator fan circuit to be switched power instead of switched ground to make the LED in the toggle switch work):
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I pulled out the garbage, sticky aftermarket wheel that was in the car and put in a grant 14" wheel:
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And finally I've pulled out the stock driver's seat and installed a Sparco Evo QRT S with their fixed aluminum side mounts:
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Interior weight savings so far:
Sound system - 12lbs
Carpet - 37lbs (15 each side + 7 for the rear bulkhead)
Seat and mounts - 15lbs (old 34lbs - new 19lbs)
Center Console - 10lbs
Total: 74lbs
1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
Jalisurr
Posts: 57
Joined: Mon Jun 07, 2021 1:14 pm
Location: Vancouver, BC

Re: 1988 Fiero track car

Post by Jalisurr »

Some more progress, mostly gathering parts. I've had a couple long phone calls with Chris over at West Coast Fiero sorting out the suspension and brake parts.

I picked up the engine that will be going in, a K20A2 out of an 03 Acura RSX type S. Came with the 6 speed transmission, shifter, cables, wiring, axles, and ecu (those those last two won't be used in my build).
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I also got my wheels in. Enkei RPF1s, in a 17x9 +35mm front and 18x9.5 +38mm rear. I've always felt that 18s look too big on a Fiero, so I'm repainting them to a two tone (silver rim with black lip) to help make the tire blend in and the wheel look proportionally smaller. Still waiting on the tires to come in, they're on order but not estimated to come in until March.
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1988 Fiero Track Car (In Progress)
2011 Subaru STI Rally Car
eHoward
Banned
Posts: 2157
Joined: Tue Aug 31, 2004 2:45 pm

Re: 1988 Fiero track car

Post by eHoward »

That's really cool! :Bravo:
pmbrunelle
Posts: 610
Joined: Thu May 20, 2010 10:07 pm
Location: Grand-Mère, QC

Re: 1988 Fiero track car

Post by pmbrunelle »

Since you're moving forward with wheel/tire/suspension parts selection, do you have an idea of what your weight distribution will be like, even though your engine isn't installed yet?

There are some other K-powered Fieros out there, so maybe those folks can tell you their weight distribution.

I want to see how the wheel blends in with the tire...
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