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Re: Rack And Pinion exploration

Posted: 12 Feb 2018 13:45
by icehouse
duke wrote:
icehouse wrote: Duke I thought of a way to get 13" wheels on your car. You can adjust your bump steer using the spherical bearing under your strut (where the old ball joint was) instead of spacing the out tie rod. The only worry is that it may need to be spaced the way you can't go. I tried to go back and look at photos to see but the one I need doesn't show up.
Interesting thought. It would be a compromise though in that it would lower the front roll center. I've got a few events left in the 15" race tires that I have, but when they are nearing the end of their life, I might have to take another look at what I would have to do to get the 13's to fit. They are really light!
You wouldn't have to change the roll center. You can use bump steer spacers to make up the difference. The bump is dictated by the relation ship of the "ball joint" and outer tie rod pivot points. Once you get that relationship established you can then move them together with a bump steer spacer and get your roll center back. We made a 1.75" bump steer spacer on Sam's car for fun. He didn't have any and if we were going to make them why not make the biggest ones we could. Although running 13's means not much of a bump steer spacer. Rob loaned me some 13" wheels. So excited to get them on my car :)

Re: Rack And Pinion exploration

Posted: 12 Feb 2018 17:34
by datsuntech
icehouse wrote:Any TC rod and lower control arm can be made to work. Some aren't a gimmy though. Sam used stock TC rods, he cut two inches out, then sleeved them and welded them back together. He wanted mega caster haha. The only sway bar I know that works is the old DGR fab bar, the datsport might but I'm not sure about that one. The orange line bar goes to far back.
That's good news as one of my cars has a DGR sway bar, but bad news for my other ones.
Is the issue just the pickup point on the sway bar and where it attaches to the control arm? Or is does it hit the crossmember in the middle?

Brock

Re: Rack And Pinion exploration

Posted: 12 Feb 2018 20:58
by icehouse
datsuntech wrote:
icehouse wrote:Any TC rod and lower control arm can be made to work. Some aren't a gimmy though. Sam used stock TC rods, he cut two inches out, then sleeved them and welded them back together. He wanted mega caster haha. The only sway bar I know that works is the old DGR fab bar, the datsport might but I'm not sure about that one. The orange line bar goes to far back.
That's good news as one of my cars has a DGR sway bar, but bad news for my other ones.
Is the issue just the pickup point on the sway bar and where it attaches to the control arm? Or is does it hit the crossmember in the middle?

Brock
Any bar in the stock location including the DGR bar doesn't let the car get all that low. Since I especially love super super low, any bar we make needs to go low! The BRE style is okay but it's just to much crap hanging down for us. So we decided we are going to do one that requires welding and mounts under the core support. A NASCAR style bar splined bar is what we want to use. So keep on the lookouts for it.

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 06:32
by Byron510
Jeff, I like the splined sway bars due to their adjustable center tubes being torsionally different rates.

When I was building stancions for my Tilton bar, I thought that a tubular bar could actually run through the box section under the radiator with plates welded to each side of the inner fender with a spherical bush to support the bar, opposed to welding in brackets under the box section. This keeps the bar tucked up out of the way and gives fairly good access for your splined end to fix towards the LCA with the longest link possible. Tire clearance is the item to watch on this design, as the bar is moved off the ground it gets closer to the tire’s operating range when approaching full lock.

Just a thought.

Byron

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 07:13
by duke
I have also thought about a tubular bar recently. The only drawback that I see is that because of where it would have to be located (under or just behind the core support, depending on what you decide) the arms end up being pretty long. Because of the long arms you end up having to run a pretty stout bar. I think I calculated that you would need a 1.25" solid bar to achieve equal roll rates to a 1.125 solid bar in the stock location. The bar ends up being a good deal heavier, and in a place that you don't really want weight. Because of this, I have stuck with a bar in pretty much the stock location. I am interested to see what you guys come up with though.

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 09:05
by icehouse
Byron, I've had the same thought, full lock it could hit the sway bar arm depending on the ride hieght of the car. My car currently hits the orange line bar at full lock. So nothing would change on my car. That said I only use full lock for parking and the sometimes overdone drifting while autoxing in the rain.

Duke, I agree the bastard will be heavy if solid. We did a quick calculation just to see ish sizing to see if it they made the size we needed and it looks like a 1.5" hollow bar would be about right. We did a makeshift how does it look protoytpe with a plastic pipe under the core support. I actually like how it looks haha beast. I will check the weight in Solidworks when I get the model done.

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 09:31
by 510rob
oh look, that's been done before...

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Re: Rack And Pinion exploration

Posted: 13 Feb 2018 10:21
by bertvorgon
That looks familiar.......

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 11:34
by icehouse
Definitely nothing new under then sun! We are wanting to go over the TC rod though. My buddy used a 620 torsion bar. Called it farm fab.

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 13:21
by 510rob
over the T/C bar? that's interesting. The problem with the setup shown in cobwebs is that the sway bar end-links attach to the lower control arm from below, and end up hanging quite low. 13" rims are an issue if you get a flat tire.

Re: Rack And Pinion exploration

Posted: 13 Feb 2018 14:35
by icehouse
510rob wrote:over the T/C bar? that's interesting. The problem with the setup shown in cobwebs is that the sway bar end-links attach to the lower control arm from below, and end up hanging quite low. 13" rims are an issue if you get a flat tire.

The best thing about being able to model it is the "I wonder if this way even has a chance of working..." Can be checked very easily with just a small time investment. Although, somethings are so easy on the computer turn out to be much harder to reproduce in real life. Well, within a budget anyways.

Re: Rack And Pinion exploration

Posted: 14 Feb 2018 23:48
by icehouse
More updates. We just made a new version. You can check out the details on the sight. JBcoachwerks.com for those of you who are new. For fun here are some photo's of the sheet metal parts coming in and being put together.


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