Once again, has anyone seen any dyno tests b4/after cats?
- Thread starter Pokageek
- Start date
In the past, I've seen articles about hp loss with cats 
Don't know how much help it would be to you Keith
The test motors used were typical 302 or 350 ci
The comparison was usually with the OEM cats
What I remember was the loss was 5 to 10
Of course, you would see more of a loss due to additional cubes
A high flow cat would be maybe half of that
I quickly Googled up this bit of info
Catalytic Converters
Grady
Don't know how much help it would be to you Keith
The test motors used were typical 302 or 350 ci
The comparison was usually with the OEM cats
What I remember was the loss was 5 to 10
Of course, you would see more of a loss due to additional cubes
A high flow cat would be maybe half of that
I quickly Googled up this bit of info
Catalytic Converters
Grady
Adam95GT
New Member
Thanks guys. Grady, is car-sounds also magnaflow?
Actually, I am 99% sure the answer is yes after researching. Ok guys, after reading Grady's article, the magnaflow looks good. What are you opinions on this one?
Magnaflow #642-59959
# Spun Catalytic Converter Center In/Out
# 3.00''
# up to 6.2 Liter Engines
Adam, what is catco?
Actually, I am 99% sure the answer is yes after researching. Ok guys, after reading Grady's article, the magnaflow looks good. What are you opinions on this one?
Magnaflow #642-59959
# Spun Catalytic Converter Center In/Out
# 3.00''
# up to 6.2 Liter Engines
Adam, what is catco?
Adam95GT
New Member
Adam95GT
New Member
As with any bolt on I don't thinkit's a ton of hp but will allow the engine to breathe and excelerate quicker. I've always noticed a good difference going from a stock h with 4 cats to an off road. My 5.0 there was a difference but the 2001 and 2003 I had made a huge difference.
Adam95GT
New Member
In this case we are talking about a beast ass 418w. Keith there is no dobut that cats will restrict flow. Every thing i have ever seen on a 302-306 is loosing about 5-10ish at the wheels. I however like how my car sounds with cats and i dont want to polute any more then i already do by driving a gas slurping v8. Cats are good for the enviroment and make your car sound good. I dont think i could stand the sound of that monster you have without cats. Ive noticed more and more you saying you want a car thats drivable. So why kill your ears? get a nice set of high flowing cats along with a nice mild cam and good tune. Whats the use of XXXrwhp if your not going to enjoy it.
For being a guy that loves the track my views are a little off. 
I have a set of pypes 3'' sitting at the garage. I need 2.5'' cats if you have a set to trade. Also let me know if you still want me to come down even if it is for lunch. My uncle is in st. michales so i even have a place to stay.
http://www.randomtechnology.com/tests.html
141-30000- 3" inlet/outlet
Earlier i think i had catco and carsound mixxed up!
nmcgrawj
Advanced Member
I've gotta agree with Adam. It seems like your original plan was to build a monster.....then you regretted a lot of it and toned it down some.
Simple question, how much power are u willing to give for the benefit of what cats offer?
Just like in turbo applications.....its forbidden to run flows for mufflers. But you always find those couple of guys who just love the sound....so 420rwhp....450rwhp....they dont really care. The car is fast enough for them and they love the sound, so they're happy.
Simple question, how much power are u willing to give for the benefit of what cats offer?
Just like in turbo applications.....its forbidden to run flows for mufflers. But you always find those couple of guys who just love the sound....so 420rwhp....450rwhp....they dont really care. The car is fast enough for them and they love the sound, so they're happy.
My car isn't too loud, and I don't have cats. If you have good mufflers, it's really not much of an issue.
Kurt
Kurt
pypesexhaust
Premium Sponsor
Keep in mind that high flow cats have minimal effect on performance. On a 225hp small cam 5.0, our Dyno tests only measured a 2.2 hp improvement with the cats removed. Now a 500hp motor could experience up to a 10hp drop but you still got a lot of power there unless you are trying to shave 1/10ths in the 1/4. I put cats back on my SC 05' because I like the sound way better. It got rid of that blatty super loud sound but is still plenty loud.
One other point, if you have added any significant power adders, don't even mess with ceramic cats. If your car isn't tuned perfectly, the ceramic brick will have a pretty good chance of failing. Big motors should have metallic substrate cats.
One other point, if you have added any significant power adders, don't even mess with ceramic cats. If your car isn't tuned perfectly, the ceramic brick will have a pretty good chance of failing. Big motors should have metallic substrate cats.
Ok guys. Makes sense to me. Right now I need to get rid of my 42# injectors and my lightening 90MM MAF. They are screwing up my drive-ability with this PMS that only kicks in at 4k RPM. If I had a computer that tuned me down low I could pull it off but I am SOL.
