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| Blooze Own: An F355 Six Speed N* Build Thread (Page 84/126) |
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doublec4
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NOV 03, 07:54 AM
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DIY camber bolt, very cool!
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Bloozberry
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NOV 09, 10:22 PM
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I finished getting both trailing link mounts fabbed up and managed to get the outer halves tacked in their precise location after much testing and measuring. I want to leave the final welding to the pros, so I'm not tacking the inner halves in place otherwise they'll get in the way of welding the outer halves. Nevertheless, I was able to clamp the inners in place tight enough to rebuild the suspension and check the alignment side to side. Since the trailing link was the last of the five links on each side, adding it secured the location of both hubs in three dimensions. Out of curiosity I ran a long straight-edge through the center of both hubs and double checked that the axes of the wheels lined up and were concentric, and much to my relief, they were perfect. Here's the driver's side built back up with the trailing link in place (less the shock and bell crank system):
Next up was to cycle the suspension up and down through it's range of travel to see if there were any problems with binding or clearance issues, and to do a rough camber check. To do that, I left the back end of the car raised up quite high so I could cycle the suspension in rebound, and then set the wheel on top of a hydraulic floor jack. I pumped the jack up until suspension was at ride height, relative to the frame, which I could determine by matching the angle of the lateral inks to the angle they would be at if the car were on the ground:
Measuring the clearance between the top of the tire and the underside of the upper frame rail gave 2.25". Disregard the lower hanging weld flange at the back of the rail because it doesn't interfere with the tire.
This next shot isn't the greatest but what I was trying to capture is that the wheel at ride height is currently vertical (ie no camber). I will add -1 degree of camber to the suspension when I finalize the alignment.
To measure the camber, I used a long straight edge across the tire side walls and an angle finder. You can't see the angle finder's scale because of the camera flash glare so you'll have to trust me. The angle finder is really easy to use, it has a bubble level on one side that rotates along with the center section of the dial, so all you do is set the finder on a straight edge, rotate the center dial until the bubble is centered, then read the angle on the dial from a stationary pointer.
Next, I pumped up the jack to give max jounce which is where the tire contacts the underside of the upper frame rail:
There were no binding or clearance issues with the suspension arms whatsoever. At 2.25" of jounce, I measured the camber change at about -2.5 degrees which is exactly where it should be according to my earlier camber vs jounce graph (note that the graph shows about -3.5 degrees at 50 mm (2") of jounce, however the static camber is -1 degree on the graph, whereas here I'm starting with zero static camber.) You can easily see the negative camber in the photo though:
Next, I lowered the wheel into 2.25" of rebound, keeping the lower end of the travel the same as the upper limit for comparison's sake. In this photo, there is 5.5" of clearance between the top of the tire and the underside of the upper frame rail:
Once again, the camber change is clear from the rear view, and once again it was what the Lotus software projected: +1.5 degrees
For those interested, I did cycle the suspension without the wheel on the hub through a huge range of travel to see what the physical limits would be. I didn't measure the actual jounce or rebound at each limit so I'll post that info the next time around.
With that cleared up, I can now focus on the bell crank mount design. My perspective changed by being able to sit in the empty engine bay so I've got some better ideas now how I'm going to tackle it. I also noticed that the rust bug had taken it's toll on the inner wall of the upper frame rail where the strut tower used to be. The driver's side is worse (first pic), but I'll need to address both sides as part of the bell crank mount solution.
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motoracer838
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NOV 10, 11:24 AM
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Blooz, have you given any thought to backhalfing the frame, something along the lines of what I did in the back of this project? http://www.fiero.nl/forum/Forum1/HTML/086876.html
you have put so much effort in to this that it just seems a shame to see the remnants of the Fiero chassis when you open the hood.
Joe
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Bloozberry
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NOV 10, 12:43 PM
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Thanks for your input there motoracer. The thought has crossed my mind, but it would be a substantial amount of work at this stage. You have to keep in mind that when I started out, my goal was to create a conversion that would be much simpler for the average joe with a few fabrication skills and tools to replicate. It's morphed away from that basic idea but it's too late for me to change course now. Too much time and effort have gone into accurately locating the suspension mounts for me to want to start that process over again. The time to have done what you suggest would have been when the frame was cut in half and before it was welded back together again with the 3" stretch. Even then, I would still need major structures at most of the same locations as the stock Fiero rear frame.
As for appearances, I'm pretty confident that once I've finished trimming up the remnants of the strut towers and the side walls, that it will be unrecognizable as a Fiero engine bay. The N* engine framed at either end by longitudinal coilovers will draw all but the most discerning people's attention away from whatever sheet metal is left. 
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motoracer838
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NOV 11, 08:59 PM
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hears an idea, since the vast majority of your work connects to the lower frame rail, leave it and do the upper, Helm used to have a fabricated piece that did the same thing.
Joe
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Bloozberry
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NOV 13, 11:12 AM
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Thanks for the ideas Joe, it would make good sense if I weren't so enthusiastic about moving onto other parts of the car at this stage. Once I gained access to the insides of the upper frame rail, I could see that the rustiness was limited to the area right around the strut tower, and except for the inside wall which I cut away, the rest was only surface rust. Replacing the entire upper frame rail just doesn't seem like it would pay off. Here's how it looked after localized sandblasting and priming:
I'll replace the inner wall of the rail as an integral part of the shock bell crank mounting system.
As for what the suspension links look like (without the tires obscuring the view) here are a couple pics showing them at various states of compression. First up is at ride height:
Next is at 3" of rebound. To note, there were no issues of clearance or binding at this point, although the trailing link bushing started to twist in it's mounts (as it's supposed to do) when I got to around 3.5" of rebound.
Lastly, this is what the links look like at 3.25" of jounce. I purposely moved them beyond the design limit of 3" to see at what point the system would bind or interfere with itself:
At 3.25" the mounts were still very free to move (no binding), except that the forward lower lateral link comes into contact with the trailing link. This is the view from the front looking back:
Way before this happens though, the tire touches the underside of the upper frame rail at 2.25" of travel so I shouldn't need to worry about this problem.
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Yarmouth Fiero
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NOV 13, 11:25 AM
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It all looks great Blooz. Very clean and well thoughtout. As I don't have alot of suspension experience, is it necessary to put in some sort of travel limitation to prevent the tire from contacting the chassis/ body? I've driven your road and 2.25" of travel is not that unrealistic. 
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Bloozberry
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NOV 13, 12:07 PM
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What... you don't like the way the municipality maintains my road? We pay extra to have a team of six guys to come twice a year to fill the pot holes. One to drive the dump truck, one to shovel the asphalt, another to flatten it with his pickup truck tires, and three supervisors. 
I'll definitely put in some kind of bump stop. There are a few spots where I could place one including on the chrome-moly shaft of the shock, or on the bell crank mechanism. Perhaps there are other/better locations as well but those two come to mind right away.
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RCR
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NOV 14, 06:56 AM
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ccfiero350
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NOV 14, 08:56 AM
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Keeping the hi-tech flavor of your suspension have you seen these jounce shocks?
http://www.spcalignment.com/off-road------------------
yellow 88 GT, not stock
white 88 notchie, 4 banger
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