997slover

Here in Brazil there´s an option that i believe is not available in Europe. i order my car withouth cats. The option is called "deactivated cats" . i believe with this option I have some more ponnies to play with. Here there are no restrict regulations regarding C02, so there´s no need to have cats. How many HP do you think this engine can gain by the removal of cats? Thanks in advance

Carbon_Ted

Not sure, but I would guess 5 hp-10 hp. I hope it's a no-cost option. In fact they ought to PAY YOU for the trace platinum in the cats. Have a dyno done if you spec the car without cats, I'm sure lots of folks here would be interested to know.

Edgy01

Back in the 80s Porsche worked hard to switch their engine line over to unleaded fuels,--and doing it in such a way that resulted in no performance differences between a leaded engine and a 'blei-frei' engine. I'm guessing that you may ultimately find little difference between them when you pull the cats off,--of course, you'll have less restrictions,--and if anywhere, what would be where the hp savings might be.

dan

meaker

I would guess around 5-10hp also. Just going by what some of these highflow cats add. No cats would be a little less restrictive over the high flows..

997slover

Thanks friends!!!
I posted this question in others 3 Porsche´s foruns, but here in the RENNLIST i had the best answers
Then my 997s has 365hp and is total stock, great
cheers

allegretto

Not to throw a wet blanket on the permanent pursuit of more power but pulling off your cats alone would likely lead to a decrease in power.

While it may seem intuitive that to remove any back pressure on the flow system of the engine would result in more flow and therefore more charge entering the cylinder, this is virtually never the case.

The balance of pressure at each stage from the front intake to the exhaust tip is all carefully researched and controlled by the experienced engineers at Porsche and every other company. These values may certainly be modified by deleting one component, but almost never is this beneficial to the overall flow which is what IC engines are all about. Each succesive stage depends upon the previous one.

Add to that, the timing values are likewise developed to take best advantage to the presumed flow characteristics of the entire system. Without changing them as well to accomodate any real gained efficiencies, additional power may not be realized and likewise may result in a net negative effect.

To blithely assume any additional HP is optimistic at best.

Coochas

Out of curiosity, is leaded gasoline (i.e. real tetraethyl lead or similar) still sold in Brazil? I am wondering if this is why Porsche allows "cats delete" (Oh that sounds awful) because of the potential for accidental catalyst poisoning with leaded gas.