awe exhaust rattle

[Jaymax85]

hi all

i bought a 6 month old awe non resonated switchpath from a forum member. Its in perfect condition. I had a local shop install it, fitment was ok, had to use a couple of washers on the new AWE brace to ensure fitment. Sound is nice and deep, a bit loud on WOT, def took a bit getting used to.

I am, however, encountering a cold start exhaust valve rattle, that is pretty loud. I had heard about this, but doesn't seem like there is much info when I searched. I know there was an early change in the design of the switchpath mufflers.

My question is: is there something I did not adjust to tighten the valves?

[iamvietness]

Josh/AWE

[ricerx1]

Originally Posted by HELLOimJ

hi all

i bought a 6 month old awe non resonated switchpath from a forum member. Its in perfect condition. I had a local shop install it, fitment was ok, had to use a couple of washers on the new AWE brace to ensure fitment. Sound is nice and deep, a bit loud on WOT, def took a bit getting used to.

I am, however, encountering a cold start exhaust valve rattle, that is pretty loud. I had heard about this, but doesn't seem like there is much info when I searched. I know there was an early change in the design of the switchpath mufflers.

My question is: is there something I did not adjust to tighten the valves?

If the exhaust you bought was 6mo old, most likely it has the updated exhaust valve with the spring clips. These exhaust valves should not rattle. If you stick your head under the car and see if exhaust valve looks like the pic i attached. That should be the new style valve.

If it is the new style valve look under to see if the silver u clip that holds the shaft for the exhaust valve is still there and tight.

Take a look under your car and look at the brace and see if the pipes are touching the brace.

I'm thinking most likely you are getting a loud rattle it is most likely against the cross brace.

I just installed an awe exhaust that I bought off a member here. I installed it myself and I have readjusted the exhaust about 6 times before I finally got it right (installed without any spacers). I blame it on learning curve to installing a multi piece slip fit exhaust that can adjust length and pipe clocking on 6 different joints. So best to go to a shop that has installed the exhaust before. Also working on jack stands didnt help.

Few things i noticed.
-Cold start rattles are usually from the cross brace, as the exhaust heats it expands (length) and clears the brace better.
-Muted knocking / rattle is usually from the driver side pipe against the diff carrier. This usually happens when the exhaust gets hot.
-The undercar heat shielding is inconsistent some cars needs to be pushed away slightly in some spots.
-torque the accuseals to 40ft/lbs retorque to 40ft/lbs after about 50-100 miles as they do loosen a bit when it settles in
-for the 108mm tips put only 2/3 - 3/4 of the clamp on the exhaust tip and let the rest overhang. the clamp are too wide and the inside edge sits too close to the cuts to clamp strongly. (i broke 2 t bolt clamps till i figured it out)
-when installed properly the left pipe sits slightly lower then the right pipe.

[Jaymax85]

i definitely have the new style valves
i will check this all
thanks

Originally Posted by ricerx1

If the exhaust you bought was 6mo old, most likely it has the updated exhaust valve with the spring clips. These exhaust valves should not rattle. If you stick your head under the car and see if exhaust valve looks like the pic i attached. That should be the new style valve.

If it is the new style valve look under to see if the silver u clip that holds the shaft for the exhaust valve is still there and tight.

Take a look under your car and look at the brace and see if the pipes are touching the brace.

I'm thinking most likely you are getting a loud rattle it is most likely against the cross brace.

I just installed an awe exhaust that I bought off a member here. I installed it myself and I have readjusted the exhaust about 6 times before I finally got it right (installed without any spacers). I blame it on learning curve to installing a multi piece slip fit exhaust that can adjust length and pipe clocking on 6 different joints. So best to go to a shop that has installed the exhaust before. Also working on jack stands didnt help.

Few things i noticed.
-Cold start rattles are usually from the cross brace, as the exhaust heats it expands (length) and clears the brace better.
-Muted knocking / rattle is usually from the driver side pipe against the diff carrier. This usually happens when the exhaust gets hot.
-The undercar heat shielding is inconsistent some cars needs to be pushed away slightly in some spots.
-torque the accuseals to 40ft/lbs retorque to 40ft/lbs after about 50-100 miles as they do loosen a bit when it settles in
-for the 108mm tips put only 2/3 - 3/4 of the clamp on the exhaust tip and let the rest overhang. the clamp are too wide and the inside edge sits too close to the cuts to clamp strongly. (i broke 2 t bolt clamps till i figured it out)
-when installed properly the left pipe sits slightly lower then the right pipe.

[peterke7758]

I have the exact problem with my new AWE non-resonated exhaust installed on my F80 M3. The rattle only happens during cold start, for about 10 seconds, and then goes away when the car warm up. The rattle seems coming from the middle section of the car, which at first I thought I have some coins in the center console whih vibrates and making the noise.

Today I went to my body shop and lifted it up. Cannot see anything wrong with the exhaust installed and the cross brace is not touching the pipes at all (we trimmed and made it thinner when installing, so it will not touch the pipe).

All my shop did is to retighten everything up, since they said they did not make it too tight when installing.

And now the rattle sound was gone.

Hope this will help.

[MrMegambo]

Originally Posted by ricerx1

If the exhaust you bought was 6mo old, most likely it has the updated exhaust valve with the spring clips. These exhaust valves should not rattle. If you stick your head under the car and see if exhaust valve looks like the pic i attached. That should be the new style valve.

If it is the new style valve look under to see if the silver u clip that holds the shaft for the exhaust valve is still there and tight.

Take a look under your car and look at the brace and see if the pipes are touching the brace.

I'm thinking most likely you are getting a loud rattle it is most likely against the cross brace.

I just installed an awe exhaust that I bought off a member here. I installed it myself and I have readjusted the exhaust about 6 times before I finally got it right (installed without any spacers). I blame it on learning curve to installing a multi piece slip fit exhaust that can adjust length and pipe clocking on 6 different joints. So best to go to a shop that has installed the exhaust before. Also working on jack stands didnt help.

Few things i noticed.
-Cold start rattles are usually from the cross brace, as the exhaust heats it expands (length) and clears the brace better.
-Muted knocking / rattle is usually from the driver side pipe against the diff carrier. This usually happens when the exhaust gets hot.
-The undercar heat shielding is inconsistent some cars needs to be pushed away slightly in some spots.
-torque the accuseals to 40ft/lbs retorque to 40ft/lbs after about 50-100 miles as they do loosen a bit when it settles in
-for the 108mm tips put only 2/3 - 3/4 of the clamp on the exhaust tip and let the rest overhang. the clamp are too wide and the inside edge sits too close to the cuts to clamp strongly. (i broke 2 t bolt clamps till i figured it out)
-when installed properly the left pipe sits slightly lower then the right pipe.

My shop removed the m340i cross brace at the exhaust was that a good idea or should I put it back. I have the LCI 23 m340i and my exhaust rattles alot.