Cats
07-26-2006, 01:39 PM
#1
Cats
Excerpt from 993tt.com:
Sport Catalytic Converters
As our 993TT's age, one of the things that happens is the stock catalytic converters become plugged-up drastically reducing airflow, and robbing power. It's not uncommon to see a 60% blockage. The Sport Catalytic Converters are designed to pass more air through them as compared to the OEM units. However, dollars can be better spent elsewhere unless the ECU is programmed for the Sport Cats. There are a few different types of Sport CATS available in the marketplace. Be sure to get the 100-Cell 130mm Sports CATS, not the smaller ones. A good source for these is Kevin at Ultimate MotorWerks. Kevin removes the OEM CATS and replaces them with the 130mm Sports CAT Inserts.
Catalytic Converter Replacement Pipes
Steve in Los Angeles installed a set of pipes that replaced the CATS. He has added the GT2 K-24 Turbos / ECU, and noticed the loss of power below 3,800 RPM. With the replacement of the CATS, Steve has noticed a dramatic power gain at 2,500 RPM and above. These bypass pipes can be bought from Hershel at Car Graphic USA. Just remember it is illegal to run without catalytic converters, although the difference is huge with running the bypass pipes. The big power gain has been confirmed by several people on the Rennlist message boards.
Does this seem like contradicting statement concerning power below 3800rpm and above 2500rpm?
Which would you choose, 100 cell cats or cat bypasses?
Any "Check Engine Light" issues?
Any furthur confusing the matter:
Excerpt from 993tt.com:
Sport Cats $ 1,600.00 ea Schatz Motorsport Minimal Gain - (Don't Bother)
Cat Bypass Pipes Car Graphic USA Big Gain
Or is it only me thats confused or uniformed?
Sport Catalytic Converters
As our 993TT's age, one of the things that happens is the stock catalytic converters become plugged-up drastically reducing airflow, and robbing power. It's not uncommon to see a 60% blockage. The Sport Catalytic Converters are designed to pass more air through them as compared to the OEM units. However, dollars can be better spent elsewhere unless the ECU is programmed for the Sport Cats. There are a few different types of Sport CATS available in the marketplace. Be sure to get the 100-Cell 130mm Sports CATS, not the smaller ones. A good source for these is Kevin at Ultimate MotorWerks. Kevin removes the OEM CATS and replaces them with the 130mm Sports CAT Inserts.
Catalytic Converter Replacement Pipes
Steve in Los Angeles installed a set of pipes that replaced the CATS. He has added the GT2 K-24 Turbos / ECU, and noticed the loss of power below 3,800 RPM. With the replacement of the CATS, Steve has noticed a dramatic power gain at 2,500 RPM and above. These bypass pipes can be bought from Hershel at Car Graphic USA. Just remember it is illegal to run without catalytic converters, although the difference is huge with running the bypass pipes. The big power gain has been confirmed by several people on the Rennlist message boards.
Does this seem like contradicting statement concerning power below 3800rpm and above 2500rpm?
Which would you choose, 100 cell cats or cat bypasses?
Any "Check Engine Light" issues?
Any furthur confusing the matter:
Excerpt from 993tt.com:
Sport Cats $ 1,600.00 ea Schatz Motorsport Minimal Gain - (Don't Bother)
Cat Bypass Pipes Car Graphic USA Big Gain
Or is it only me thats confused or uniformed?
07-27-2006, 01:33 AM
#4
Originally Posted by Kevin
Not all 100 cell Cat systems are the same...
If it isn't at least 130mm, don't waste your time and money..
If it isn't at least 130mm, don't waste your time and money..
Since the information under "Sport Cats" on 993tt.com refers to you as a good source, can you elaborate more?
Can your 100 cell 130mm cats be installed alone or should the ECU be also programmed avoid CEL from coming on?
Why the issue of Sport Cats-Minimal Gain/Don't Bother vs. Cat Bypasses-Big Gain?
And aftermarket muffler or muffler bypasses recommendations?
07-27-2006, 01:13 PM
#5
Addict
Rennlist Member
Rennlist
Site Sponsor
Rennlist Member
Rennlist
Site Sponsor
Your ECU always need to see the O2 sensors, and a result thus the 2nd set of O2 sensors. Yes, many people will tie them up outside the exhaust but this is not a solution. Especially if you have a stock ECU or one that is programmed with CATs in place.
Large diameter CAT's will a tuned ECU will out-perform a similar car with cat bypasses. Now if one has custom tuning that deletes all emission aspects and OBD2 compliance, that's a entire different story. But, for most of us, we have to meet emissions.
Like wise, if you install 130mm highflow cats on a stock engine with stock ECU you will see a small boost increase. However, to maximize your performance, buy the ECU and turbochargers which are tuned together..
Large diameter CAT's will a tuned ECU will out-perform a similar car with cat bypasses. Now if one has custom tuning that deletes all emission aspects and OBD2 compliance, that's a entire different story. But, for most of us, we have to meet emissions.
Like wise, if you install 130mm highflow cats on a stock engine with stock ECU you will see a small boost increase. However, to maximize your performance, buy the ECU and turbochargers which are tuned together..
