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On the arms, it seems a close tolerance slip fit rather than press fit would be better for the structural adhesive microspheres, the carbon, and the matrix stress. No pinning.

Have you decided on which structural adhesive yet? 3M 9323 b/a may suit your needs.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Correct that would be for the Epoxy. I was looking for the oull out force of a stainless pin into an aluminum housing. X amount for press fit will result in x amount of pull out force.

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You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

Yeah you are right. The rod ends can be rotated but not the lower housing. I changed that! Thanks

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

I think this pic might clarify. The press fit will be on the lager OD and the smaller od will maintain the epoxy gap. For the structural adhesve i went with E-120HP per some of my buddies who work at Yetti. I am definitly going to test the bond for sure though. I have looked in to the one you had mentioned too. If i repeated failures then i will try that.



As far as pinning (which i might have made confusing). Instead of the machining post on the lower housing, i was going to drill ream holes for a press fit pin and pin that from the side to ensure that the pin wont come out. The carbon tube would then be bonded to the pin like above.

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

are you sure you are comfortable with running 100+ mph over a curb with such an arrangement???? I wouldn't..

If you are to make a sample and test it, it would be real smart to test it with repeated 3 or 4 G cycles not just once for ultimate test..

looking at your A arms I would definitely not use such a design... Either make a proper all carbon A arm with structural inserts at spherical joint points, or at least make the ends one piece instead of this alu housing + steel pin.. if it has to be carbon at all..

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Building a single seater middy BEC with GSXR 1000 power
build log: http://locostusa.com/forums/viewtopic.php?f=36&t=5899

day job: http://smg.photobucket.com/albums/v723/turbolimac/portfolio/

By the way, i am aware that some of my approaches are definitely not in the Lo(w)cost spirit and that is due to my desire to make the very best, light weight, etc designs that i can to some extent. However, i have decided to also create alternate options for some of my designs. Please let me know if i can help.

If you want to try to make my style suspension i have put some notes below. However as a disclaimer, wait until mine is rolling so that i can be the guinea pig!

Carbon Suspension
Always test! I am not sure the best way to do this but I have local place that will test them for $20. You probably can also make a fixture with a hydraulic pump and a few digi key sensors and some online designs.
Upright : There are tons of designs by guys here that are great and low cost so i am not going to go into that. However if you have access to a 3-in-1 machine mill or shop, you can make aluminum uprights fairly cheap. I have a local aluminum place that i can get a piece of 8x17x3 piece of 7075 remnant for $60. Also there are tons of light weight sheet metal designs out there too but i am sure you have seen and can get details on those.

Control arms:
You can find places with dumpsters full of carbon tubing that you can use but make sure it has the layup and tolerances that you need for strength and bonding. Call around and see if you cannot get some cheep. No Pulltrude ebay garbage! Get quality tubes with data if possible. This will be the most expensive part and rightfully so. FYI you have to drill a pressure relief hole in the tube before bonding, otherwise the pressure in the tubes will push the housings off. You can and i suggest wrapping your tube in Kevlar to aramid for added impact strength. I sheet will be fine and i will post this once is wrap mine.

Here is a cheaper spherical ball housing.
Take a standard monoball housing from online or make your own and weld some pins, tubes or dowels to it. Make sure you place a piece of brass or something in the housing so that you don’t distort it when welding. You can use rod ends (even though they might be in bending) on the alternate side but machining down a few tube ends and adhering those to the tubes. Really hope this helps.

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

Man i would be worried about hitting a curb at 100+ with any control arm. I remember hitting a stump at a rally event in my saab at 70+ and it completly broke the lower control arm and bent the frame. However, right now i have two carbon test set ups ready to go. I will take your suggestion and get the other cycle tested. This car wont be seeing much over 100mph. Just a track day maybe twice a summer.

I am pretty against the pin/aluminum thing but i wanted to run it by you guys and get your thougths before i completly x'ed the idea

You are also right, i could make a non carbon control arm but that wouldnt be fun

Thanks kikiturbo

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You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

7075 cracks easily, where 6061 will just bend.

You might want to order some small pieces of round or flat stock and destroy them in the bench vise, just to see what they do. Having machined (literally) tons of 7075, I wouldn't have the stuff anywhere near a suspension member.

Yes, airplanes use lots of 7075, but not in places that see much in the way of bending, and particularly not stress reversals.

Don't take my word for it. Invest a few bucks for some test pieces and break them off in the vise.

If you want to do carbon just to do it, that's fine, but I ecourage you to design up a steel version (you clearly have the skills/tools) as a baseline for comparison. I think you are overestimating the benefits and underestimating the drawbacks to the carbon.

I'm not sure why you gave up on your first concept for the LBJ holder, what you have is manufacturable, it just takes multiple setups. We made ours bond to the OD of the tube, similar to your second version (without the press in pins), but it still takes multiple machining setups to drill those holes.

The steel one is sitting on the bench unwleded. I can make the steel version but the reasons (please feel free to comment) are:
1) Much Stiffer resulting in better handling
2) Less unsrung mass (which is small and outweighs the complex bnding)
3) more challenging

The first LBJ holder was abonded becasue I couldnt find a way to hold the OD tolerances tighter. No one really supplies a tight tolerance od tube.

The FEA on the tubes will be done shortly. I can post those and compare them against the steel version.

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

I have a question, based on an assumption and also something I thought I once heard... My assumption is also based on something mentioned earlier in this post, the fact that McLaren use Aluminium control arms on their CF tubbed road car. This is a company that is at the forefront of CF control arm design on their F1 cars.

So my question is: Are CF control arms/suspension components even road legal? My assumption is that they are not, due to the catastrophic failure mode of them. So have you checked your state regs for this? Wouldn't want to go through all this effort to be told "Err, sorry pal, not on the road you aint!".

I guess before I ask that question, I should ask if it is even a road car

CF tubs, however, interest me

I need to ask that. I am sure some DMV lady won’t be able to answer the questions so any suggestions on who to ask? State Trooper?
Let's say it like this too, if i can’t make it street legal oh well (the wife said i have too) but i will lose $500 on a bet that i can make it legal. Colorado is really vague on registering.

I am staying away from aluminum arms. They will need to be billet which will be way more expensive and the buckeling issues are kind of scarry.

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

Transmission Guys!

I know nothing on gearing for cars so... if i switch my GSR trnasmission out for a CRV one, how will it affect driving the car. Ratios below. I am trying to go from Rod Linkage to a cable one. Anyone seen this done?

CRV gear ratios
1: 3.500
2: 1.956
3: 1.344
4: 1.071
5: 0.812
FD: 4.562
R: 3.000 (97-98 models), 3.461 (99-01 models)

GSR Gear ratios

1st Gear Ratio 3.23:1
2nd Gear Ratio 1.90:1
3rd Gear Ratio 1.36:1
4th Gear Ratio 1.03:1
5th Gear Ratio 0.79:1
Final Drive 4.40:1


Maybe this might work??
http://www.youtube.com/watch?v=ncmaxYd1 ... re=related

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

State Trooper knew
The vehicle suspension would need a sreport by a mechanical engineer with a PE and no the designer/ower cannot signoff on it. I also need a full windshield with safety glass that cover the drivers and passengers sight. Funny that a motorcycle doesnt require it... wonder if i wear a helmet while driving is ok??

You guys are killing my dreams!

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.

Even worse! The windsheld has to be made of saftey glass and have wipers! Maybe i can make a dissconnecting one..hummmmm. Well lets say it like this too, i am probably stuck with steel control arms too.

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My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.