pre cats

Dooz · 10-17-2009, 05:43 PM

so im hearing a lot of stuff about pre cats in the spyders what are they exactly and what do they do

lbridges · 10-17-2009, 11:09 PM

The 3rd gen MR2 Spyder was a ULEV (Ultra Low Emissions Vehicle), achieved through what I presume is a two-stage catalytic converter system. The Pre-cats are the first stage, located in the widened section of the exhaust header (under the head shrouds). The catalytic material removed during a gutting process looks somewhat like a bunch of fiberglass. The material itself is held in the chamber, top and bottom, by a ceramic disc with holes big enough for the exhaust gas to pass through, but that will retain the cat material. The main cat is parallel to the OEM muffler system. And since the catalytic material is so close to the exhaust ports, there is a very quick rise time to meet emission standards -- if they are "gutted" and you live in a state/locale that measures such things, passing the emission test may require a warm engine.

10-17-2009, 05:43 PM	#1 (permalink)
Dooz No Skills Join Date: Dec 2008 Location: wagoner, OK Posts: 17 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	pre cats so im hearing a lot of stuff about pre cats in the spyders what are they exactly and what do they do

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10-17-2009, 11:09 PM	#2 (permalink)
lbridges No Skills Join Date: Jul 2006 Location: East Central FLA Posts: 143 Thanks: 1 Thanked 12 Times in 12 Posts iTrader Rating: (0/0% )	The 3rd gen MR2 Spyder was a ULEV (Ultra Low Emissions Vehicle), achieved through what I presume is a two-stage catalytic converter system. The Pre-cats are the first stage, located in the widened section of the exhaust header (under the head shrouds). The catalytic material removed during a gutting process looks somewhat like a bunch of fiberglass. The material itself is held in the chamber, top and bottom, by a ceramic disc with holes big enough for the exhaust gas to pass through, but that will retain the cat material. The main cat is parallel to the OEM muffler system. And since the catalytic material is so close to the exhaust ports, there is a very quick rise time to meet emission standards -- if they are "gutted" and you live in a state/locale that measures such things, passing the emission test may require a warm engine.