Arc Asylum subframe

[gobuffs]

Just a PSA to check your Arc Asylum subframe. I was doing some work on my car and noticed the suframe is cracked where the modifiction was done on one of the sides. Looks to be a weld failure. The other side has an issue as well, but it appears to be a material failure of the remaining stock metal (but not nearly as serious as the other side.

This was running an S65 which is SIGNIFICANTLY heavier than an S54. The weight difference HAS to have an impact. S54 engine cars might not show this, but, please check yours. I am not sure how much longer this would have lasted in the car.

Bottom side


Front side


Other side

[TimeMachinE30]

Contact the manufacturer?

[butters]

Actually the S65 is something like 30 pounds lighter than the S54 FYI.

How long have you had the modified subframe in use?

[carlb]

Can you show a wider shot of the subframe? It's easier to see the vector of the stress if I have the whole subframe as reference.

[gobuffs]

Actually the S65 is something like 30 pounds lighter than the S54 FYI.

How long have you had the modified subframe in use?

If you believe the BMW marketing hype then you are right. If you believe my scales then you are completely wrong. The S65 might be lighter comparing short block to short block. Adding 2 heads and all the other ancillaries then you add a lot of weight. My old S54 with a lightweight flywheel and a 5 speed tranny was about 130 pounds lighter than an S65 with stick FW and 6MT. 130 pounds! The tranny alone weighs 130 pounds. There are no alternate manual options to mate to the S65.

This subframe has been in use for about 2 years...race car so infrequent use.




The angles of the subframe are what you typically see in modded subframe of this type. A butt weld doesn't seem like the appropriate solution for this mod.

My post was a PSA for people that have these to look at theirs. Looking for alternate solutions at this point in time.

[butters]

If you believe the BMW marketing hype then you are right. If you believe my scales then you are completely wrong.

Interesting to hear, I suppose the transmission is an important factor.

Have you contacted Tyler @ arc asylum (TinyT here on the forum)?

[flyboyx]

holy crap! that is terrible! out of curiosity, did you brace up your rear diff? if not, i would assume your rear subframe/diff cover/diff cover bracket would look like this too?

[R3Z3N]

Personally this is something I would contact ArcAsylum about first.

It's of the same respect by contacting a company before yelping a bad review or complaint.

[gobuffs]

Personally this is something I would contact ArcAsylum about first.

It's of the same respect by contacting a company before yelping a bad review or complaint.

I knew I'd get a number of these posts, however...let's say I did contact him and came to some kind of agreement and I never posted this. The people that have the subframe wouldn't be inspecting theirs right now. This ONLY purpose of this post is to say "if you have this part, go inspect it", nothing more. Mine might be the anomaly, I don't know.

[Northern]

Mine looks fine, only like two months of actual driving and only an M52 though.

Planning to remove it at some point to add some swaybar mount reinforcements like the newest ones have, and I'll probably strip it and look for any cracks then.

It looks like it cracked at both the stock welds and his welds? Any chance you hit something?

[Chase Bays]

It's awesome to see rational considerate people on forums instead of people waiting around to burn companies at the stake. Progress doesn't happen until after mistakes or mishaps occur. :D

[bataangpinoy]

A few things that I can tell just by looking at it these pictures (I also creeped on their website to look). Not bashing his work, merely critiquing it. I'm a co-owner and operator of a motorsport shop, and our daily operations include MIG/TIG welding as well as other facets of metal fabrication(roll cages, suspension components, fuel cell cradles, etc). I digress.

In regards to the subframe:

1) It seems that he did not use enough amperage to fully penetrate the base metal and/or the weld was ground down too far. Either way, the weld is not as strong as it should be.

2) OP nailed it right on the head. A flat plate and butt joint being used as a cap for the subframe is not a sufficient for the kind of torsional load a front subframe sees, especially as an anchor for the DOM.


3) Assuming the steel he is using is similar gauge (thickness) to the OE metal of the subframe, he should make a cap/box that slides over the end of the cut subframe. That would allow him to rosette weld the box in place so its fixed to the subframe. Makes it was easier to run a bead on the overlapped edges of the box to weld the lap joint. In using a lap joint, you can run a little extra amps on your machine for better penetration of the base metal. If he moves fast enough with the filler rod, he can avoid undercutting the base metal.



IMO, welds along a torsional load bearing item should never be ground down!! If the root pass didn't come out as pretty as you'd like, you can always run a 2nd pass to pretty it up. The gusset fins on the DOM are a nice touch though. Just my 2 cents.

[328ijunkie]

interesting. Welding to the factory subframe there needs to have alot of reinforcement IMO as that box stamped sheet metal is no longer as strong as it was now that youve broken it open.

[hoveringuy]

Here's what mine looks like.

[TinyT]

Please contact me at Tyler@thearcasylum.com and I will get you a redesigned one sent out.

I have added strapping to the area where the plate meets the subframe to prevent any tearing in that area

I have a fully fabricated version in the works and will replace any cracked subframes with these when they are available.

I am terribly sorry for this issue