Blooze Own: An F355 Six Speed N* Build Thread (Page 59/126)
ccfiero350 DEC 03, 08:49 AM
With all the fabrication in mind what about lifting the constraint of the stock 88 knuckle and make your own and put the pickup points were they work best for you? Since your going multi-link I'm thinking a simple plate/pan style and hub bearing of your choice would allow you to optimize what you have going on so far.

Great work! The attention to detail is just amazing!

------------------
yellow 88 GT, not stock
white 88 notchie, 4 banger

FieroWannaBe DEC 03, 09:32 AM

quote
Originally posted by fieroguru:


The C5 uprights are the same front to rear (they swap sides as they swap ends), but the a-arms are physically different front/rear.





My mistake, I thought there was a GM car that did have the same parts front and rear.

Great work so far Bloozberry, keep it up.
Bloozberry DEC 03, 12:25 PM

quote
Originally posted by ccfiero350:
With all the fabrication in mind what about lifting the constraint of the stock 88 knuckle and make your own and put the pickup points were they work best for you?



That's a valid consideration. I started this exercise with a secondary goal in the back of my mind though: to come up with a system that would be affordable for the stock '88 owner who's looking to lower the rear of his car and improve the kinematics rather than worsen them. Every change I make takes me further from that goal of affordability and new knuckles would add significantly to the cost and complexity of the fabrication.

New knuckles don't appear to be necessary at this stage anyways... the system is nearly worked out, with new mounts and development of the upper control arm geometry well under way. Theoretically, the system appears likely to out perform the lowered stock geometry and also likely better than stock at ride height too (not to mention the wow-factor of an SLA with pushrod shocks). This will be backed-up with Zac's Lotus software analysis, not just a claim made in the wind. At this stage it's still possible that someone might be interested following in my footsteps because so far it's not any more involved or complicated than many builds out there: a bell crank, a knuckle adapter, a couple push rods, a new coil over shock, and some mounts. The elimination of the strut towers is also a bonus for those looking for more room in the engine bay or for kit builders trying to get away from the immediately recognizable Fiero strut tower look. If it works out, the plans and parts lists will be free.

[This message has been edited by Bloozberry (edited 12-03-2012).]

RCR DEC 03, 12:41 PM

quote
Originally posted by ccfiero350:

With all the fabrication in mind what about lifting the constraint of the stock 88 knuckle and make your own and put the pickup points were they work best for you? Since your going multi-link I'm thinking a simple plate/pan style and hub bearing of your choice would allow you to optimize what you have going on so far.

Great work! The attention to detail is just amazing!




Don, 355Fiero, built up rear uprights for his 355 build. At one point he sent me the plans, but that was a few years back. not sure what I did with them. I don't think it was specifically for an 88, but I'm sure it could be adapted.

Bob
355Fiero DEC 03, 02:13 PM
Hey Bob;

My control arm setup was for a pre 88 as it has the ball joint setup etc. with a 4" extension. I didn't go through the detailed investigation Blooz has been going through. I also sent him any pics and info I had of that work when he was first starting up this investigation.

Now that my 308 is on its way to paint, I am pulling the 355 back into the workshop to finish off and I may well go for a Longitudinal engine/trans and use the suspension setup he is coming up with here.... This setup looks great and would be pretty easy to redo my rear engine bay area to use this. I have a spare 88 rear cradle as well...

Keep up the work Blooz, we are all following closely. I have learned a lot from this thread.

Cheers
Don
RCR DEC 03, 04:03 PM

quote
Originally posted by 355Fiero:

Hey Bob;

My control arm setup was for a pre 88 as it has the ball joint setup etc. with a 4" extension. I didn't go through the detailed investigation Blooz has been going through. I also sent him any pics and info I had of that work when he was first starting up this investigation.

Now that my 308 is on its way to paint, I am pulling the 355 back into the workshop to finish off and I may well go for a Longitudinal engine/trans and use the suspension setup he is coming up with here.... This setup looks great and would be pretty easy to redo my rear engine bay area to use this. I have a spare 88 rear cradle as well...

Keep up the work Blooz, we are all following closely. I have learned a lot from this thread.

Cheers
Don



I thought you were following this thread. Looking forward to seeing your results...

Bob
RWDPLZ DEC 03, 09:19 PM
I love this thread and all the engineering pron
rourke_87_T-Top DEC 04, 02:40 PM
PM sent
Bloozberry DEC 07, 04:01 PM
Here are the same drawings as above except with the suspension compressed and extended 76 mm in each direction, superimposed on each other. The blue lines are obviously in jounce (compression) and the red lines are in rebound (extension). I've also shaded in green the areas I was able to determine there would be interference. I know these aren't the easiest drawings to decipher so I'll summarize what I've determined using the higher resolution drawings on my desktop.

Side View:



The side view gives the clearest view of what's happening. As I had already mentioned several pages back, the upper side rail will need to be clearanced to make room for the larger tires and lowered suspension (note the larger green area). I suspect I will simply bump the rail upwards by trimming and boxing the bottom and adding the lost cross section to the top of the rail with new steel.

The smaller green area to the left is where I noticed there will be interference between the bell crank and the spring hat in rebound. I'm not too worried about that since this is only a conceptual spring and shock, not an actual one. It's something to watch for nonetheless. Once the adjustable spring seat is located where it needs to be, several companies offer hats with a greater angle if the interference still exists, or I can simply change the profile of the bell crank in that area.

Rear View:



The rear view shows the extent of the interference with the stock upper frame rail in full jounce. It also shows how little the pushrods change angles making the selection of the rod ends easier since high angle spherical joints are more expensive and more limited in strength.

Top View



The top view has to be the worst to see what's going on with the bell crank and shock, but it is interesting to note how much the rear wheel moves longitudinally and laterally in the wheel well, shortening and lengthening the wheelbase and the track. That's due to the trailing link and lateral links pulling and pushing on the knuckle respectively as they swing through their arcs of movement. This happens on the stock suspension as well.

The next thing to do before designing the mounts for the shocks and bell cranks is to locate the upper control arm in the side and top views. That way I'll be able to take into consideration all of the mounting requirements at the same time and hopefully avoid any problems.

[This message has been edited by Bloozberry (edited 12-07-2012).]

Yarmouth Fiero DEC 07, 06:43 PM
Great drawings Blooz. They contain a tonne of info and I commend your ability to show this in all three views. I don't have much experience with automotive suspension systems so I am going to ask a basic question. Is it possible to design the suspension with a variable rate so that as the geometry approaches the point of interference, the rate increase prevents contact of the components and frame? It seems like 152 mm of total travel is alot as I envision the suspension on a car like this to be much " tighter".