Quote:
Originally Posted by 420sx
I dont think youve ever removed a cat then. My integra went from 197whp to 176whp with the addition of a Carsound 2.5" high flow cat, and no other changes made (aside from the tune). I've gutted a few cats in my day, and the difference is definitely noticable in the butt dyno. Have a look inside a catalytic converter, and then tell me its not an obstruction.
|
Quote:
Originally Posted by 420sx
I sold the integra long ago, but it was a B18C1 w/ B16 pistons and stage 3 crowers tuned on Hondata S200. The cat was a carsound- not an ebay brand, and the car was re-dyno tuned after the cat was installed. The cat was only installed so I could sell the car, the new owner wanted it put on. I couldnt beleive how much power was lost either, but dyno #'s dont lie. Obviously there could have been a difference in ambient temperature, humidity, etc (as the pulls were performed on different days), but they were made on the same dyno. Perhaps not ALL of that 21whp loss can be attributed to the cat, but I would have no problem blaming at least 15whp on it.
|
If you don't belive me, google it and there are some studies(one of them I read was actually a Honda) out there with cars that were stock, high flow, and catless... they dyno'd the same amounts and were all done back to back on the same day.
If you don't dyno back to back on the same day, you don't really know what changed because weather makes huge differenceso on numbers. Even something as simple as a different dyno will through everything off. So changing cats out at different times doesn't prove you actually gained. You wold need a baseline the day off the install and a run after the install to see if you actually benifit. Maybe on extremely high HP applications you get more out of it but typical street use shouldn't.
If you don't belive me, we can take my car to the dyno. I'll do a run as it is now(catess) and then we can put the stock catted mids back on and rerun. I guarentee I net less then 2HP difference and that is mostly because of the piping, not the cat itself. Gutting a cat loses HP because you are losing smooth airflow of a constant round pipe... atleast thats what I think(no research done).
Quote:
Originally Posted by The01Cav
all i'm trying to do is get a little more sound out of the car. I already put a small resonator and a aftermarket muffler on it, and it's quieter than a stock G35/350Z exhaust.
|
Do some research before you buy next time.