LocostUSA.com

Just remember: Aluminum is 1/3 the weight of steel, with 1/3 the strength & 1/3 the stiffness of steel, and design accordingly. The 1/3 the strength assumes that you are not doing post-welding heat treatment, and heat treatment of aluminum is critical for strength (6061 T6 temper is like 40,000 psi yield, vs 8,000 psi yield for annealed 6061). The annealing of steel reduces its strength too, but not by the factor of 5 that happens for many aluminum alloys.

JustDreamin

And don't forget to decrease aluminum strength for fatigue loading.
Have we scared you away from aluminum?

My intent wasn't to scare him off aluminum. Only to realize that aluminum isn't always lighter, and that there are design alterations that need to be made.

Aluminum might be lighter and strong enough, if designed properly for the application and material.

In 4340 it could probably be made lighter and stronger than the current parts, but you open up a different can of worms there. Other steel alloys might even be better, but again, you need to do the engineering work.

Titanium would probably be lighter and stronger still, but certainly not locost....

JustDreamin'

Looking at the failure modes of steel versus aluminum can also be enlightening. Steel is very forgiving, relatively speaking.

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

Lots of good info and I know I need to do some homework. Like most on here I love a challenge, and there are lots of parts I can make with Aluminum to be lighter. I also realize that a lot of parts may not end up being lighter after I use enough to make it strong. However you still have the cool factor and the fact that you do not need to paint it, it wont rust etc.

Speaking of cool Aluminium parts. These are lightweight replacement pulley's the 3 weight a total of 1.5lbs. I should save around 5lb. It is rotating engine mass too so should feel like a lot more (Apparently around x15).

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Here is a quick video comparing the stock to aluminium pulleys.
https://www.youtube.com/watch?v=D9Opz5fQd0s

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

My first aluminium creation. Here are my $500 pedals. The clutch is not finished yet and the brake needs some tweaking. It is a pain in the butt to weld aluminium.

They seem a little expensive but that is about $200 for the spool gun, $200 for a bottle with gas and $100 worth of aluminium.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

I decided to completely redo both pedals. The originals had too much play in them.

I am really happy with the way they turned out. The welds are not pretty but I got good penetration about 80% of the time so they should hold together. There are very solid on the car and feel much better than the steel ones did despite being 20% of the weight.

I installed a Miata brake booster rather then the Supra one. It was 4lbs lighter and I managed to mount it just over an inch lower so I got a much better pedal ratio. Now the pedal has about 2" of travel, rather than the previous 1" Hopefully this will make brake modulation much easier and allow me to apply more brake force without locking up the tires.

Between the booster and the pedals I saved 6lbs. Not a huge amount but it is off the heavy side of the car and every little helps.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

I like working in aluminum. My best experience was making and breaking the things we fabricated for diving jobs. CALOSHA required destructive testing of our equipment to prove the designs. Take some surplus aluminum and bend it and break it to see just what it does vs. a similar steel piece. Especially break-test your welded things and see how far the heat affected zone reaches (we design for 1").

Break things! Have fun! learn.

Will do Bobber. It took me ages to get the welder set up so I can run a bead but once it was set up it was not too bad. I figured the pedals are a good think to make as virtually all the load is compression so not really relying on the weld very much at all. It is very easy to have a bead look ok then pull it apart and only one piece of the aluminum melted.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Well I ordered a post office scale which is cool as it will weigh anything from under 1lb to about 442lbs. I have been using it to weigh small things like the pedals I made. It also just covers the corner weight of the car. So I redneck corner balanced the car with it. Not a very accurate process as you have to weight the car 4 times then calculate the weight and any height discrepancy results in scewed figures.

The car came out to about 1670lbs with me in it (I need 1700 to EMod) Pretty much 50:50 Front to Rear and Left to right (Accuracy 1%). However based on the weight at the last National Tour event and what me and the car have lost I think the car is actually between 1690 and 1700LBs. I guess I had better take some ballast this weekend to make sure. My helmet and seat covers are about an extra 10lbs so I should be right around the limit.

I was bleeding the brakes today and virtually nothing was coming out of the rears. I did a little investigating and found the rear line was completely crushed. I'm glad I found it and it is fixed not. I think the brakes should work really well now.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

My car is really coming along. I went to the SCCA National Match tour in Moultrie hosted by Dixie Region SCCA. I had a great time and managed to finish 3rd in EMod of 6 and had the 9th Fastest Raw time with over 130 drivers.
https://youtu.be/5k_xktUQU6Y

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Awesome video. Did you spin every run? Snap over steer pretty bad. Is there anything you could do to make it more stable? Or do you think it's you trying to drive the car to hard or just no grip on that strip?

Look like a lot of fun and a fast course.

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30 years old, not sure what I want to be when I grow up…

The Course was great Dixie region did a very good job with the whole weekend.

The car has been pushing and I guess I over corrected the problem. The car spun 4 or 5 times out of 15 runs so most of the time it was fine. I think the problem was caused by the LSD slipping coming out of the corners.
I also completely redid the brakes just before the event they are now amazing but initially I had a little too much rear bias which I dialed out.

I have bought some additive for the LSD to get more bite. If that does not work I can open the LSD and pack the clutch plates tighter. I have also ordered some 15x 14 wheels for the rear to replace the 18x8 so nearly double the tread width and a full on race tire so I will have more than double the rear grip.

When I needed to get a good run it was easy enough to get round clean. I was just pushing hard and I have made loads of changes to the car recently. I think I gained about 2 seconds over the field compared to 3 months ago which was mainly just tuning and a few small changes.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

That's looking awesome Paul. I did my first event this past weekend in my little F500 that I just bought last week. I would give ANYTHING for a more open course like that one. We were at Darlington speedway in the rear parking lot with some super tight hairpins and ended with a 5mph switchback. Even the prepped Miata's weren't getting out of second gear.

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Too much week, not enough weekend.

OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

Blood Sweat and Beers
http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216