Now that I’m putting everything back in with the billet subframe bushing which holds everything to the car much more closely and tightly, the crossmember has managed to crack.
Before you think it was because I over torqued it, let me say that I didn’t. Bentley Manual says torque it to 110nm + 1/4 turn.
That being said, I’m assuming I absolutely need a new one correct? Here are some more photos to get a full view of what cracked.
Your help is always appreciated euro. But do you mean yes you need to replace your subframe but I’d pay to have one built, or no you don’t need to replace it, but if you do you may as well pay somebody to make one? Thanks bud.
I’m not sure man, other guys like Justin and Jimmy may want to chime in. Considering the amount of power you’re making I might be a little more worried about the crack. I know 91gl broke his tranny crossmember while making far less power than you are.
Now I haven’t done this with a cross member but it may work…
I have a local shop that does a lot of welding for me and I had them weld a cast aluminum diff case. I have not seen any ill effects but obviously your crossframe will have more stress on it
Also, I wouldn’t personally drive with it like that as it looks like a pretty decent sized crack. It almost looks like its pulling the outer edges apart so I would assume it will only get worse unless replaced or repaired.
Yeah I think I’m just gonna buy a used one. No need to risk something catastrophic over $120. I just need to figure out how to wiggle it out now. I couldn’t get it out because of the headers when I pulled everything out the first time.
Cast aluminum is quite brittle. Was there some debris between the new AL subframe bushings and the subframe itself? Just tightening the bolt to spec, or even less, with debris in the way, could cause a failure like that, or could it have been not enough clearance or misalignment issue with the new bushings?
I little concerning for me as I have those same bushings sitting on my shop bench waiting to get installed after I get my car back from JHM…again.
When you get the subframe out, would love to hear an update to what you believe may have caused it.
In the meantime, no way in hell would I drive around with that crack.
It looks like the car bottomed out there at least once. Probably on a speed bump or something. You can see a chunk out of the crossmember right where the crack started. Look closely at this photo.
The subframe bolt is on the bottom in the above picture. According to Bentley you tighten the 2 other first then the subframe bolt. While I was under he car I put the subframe bolts in first obviously to hold the thing in. I turned the subframe bolts all the way until it was snug up against the car. At that point the holes for the other 2 bolts were so far from the car that I couldn’t even thread em.
I decided to read a little more closely and it said tighten the other 2 bolts to spec first and then tighten the subframe to spec. I went driver side first and then passenger. Torque spec for the subframe bolts is 110nm + 90*. By the time I was at 75 maybe it just snapped.
Luckily I was able to find one on VZ for $100 shipped. It’ll be here Friday and I’ll finally be able to pull the car off jack stands for the first time in 3 weeks.
In the meantime I decided to order the 034 subframe carrier inserts.
just work bro. busy as fuck but im done now. im officially on vacation. wife and I are off to panama on Thursday and once I get back its all about the car. im going to get the supercharger finished up and then im gonna have my local audi guy help me with the clutch. its killing me to walk past it covered in dust and torn apart especially now that the sun is out.
Got the crossmember I bought from an AZ member in over the headers without too much of an issue. Started torquing everything down and again I get a pop. No it was the torque wrench letting me know I was torqued to spec but rather the crossmember snapping again. WTF!!!
Somebody please chime in if you think I’m doing something wrong. Im lining everything up before tightening it down. Is this just not going to work unless I get a crossmember that is in perfect condition?
