Suspension modeling - anyone doing for Solo II?

[rlhammon]

Ok.. so I know Alex's background while at Kettering was in suspension systems or something like that... and I'm fairly sure he's commented on here a few times about modeling the suspension as well.

Anyone else doing actual measurements and modeling?

I'm after basic information, which yes... I could measure on my own. Mainly the suspension points of interest for a proper dynamic model. I unfortunately don't have a suspension modeling package like WinGeo3 or similar. I do, however, have a friend who's job is dynamic analysis in CAD and he is willing to put together a model for me. The hard part at this point is getting the actual points and mass measurements.

Has anyone here gone this far with the Kappa yet, or has most of the work been "feel" at this point?

Also.. anyone have pointers as to where to find a shop that can do corner weight measurements? I've got a local circle track and assuming there are some setup shops somewhere, but this is new ground for me. Somehow my bathroom scale doesn't seem anywhere near adequate (LOL) for this task!

[snaponbob]

Originally Posted by rlhammon Ok.. so I know Alex's background while at Kettering was in suspension systems or something like that... and I'm fairly sure he's commented on here a few times about modeling the suspension as well. Anyone else doing actual measurements and modeling? I'm after basic information, which yes... I could measure on my own. Mainly the suspension points of interest for a proper dynamic model. I unfortunately don't have a suspension modeling package like WinGeo3 or similar. I do, however, have a friend who's job is dynamic analysis in CAD and he is willing to put together a model for me. The hard part at this point is getting the actual points and mass measurements. Has anyone here gone this far with the Kappa yet, or has most of the work been "feel" at this point? Also.. anyone have pointers as to where to find a shop that can do corner weight measurements? I've got a local circle track and assuming there are some setup shops somewhere, but this is new ground for me. Somehow my bathroom scale doesn't seem anywhere near adequate (LOL) for this task!

I have an Excel spreadsheet that does some of the math involved in selecting springs and shocks. On an SCCA Stock, ST, or SP classed cars one can only change shocks, front bar, and alignment (Stock, exclusive of Z0K conversions on Sols), and springs, perches, both bars, "strut" braces, ride height, and bushings in ST and SP classes. The SM classes have a few more allowances, but not much. Modeling, per se, won't do much beyond alignment, rate selections of bars and springs as well as shock profiles except for suggesting ride height based on CG calculations. The spread sheet generates some recommendations for rear spring rates based on front rates and motion ratios. All that said, once one gets in the ball park, it is going shake down to how the car feels to a particular person.

That said, it would be interesting to see what a software program would come up with. I have used the above mentioned spreadsheet (that, BTW, some real go-fasters use with success) only to discover I got pretty close based on seat of the pants. But I will be making some changes over the winter!!!

[sodamninsane]

in short. yes. I have wingeo3, which isn't that good for real time dynamic stuff, you can't funnel shock travel data in to it or anything.

When I get that computer up and running (moved in to a new house) I'll send you the points.

[rlhammon]

@snaponbob:

Is the Excel file something you can share? I've been working on putting my own together since I haven't found something online. Obviously Grant's website has the ability to do some calculations, and I'm guessing here... that you might be using the Excel file he had developed the website on (at least his calculations page).

@sodamninsane:

Thanks... that would be incredibly helpful!

@snaponbob:

You're right about what modeling can do. And that's what I'm interested in. Basically I'm more concerned about figuring out spring rates right now. Looking at what can change (for BSP):

1) Shocks - yep... working on that right now
2) Springs - the main reason I'm looking for suspension points to model
3) Alignment - I like what I have now, but modeling might help define it better
4) Strut braces - no plans on those
5) Ride height - yes... looking at coilovers actually
6) Bushings - not convinced I need to change just yet

If I can get a good model going... well, there's some options here.

As for your Excel file... that's doing essentially the same thing as the model. I mean.. it's all science, it's all equations... doesn't really matter the software method used (WinGeo3 / Excel / hand calculations) to figure things out. I'm not open to buying WinGeo3 as I'd rather that money go to the car if I can get the information I'm looking for... but at the same time I'm not going to turn down any assistance if someone with WinGeo3 wants to lend a hand of some sort.

[snaponbob]

rlhammon

You have an e-mail

[88Fiero_09GXP]

I'm very interested in this as well. I just picked up my GXP in July and have done a few events this year and am looking to make some major upgrades before next season. I've been reading through the posts here but if anyone else has some info to share it would be greatly appreciated.

[sodamninsane]

I'm running the stock alignment and from the scrub patterns on my falkens (azenis), I don't need any more camber, so I'm not running it. I daily drive on these tires and am getting them right to the edge with the stock alignment. I could probably BENEFIT from a little more, but I don't need it, so I'll keep the wear nice and even for now.

[snaponbob]

Originally Posted by sodamninsane I'm running the stock alignment and from the scrub patterns on my falkens (azenis), I don't need any more camber, so I'm not running it. I daily drive on these tires and am getting them right to the edge with the stock alignment. I could probably BENEFIT from a little more, but I don't need it, so I'll keep the wear nice and even for now.

Are you racing it, or just a daily driver? FWIW, with 2.7 neg front and 1.8 neg rear I am at 23K miles with plenty of tread left on the OEM F1's. I just "flipped" them to even the wear a bit. I can take digital pics and post them late next week if you like. I don't race on them, but I am not real kind to them either. Hoosiers are the race rubber. It just seem that camber is not an enemy of the tires, just bad toe adjustments. If you tried GM's published "race" alignment on the car you might love it.