8YourV8

Alright. I have a peakboost Ramhorn manifold. Running a B18c stock block wih ARP head studs and a Garrett t3/t04e 60 trim .63 a/r at 10 PSI.

The top and center two bolts snapped off at the head flange on my manifold. They didn't come loose, they literally snapped off where the bolt screws onto the stud, and now there's about 1/2 - 1 cm of stud left that I might be able to remove with vice grips...

I'm guessing it's causing a minor boost leak since you can see carbon build up on the head right above the manifold's head flange.

Here's something I whipped up in paint.exe because I'm at work and don't have the car with me to take a photo.

What would be causing this to happen? Should I upgrade to ARP studs, even though it would be rather difficult to do with this type of manifold? Lock-tite? I am also guessing that this has also resulted in a slightly warped head flange, so I'll have to have it milled out and flattened so it seats onto the head properly....

dpetro1

the excess vibration and weight can cause them to loosen and/or snap. do you have a flex section in your exhaust?

also, you may have developed an exhaust leak. but since the area before the turbo is no pressurized, it isnt technically a boost leak. a pre-turbo exhaust leak will cause slower spool time though so you want to get that fixed ASAP

8YourV8

Ahh I see. Thanks. Yeah it is spooling a bit later than normal, but not really by that much. Will get this fixed within the next couple weeks. I'll post an update when I do. Working on some other things first.

And yeah, I have a flex pipe on my DP. (Purchased the DP from Full-race)

What is your preferred setup though, stock studs/bolts or ARP bolts? Is there really a difference when it comes to an exhaust manifold?

saywhat

Were they torqued to spec? It seems like a lot of people over torque those bolts and they end up snapping pretty easy.

8YourV8

Is FI spec the same as NA/stock? If so then yes. I've not read anywhere or heard anything about a turbo manifold needing more or less.

DeLucia

This is due to the manifold flange at the head heating up and expanding too much, thus breaking off the bolts

AlexDphoto

heating up too much? Would that indicate high EGT/Running lean?

fcluddington

when you pull the manifold off drill the attach holes a few sizes up in the manifold that way it will give it a little room to move around. I dont think it should be expanding and popping bolt heads off. use c5a anti seize when you install bolts.

8YourV8

I knew that much, but that would lead me to believe that re-torquing those bolts while the manifold is hot (which in my knowledge is supposed to be done?) would cause even more breakage. No?

My car runs on the rich side BTW. I don't have my data log sheets from my last tune atm, but I plan on going for another hour or two on the dyno once I finish all the crap I'm doing these next couple weeks.

I'll let everyone know how things work out after everything is finished. Thanks again for all the responses.