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Removing Cat Converter?

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Buildercher

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I have read the threads and cannot seem to get a simple answer. What advantage do you get removing the cat in the headers?. Some say it gives you 2-3hp in the top end whilst losing low-mid range?. Some say it makes the bike louder? we'll my Mivv-gp w/o baffle is offensive enough so what is point in that?. When I dynoed my bike the technician advised me to leave the cat in, he explained if you want more power get a full system or 4>2>1 headers with your slip-on. If correct it leaves me to think that some members have butchered their exhausts pointlessly if you lose hp especially in mid- range were you want the power. Has anyone done a dyno with and without cat to see the difference in performance?
 
For the most part you are 100% correct about butchering their exhaust for very little improvement in performance except maybe at the very top end. I just have a slip-on which automatically removes the cat in the mufler portion of the exhaust and I have a MIVV Suono which is also right on the edge of being obnoxious. It has been a fad in some areas to gut the cat , trim the secondaries etc,etc but the vast majority of riders never get a dyno run to see if they've actually improved the performance or decreased it, which can happen quite easily when the hunt for top-end h.p. is the case. In actuality, the midrange is where almost all of us run about 95% of the time so when you get a couple more H.P. at the top end, is it ever worth the price?
 
I don't know a lot about this topic so I went to the other place and found a thread that, after weeding through several pages of name-calling, flaming, and off-topic trash-talk, I found this from Ivan and seems to be the general consensus of the more knowledgeable folks in that thread.

Ivan said:
Removing the CAT will allow the pipe to resonate.... this will give another 8 hp or so in the midrange over a fairly wide area.

The bike will run cooler as well because the engine won't have to work as hard to push the exhaust out.

There is no down side to removing it other than higher emissions.

When removing the CAT, you will want to just remove the material and leave the welded ring in place.

If you don't want to take a chance in damaging the stock O2 sensor, remove it first.

When I did mine, I used an air chisel and a shop vac... The header does not need to be removed from the bike, in fact it's easier to do on the bike.

Others have used a long drill bit and made a lot of holes and then broke up the remains with a long punch/chisel.

After you get out as much small pieces as you can with the vacuum, just start the bike and blow out the last pieces before you put your muffler back on.
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Question though... where you live and ride, do they do emissions testing? If so, I'd just get a full system and set the stock system aside for getting the testing done yearly. ;)
 
No they don't test for emissions were I take my bike for WOF and the cops don't care, i like the idea of a full system but is their aftermarket headers you can buy that will fit most slip-ons, I really like the Mivv exhaust.
 
Buildercher said:
No they don't test for emissions were I take my bike for WOF and the cops don't care, i like the idea of a full system but is their aftermarket headers you can buy that will fit most slip-ons, I really like the Mivv exhaust.
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As you probably already know Dale Walker is the only one that makes a stock replacement header that allows you to use any slip-on designed for the stock exhaust. The downside is price.

If you could find a cheap aftertmarket header then I'm sure any competent muffler shop should be able to fabricate a mid-pipe to mate the header to your choice of slip-ons.
 
I'd really like to get the MIVV full CF can. That thing is DA BOMB for the FZ1. But, it is also over $600.00. Not only looks, but it weighs less than 4 lbs total.

As for headers, a good 4->2->1 design will far exceed the stock pipes even after gutting the cat. The Yoshi full system "claims" to put back some of the lost backpressure that is needed too.
 
Not that bad

FZ1inNH said:
I'd really like to get the MIVV full CF can. That thing is DA BOMB for the FZ1. But, it is also over $600.00. Not only looks, but it weighs less than 4 lbs total.
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I paid $404.00 US from PJ for mine.http://www.pjsparts.com/catalog/product_info.php?cPath=24_125_247_77&products_id=223 And yes it is "Da Bomb". I will post a sound clip ASAP.
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vs Stock Monster.
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I don't own a scale, I think my wife has something against them.:poke: so I can't vouch for the weight. It is a feather compared to the stock can.
 
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Ooops... sorry Lee. I should have been more specific. It's their Suono can that I want. This is pure street-sex! :D

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Also at PJ's but it is the $602 can. :(
 
I see

FZ1inNH said:
Ooops... sorry Lee. I should have been more specific. It's their Suono can that I want. This is pure street-sex! :D

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Also at PJ's but it is the $602 can. :(
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Yes it is and that is why I went with the cheaper option. Should I at some point find myself with some extra change I would probably look into getting one of those. I'll be getting the Holeshot header next along with the PC. Then the Ohlins,etc. You know how that goes.
 
Oldschool said:
The titainium one was my original plan but $$$$ made me rethink that.
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I would have thought the titanium was the middle or the road and CF was the expensive one... like Two Bros. I bought the titanium Two Bros because the CF can was over priced.

However, after reading about how the Italians built it, it is a TOTAL titanium can, not just a sleeve of it over steel. Makes perfect sense now.

Those are very nice though. Not too small, not to big.... just right!
 
FZ1inNH said:
I'd really like to get the MIVV full CF can. That thing is DA BOMB for the FZ1. But, it is also over $600.00. Not only looks, but it weighs less than 4 lbs total.

As for headers, a good 4->2->1 design will far exceed the stock pipes even after gutting the cat. The Yoshi full system "claims" to put back some of the lost backpressure that is needed too.
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You brought up a good point about the 4->2->1 header design. The main problem with the stock header once you remove the cat is that you end up with a 4->1 header, which is better suited for top-end power. And that is something this bike doesn't really need, it needs the mid-range of the 4->2->1 design. I know my R-77 might not look as "nice" as the MIVV, but from a dollar/performance ratio it can't be beat.
 
I had a look on the holeshot website at the 4>2>1 headers, it looks very nicely fabricated and will work with most slip-ons, but it is $ and on ebay I see a full yoshi system for not much more?. So please correct me, in order to keep back pressure leave the cat in. It got me thinking has anyone removed 1/2 of the cat or has replaced the cat wih something that allows more flow but still has the required back pressure?. I suppose if your gains are minimal only noise it is pointless mod. I have the Mivv titanium slip-on is it awesome fully recommend it.
 
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