Hey guys, in my never ending question for putting both people (i'm a personal trainer lol) and cars on a diet I had an idea. Would it be feasible to construct an ALUMINUM wonderbar? I know that the front of the car is under stress alot of the time but I think it wouldn't be that big of an issue if large enough/thicker tubing was used. I've been running just some aluminum stock for a crash bar in the frontend for a few years with no sign of bending or warpage. So what do you guys think? can it be done????

 

That bar is so short and it hardly weighs much. No offense at all but it would be pretty pointless to make one from aluminum... With aluminum tube you would want to enforce the interior walls to gain strength or come up with something else to increase strength and stability, i think by the time you accomplished making it as strong or stronger then an OEM bar it would weigh about the same (just off the top of my head with out calculating weight per inch and taking in consideration of the material, gauge, shape and size)
I would be less worried about weight and more worried about reinforcing the frame rail where the gear box mounts honestly...

 

yes you could absolutely do it.

Aluminum and mild steel have similar yield strength, but steel has a modulus of elasticity 3x that of aluminum. That translates to dimensionally identical wonder-bars made of 1018 or a36 steel and a 6061-t6 aluminum being similar in strength but the steel will be stiffer, although the aluminum will be lighter.

You'd really have to quantify the force that a wonder-bar experiences and see if it will deflect the aluminum significantly more (you have to define that too!) than the steel. Then you could say yes or not to an aluminum wonder-bar.

The other issue with aluminum is it does not have a fatigue limit so it will be more prone to cracking after a while than steel.

I say do it, it's cheap and easy to make a wonder-bar, it's not going to be weak just because it's aluminum, and it will be lighter. The chance of you noticing a the slight change in stiffness is very small, and it may not even be significant. Worst case the aluminum fatigues, which we are talking thousands and thousands of load cycles, millions if the stress cycles are low magnitude which they most likely are unless cornering HARD like autocross all the time.

 

Interesting subject, maybe with reinforcement plates on the other side of the mounting bolts or a double bar.

 

Why not use a solid round stock, not a round tube? I would be interested in it just because I could polish the bejesus out of it.

 

Round stock isn't that expensive, 2' of 1" round is only $12. For $20 total aluminum cost I might beat you to it.

http://www.metalsdepot.com/catalog_cart_view.php?msg=

 

You'll need at least 26 inches for the bar lol

 

OK OK, still pretty cheap.

 

I wasn't thinking about a solid bar but I guess that would work as well. I can get 1/2-3/4 solid bar here for almost free from the metal shops here in town. I figure a solid 26 inch bar and two 1/4 inch aluminum plates would be all that's needed. I can cut everything up and basically bolt it together and then take it to have it welded.

 

Not to ruin the party here, but wouldn't it be better if someone came up with a REAL rack & pinion solution for our cars? A nice, lightweight, unit that can mount to the stock or aftermarket k-members, that way it takes the strain off the frame rail and you get the benefit of modern steering technology.

Back to topic.. Aluminum wouldn't reinforce that area as much as a steel bar would and it wouldn't save much weight IMO which sits low anyway..

 

Especially if it could achieve the stock 15" box steering angle or more while maintaining a quick ratio and good feel... no more steering box woes, less weight, it would be a dream for the autox and drift guys... Someone jump on this already and earn yourself a small fortune!

 

Small fortune? Maybe smaller then what you start with.

I doubt there is that big of a market for a rack and pinion conversion for our cars,

btw, what part of Southern Indiana are you in?

 

false.

please do not post false info because "in you opinion" something will/won't when you clearly have limited knowledge in the area. You can design an aluminum piece to be lighter and just as strong and stiff as steel. It will not be the exact same design, and will cost more but it CAN be done.

 

Yep, the info has already been posted here showing what aluminum would be up to the task.

 

Easy there.. You're right, I do have limited knowledge on metallurgic properties, and most of what I know is based on things I've read on here or on the net or from experience with buying and trying out parts.

And you are also right that aluminum CAN be as strong as steel or stronger if it's a better more expensive alloy (say 7075 vs 6061 for example), and is physically larger in size (which takes up more room in the engine bay in which there are already clearance issues with some people for wonderbars with the lower radiator mount IIRC so size for size steel is stronger, and larger than that means it wouldn't fit without further modification to other parts). I mentioned also that it sits low so in terms of handling it would not make much improvement at all (it sits lower than the center of gravity so removing weight below the CG isn't all that beneficial, in any case too small to notice). It may benefit drag because the weight sits up front but at that point if you are doing drag only you might as well just remove it altogether and save the weight like that.

I guess the bottom line is that yes it can be done, but is it practical? Perhaps I should have rephrased my initial post to explain it in this way to be clearer on the information that I was trying to convey, which was more along the lines of it being rather impractical to do.

Forgive me if my lack of knowledge of aluminum vs steel was misleading, but here is a link that I read that explains a bit about why my opinion is what it is in regards to steel vs aluminum strength: http://www.cineventions.com/steel_aluminum.html

Johnny Blaze: There is a market for R&P for our cars. For instance, I am one buyer. I spent 550$ plus shipping plus tons of headaches for a Lee Performance Box and it doesn't work nearly as good as any R&P i've driven (it lacks dead center accuracy and is still heavier than R&P and not as precise although it is advertised to be just like R&P). I'm not the only one who has that box that isn't satisfied with it either. I have replaced every suspension piece known to man on my car and with top dollar stuff. The lack of precision is in the box and the ancient steering linkage system that our cars have. Considering all the money people put into these cars who care about them, I see a huge market potential for a real power steering streetable conversion to a modern steering system.

 

I'd be suprised if you got 10 people here to buy a rack kit.

Not saying there is not a need for it, but figure the cost, the ones for 1st gens and other popular cars go for $600 up. Even if you could sell them for that, I doubt many 3rd geners would buy.

 

Eh the AGR box goes for $400. I think the Slowreilly's remans go for around $2-300 last time I checked. Mine's not quite as good as I'd like it to be but it's not bad enough to justify tearing it apart or gambling with a different one. A really nice power R&P would be a great alternative for people wanting more precision out of their steering, and the drift and autocross guys would love it in the never ending quest to get more steering angle out of these cars since once you get past the limited stock steering angle the car likes to swap ends. There are rack kits now but most of them sound like a huge PITA to install and from what I understand they limit the already bad turning radius which is a deal breaker for most unless it's a drag only car. (27 point turns suck in a street car and spinning ain't winning lol)

And I'm just down the river, over in Evansville.

 

What about stainless steel, making 1 out of stainless steel would still cost less than having 1 from our retailers.I would tend to think that it would be just as strong, it would be cheaper, and it would be polished for those of us wanting car show quality engine bays.

 

It appears sailtexas is the only one here who has a clue what they are talking about.

Yes, you can make an aluminum part as strong as steel. Yes, you can make an aluminum part as stiff as steel.

Yes, you can even make a part as strong and stiff as steel with balsa wood, it will just take a lot more (volume) material.

This piece is almost certainly sized for stiffness, not strength. Which is bad for aluminum. No fancy aluminum allow is going to gain stiffness, it is all pretty much the same. Yes it can still be done but you need to understand the loads.

Are they all axial, all torsion, all bending, or a combination?

I would bet the loads are primarily a combination of axial and torsion. You could up-gauge the tube slightly and take care of the torsion easily. Then you can increase the wall thickness significantly to make up for the axial stiffness.

IMO the gains here are too low to bother with the effort. The stock piece is not that heavy. A much better target would be an aluminum sway bar. But again, still to much effort for the gain.

Stainless would be a piece of cake as its roughly the same stiffness as mild steel. So just copy the stock piece into stainless.

 

I agree with you on the R&P. I would like that too. Make it afordable. It might be that it could also be adapted to fit the G body cars as well.

 

I'm laughing (not at the original poster or people contributing) but just the idea, like i said before that bar is pretty light weight to begin with just being made from steel, same goes for the aftermarket ones. There easy and cheap to make, You could probably even improve on design but no mater what you do that area where the box mounts is the weak link, every one knows that even GM, hence GM's "band aid" steering brace... If I WHERE going to do a stronger steering brace, i would have a bottom bar connected to the lower frame rails (like the stock steering brace was) and a top bar connected to the top frame rails, then i would tie the upper and lower bars together to triangle them, and in the process a plate that fits between the gear box and frame rail that is connected to the upper and lower bars... and i would still use steel...

 

R&P- you guys realize that the only reason that newer cars have gone to R&P over steering box is weight and packaging. A steering box is stronger, more precise and more tuneable for feel. There's a reason that all larger vehicles have stayed with steering boxes. Sure, if you replace a steering box with 200K miles on it with a new R&P the R&P will be tighter, that's not because it's a better technology.

 

But the R&P does have a better on-center feeling than the steering box, making it more precise and safer at higher speeds, no?

 

To do the R&P properly, you will also need spindles with shorter mounting points for the tie rods.
Shorter from the spindles bearing mount centerline to the tie rod hole. I figured it all out once buuuuut that was a long time ago and it would cost a lot.

I do think I have seen these steering boxes and pitman arm made in aluminum. that would shave some weight.

 

Right about the spindles.. This is so that ackerman would remain the same right? Also, I think Racecraft made those shorter spindles, but I wouldn't buy them from racecraft anymore because of the recent case of one of them breaking..

If you factor in a Lee Box (650$ for me in Canada), a complete steering linkage system (300$), it costs almost 1000$ for my current setup.. (not including modified spindles for my LS1 brakes, new steering shaft and ujoints, etc. I am talking strictly steering box to outer tie rod) Could doing this swap be that much more expensive than 1000$? (saying this for those who have not changed anything in their steering yet but might want to upgrade the whole system, maybe getting a R&P isn't that much more than a complete steering box system?).

 

read my post right above that one

 

if youre gonna go this far, why not go all the way to composite materials? eg: carbon fiber, carbon kevlar, etc

 

Composite materials are generally a poor choice for axially compressive loads. You are relying on the matrix material compressive strength/stiffness which is not very good.

Granted a carbon tube with machined aluminum end fittings would look nice.