1991 RS 305

Does anybody know which of these cats is prefered:

magnaflow 3" inlet/outlet metallic substrate, heavy metal catalyst:
http://www.summitracing.com/parts/MPE-99009HM/

magnaflow 3" inlet/outlet ceramic substrate catalyst:
http://www.summitracing.com/parts/MPE-94019/

94019 has a capped airtube. I don't need the airtube, but it costs less. Both are the same size, I'm wondering if the metallic is freer flowing and/or more resistant to substrate issues like ceramic is known for over time? The common thought today seems to be that all cats are 'high-flow', and that one brand flows as well as the other, but I'm not so sure with so many options to pick from.

Heres one thats longer--19.5" overall. I assume a larger one would have more backpressure, but I read on here somewhere that larger have less...does anyone have any ideas?
http://www.summitracing.com/parts/mpe-99509hm/overview/

Chevy2035

Its true that no cats flow any better than another. They are all the same, The difference in the Steel Wire and the Ceramic is OBD or OBD2 car. Also burning Temp's. Wire is for lower temp, Ceramic for higher.
Newer cars are getting more complicated, They are reading more with the o2 sensors that provides the Air / Fuel mixture and other things so without programming the car you need to have the right converter on it.

Larger cat will decrease the back pressure slightly, But not enough for any type of performance gain, Your exhaust still travels through the exact same catalyst at the same speed, The only difference is there is more air volume in the bigger one. Bigger cat = Quieter car for the most part.

Use a Catco, Lifetime Warranty and they really do replace there stuff, Magnaflow will say spin ya for years.
http://www.summitracing.com/parts/cto-6907

Dont spend all the extra money on a high flow performance cat, its like throwing money in the wind.

Orr89RocZ

iTrader: (20)

If you havent bought one yet i still have an unused magnaflo cat i believe, its 3", no air tube. I'll see if i can find the part number

1991 RS 305

Thanks for the info Chevy2035 and Orr89RocZ. The Catco 6907 sounds like a good way to go and a lower cost alternative to the Magnaflow 94019. In fact, its about 1/2 the cost @ $45.97. The body and OAL is less on the Catco, but the amount of catalyst inside is probably close to the same in both. Since I have no cat now, Hooker 2460's and a Heartthrob HVS muffler, http://www.heartthrobexhaust.com/hea...smufflers.html the exhaust note is slightly aggressive, a cat might take the edge off abit.

Heres another, Catco 6577. http://www.summitracing.com/compare. Its 2" longer than the 6907, same price. In the spring, I'll check out which of the 2 will fit better. With headers, the int pipe is modded for no cat.

1991 RS 305

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1991 RS 305

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