Tob Posted September 23, 2012 Report Share Posted September 23, 2012 An update on the MRT High flow catted H. after about a 1K miles of driving on a car with a pulley and tune. The passenger side cat is toast! I've been getting a P0430 for about 2 weeks that became increasingly more often and finally as soon as I would clear it. Started noticing a rattle this past week upon starting the car each morning. Pulled the pipe off yesterday and it sounds like rocks rolling around in the passenger side cat. I'm interested to hear what MRT has to say. MRT has a sub standard part for these cars. Wow, very disappointing to hear. I emailed them awhile back asking about the cats since I was wanting to run this H pipe: thank you for your note and your question. The cats we use are constructed especially for MRT....there isnt a horse power limit on the cats. Catalyst life is almost completely dependent on the tune and fuel. If the tune is too rich or too lean catalyst damage will occur, if leaded fuel (some race gas still has lead in it) is used, catalyst damage will occur. We had high performance and supercharged applications in mind when we selected the catalyst construction used on MRT h-pipes. I hope this helps, please feel free to contact us at (734) 455-5807 if you have any further questions. This isn't an easy subject to address. MRT is responding to consumer demand for a relatively low cost custom exhaust with catcons that aren't rated or certified to withstand a specific engine combination. When teamed with a myriad of power producing combinations in the area of 500rwhp and above, eventual failure is imminent. Haven't you guys noticed how little MRT actually mentions regarding the cats themselves in their ads? Here's a blurb from them on the subject... ...premium high-flow catalytic converters that allow your Shelby GT500 to breathe much easier From here. Did any of you inquire as to who and where these are manufactured? What hp/limits they are rated for (other than Ron)? Substrate type? Cell count? You're relying on pure advertising with nothing to back it up other than the hope that MRT wouldn't steer you wrong. And all of this for an alleged "10% Improved flow over factory system"? You should be asking: -The core/substrate. Is it metallic? - Is it ceramic? MRT mentions on their site that they offer two types (depending on application) of substrates' date=' either a street (ceramic) or race (metallic). [i']Neither[/i] of which is EPA legal. The metallic substrate (or race as they call them) cats they use are pretty much guaranteed to blow out in short order behind a huffed 5.4 or 5.8 liter engine in a GT500, stock or modified. Because the improvement in flow comes from a restriction reduction, or decreased cell count, the wound structure of the core can be a bit fragile to say the least. After a given number (entirely random) of pressurized heat cycles the core is apt to blow through, such as in the following generic illustration You'll know when the above happens as there will be a noticeable change (read: loud) in tone. And if you have the choice, better the blowout style failure than a melted/plugged cat. Serious engine damage can result leaving you with a second mortgage for an engine replacement. Some cat manufacturers have come up with different style matrices in an attempt to strengthen the inherent flaw with a simple wound metallic core, such as that of an "s" style core... The claim? Unique S-winding construction, which makes it four times more durable than other metallic catalysts. This construction also prevents breakdown and telescoping, which other catalytic converters are prone to. From here. I've yet to see any scientific evidence regarding improvement when used on a GT500 or otherwise. Regarding MRT's use of a ceramic core, I've yet to see any mention from them regarding cell count or the bonding method their manufacturer (unknown) uses to adhere the core/substrate to the outer shell. Again, a lower cell count will typically flow more but won't reduce particlulate as well as one utilizing a higher cell count. Technically, the core structure of a lower cell count cat will be physically weaker as well. From what I've seen, typical cell counts are halved (approximately) when going from stock to a "high flow" unit. My take - avoid aftermarket cats. Either utilize the stockers or get rid of them altogether. To date, the 'best' factory cat Ford has offered for our beloved GT500's are those used on the '13 GT500. The improvements Ford made to them over what were used from '11/'12 are minor but rather significant. The canister on the '13 cats has been upgraded to 304 stainless from 409 stainless and the ceramic media Ford uses are now bonded to the shell with a heat catalyzing cement. From here. You'd be hard pressed to tell the difference between an H pipe/cats from an '11/'12 and a '13. I know, I've compared them in detail (here). In the above shot, the '13 assembly rests on top of the '11/'12 assembly. If you plan on modifying your engine and would like to use headers (for example) and use converters, I'd consider modifying the stock cats so that they can used. They'd be further downstream than stock, cooler, and would need to be accounted for in an aftermarket tune. But they'd be much more likely to last than anything offered by MRT or anyone else for that matter. Link to comment Share on other sites More sharing options...
03 DSG Snake Posted September 24, 2012 Report Share Posted September 24, 2012 Doesn't seem too difficult for a good exhaust shop to take the MRT pipe and stocker, chop the cats and swap them over. But at that point it would be easier just to take the stocker and cut the X for a weld in H. Link to comment Share on other sites More sharing options...
Tob Posted September 24, 2012 Report Share Posted September 24, 2012 Therein lies the rub (and you are spot on, Ron) - there are plenty of alternatives, however custom, that are much better than the cookie cutter compromise from companies like MRT that will ultimately fail their customers as well as the cars they seek to improve. Link to comment Share on other sites More sharing options...
aclass Posted September 25, 2012 Author Report Share Posted September 25, 2012 You obviously know a lot more about cats than I do. I guess it's my mistake to have confidence in a major exhaust manufacturer to develop an item specifically for a GT500 and have it last for less than 1000 miles. They certainly won, and I learned a valuable lesson the hard way. Hopefully my mistake will prevent someone else from making the same one. Link to comment Share on other sites More sharing options...
Tob Posted September 27, 2012 Report Share Posted September 27, 2012 I guess the best lesson is that you really have to research any mods you'd like to make. Hopefully, somebody comes out with and extremely robust, high flow, aftermarket catcon (that isn't ridiculously expensive). Link to comment Share on other sites More sharing options...
mikes35 Posted November 10, 2016 Report Share Posted November 10, 2016 Hopefully my mistake will prevent someone else from making the same one. Reading your post helped me! I'm currently looking for something to replace my stock cat that is leaking. Was doing research on the MRT catted H and came across this old post. Thanks for sharing, they are now off my list. Back to the drawing board, hopefully I'll figure out a reasonable replacement for what Ford want's $1200 each... Link to comment Share on other sites More sharing options...
03 DSG Snake Posted November 12, 2016 Report Share Posted November 12, 2016 Reading your post helped me! I'm currently looking for something to replace my stock cat that is leaking. Was doing research on the MRT catted H and came across this old post. Thanks for sharing, they are now off my list. Back to the drawing board, hopefully I'll figure out a reasonable replacement for what Ford want's $1200 each... You can find the 2013 Hmpipe with cats for about $650 new if you know where to look. Link to comment Share on other sites More sharing options...
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