FT-86 SpeedFactory LCA by Verus - Lightest LCA for the Twins - Development Thread

[Shankenstein]

Originally Posted by NotEric6

How many threads were still engaged at -4 deg camber? Most wheel studs call for 8 threads of engagement, but realistically 4 threads is game for the average hard-parked tuner.

What about thread tolerances? Wild guess is that's 3/4-16 UNF thread. You've got options to fiddle with (Class 1A, 2A, or 3A). If tolerances are loose (read 1A), the free play could be contributing here.

[PowderfaceTr.]

Is it possible that the your prototype has overheated? I would recommend you cnc a billet of 5083. It is most stable. You wont need to replace the LCA it after 100 hours of driving. Most areospace grades have time limits. Think of the long term loss of tempering from shock rebound stress and lateral forces.

Structurally, I would put the meat on the belly and curve that mass up to the ball joint and waffle the topside. A plastic cover would keep rocks from collecting.

[VerusEric]

Originally Posted by Shankenstein

How many threads were still engaged at -4 deg camber? Most wheel studs call for 8 threads of engagement, but realistically 4 threads is game for the average hard-parked tuner.

What about thread tolerances? Wild guess is that's 3/4-16 UNF thread. You've got options to fiddle with (Class 1A, 2A, or 3A). If tolerances are loose (read 1A), the free play could be contributing here.

Over an inch of thread engagement on the adjuster, which would be 18+ threads. I specified 2A on the print, but I think due to manufacturing techniques it came out closer to 3A. This is just a result of improper material selection in my opinion, which is my fault.

[VerusEric]

Originally Posted by PowderfaceTr.

Is it possible that the your prototype has overheated? I would recommend you cnc a billet of 5083. It is most stable. You wont need to replace the LCA it after 100 hours of driving like the super light weight stuff. Think of the long term loss of tempering from shock rebound stress and lateral forces.

Structurally, I would put the meat on the belly and curve that mass up to the ball joint and waffle the topside. A plastic cover to keep rocks from collecting.

We think it contributed to the failure, but we don't think it would have increased the longevity to the point of passing our tests.

5083 isn't strong enough to handle the loads we're asking of the LCA, adjuster, or rod end (as designed). Thanks for the thought though! Always like learning and researching new materials.

[PowderfaceTr.]

Originally Posted by NotEric6

5083 isn't strong enough to handle the loads we're asking of the LCA, adjuster, or rod end.

Meant to say H323

Most people use 6082-t6 with a 3 mm minimum gage

They both weld great. So you can add a bead to the weak areas for proto and then CAD the final.

[Calum]

Originally Posted by NotEric6

Thanks for the words of encouragement. I was personally fairly upset as I'm the main person working on this project. When I put it in context though, it really didn't do that bad and would have lasted a few seasons under severe race conditions. We are dealing with a street car though and we want even more longevity built in.

I should also point out we are testing this at around 4 degrees of negative camber. This is to stress it in the absolute worst case we can.



Since we need to prove that it broke.

I wasn't asking for pics of the break, I was asking for pics of how the stock one fails. But thanks.

[VerusEric]

Originally Posted by PowderfaceTr.

Meant to say H323

Most people use 6082-t6 with a 3 mm minimum gage

They both weld great. So you can add a bead to the weak areas for proto and then CAD the final.

Both materials are still too weak to handle the loads as currently designed.

Originally Posted by Calum

I wasn't asking for pics of the break, I was asking for pics of how the stock one fails. But thanks.

Ahh, understood. I have a suspicion that the OEM may not break like most people think it will. It's designed well and probably costs next to nothing to make. I see it being weak in lateral acceleration (enough to withstand 2G turns though) but strong in bump. Time will tell.

[PowderfaceTr.]

My understanding is the stronger alloys are not able to keep their strength for long periods of stress. Given the conditions of use, one may not be able to get a lighter design. A stronger unit of the same weight is possible.
I read someplace that alloy has better lateral strength than a steel LCA.

Where are you calculating for the greatest loads and what are they?

[VerusEric]

Originally Posted by PowderfaceTr.

My understanding is the stronger alloys are not able to keep their strength for long periods of stress. Given the conditions of use, one may not be able to get a lighter design. A stronger unit of the same weight is possible.
I read someplace that alloy has better lateral strength than a steel LCA.

Where are you calculating for the greatest loads and what are they?

The FEA analysis is listed earlier in this thread.

Largest loads are lateral load (1.7G lateral, which is actually very little in comparison to the bump load, which is 4.5G for our tests.

[PowderfaceTr.]

w=900&h=423

This seems like the weakest link. LOL

[VerusEric]

Originally Posted by PowderfaceTr

The place where you removed the most material is the place where strength was needed most.

1) We used to be Hancha, but separated as the owner was no longer active. As a result, the information is not updated as we find flaws.
2) Please refer to this FEA analysis and not that FEA analysis; we believe ours is more accurate than that model.
3) We aren't breaking the LCA, we're breaking the adjuster.

We believe we have the update to fix this issue under control .

[VerusEric]

Locked and loaded for a new round of cyclical loading events. We highly doubt we will see an issue from this barrage of tests but we should know after this weekend .

[RJasonKlein]

I've really enjoyed reading this thread and think you guys are doing a great job - between this product and the intake you're working on, I'm very impressed with your company and your attention to detail.

[VerusEric]

Originally Posted by RJasonKlein

I've really enjoyed reading this thread and think you guys are doing a great job - between this product and the intake you're working on, I'm very impressed with your company and your attention to detail.

We enjoy positive feedback, so thank you! We are learning a lot and having some fun doing it. Hopefully someday it will be our full time job .