Building our Lemons/Chumpcar (Page 24/29)
DonP OCT 29, 12:51 AM

quote
Originally posted by kwagner:

Wow, there's tons of great info here since I last read
Glad to see you guys still representing the fiero out there. Keep it up!



You know, we just don't have a life. There's always something to change on a "race" car. Thanks!
DonP OCT 31, 12:57 AM
With the ride height set and the upper and lower A frames mounted and all points measured and defined, and the outer tie rod measured we had our roll center, static camber, camber gain, caster, caster change during roll, and anti dive set. Now it was time to mount the Camaro rack and locate the inner tie rod to deal with the whole bump steer issue.
To find the amount of bump steer on a car that has a fixed outer tie rod, you draw a line from the outer tie rod pivot point to the instant center. You then draw a second line from the upper A frame inner pivot points to the lower A frame inner pivot points. Where these two lines cross is the inner tie rod pivot point.



All that is easy to say, and easy to plot out on paper. Finding that magical point on the jig is a much tougher assignment. Oh, I almost forgot, moving that inner tie rod pivot point forwards or backwards also affects the Ackerman steering geometry. http://en.wikipedia.org/wik...nn_steering_geometry So you really are working an all three axis.

To help us achieve our goals, we had ordered a kit from West Coast Fiero that had mounts for the Camaro rack and threaded gender changer/spacers for adapting the Fiero tie rods to the Camaro rack. We had already located a couple 2000 Camaro racks as specified on the WCF website.





The threaded adapter, used in conjunction with a large washer designed to act as a stop, is the heart of the conversion allowing the Camaro rack to mate with the "88 Fiero tie rod ends.







When we received the WCF kit we noticed that the mount for the Camaro rack was not adjustable so we went to work and designed our own mounts that would sandwich the "eyelet" type mounts on the Camaro rack.











We would make adjustments with the simple expediency of adding and subtracting washers under the top plate held in place by the clamp.




Our next step was to install the threaded gender changer/spacers and measure the bump steer in 3” of bump and droop.





When plotted on a graph, these measurements tell if the inner pivot point is too high or low, and if the outer tie rod is too long or short. After making several adjustments to the rack height and tie rod length we were getting close, but the threaded adapter, used in conjunction with a large washer designed to act as a stop, was too short. There was just no way that the supplied spacer/gender changer was long enough to work. At best, we would only grab a couple threads in the rack and inner tie rod end.

So Rich talked with Chris at WCF for some time trying to describe what we were seeing. Communication over the phone was difficult, as you might imagine with some confusion over what components were being used on what year Fiero. But ultimately, once Chris decide that Rich might have some experience and know what he's talking about, the two came to an understanding of the problem. But I did send a series of photos documenting the measurements and components used.
















So once they came to an understanding, Chris agreed to cut another set of spacer to the length Rich specified.




We did use the new, longer spacers to get our correct tie rod length. This required extra nuts and washers as spacers to achieve our correct tie rod length.



This actually worked out well as we were able to have some adjustability during the setup.

Once we had everything mounted and set at a correct length, we could take an actual measurement of the final piece. But we decided that we would all feel a bit more secure with a design change. We contacted some friends back in Oregon with a proper machine shop and asked them to make our spacers to spec. Rather than just using what was essentially threaded stock, we asked Rod Riel to start with some hex stock. That was to allow us to properly tighten the adapter in the rack. He cut the different threads on each end and we then attached the spacers using the large washers as travel stops. We still have no idea what we owe Rod for doing the machine work, but I am sure we will have to sell our souls to pay the bill.






You can see here that we also added a roll pin by drilling through the steering ram and adapter. We felt this was much more secure than just using lock-tite.



This whole bump steer project took several weeks and was a pain in the .. uh, it was a pain as we had to make a number of changes and measure and plot the bump steer a whole lot of times. Was it worth it? You bet. If you ever drive a racecar with corrected bump steer, you will never go back!

After endless hours on the jig we came extremely close to our front end goals.
+ 3 1/5 degrees negative static camber
+ 7/8 degree of camber loss in 10 degrees of chassis roll
+ No change in caster in 3” of bump and rebound
+ 10 percent anti dive
+ .032 bump steer in 3” of bump and rebound
+ 125 lb to 600 lb spring selection in 25 to 50 lb increments
kennn OCT 31, 10:42 PM
Excellent work, Don. Thanks for taking the time to explain and illustrate your reasoning and progress.

Ken

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'88 Formula V6
'88 GT TPI V8

DonP NOV 10, 01:43 AM
Okay, we had accomplished most of our goals for the front suspension. Or at least we gad reached a point where we were willing to settle. Our next task was to actually mount the new coilovers that we had built.






The bottom mount was built to bolt to two tabs mounted on the lower control arm



That was fairly straight forward. Rich also started working on the top plates by adding a couple ears to mount to... well, something yet to be determined.





One area we had concerns with was the end on the cradle that we had cut. Robert dug out the circle adapter for the plasma cutter and made some plates to fill in the top of the cradle where the spring had originally passed through. Don't know that it was totally necessary, but we felt better with the additional brace.





The other thing that we knew was that we wanted the shock assembly to tilt in at the top by 10 degrees. I do not know why ten degrees, but that seems a fairly common setting for most suspension designs we were able to find. You may notice in the two pictures above that the end of the cradle had been shortened after we plated the hole. It got shorter several times in the process.

Rich carefully measured the amount of travel available in the shock and made up a piece of all-thread to replace the actual shock and spring for assembling the upper mounting points. It was important that we essentially split the travel available for compression and rebound. With theplates bolted together with the all-thread, we had to decide on how we wanted to construct the upper mount. What we found was a piece of 2x5 square tubing that would fit the bill. Rich cut out a portion of the side wall and created kind of an "L" shaped mount turned upside down. He then boxed in the side where we had removed the material in order to restore the structural integrity of the mount.





Perfect! once we decided to close the top of the tube, we would be set to go. We had the ten degrees we wanted. All was good. Until we measured and determined that the whole thing would likely stick through the top of the fender. St the very least we would have to cut the inner fender flares to allow the mount/tower pass through into the front compartment. It was too tall. Call us picky, but that didn't seem like the right way to go.

Because the operating length on the whole coil over was determined by the length of the shock, and because we had no ability to change that, we needed another solution. One that would fit the "fixed" constraints.
I cannot now locate the thread here on the forum where a couple participants (fieroguru?) talked about constructing tubular front arms. But one person talked about mounting the lower coilover pick up points below the arm. So we started along this path. The initial perches had to be removed.



New mounting tabs were welded on below the arms.



We also added a tab to the lower control arm, allowing us to use a piece of all-thread to adjust the lower arm to ride height when the car or cradle was suspended.









And, with the new lower mounting points, we reduced the size of the upper mounting "tower."



Rich was out of town one weekend and I was done with sweeping the floors. So I did a trial fit too see if all this stuff would fit.







This thing might actually work!
DonP NOV 17, 12:46 AM
One of the things that really caught us out was incorporating the sway bar back into the front suspension. The lower control arm was constructed with the same basic pick up point and ball joint configuration as the original pieces. The same was true for the upper control arms. The upper control arm mounting points were different, but the layout was still similar. And the steering rack, though different was reasonably close to the original position. So we had hopes that the original front sway bar COULD be a bolt back in affair.

A trial fitting early on in the process helped to sell the "it'll fit right in" concept.







Okay, we see the same things you see. The tie rods were likely not going to allow us to mount the bar in the stock location. And the upper control arm MIGHT interfere with the bar as well. But we squinted real hard and said "sure, no problem!" Of course, it became a problem once we started bolting the finalized pieces in place. But honest, we recognized it way before hand despite being in denial.

We really looked closely at the sway bars offered by Paul Hosler at Hosler High Performance. Here on the forum he sign on as R Runner. His sway bars can be found here. http://www.fiero.nl/forum/Forum4/HTML/036556.html Given that we had been reading magazines such as Stock Car Racing and Circle Track for years, we were familiar with this type of sway bar design. You can see examples here. http://www.schroedersteering.com/COT_BarsPg.html http://www.schroedersteering.com/ArmsPg.html Cool, and we would have loved to use them, but there was no way we could get these through inspection on a $500 race car.

So our solution was to take a few measurements and head out to the local wrecking yards. We checked out all the obvious performance options such as Camaros and even 'Vettes. What we eventually found, after maybe two days of looking, was a big bar out of some generic GM car. A Skylark, or early '80s Malibu. One of those generic early '80s GM sleds. Of course it too was not a direct bolt-in fit. Rich may of had to do some modification to make it work.





Okay, I don't know if this kind of treatment affects the spring rate or properties of the sway bar. But the we didn't know what the effective spring rate of the bar was to start with. All we really knew was that the ends had to be drawn in just a skooch. (sp)



What became apparent was that once the bar was bent to a workable length, we would have the best luck hanging the bar UNDER the lower control arms. Once we had the bar landing in what appeared to be an open spot on the lower arm, we created some tabs for some very short end links. Sorry Mr. Dickman, but your zero lash end links were not going to work








What made it possible to set up and locate the bar while the front cradle was just sitting on the cart above was the fact that we had created some tabs and all thread pieces to "hang" the suspension at ride height. You can see the all thread bolted to the cradle and the tab on the lower control arm in the next picture.




Taking the time to set this up should also help us in setting the suspension in the field.
Okay, with the end links landed at the control arm, we needed to find a usable mounting point on the frame.


Well, we had these horns at the front of the cradle. The only really necessary use for the horns was to bolt the cradle to the car frames rails. The horns are fairly high, so what about..........






]


I believe Rich used some 2x4 square tubing. He capped the open end that was the bottom of the mount. We debated welding some flanged nuts to the bottom plate for the sway bar bushing mount. In the end, we created an opening to access conventional nuts. The thought was that even though welded in nuts would be easier, conventional nuts would work easier if damaged while racing.
Later in the process, we added some tie-down points to the same structure. This gave us some tie-down points when hauling the car in the trailer. Much easier to get to than reaching clear back to the cradle.



A mock-up shows no interference with the tie rod or other suspension components.






At this point we could actually start assembling everything for installation


Including the Rodney Dickman new '88 hubs mentioned earlier.



























You can clearly see that, suspended at ride height, we have some static negative camber to work with.

It was getting closer to install time!
Gall757 NOV 17, 08:40 AM


Looking forward to seeing how that sway bar holds up after the heat treatment.
DonP NOV 17, 11:15 AM

quote
Originally posted by Gall757:



Looking forward to seeing how that sway bar holds up after the heat treatment.




So were we. We had no idea if abusing treating the sway bar this way would have an effect on, well, anything. Did it? Couldn't tell you. We changed so many things and have no way to do a before/after comparison with the bar that I cannot say if anything really happened.

I will get ahead of myself and say that the whole package, including our modifications at the rear which I haven't gotten to yet, worked terrifically on the track.
Gall757 NOV 17, 01:40 PM

quote
Originally posted by DonP:
So were we.



Well, if it did not bend like a wet pretzel, you won that battle. Looking forward to the rest of the story.
Francis T NOV 19, 07:32 PM
If you let it cool slowly you annealed it; made it softer/removing some of twist or springyness in that section. If you quenched it, -cooled it quickly- you probably kept the spring in it but may now have a brittle area. Either way..... Good luck with it.
BTW do you have any plans for addressing one of the Fiero's major shortcomings for these long races; namely it's small fuel tank? With a required minimum of 5 minutes for every fuel stop You will likely lose at least a lap or two with every stop.
FIEROPHREK NOV 19, 08:27 PM

quote
Originally posted by Francis T:

If you let it cool slowly you annealed it; made it softer/removing some of twist or springyness in that section. If you quenched it, -cooled it quickly- you probably kept the spring in it but may now have a brittle area. Either way..... Good luck with it.
BTW do you have any plans for addressing one of the Fiero's major shortcomings for these long races; namely it's small fuel tank? With a required minimum of 5 minutes for every fuel stop You will likely lose at least a lap or two with every stop.



I was actually wondering this as well. What kind of stint times are you guys able to achieve running the series1 3800sc? Im' going to be running a series 2 3800 na and am wondering if i'll be able to hit the 2 hour max stint time. Oh yeah I haven't said it yet but your build is freeking AMAZING!
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ARCHIES JUNK IS FASTER THAN SHAUNNA'S JUNK

12.3 is faster than a 13.2

[This message has been edited by FIEROPHREK (edited 11-20-2014).]