MRT H Pipe.... CRACKED.. No warranty.!!

[Bridgie]

I've had my MRT H pipe on the car for about 18 months, when I started to get a rattle sound at about 1900-2000 rpm.. it sounded like a heat shield loose or something touching within the system

With the car up on ramps, I crawled under to find nothing loose or touching.. so off to my local mechanic.
After 20 minutes of searching for loose parts or clashing brackets, we noticed this Crack through both the H part of the pipe, the weld and the main through pipe.

MRT consider this as an outside influence and not down to material or Workmanship.. NO Warranty coverage

Has anyone seen this before or can make an educated opinion on the cause..? The crack would be going against the grain of the cold rolled Stainless steel, so I cannot fathom how this can happen... what do you think...?

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[Mike's Mustang]

Wow, those welds look bad.

 

[Southview]

Looks like they put it together with JB Weld:lol:

 

[GTBOB]

Welds should never look like female anatomy....

 

[15RRGT]

Welds should never look like female anatomy....

Lol very funny but true :lol:

 

[FrancoP]

My ford racing X pipe cracked too.. I thought mine was do to the MAK cat deletes and not having the flex pipe anymore

 

[jasonstang]

That is weird it's cracking that way.

 

[HISSMAN]

It didn't crack at the weld, which leads me to believe that you struck something. Welds don't have to look good to be strong.

 

[Bridgie]

Nothing hit and no impact damage to anywhere along the exhaust.
My garage is very surprised that MRT have not warrantied the fault.

As you can see from the pictures it is a strange angle for the crack to be, there is no shifting of brackets or clamps evident, which would be much weaker than a welded pipe, had an impact occurred.

 

[jasonstang]

It didn't crack at the weld, which leads me to believe that you struck something. Welds don't have to look good to be strong.

It didn't crack at the weld but it cracked at the cut. When you have a cut point it weakens the pipe. Repetitive heating and cooling cycle can cause the metal to fatigue and crack.

 

[Bridgie]

It didn't crack at the weld but it cracked at the cut. When you have a cut point it weakens the pipe. Repetitive heating and cooling cycle can cause the metal to fatigue and crack.

Exactly, which is why as an engineer myself and with the opinion of my mechanic, having not see this type of failure before, we assumed that workmanship or materials in this case led to its failure.

A hot Pilger rolled or funnel Milled process of the tube manufacture itself would not cause a crack in this way, more likely with the rolled grain within the Steel as a result of the working to produce crack proporgation longitudinally.

To make the assumption that something has struck the system could be a natural conclusion, but in this case I cannot agree.

 

[jasonstang]

Exactly, which is why as an engineer myself and with the opinion of my mechanic, having not see this type of failure before, we assumed that workmanship or materials in this case led to its failure.

A hot Pilger rolled or funnel Milled process of the tube manufacture itself would not cause a crack in this way, more likely with the rolled grain within the Steel as a result of the working to produce crack proporgation longitudinally.

To make the assumption that something has struck the system could be a natural conclusion, but in this case I cannot agree.

I find it funny that MRT would conclude the failure was cause by outside force when they have not even looked at the whole assembly or shown evidence of the said impact. To me that is just pure ignorance.

 

[Bridgie]

My thoughts exactly.. hence the post on here to see if anyone else has seen similar issues.
I have not approached MRT directly, as I purchased through a well known Parts retailer to the market...

I’m not sure what good going direct to MRT will do...!

 

[jasonstang]

My thoughts exactly.. hence the post on here to see if anyone else has seen similar issues.
I have not approached MRT directly, as I purchased through a well known Parts retailer to the market...

I’m not sure what good going direct to MRT will do...!

Can't hurt to ask. Maybe they will aware the issue and make changes such as a more rounded cut instead of a sharp cut like now?

 

[kz]

I've had my MRT H pipe on the car for about 18 months, when I started to get a rattle sound at about 1900-2000 rpm.. it sounded like a heat shield loose or something touching within the system

With the car up on ramps, I crawled under to find nothing loose or touching.. so off to my local mechanic.
After 20 minutes of searching for loose parts or clashing brackets, we noticed this Crack through both the H part of the pipe, the weld and the main through pipe.

MRT consider this as an outside influence and not down to material or Workmanship.. NO Warranty coverage

Has anyone seen this before or can make an educated opinion on the cause..? The crack would be going against the grain of the cold rolled Stainless steel, so I cannot fathom how this can happen... what do you think...?

The cause is degraded material properties after welding (and likely no heat treatment after) and HCF (High Cycle Fatigue) - vibration from the exhaust / engine.
Poor quality weld + poor quality material choice (and maybe pipes were from bad batch - there's always a distribution in material properties). Also could have been damage that initiated the crack at the cut which you can't see.
Cutout in the pipe concentrates stress (since the whole thing is under bending from the weight of the exhaust)...
It is a classic crack at the weld. Saw that 1000 times.

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