NS F355 Project (Page 67/73)
TXOPIE JAN 27, 11:42 AM

quote
Originally posted by Yarmouth Fiero:

Thanks for all the comments guys. I just got back in from a couple hours of snow blowing so I need to let the feeling come back in my fingers. I have a lot of widows on my street needing to be dug out.

Back with more shortly.



My Condolences...don't know how you northern guys do it!
Yarmouth Fiero JAN 27, 12:05 PM
Thanks for the feed back Blooz. I've read not only your thread over and over but a tonne of info online. It can get pretty detailed but there are some good sources out there that the authors have really made an effort to be clear and concise. But the best education has been modeling the suspension geometry and indexing through the range of motion of the various analyses. Its quite eye opening and there were many times I went backward and repeated the motion just so convince myself. It is going to be very interesting to actually drive the car hard one day on a track or open space and get a feel for how it handles.

With regard to Lotus Suspension software 85-308, I am sure it is a powerful tool and would certainly make it easier to make on-the-fly suspension design changes and see the results immediately. Its pricy stuff though. For me, I am just using Rhino for my 3D design and then modeling the linkages as lines and the joints as points in space and then slowly adjusting them through a range of motion. I also have Inventor which can model motion and you define the characteristics of each linkage and joint. Unfortunately, I don't know the software well enough to use it properly. Atleast in Rhino, I put each instance of suspension analysis on different layers so that I can save them and turn them off or on at will so I can scroll through the motion. Its usually pretty clear if you made a mistake somewhere as the geometry suddenly moves in an uncharateristic way.

Overall, I am happy with what I have found in the analysis of my suspension. Just by keeping a few conditions like control arm angle and strut position in a desired range, its allowed the chassis drop and track width increase to add their respective improvements. Now I just need to built is properly so it doesn't fall apart or send me flying ass backwards across the highway one day. Thanks to Blooz for being patient answering my many off the wall questions day and night.

Edit typos.

[This message has been edited by Yarmouth Fiero (edited 01-27-2015).]

Yarmouth Fiero JAN 27, 12:07 PM
One good thing about the cold winters TXOPIE is that it drives the pesky Nova Scotia spiders and scorpions out of the garage for a few months a year.
Bloozberry JAN 28, 07:31 PM

quote
Originally posted by 85-308:
I am wondering IF and WHEN you would get to (ie) 6 degrees of roll; if it might be less or it might be even more? Do you have a goal in mind for maximum roll amount?



I forgot to mention that as a starting point, the stock '84-'87 Fiero had a documented 3.5 degrees of body roll per lateral g, and it was capable of sustaining a steady state 0.82 g on a 100' diameter skid pad. Theoretically that translates into a steady state 2.9 degrees of body roll.

So if you consider the wider, grippier tires, better camber, and roll center location, Yarmouth Fiero's car should be able to generate better lateral grip than the stock 0.82 g. If everything else were equal, then you might expect to sustain up to a max of 3.5 degrees of body roll in steady state. The thing is, everything else isn't equal. He'll probably end up using stiffer springs, different roll bars, etc. which will lessen the degrees/g.

Sustainable lateral g's are less than what a typical car can generate temporarily though, so designing a suspension that still performs decently up to a max of 6 degrees body roll is a sound decision. (full disclosure: that's what I designed mine around too)
Yarmouth Fiero JAN 28, 08:38 PM
Thanks for that interesting factoid regarding body roll Blooze. I agree that it's certainly a good idea to design around the extreme, knowing that the actual operating conditions are well within that envelope. It just so happens that the 6 degrees of body roll put the tire almost perfectly against the notched out upper frame rail. That would also be the maximum travel of my coil over struts. It would certainly be an interesting exercise to push the car to the limits on a skid pad one day. Be sure to keep some contacts at the base Blooz. We may need 100 ft x 100 ft section of their tarmac one day.

[This message has been edited by Yarmouth Fiero (edited 01-28-2015).]

Yarmouth Fiero JAN 28, 10:28 PM
Keeping with the theme of rear suspension designs, I've been thinking about ways to install a rear sway bar should I decide to at some point. My goal is to not decrease ground clearance any further and also not interfere with the engine/ gearbox arrangement. Here is a possible solution where the sway bar passes through the rails of the engine cradle with the sway bar bushings fastened to the fwd side of the rear transverse cross member of the cradle. Just a thought........
85-308 JAN 28, 10:33 PM
just make the sleeves where they pass thru the frame the bushings as well?
Yarmouth Fiero JAN 28, 10:45 PM
I like that idea.

Thanks 85-308.

Edit to add..... something like this?

[This message has been edited by Yarmouth Fiero (edited 01-28-2015).]

85-308 JAN 29, 06:42 AM
You would need to come up with some sort of retaining caps both ends but it might look a bit cleaner plus 'sorta' keep dirt etc from accumulating in that sleeve anyway. The sway bar bushing is split of course so should be 'doable' - just slide it over the bar and press into the sleeve. And it gives you the widest spread on your bar support points so the arms do all the work (the centre portion will twist regardless). Only thing is being able to grease it.... hmmmm.

With my poly bushings I grooved them and drilled them so grease had a chance to get to the inner parts where the friction surfaces were; I guess you could do that from the inboard side then install a zerk fitting.
Yarmouth Fiero JAN 29, 02:59 PM
85-308........