tubular subframe and a arms...?
 

i was thinking of making some a-arms (front ones first) to save som weight and maybe some better handling. what should i look for while making these, as in...a way to improve upon the stock ones? material choice is chromoly so far. but would aluminum be strong enough.?its lighter and cheaper than moly...

also, what about a tubular front subframe. they have them for foxbody stangs and various other cars. theres only a few mounting points and sshouldnt be much harded than the a-arms to make. just a larger piece...

but if the benefits wouldnt equal money and time spent, i'll put my efforts elsewhere...

comments and helpful info is appreciated...

Well im unsure if you could make tubular a arms out of cromoly, steel or whatever lighter than the cast aluminum ones because, they are very light

yes they are light. but very bulky. if made from 1 inch 6061 tubing with an 1/8 inch wall thickness, they would be much lighter. but im unsure if they would be strong enough. also i wouldnt have any bushings. just direct bolt to the sub frame and spindel...

if i made it with 1" O.D. 6061 T-6 Aluminum tubing with a wall thickness of 0.1875".

i could make each one for about 40-45 at the cost of material. but im still not 100% sure this will be strong enough. no one has custom a arms on there race car???

I can probably bend a piece of that AL by jumping on it, and I'm fricken LIGHT. It's what I'm making a roof-rack for my Jeep out of and I have doubts about it's strenght for that purpose. Perhaps the reason no-one has bother with them on a race car is because the stock pieces really can't be improved upon that much, or don't need to be.

Front subframe, I was surprise when I first picked one up how light they were. Don't think anything needs to be improved upon there either.

i GAURANTEE you cannont bend even a 1 inch OD piece of aluminum tubing even with 1/16 wall. bending a sheet of 6061 1/8 takes a brake or a press after annealing it. and sheet is soooo much easier to bend. there are many tpyes and strengths of aluminum. now im no expert, this is why im trying to gather info. but i do work with metal everyday. im a welder.

now it might be a small improvement, if any, to make tubular a-arms and a subframe. but just like taking out 1lb here, and a few ounces there. it all adds up in the end. and people have made custom a arms on full race rx7's. but form what i've seen they use chromolly. wich is light and very strong when compared to cold rolled steel. but i have seen tubular subframes and a-arms in other metals for other cars. such as the foxbody mustang.

im going to see what the cost difference between the molly and 6061 would be and just go ahead with it...

You want to GAURANTEE that? Ok

Two nights ago I bent some 3/16 AL plate with my HOME-MADE 36" 1/4" steel bender.
Last night I bent some 3/16" plate in my 6" VISE BRAKE
I have ~60' of 1" od .125" wall 6061 tubing. I think I'm going to stand it across two bricks and jump on it and post pics. Maybe I'll be brave and put a long enough piece across my "bionic" knee :icon_no2:

By bionic I mean I had ~65% of the cartilidge removed a few years back. Although now that I think about it, that's probably not a good idea, PT was literally an ongoing pain. Instead I'll sit on my ass with it across a door way and push like hell.

Then again, I do have a bunch of scrap 2mm intercooler piping laying around. Lets see, 2mm, 2/25.4 = .0787 = 1.2598/16's. I'll jump on that too and post pics. And just for tomorrow's pics - I'm <150lbs right now.

ive never seen or heard of them being made of tubular aluminum, and im sure there is a reson for it...

just be safe and go chomoly or steel.

Seems like a ton of work for very little pay-off.

If you do it post pics.

good luck

im not concerned with the work, i enjoy it. this is my hobby. i just try and keep the cost down. im leaning towards chromoly just because i know its strong enough, and it will cost me about half the price over aluminum.

My point is that your time and effort focused into other areas may be more beneficial... Yeah it's a cool idea -but at the end of the day fabbing something like this is really not going to get you ahead in any department... handling, braking, ect... In fact if done wrong it could set you back... so why bother? The FD has a great suspension configuration, even the best builders in the world use stock control arms.

I agree with doing it for fun. This is my hobby as well and I REALY enjoy all the fab work that I've done for the car. So in that sense, I totally agree.

As for gaining over the stock suspension. I really think other arears other than control arms should be addressed.

Saftey is another concern. How are these going to be tested in a safe controlled envirornment to ensure that they can stand up to the rigors that a suspension is subject too? They can't, therefore I would deem them unsafe.

And sunburn, I believe this is for his Renni powered FC project.

ahhhh -Still the FC has a great suspension as well.

Meh, that's a seperate debate though. Personally I love my FC and the way it handles, but struts leave something to be desired on a predominantly street car..... although tell that to the hoards of BMW/Porsche owners :rlaugh: This thread isn't about improving the FC's suspension design as much as it is making replacement parts to serve what purpose?

i doubt it would hold up, ive bent 1" solid aluminum rod at work accidently with forces much less than an A arm would see

Don't always believe what you read on the internet
 

Let me preface ALL of this with I DO HAVE PICTURES. The site will not let me load them. It's really pissing me off. If someone would like, I will be GLAD to email them to you. Perhaps someone can host them elsewhere and link them here. I don't have any of those photobucket image whatevers. Thepics have been resized though, and I'll be MORE than happy to send them out. With that said

So tonight I proved your gauruntee wrong. I didn't have any scrap pieces of AL that would span a doorway and I was not about to cut one up. I did have one that was a little ove a foot long though. The doorway to my shop is raised up about 2.5". What I did was place the piece of 1"od .125" wall 6061 piece of aluminum down on the ground and stomped on it. I did not jump on it, I one legged STOMPED it. I'm ~150lbs DRESSED. I am however by no means a weak person, I'm actually stronger than just about all of my peers. However, this was still the force of ONE leg of a 150lb person that bent the snot out of a piece that you gaurunteed I couldn't bend.

I also went ahead and took a scrap piece or 2.75" od 2mm wall (roughly 1.25/16") placed it on the ground and stomped on it. It's nearly FLAT from ONE hit.

And you want to use material like this for SUSPENSION!?!?!?!?

I hope I don't need these pieces in the future. Even if I do though, I'll know they went to good use.

Let me reiterate. If anyone wants pics to host and link to this thread, PM me your e-mail and within 5 minutes of recieving your e-mail, you'll have the pics.

That is all

-B

make a double a-arm set up ;D

Is it working now?

https://www.rx7club.com/attachment.p...1&d=1235509213

https://www.rx7club.com/attachment.p...1&d=1235509213






YUP!

Wont be strong enough. I know this because I had a friend build a whole quad chassis out of aluminum. the chassis was fine. the sus arms were constantly getting tweaked.

Aerodynamic/ "teardrop" chromoly tubing....Sexy, light, strong, AERODYNAMIC...would be a better improvement for a race car...I would know...worked for a race team. And use heims to aid in sus travel.

-J

you have a picture on "teardrop" tubing??? or where i could get some...

sounds interesting...

What? No comment on the "garunteed not to bend" bent aluminum? I mean you declared that I couldn't bend a 1" od 1/16" wall piece of aluminum, did you not? I stomped on a piece that had 4x the total wall thickness and it bent to shit. Not one comment huh? Damn, at least I'm man enough to admit when I'm wrong. Then again, I'm also smart enough not to gauruntee something that I'm not sure of.

this is why i hate the internet, you wouldnt speak to me like that if you knew me...

man enough? im no internet nerd. i dont argue through my key board. you proved it. you showed the pics...big deal. move on little guy. you, and people like you are the reason why people call this "the evil forum"

chump...

:rlaugh: Actually I would rub it in your face more if I knew you, becuase, that's the sarcastic, sinister nature I have. My close friends and I CONSTANTLY rank on each other. Good friend of mine showed up tonight to do some work on his rig, went like this

Hey shit stain, how you doing?
Not bad, dick fuck.
So you gonna get something done tonight or just stare at the bumper and touch yourself repeatedly?

I appreciate the mature namecalling though. A little hypocricy only scales back the already overly mature attitude consisting of, "oh shit I was wrong, should I man up or ignore it...... I'll ignore it"

Whatever - I offered the critisim you were looking for, didn't like it, you GAURUNTEED something that was wrong, the rest is, whatever.... oh - internet nerd?:hahaha: You claim to be a proffesional welder yet an Econ/Finance grad whoes career is in finance knew more about material strength from his own experience. Yeah, I'm an internet nerd

Great!, now that you guys have cleared all that up. Lets get back on topic!