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Alloy mustache bar


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#21 waxhead

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Posted 03 November 2009 - 12:57 PM

was going to go for 6061 or maybe just 5000 series
this depends on the results of your tests

#22 stevo_gj

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Posted 03 November 2009 - 08:38 PM

So I was thinking about how we can actually estimate some of the loads involved in this bracket, however without access to testing equipment and data I can only use rough figures...

I think if we picked the maximum torque than an L Series motor is capable of producing at the drive shaft and then tested that torque acting entirely through the two bolt holes we would get a benchmark figure that we could say was a 'worst case scenario'.

So what I need to know is: what is the max torque that a high end L28 is capable of producing (at the driveshaft)? Ballpark will be ok.

#23 zedevan

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Posted 03 November 2009 - 09:08 PM

alternatively you could always do a rough model estimation of the AZC mustache bar, and see what force it fails at to use as your benchmark?

how many other autocad operators do we have here

i'm a cad monkey, jump onto solidworks sometime and watch a few tut's on it on youtube and u should go fine. its only downfall is it craps itself to easily...yet sadly its still my prefered program

#24 stevo_gj

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Posted 03 November 2009 - 09:17 PM

Yeah i was thinking that Evan, that would definitely be the best solution. However it would require me to know the dimensions of the bracket and materials it is made from, which is probably very difficult to get.

If someone wanted to provide this information we would be very very grateful :) (hint hint)

#25 waxhead

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Posted 03 November 2009 - 09:27 PM

Its made from 6061 and its half inch alloy
I think the major issue you would have is if you had a worn front mount
The front mount should take the majority of the torsional load
I'm still waiting on exact dimensions to finish it off then off to the water cutter

#26 stevo_gj

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Posted 03 November 2009 - 09:38 PM

I didn't realise you were so close to making it, let me know if I can assist in any way.

#27 waxhead

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Posted 03 November 2009 - 09:54 PM

Yeah once i get the right measurements im going to make one
I need one for my car

#28 Mr Camouflage

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Posted 04 November 2009 - 05:22 AM

Mr camo man
I need to get it right with the holes in there as its a water jet job and as such they cant do depth
I suppose i could do it with out holes at all but it wouldn't look as trick


Yep, maybe make it not as wide with no holes, if that's stronger.

Not sure about how much load the front diff mount takes. I do know if the mount is worn out the diff wants to tilt up into the underside of the car, which is why there's an strap over the top of it. I'm no engineer but, I'd think most of the loads are on the mustache bar.  I think the front mount is just there to stop the upwards motion.


Stevo: Some torque figures I found on Hybrid Z
Modified L24:
231.5 HP at the wheels
195.9  lbft torque

Turbo L28:
341.44whp
390.31  lbft torque
at 23.7lbs max boost

Another turbo L28:

403.16 whp
365.92  lbft torque
at 17lbs max boost

Not sure where that torque is though.. engine, or wheels?

#29 waxhead

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Posted 04 November 2009 - 06:39 AM

Mine is going to be running an rb30det so there is going to be some torque through it
There is a certain amount of force from the sheer weight
But i believe as long as the front mount is ok your going to be transferring load to the chassis through there more
The front of the diff is further away from the twisting cntre so its going to hit that mount hardest first

#30 620Z

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Posted 04 November 2009 - 07:53 AM

Yes I have to say I think the original design is flawed in that any holes straight through the bar would weaken it too much. As we all know there will be movement especially if there is not a solid mount on the front of the diff. This movement will fatigue the metal and eventually break or crack it where the holes are. Personally I think you might be re inventing the wheel. The earlier link to the alloy Bar in the States is good value given the state of the dollar at present. For me I still question that one because it has 8 screws that might make there way lose with the vibration.
So as silly as it sounds my old moustache bar is going back into my car. Whilst I did break one of these years ago I think it might have been due to the movement and not having the front diff locked down. With this done (Brace) I think the original should be up to the task.
Personal opinion only guys. Good luck with it as I will keep an eye on this thread and see where you end up.  ;)

#31 waxhead

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Posted 04 November 2009 - 07:57 AM

I am reinventing the wheel
Its just part of my playing with my car
I'm trying to make things look different / better
Thanks for your input I'm not sure myself yet if its going to be strong enough but I will keep working on it

#32 Scoota G

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Posted 04 November 2009 - 08:26 AM

Ok i have the mustache bar. What is the best way to measure it for your purpose?

#33 waxhead

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Posted 04 November 2009 - 08:28 AM

It may be easier to call you
Can you pm me a number please

#34 stevo_gj

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Posted 04 November 2009 - 09:57 AM

Hey Wax, could you resend me the design with the extra bolt hole in it as an .igs? Adding the bolt hole myself is giving me geometry errors when I use my professional software. I'm just going to confirm that simulxpress was giving us accurate results for stress concentrations, and I'll also test those torque figures.

Also, perhaps send us an .igs file with the cutouts removed, and we'll see how much different stronger it is compared to your current design

#35 waxhead

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Posted 04 November 2009 - 10:02 AM

Yup no issue
I will have to do it later today.


#36 Scoota G

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Posted 04 November 2009 - 03:47 PM

This is the template so i'll cut it out and send it up Tomorrow.

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  • 11759_a71e9507d019e695816f189ffa90ec202dbf58e4.jpg


#37 waxhead

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Posted 04 November 2009 - 04:22 PM

Thats awesome
Thanks for that , and the time taken to help me out

#38 waxhead

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Posted 04 November 2009 - 05:14 PM

OK try this
It has the dimensions corrected
Posted Image
I emailed it to you

#39 stevo_gj

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Posted 04 November 2009 - 05:57 PM

Yes I have to say I think the original design is flawed in that any holes straight through the bar would weaken it too much.

As we all know there will be movement especially if there is not a solid mount on the front of the diff. This movement will fatigue the metal and eventually break or crack it where the holes are.


I think there is potential for this design to perform well. The way I see it, the holes are removing 'lazy material' in the design, which is material that does not have much stress acting on it during a stress cycle.

You are right that a design with holes may have higher stresses than a design without, but what if the material removed from the holes was added to areas where the stress concentrations are high?

I'm just working on the latest stress analysis using Straus7 atm will post results soon. I'm going to use some of the torque figures that were supplied as estimates and see what stresses you get if the front diff mount goes and the entirety of the torque is transmitted through the mustache bar when you drop the clutch. In other words I'm going to apply the entire torque of the motor through the two bolt holes.

#40 Zeddophile

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Posted 04 November 2009 - 06:24 PM

I think there is potential for this design to perform well. The way I see it, the holes are removing 'lazy material' in the design, which is material that does not have much stress acting on it during a stress cycle.

You are right that a design with holes may have higher stresses than a design without, but what if the material removed from the holes was added to areas where the stress concentrations are high?

I'm just working on the latest stress analysis using Straus7 atm will post results soon. I'm going to use some of the torque figures that were supplied as estimates and see what stresses you get if the front diff mount goes and the entirety of the torque is transmitted through the mustache bar when you drop the clutch. In other words I'm going to apply the entire torque of the motor through the two bolt holes.


There is one thing you may be overlooking here.  Most torque figures picked off a dyno are done in 3rd or 4th gear.  If you use 1st gear, surely the amount of torque produced is far greater, due to the gearing change?  Likewise the diff ratio would probably have a similar effect?




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