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You can make power with catalytic converters.

727 Views 3 Replies 3 Participants Last post by  Macgyver
There is a stigma attached to cats in the performance world. That you can't make good power with them on your vehicle. This may have been true 20-30 years ago, but it just is not anymore.

We recently installed a catalytic converter on our customers 500 whp car to be more emissions compliant and get the over-all noise of the exhaust a bit quieter. We also switched over to ECUtek from uprev on this car, so a full re-tune was in order. The car easily made 480 whp and 369 ft lbs of torque at a similar boost level to when it was cat-less, with a 8000 rpm rev limit. To make the boost curve a little less violent, we brought it on a bit more gentle, which resulted in the "20" whp loss. But in reality, on a colder day, it probably would still have made 500 on the dyno.

It is the smoothest curve we have gotten out of this much power, and shows that just because you want a race car, does not mean you cannot be friendly to the planet.

This is the same federally legal catalytic converters we use in all of our downpipes and second cat pipes.

We have a few other little changes to make to the car for the owner, and then hopefully we can get him to shoot us some driving footage.

Video of the last power pull.

Grille Mesh Rectangle Net Pattern
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An OE cali spec cat can see upwards of 1000 degrees when exposed to excess exhaust pressure and increase heat from higher combustion temps. These high flow ones might see 800* under heavy loads. They flow nearly 50% more air through them, so they don;t create a lot of back pressure, and as we all know, pressure creates heat, so it really does help. I also position the cats far enough away that a good amount of heat should be out of the exhaust, but close enough that the cat warms up and does its job.

Melting (damaging really) a cat is just out-flowing it and applying more heat that is was intended to see. That's why you can "melt" the stock cat if you really crank the boost up. It bottlenecks to a ~1" pipe before the cat, which means the heat stay to it for longer under heavy load, and the pressure increases a LOT, then after the cat (on fwd model) the reduces to a sharp 90* bend with an ID of ~1.125" which means the pressure AFTER the cat is not much better.

Modern aftermarket cats can still be damaged. If I did a pull and looked at the cat and saw it glowing, then I would say its getting too much power put through it.
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