Is there a precat on on some 107's?

In fact, now that I've looked more closely at the way the left catalytic converter feeds exhaust into the right catalytic converter, I also have to wonder whether the left one is a precat. too.

Admittedly, I dont really know what differentiates a cat from a precat, or if there even is a difference. But is it normal to have two cats feeding exhaust into another cat?

Thanks for the clarification.

Bill

Yes, they all have precats. Precats are smaller and hotter cat to help burn off any unburned fuel before it hits the main cat.

Old cats are not as efficient as the new one today... so it is not really necessary for precats anymore. However, two cats is better than one.

Thanks Tiger. You're a gem.

Bill

Precats are needed for the cars with 2 O2 sensors, upper and lower. Called a 3-way cat system.

Just curiou if that's really true? Wwhat effect does two cat or a precat - cat system have on power? Can't imagine it would be a very good one, especially with their tendency to get clogged over time?

Bob

They only get clogged due to lack of maintenance, oil burning, or coolant leaks due to cracked heads or blown head gaskets. Under normal conditions, they last a lot longer than the 8/80 warranty that the government mandates.