SCUD CAT Flow Dynamics

Richard, a 200 cpi in a large diameter cat would let too much flow going through. As a result, the cats would never be hot enough to be efficient which would give a CEL. With 200 cpi, the only choice is to reduce the diameter to keep the cats a the right temperature when cruising. Too small, isn't good neither as it is the case with the Fabspeed cats. The best solution are the Capristo cats which have the right diameter but they must be wrapped in heat shields to keep them hot enough (there is reason why the stock cats are wrapped). No lamba sensors extenders needed and no need to cheat on the DME. The length of the coated matrix plays here also an important role. We've been debating this subject in some very long threads

 

Thanks for sharing this pictures Richard. The cat interiors looks 100% simular to the 430 cats, interesting. They are dense but far from normal cars which have a much higher density. The ideal would be to go for a 200 cpi cat but having a diameter close to stock so that the length of the coating remains identical. You will be obliged to insulate them though if you want to avoid a CEL or avoid troubles with polution inspection.

 

do you know the weight of the Scuderia cats?

 

I have cargraphic cats if anyone is interested

 

How are the cargraphic cats doing? Have you got any issues with them? Improvements vs stock? I found their products quite interesting and they have a good reputation in the Porsche community.
Many thanks in advance,
Stef

 

What are my options if I want to remove the Scuderia CAT's completely without engine trouble?

 

Richard, are you commenting about how your cars sound inside, outside or both? It's hard to believe that a Scuderia - and a modified one at that - doesn't sound as good to you as a (stock?) 430 Spider.

That said, I have received many compliments on my stock 430 coupe's sound. People often ask me if it has a sport exhaust on it (or flat out..."what exhaust is on it?").

Good luck.

 

Do the Scuderia's exhaust valves seem to open at a higher rpm and with more throttle than the 430's (assuming both cars are set to the same manettino mode)?

How does the Scuderia sound with the exhaust valves set permanently open (disconnecting the vacuum lines)?

 

Rob, the valves on the Scud and F430 open exactly in the same way. I posted once a diagram which shows how the logic works. There is no difference between the Scud and F430.
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Who does them for the 430 Scuderia?

Thanks......

 

I do remember you posting that, but I was wondering what Richard was hearing when driving his own cars. Since, technically, the valve systems operate similarly, both cars' exhausts - though slightly different designs - should be somewhat close in volume throughout the rpm range. If anything, the Scuderia should be louder, period (no pre-cats, shorter piping).

Maybe one or both of his Scuderia's valves are a bit slow to open under vacuum. I would check their movement by manually turning them. Maybe they're binding or hard to turn for some reason. Every so often I give mine a shot of lubricant so they turn easily.

 

I agree, they can get a bit stuck. I do the same, a bit WD40 or better, copper greace, and they are all good again. But I think that Richard's frustration is not just the valves. Even switching the muffler doesn't improve the sound. Really weird. I've heard his Scud for real at his home and I can confirm that it sounds much quieter than my F430.

 

It's a mystery, for sure.

 

Tubi makes specific decat pipes for the scud.