My exhaust manifold solution

[DMS]

It fits now

[DanThe]

DIY anti-roll bar, does it work as well or better than the original?

[DMS]

Donno it's not on the car yet. I'm doing this conversion on my daily so one step at a time and I'm spending lots and lots of time preparing. I'm trying to get everything around the engine sorted and installed without taking the car out of use for more than one of two days. As you have seen perhaps I've already changed the brake booster and pedals on the car. Besides that the wiring is already done (4-pot housing) and the subframe and arb are modified to fit. Hopefully I've time next weekend to do the firewall. Also the gearbox mount and shift linkage is already done (I'm using the M20 gearbox).

The pics I've posted of the ARB are taken with the engine subframe etc. on the engine stand .

[b12rlw]

Might be worth getting it heat treated after roasting it in order to bend. What material have you used? I'd say you've landed up with possibly quite a ductile main form with potentially brittle bends depending on how you've worked the steel mate. I'd question using it buddy!! Good idea tho!!

[b12rlw]

Don't get me wrong, it's unlikely to bend out of shape due to the section, I'd just wonder about potential stress concentrations.

[DMS]

I've used 42CrMo 20mm. I do think there will be stress points as the material has hardened pretty good due to the heat. I know for sure it won't bend out of shape. The only thing I would see happening at tremendous stress/torsion is that it will snap at one of the bends. The material has hardened pretty good but that also made it more brittle.

I'll look into possible treatment but mostlikely I'll run it as it is.

[b12rlw]

Best bet would be to have it normalised somewhere. They'll roast it for a couple of hours then let it slowly cool to bring its properties back to standard, which looks easily suitable. Looks good mate and you might have a wee money earner there if they're treated and powder coated.

[UweM3]

I've used 42CrMo 20mm. I do think there will be stress points as the material has hardened pretty good due to the heat. I know for sure it won't bend out of shape. The only thing I would see happening at tremendous stress/torsion is that it will snap at one of the bends. The material has hardened pretty good but that also made it more brittle.

I'll look into possible treatment but mostlikely I'll run it as it is.

A friend of mine is using the same material and methods to make ARB's and they work just fine.

[DMS]

No heat treatment afterwards?

[UweM3]

No heat treatment afterwards?

Nope! I can ask him for an exact material spec if you want.

He suggested making an ARB when I showed him my S50 install with the reverse mounted M3 ARB and moaning how little room there was

[DMS]

Please do. That would be really nice.

[UweM3]

Material he used is 42CrMo4 and after bending he heated the whole bend to cherry red evenly and let it cool on it's own.

From my own experience, they key is not to score the material surface with the flame getting to close.

[b12rlw]

Material he used is 42CrMo4 and after bending he heated the whole bend to cherry red evenly and let it cool on it's own.

Theres a possibility you're gonna end up with a transition interface here that could cause weak points (i.e the areas adjacent to the cherry red bends.) part treating a component may cause cracking ( even tiny inclusions, that will propogate and fail after the Nth load cycle, also crystal formation in the material will be diferent at this interface possible leading to embrittlement.

[DMS]

Thanks Uwe,

It's the same material as I used. I believe it's the same as BMW used with the stock ARB's.

[b12rlw]

Thanks Uwe,

It's the same material as I used. I believe it's the same as BMW used with the stock ARB's.

Yeah, and im sure they would have had the material treated correctly. Never mind, its not on my car. Good luck with it mate, it'd look the part powder coated btw. Its always good to see someone engineer a solution to their problem keep up the good work!

[DMS]

Thanks Uwe,

It's the same material as I used. I believe it's the same as BMW used with the stock ARB's.

Yeah, and im sure they would have had the material treated correctly. Never mind, its not on my car. Good luck with it mate, it'd look the part powder coated btw. Its always good to see someone engineer a solution to their problem keep up the good work!

I did only refer to the material. I'm guessing BMW indeed got it heat treated. I'm checking my resources to see if I can use an oven. I'm also looking into the temperatures and process of heat treatment for this application. It's not as simple as throwing some random heat to it. It all depends on application.

Also it will be sandblasted and coated before it goes on.

[UweM3]

Thanks Uwe,

It's the same material as I used. I believe it's the same as BMW used with the stock ARB's.

Yeah, and im sure they would have had the material treated correctly. Never mind, its not on my car. Good luck with it mate, it'd look the part powder coated btw. Its always good to see someone engineer a solution to their problem keep up the good work!

I did only refer to the material. I'm guessing BMW indeed got it heat treated. I'm checking my resources to see if I can use an oven. I'm also looking into the temperatures and process of heat treatment for this application. It's not as simple as throwing some random heat to it. It all depends on application.

Also it will be sandblasted and coated before it goes on.

My friend is using this type of ARBS for years and never had one crack. Without any heat treatment afterwards.

Who says that BMW bends these hot BTW? We mere mortals only heat the stuff up because we haven't got big enough presses at home to bend it cold.

[Jos]

Anyone know much about heat treatments? Looking for a temp process for 817M40 steel bar

sry for the hijack DMS, maybe it might be useful if your going to normalize yours, there was someone on here who knew about material technologies, gareth maybe, I can't remember...