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I had the same feeling about the suspension. it is all numbers and how does each number translate into feel? Ultimately, I used the info from this forum to get reasonable numbers that I was able to execute (learned to weld building this). Overall, I am very happy with my suspension but I have more camber gain in bump than necessary. The biggest thing for me was to make sure there was no bump steer because I didn't want a twitchy car in mid corner.

Keep going, it looks like it is coming along.

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Gavin

My build: http://www.locostusa.com/forums/viewtopic.php?f=35&t=16005

Definitely feels like spring! Usually we would be out on the lake on a day like today, but we're quarantined. So just working on the Locost. I finally finished the trunk area of the chassis. I fabricated the spare tire mount, most locosts I see use a cradle from under the car to hold the tire. I built this pedestal type, but I haven't tacked it on yet. What do you guys think?

The spare is the only tire I have right now, I'm holding off buying the rest. Its a cheep tire, I asked the guys at discount tire to order me a tire that wasn't directional, but sure enough it comes in and it's directional. Since it was their mistake the offered to mount it for free, I'm not to concerned about it since it's just a spare. I plan to use Dunlop Direzza DZ102, Direzza Z3, or the Bridgestone Potenza RE-71R. The size is 205/50 15.

I've done some small stuff like build the battery tray, weld on tabs for the fusebox. Started planing the air-intake. Also planing the Brake system, I plan to use AN-3 lines, but I will need a flare tool. AN flare tools are expensive. I also need a better shop manual for the Miata, hopefully with color wiring diagrams. I'm also thinking about ditching the racing seat and just building my own upholstery.

I seem to have a lot of things going on, and not totally finishing anything. I just kind of go out to the garage and just start fiddling with whatever. I think I will build the roll bar today, since I'm working on the back of the car, and I have the 1.5" 14ga DOM tubing. I'm planing on 42" from the bottom of the chassis, but I'll cut it long and do the broom stick test, too set the height 2" above my helmet.

i may be all wet but my understanding is that tire 'directionality' only counts in the wet, so a directional should be fine. Don't expect that you,ll chose to drive in the rain ....

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

I like the spare mounting you built. Nice location and should be more than strong enough.

Thom

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Thom

An interesting thought. The spare is really just there incase I need to limp the car to the nearest tire store or home. Plus I've got a 50% chance of the tread facing the right way!

I think it will work. The only problem is it will make installing the sheet metal on the rear panel more difficult. I'm thinking of a way to make the thing removable.

This is a question for you Auto-x racers out there. Do I need a diagonal brace across the hoop to pass tech. I would like to leave it open, because that bar would be right behind my head!

Hot mess isn't a purpose built competition vehicle, obviously. I just want to do sports car stuff with it, at some point I will probably try autocross. I plan to drive it on the street, just a weekend cruiser.

I don't know if it's specifically required for autocross, but IMO, you are going to have other issues to worry about if your head is going through the seat and you're concerned about contact with the bar. I'd recommend a diagonal, helps the roll bar from simply folding on itself. If you put the low connection on the passenger side and it connects at the high point on the drivers side, it looks like you'd be well clear of your head swiveling and hitting the bar.

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Trochu Motor League

The latest scca rule book "suggest" having one. It's designed to prevent the main hoop from losanging i.e. moving sideways. I would say double check with your local club.

Yes it may be behind you head, but thats not a bad thing to have if you add a form of head restraint.

Cheers
Fred

Here is an article for the SCCA time trial rules.
https://timetrials.scca.com/pages/safety

Granted, this isn't auto-x but if you ever decide to do a hill climb or some type of track event (HPDE etc.) you might want to build it to the highest level of driving event you hope to participate in. Our local chapter seems to be pretty relaxed on rollbars. I over built mine and I am happy knowing that, if I need it, it will hold.

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Gavin

My build: http://www.locostusa.com/forums/viewtopic.php?f=35&t=16005

Thanks for the replies. Everyone has made some good points. I should put a diagonal in there. I'm a getting little less nervous about my head hitting roll bar, but am now just getting nervous about just driving the thing in regular traffic. Basically the car has started to materialize from pipe dream, too something I might actually drive one day. I tacked in the stanchions to the main hoop. I have them tacked to the bottom rear of the chassis as shown in "the book" in the racing section. I added some extra 1/8 plate in that area. It looks to me like the rollbar/ car would fold lengthwise vs crush diagonally across it's width. This and concerns for driving in traffic has me thinking about building a full cage.

The 1 1/2 14 ga DOM tube seems very strong, and really not that heavy. I think the 20' tube weighed less than 40 lbs. I think adding one more tube for a full cage would be worth it. I don't really mind it will make the car look more like a dune buggy. As Mnot pointed it would make the car legal for other motorsport stuff.

I didn't have a clear vision when I started building, the car keeps evolving.

If you cut the horz tube and inserted an internal tube with thru bolts, you could just cut a circle out for the mount then bolt on the mount.

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Thom

I built this crude mock up using rear struts from a 97 Honda Civic. The Strut is installed upside down to clear the upper A arm. The strut will rest in a coil bucket built into the lower control arm. The weight of the car is on the lower ball joint in this picture. I used a high lift jack to raise the chassis to check droop, and just jumped up and down on the chassis to check bump. Also removed the spring and checked travel with just the shock. Travel is 5".

The main concern I can think of with this set-up is that the strut mount bushing is not really designed to pivot. The bushing doesn't bind in travel but this probably isn't ideal. The coil bucket will be angled to allow the bushing to be flat at ride height.

The positive aspect of this strut is that they are cheep, and upgrades are available.

Thoughts, criticism, concerns?

It might be ok to invert without early failure. I assume the oem strut is monotube gas.
One concern is once the rack is located correctly for ackerman, clearance to the left spring with full left lock.

Rockers with inboard struts and pushrods would solve both potential problems.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Aha... the steering arm would be awful close to the coil spring, at full lock with the strut inverted. I don't have the steering rack mounted yet, I still need to shorten it, and order mounting bushings.

After some consideration, I think I'm going to have to install the strut as it was intended by Honda. I don't think the flat bushing, the shock shaft, and the spring will handle the articulation of the LCA. I thought about making a small strut tower and welding it to the top rail. I might have to modify the Upper A arm or even remake them. On my lunch break, I made a little sketch of what I'm thinking about;


If I have to remake the Upper a arm, I may use bushings, instead of Heim joints. I'm not crazy about Heim joints on a road car. Now that I have built a suspension, and seen how it works I doubt I'll ever change the caster. This would greatly simplify the A-arm. I think camber and toe are all that is needed avoid uneven tire ware.

Also I think the strut towers would be partially hidden by the head lights, might not look too odd.

Push rod suspension is impressive, and probably great for a track car. Or for some one who knows what they're doing. Right now I'm trying to simplify things. Still learning a lot. THanks