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Here are the other pictures from my last post. After this I will mostly just post the pictures that seem to show a lot of stress. There are six views of stresses and loads available: axial, shear Y, shear Z, torsion, moment Y, moment Z.

I will correct the wall thickness and also reduce the diameter of the cross tube out at the spindle for the next runs. So it should be understood these pictures may be rather optimistic ( better to be conservative here ). If we see a big difference later I may redo this...

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Correcting the model above for a smaller cross tube by the spindle and reducing the wall thickness .065 to .058 increases the stresses 10% or so in the above pictures.

Here is the shot of the MomentY stress which is our problem area. It is greatly reduced ( more than I would think ) by the cross tube at the base of the arm. We seem to be in an acceptable area now. At this point you would think about how our test load compares to real life and see if you are happy with it.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

This is so much fun! We have nearly doubled stress some other places now though.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Hi Marcus,

Thanks a lot for all your work on this, I will now follow your advise and go test the change to see if it works, I will also look even more carefully at them a couple of times during the day.

In the mean time I went to the dyno. The engine was running way to rich (10 to 1). We leaned it to about 12 to 1 and here it what it ended up with! These are results at the Wheel.

Well, I'm still thinking about things here. I got my previous comment on brake torque wrong. Looking at the load from car weight and cornering, it is causing the front of the control arm to rise. Using the brakes will apply torque that causes the front of the arm to go down. So the brakes will counter the vertical load on the front leg instead of adding to it.

Unless my numbers are too conservative I think you can bend that little outer tube. I would watch for cracking paint and maybe check it with a level or something.

I'll do a run with a small piece of rectangle tube in that position and we'll see if that is enough. Ultimately we may need to think of a way to make these lower arms a little more 3D to be stronger.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Hi Marcus,

I tested the car yesterday night, I did about 35 miles at a fairly good pace on a very bumpy track. Good news, the rod ends have not loosen as it was doing before. I beleive it must be because the arm doesn't bent anymore. I did a quick check for crack in paint and could not see anything. I will check more closely before going back on the track.

It might take a while until it happens however as my wife is about to give birth to our second child!

Also, I could see a difference in the new map for the engine, there is more torque at lower rpm and it definitively enable to use the engine from lower rpm (3000), that is quite a feeling, it pulls hard!!

I also have videos of this test and will post them ASAP.

Regards!

Hi!

A quick update as things has evolved quite a bit since my last post. I went on the track to test the last modifications and we seriously drove the car to its limits on a very bumpy track and everything works very well. I had a professional driver with me and he gave me very good comments on how easy the car was to drive. No sign of any specific wear! I am very happy as I now believe to have a strong and reliable car.

On another front, I initiated the discussions with the organisation reponsible to allow registration for the province of Québec. The people there are really nice to work with. I got a good reception and I am now working with a very good and experienced engineer to produce the needed report. I will keep you posted as it develops.

Some photos:

I will follow your post . I was supposed to start my buid in 2012 but when i read the story of gotboost i change my mind. I dont want the saaq refused to title my car for track only... Good luck!

It looks like you have a requirement for a completely enclosed exhaust. I remember that's what Ewen used too.

You have solid rear brake rotors are that what is on all the T'bird cars? Is that a 5"x4.25" bolt pattern?

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Hi Marcus,

They asked for the exhaust shield, I decided to completely enclose it, I would certainly not want a Kid to touch them and burn themselves.

As for the rear rotor, they are from the front of a BMW 318TI. The bolt pattern is 5x120.

Have a great week end!

It has been a good while since my last post. Most of the work since November has been to prepare the car for the registration. We completely draw the frame in 3d and we will provide them with a FEA. We are not completely done but I will post results once we are. Also, I have been working on the bumpers, muffler panels, controls, wipers, lights... I am really happy because I learned a lot while doing all this. I will add some tube to my frame that will make it stiffer,

Some pictures:

Hi all,

It has been a very long while since my last post. I very happy to report that after a great collaboration with the registration organisation in Québec, I got my car registered and it is now 100% legal on the road. Here are some pictures of the car done.

Congrats, Yohan! Car looks great. Does the bumper have to stay there?

Hi Nick,

Thanks for your nice words, yes the bumpers need to stay there. It was mandatory for the use of the car on public roads here.

Regards,