The fiance had a test fit in the car with the seat where it fits for me, and somehow the steering wheel position works decent for her too.
Big thing that will need adjusting is the pedal positions (by like 6-8 inches) fore/aft. Apparently I'm all legs. I'm not sure moving the seat is going to do it without ruining the steering wheel position in the process, so I'm thinking adjustable floor mounted pedal box.
Does anyone here have experience with doing adjustable pedal positions?
Series 1 Europa had them ...... maybe you could look at them?
In reply to TurboFource :
Down the rabbit hole I go.
Nukem said:In reply to Shavarsh :
Good suggestion to flip the coilover. Much better access to adjust. Ride height and damping adjustments should be easy.
I'm looking at your rocker arms and I''m struggling to understand how they're going to move-maybe I missed something said earlier. Are you sure that you have them positioned correctly? Perhaps the pivot-arm should, in actuality, be connected to your damper (rising rate design?) with the tie rod opening moved to the pivot point. Please school me if I'm missing something.
In reply to 2GRX7 :
I'll have to dig out the math, but this matches what I worked out in CAD (and doing the motion in CAD matched my math). In full droop as pictured, the angles put the rate at like 0.8-0.9 iirc. Should be right around 1.0 at ride height and a little above 1.0 at full bump.
In reply to Nukem :
Ah- maybe that's what's messing with my head! At full droop, I wasn't expecting the spring had any compression on it-and maybe it doesn't and it's all down to camera angles!
You come up with anything on the adjustable pedals?
In reply to TurboFource :
Most of the options I was gravitating towards cost money and only solve part of the porblem (like this OBP pedal box https://www.pegasusautoracing.com/productdetails.asp?RecID=32122, but Wilwood / Tilton have similar). I'd still have to figure out the adjustable mounting, part.
What if you made another set of pedals that were closer to the seat and attached to the originals with linkage and ball lock pins so it would be easy to swap in and out? The set for you would stay permanently mounted.
In reply to TurboFource :
This is a really interesting idea that I shall noodle over.
Maybe I should start with re-assembing the OG pedals.
In reply to TurboFource :
Great idea
How do oem adjustable pedals work? I have them on my 05 f350.
In reply to jfryjfry :
Sounds like something to investigate next time I'm at the junkyard. I don't think I've ever been in a vehicle with adjustable pedals.
A quick patent search yields the answer:
https://patents.google.com/patent/US3151499A/en
This is some quality work. How have I not seen this thread?
Exctied to follow along.
In reply to nocones :
Every time one of you hardcore GRMmers hops in here I feel like the Pope has visited or something.
How are your pivots for the bellcranks going to work? It looks like you have the plates that make the sides and then a pair of identical sleeves that the pivot bolt clamps. If I'm interpreting the pictures correctly it looks like at least at this time the pivot will be the metal side plates on the sleeve? In my experience you will want more surface area on your bushing. The loading on bellcranks is usually on the order of 2x the pushrod and you can develop very high contact forces that can lead to galling and pretty quick wear when the contact surface is small.
Both of my cars the bellcranks are Metal to Metal of some kind. On the MG I have some simple plain bronze flange bearings and am using a shoulder screw to acomplish the bearing surface. On the LMP360 I am using a one piece 4130 chromoly sleeve that takes the clamping load and is the pivot bearing surface. The belcrank iteself is a piece of 1" x .120 wall DOM with some SAE flat washers welded to the ends. That whole thing is just well lubricated. I've had both cars appart and seen minimal wear on the belcrank sleeves.
It's also possible you are well aware of this and had planned to add bushings, or I am misunderstanding your design and you may already have them. If not I imagine you could easily machine a piece of tube that goes between your side plates and gets welded to them that would provide that surface area on your existing spacers.
I overall really like your "Truss" arrangement for the bellcranks. Do you have a image of the design at expected ride height? I see you have some motion ratio rate change calculations so I am assuming your pretty dialed in on the bellcrank geometry since you've considered that. For my car I am much closer to the 1/2:1/2 bump/droop then the often cited 1/3:2/3 that many use. All 4 of the chassis I've designed that use bellcranks all targeted basically as close to linear rate (actuation rod and shock at 90* at ride height) as possible so I can't speak to how much a specifically rising or falling rate may impact that.
I had a decent bit of back-and-forth on this topic and I think landed on a good solution (though I admit, no math was done).
Here is the cross section (just have to pretend the solid bellcrank is two bits of 0.250 plate steel):
A total of 4 oil-embedded bushings (https://www.mcmaster.com/2938T45/) for each pivot (one pressed in each "truss" side, and one pressed in each bell-crank plate). The inboard end of the coilover mounts have the same bushing, but only in the "truss" sides. I think the biggest problem area is where the bushings press in (the bushings are only transferring load through the thinkess of the plate), but I can add beef with sole welded on sleeves later on if needed.
I planned in 60% of the travel for compression (so not quite the 1/3 : 2/3 ratio).
I think I owe more complete write-up on all the suspension math, but I'll probably re-write it in Python before I do that (right now its in a similar but relatively obscure scripting language that probably doesn't help much anyone).
I don't really like the idea of bushings being used in compression. There generally aren't sufficiently strong/stiff enough to have that bolt get torqued to an appropriate amount.
This is crude because I don't have access to actual CAD but I drew this up to show what I've done on the two cars I made.
On the Left is the pivot on the MG. That vehicle has had ~25 track weekends and a couple hundred autox runs as well as about 1000 street miles on it. The shoulder bolt has about 10 thousands of clearance for the bronze bushings to rotate freely. The bushings rotate against the should bolt and the chassis plates and remain fixed with bearing retainer to the bellcrank.
On the right is the "I don't want to pay $1.50/bellcrank for bushings" all metal design on the Subaru. That car has ran 1 track day and about 50 autox runs. But wear to date is fine. Here the bolt clamps a sleeve which the belcrank slides against. Again there is some clearance between the chassis and the bellcrank to allow easy rotation. The SAE washers are welded on to increase the bearing surface for normal loads because the bellcranks on the car operate under enough angle that there is some side load on the bellcrank.
For a street car I would use the MG setup.
That said there are countless other ways to do this and again if you have done sufficient analysis of your design that you are confident in it use it. I am just trying to let you know what I have used that has worked but again it isn't the only way to do this.
In reply to nocones :
Thanks for these!
Most GRM thing I think I've read in a while (these little bastards definitely add up):
I don't want to pay $1.50/bellcrank for bushings
I'll do some more thinking about my current planned setup. I see what you are saying about pivot bolt torque / bearing compression stiffness, though I think I can make some tweaks to my current design if that becomes a problem (like adding some spacers to, which is pretty similar to the shoulder bolt setup):
There shouldn't really be any actual load in compression, other than what the bolt is providing to keep the pivot bolt in, right?
Chop chop. There is a good chance I'll pull the whole trunk floor out and replace it, as it's pretty scabby, but for now I just cut a big hole.
Wow
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