LocostUSA.com

I am not an engineer and want to make sure things are strong enough. I plan on running decent power with wide tires so things could get stressed.

I would like to be able to use the same plan of 7/8" .156 wall with 5/8" rod ends through out (Control arms, trailing arms and Panhard bar) to keep things simple. and no offence to turbo bird or posthumane at all (I really appreciate all input) but I would like more confirmation that this will be sufficient seeing as they have 2 very different opinions. What is the compression and tensile strength difference in the 1" .125wall DOM vs the 7/8" .156wall? Could the 1" DOM use a 3/4" rod end?

it is unconfirmed but I am leaning towards a 3 link providing I can figure out packaging as I like the Idea o using the factory centre link location on the 2012 diff. (it was one of the reasons I bought it)

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Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

I tend to over engineer things as well but in all the calculations you need to remember that these link arms are never going to get a fraction of the same stress applied to them the oem intended. Traction is going to break way before you could damage an inch od control arm even if it was the thinnest gauge available. The top link could always be mounted on top of the gear tunnel and then add a panhard rod . Just thoughts.

Bob

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Build Log viewtopic.php?f=35&t=16640&p=187700#p187700

Mancave http://s1116.photobucket.com/user/mypic ... ow/mancave

You should definitely go with whatever makes you comfortable and is easiest to build with. There is no need to engineer things to their absolute lightest on these cars, especially for road use. When I was talking about using 1" or even 1.5" I was referring to thin wall (0.065"), but if you are using thicker wall stuff like the 7/8" x 0.156 then smaller diameters are definitely fine.

Tensile and compression strength is based on cross sectional area. For 1" x .125 the cross sectional area is .3436 sq in, and for 7/8" x 0.156" it's 0.3524 sq in., so they are pretty close. If you're using low carbon steel such as 1020 with a yield strength of 43 ksi (57 ksi ultimate tensile strength) then the loads that can be handled in tension before the tube yields would be around 15000 lbs force. Compression strength of steel is the same as tensile in theory, but as stated longer sections will fail due to buckling at well below the compressive strength limit but the calculation is not quite as simple. This would only be an issue on long slender bars such as panhard rods. Most Locost trailing links are short enough that buckling doesn't really need to be considered there.

For reference, 1.5" x .065 wall has a cross sectional area of 0.2930 sq in which gives a yield strength of 12600 lbs, whereas 1.5" x 0.125 is 0.5400 sq in for a yield strength of about 23000 lbs. 1" x .065 is 0.1841 sq in and 7900 lbs.

Weight per unit length is also proportional to cross sectional area so it is directly related to tensile strength. 1" x .125 wall tubing will not be able to use a 3/4" rod end directly since the inside diameter of the tube is 3/4", but for a 3/4" thread it would have to be smaller.

I took quick look at some aftermarket 4 link setups for full size cars and they seem to use 1" x .156" dom, either tapped to 3/4" or with 5/8" weld in bushings. One of the ads I saw said it can take any abuse you can dish out, and it had wheely bar mounts. I would think these setups are way beyond what you will need strength wise, and if 1" x .156" is enough for a 4000lb car, I'm sure 7/8 x.156" will be fine for your application, especially when you consider the typically very short links in a locost. As an example, my store bought front arms were 3/4" x .065", and the tubing was fine. The arms broke because of a poor design that had the weight of the front end on a piece of 11 gauge sheet without any gussets or other support.
Kristian

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V6 in a book frame build. Now registered.
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So I have decided that the 7/8" .156wall is the way I wish to go on all arms. this will just simplify and I am confident that it will hold up.

My next question comes from making mounts on the frame and diff. If I am using a 5/8 rod end the ball width would be .75", is there a reason I do not see any builds just using a 1x2 sq 1/8 gauge tubing for mounts. This tubing should have a .75" hole across the 1" width and would make mounts incredibly easy... maybe I am missing something? (I know the shocks will need something wider but the trailing arms should not)

As always thank you everyone for the advise, this build would not have been started without such a great and positive online community.

_________________
Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

I would expect the 2x1x0.120 to work. My rod ends are 1.25" because they are high misalignment bits. Make sure the rod ends you chose have enough movement for your needs, a little extra never hurts either.

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Gavin

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

Just thought I would post a couple pics of what might be the slowest build in locost history. Family takes priority.

Wow I do not know why they are upside down.... I'm not in Australia?

_________________
Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

While you may not be in Australia apparently the interwebs was routed through Australia on it's way to your house.

If you'll rotate the pictures on your phone BEFORE you export them it should solve the problem.

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mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.

What is odd is if you click on the photo, it loads right side up. On my phone it is also right side up. Oh well no big deal.

_________________
Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

NCLBNY,
Back to the rod ends, conical spacers will give you a bit of wiggle room. They're sold as 1/4" thick but the ones got (from either Summit or Speedway) were closer to 7/32". When used with QA1 5/8" rod ends that adds up to between a 1 1/16" to 1 1/8" space needed for mounting.

The DOM I used for the rear uppers is 7/8" x 0.156". I ran a 9/16" bit down a couple of inches before tapping. You can cut threads without drilling, but it's very difficult because you will be cutting "full" threads. From what I have read this is not recommended. I can't find/ or didn't save the article. I think 75% or 85% was recommended because of seizing and some other concerns.
Ron

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"Age is an issue of mind over matter. If you don't mind, it doesn't matter." - Mark Twain
In my defense the moon was full and I was left unsupervised

Thanks for the Tip Ron. The seizing was a concern to me at 100% but it appears multiple people have done it before. Breaking my tap is another concern when cutting that much.

_________________
Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

So I have hit a bit of a delay in the Locost build...I have wanted to build a pro-touring car for a long time but recently had a series of events that is making it happen!

Step one, Initial Purchase: A few months back my 3 year old son asked me "I want to build a muscle car!" I jumped at it and informed him I would have to sell the race car, and the Lotus build will have to be put on hold. He told me "That is okay." and with in 2 weeks I had sold the Miata (race car) and bought a 1968 Plymouth Satellite.

Step two, The Motivation: About a month ago two good friends purposed a challenge, THE GREAT AMERICAN CHALLENGE, this was the push I needed to get things going. The challenge is 3 engines a Ford Coyote truck motor, a GM LQ4 and finally my Mopar 440. Engines are considered no cost, the budget for our builds are just $7000 CAD including cost of vehicle (I am grandfathered in and my vehicle cost is equal to the more expensive of the other two cars as I already had mine). The vehicle would have just one year to be completed (July 1, 2017) for a series of challenges including an Autocross, Drag race, Car Show, and finally the ringer of the challenges; a 3000km+ road trip from Calgary Alberta to Tofino British Columbia and back. This is a competition is between 3 friends and more importantly the big three manufactures. It is going to test our resourcefulness and our drive to complete these cars for the very restricted budget and time.

Vehicle requirements:
-Vehicle must be finished, safe, street legal, and drivable on July 1, 2017.
-Budget must not be exceeded, but costs may be recouped through selling of existing parts.
-Each dollar over budget will be penalized with a 1 lb ballast.
-Vehicle must be RWD American Model year 1965-1985.

Restrictions
- No forced induction.
- Nitrous oxide allowed.
- No fuel restrictions, but chosen fuel must be used for all competitions.
- One set of DOT legal tires is to be used for all competitions.
- Vehicles must be successfully driven to each event in order to participate.
- Maintenance is only allowed between events, no modifications.

I hope it is also motivation for anyone following to do the same and keep more of these cars on the road. It is going to be proof that engine swaps and pro-touring cars are not just for people with a lot of money, everyone can enjoy this car culture.

So my friend Marc bought a 1975 Chevy Nova SS for $600 and my Friend Andy bought a 1982 Ford Fairmont Coupe for $750. This means I have successfully "bought" a 1968 Satellite for just $750.

For multiple updates, please check Instagram with #thegreatamericanchallenge, I will also give an update once we get the Facebook page up and running and other sources for updates as well.

Wish me luck!

To follow this build you can view it at [url]http://www.pro-touring.com/threads/121711-NCLBNY-1968-Plymouth-Satellite-THE-GREAT-AMERICAN-CHALLENGE/url]

_________________
Convincing yourself you can do it is one thing, convincing your wife it is a good idea is another. Glad I have a great wife!

1999 Dajiban build
Autcross car currently 2009 Mazda RX8 R3.

Build is a plus 4" width, 13B Renesis. Wish me luck.

I'll have to admit, I didn't know what a pro-touring car was. I did check out the website. I'll go back soon and read the FAQ. If it's taking and American car and tweaking the crap out of the suspension, that looks like fun - if you could keep it low cost [SMILE].

Good luck with your build!

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

Lonnie, where ya been? There are various freeway ramps where you can't hurt anybody that are used for suspension tuning (I8E to I805N 83mph).

Yup, I need to get out more!

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886