why would you hollow out a cat just because you've added a turbo?

 

exhaust systems work differently in turbo, you want to free up as much restriction for a turbo setup to allow faster spool up time.

In NA cars, you need back pressure for the car to have any torque or you loss all torque if you have 0 back pressure.

 

you NEVER NEED BACK PRESSURE, EVER!!!

i hate when people say you need it...so annoying!


what you need is exhaust velocity, and backpressure is the negative result of getting velocity. but as we've found on the dyno, it's MUCH easier to keep velocity in a vtec engine...seeing as they're well over 100% volumetric efficiency. Any b-series vtec engine loves 3" exhaust, n/a. even stock, we've seen 8whp/8tq gained over the entire powerband over stock...and 2-3 al over the plot when going from 60mm exhaust! on the fit...i think 60mm would be just about perfect for a stock or mild (you can't do anything but mild...lol) n/a setup.

 

still, why would you hollow out your cat? it doesn't make sense. hollowing out your cat rather than buying a test pipe is like taking a crow bar to your headlights on a track car rather than buying the lexan headlight replacements.

the point is this - even on my turbo car, which makes 340whp, i still have a high flow cat. i would probably gain another 5 or so whp with a cat delete test pipe, but i think it would be entirely irresponsible to do so. i mean, do you know how tough it is to feel 5whp? and people are typically not racing their fits,

so i have to ask again, is there a good reason to hollow out a cat?

 

ohh...in that case. No reason to. Buy a downpipe, or a cat replacement. I though the question was more so in regards to why to by-pass it.

 

i'm with you 100% brotha. though i'm interested to hear people talk about their loss of power when using a hollowed cat. i've seen it posted in quite a few forums.

 

thx again for the pros and cons as to keeping the cat/losing the cat. and gaining 5 hp seems like a lot when it comes to the fit...every little bit helps.

 

just my opinion, but unless you are in a competitive drag racing class that allows test pipes, the inconvenience of not having a cat outweighs the maybe 5hp you'll utilize once in a while.

 

since we all know fits are the king of the streets, 5hp counts right?

have fun cleaning the build up off your rear end...

 

Hollowing out your catalytic converter is destructive, illegal, and very expensive to replace. Replacing the catalytic converter with a test pipe might help spooling of a turbo but it is not needed and is illegal. The catalytic converter on your Fit is not going to impede a bolt-on turbo kit very much at all.

What I would look at if you were installing a turbo is the design of the o2 housing, some people call it a dump pipe. Since this is an after market bolt-on kit it probably has a very good outlet and down pipe as well.

I hope this helps.

 

i just ordered a megan header, im running a fujita sram, and skunk 50mm ex. im gonna order the megan cat del next week. will post my comments on setup with cat compared to cat del. just butt dyno and mpg.( the cat del will not be ran every day, just for kicks)
stay tunned for post!