Removing Cat

I have a 02 VFR 800 and I want to remove the cat for more sound. I was wondering if there are issues in doing so. Possible loss of power or back pressure? Any help would be awesome.

 

What did the cat ever do to you?!!!




BTW, welcome to the club newcomer! Where do you reside?

 

I'm curious too, I have an '05 and I work as a QC inspector in a weld shop to making something would be easy for me. After mod will PC3 be required?

 

Just get a big dog, cat'll never be a problem again...

 

On a more serious note...You'll need to take care of the O2 sensors in the exhaust system. Most folks add a power commander for smoother power curve. Other than that, hack away.

You should notice a drop in heat too.

There are several threads about removing the cat and O2 sensors here. The search function is your friend.

 

Thanks. I'm gonna have to do some searcing and reading then.

 

It ate my goldfish.

 

Sorry, missed the bottom part. Thanks for the welcome. I'm from Grand Rapids, Michigan.

 

Then my question is this. By removing the cat, would the system then perform similar to putting 98-99 headers on the bike.

98-99 headers
O2 elim
PC3
Two Bros slip on

equate

2002 cat less headers
O2 elim
PC3
Two bros slip on

 

Theoretically X, the answer is yes... BUT there are a huge mess of threads (some closed because they got kinda messy) on here about it...

 

If Dos Echo3Niner says so! Lets forget I even asked the question Don want to be the reason to cause another messy thread. Lest I get :chairshot:

 

98-99 headers have 32mm primaries vs. 2002+ headers 30mm primaries. No matter what you do to 2002 onward headers they will not flow as much as 98-99 headers will. Also in gutting the cat (if that is the method you are using) you are creating a large hollow cavity where the catalytic converter used to reside. This will lower the exhaust velocity and add turbulence, losing torque in certain areas of the power band. You may gain power here and there, but I doubt it. You will definitely have a louder smellier bike though. Best choice would be finding a good used set of 98-99 headers and ceramic coating them or going with one of the various aftermarket headers out there. I initially went with a Motad header and it did nothing for performance, but sounded/smelled the part. I eventually found a Two Brothers Race header, that made huge gains in mid range and top end power.

 

How much do motad headers run?

 

they are pretty pricey, but still cheaper than your average slip on...

Honda VFR-750 VFR-800 VTEC SS Motad exhaust NEW:eBay Motors (item 190316592812 end time Jul-23-09 10:22:59 PDT)
i dont remember paying that much, but i bought mine through steve not ebay...

send stevelarson a PM and see if he can cut you a deal.
hes a real nice guy.

 

I might be asking much, but i was hoping for better quality like where the welds and collectors are. Maybe i am just accustomed to high end automotive systems constructed like this:

 

you know that the 4-1 headers for subarus make them sound like civics right? lol
on a serious note even if you could get headers like that they wouldnt stay that shiny for long. with all the road grime being flung on them. your only kidding yourself if you think that your going to take your bike a part and polish them up after every ride.... i just wrapped mine up from day one.
anyways thats about what my motads looked like before i wrapped them up. they didnt look anything like the ebay picture.

 

I don't mean as in shinyness or finish, I meant more towards weld quality and collector construction, you'd be suprised how much difference collector design varies in gains. A long merge y pipe collector makes more gains then 2 pipes just squished in a expansion y chamber. I used to work for escort racing that hand made racing manifolds and many race parts for pro race cars and they had showed me how much the small details make the sizable difference.

 

i hear ya... but at the moment the motads are the best option avaliable, so feel free to build a better set.

 

best bet to mod the cat is
1) drill some 1/2" holes thru the core ( dont remove it all you need some back pressure )
2) cut cat in half and add a baffle inside after removing the core material and weld back together.
if you remove the core material and leave it empty you will lose power in some rpm ranges and might get gains in other areas, with the baffle or drilling the holes thru the core will keep some back pressure in the system to help w/ scavaging.

 

Worst advice ever.