Decat...power increase.

[Trev]

I have this morning fitted an Arrow decat pipe to my 2009 FZ6 S2.
On inspecting the cat it is a very fine honeycomb inside and must be very restrictive for gas flow.
Anyone done a before and after dyno, or know where I can find that info?
Interested to see what power increase it will actually give.....

 

[greg]

the only difference i noticed was my bike sounded awesome when i fitted a set of leo's with a decat pipe

fueling it a bit lumpy when the baffles out though, would probably need a power commander and dyno time to properly set it up

 

[Trev]

I really fancy a set of cans, but new ones are strong money.
Got my eyes peeled for a used set.

 

[Norbert]

I've read about people removing their catalytic converters before.
The bike breathes a lot better. This supposedly translates into better performance either in the mid or upper power band.
Could be a placebo.
They do sell exhaust pipes with no catalytic converters. I haven't seen one for the fz6, though.
My advice is to do a dyno. Remove the cat. Then, do another dyno! :thumbup:

 

[Trev]

Takes too much time and effort to remove the cat for me to want to do it again.

 

[ChevyFazer]

Even though it looks restrictive its really not, I gutted mine just for the heck of it but before I did I actually blew through it to see just how restricted it was and I noticed nothing almost like just blowing through a open pipe

 

[Trev]

Fair enough, never thought to do that..
Looks really restrictive when you look down the tube.
The big issue for me was the heat, was hoping for a little power as well but aint gonna cry about it.
Would still like cans for it, prices tho..!

 

[ChevyFazer]

Yeah I know thats why I just made my own because I couldn't bring myself to spend that kind of money

 

[greg]

I really fancy a set of cans, but new ones are strong money.
Got my eyes peeled for a used set.

keep an eye on ebay, but they will still probably be around £250 at least

think i paid around £300-400 on ebay for a new set from italy, there's no extra tax to pay, and shipping was included

 

[Downs]

If you don't think you are ever going to put it back on you can take it to a recycling place and get decent money for it as Cats are full of precious metals such as platinum.

Back in the day when Cats were first put on cars yeah they were restrictive but nowadays it's usually counterproductive to take them off. They've been designed well enough today that they flow pretty dang well.

For a street bike it's not going to be big enough of an increase in power to care about, and to get the most from it you're going to have to get a powercomander and some time on a dyno. It's also illegal but it's something that's not enforced...........for now anyway. They actually do help scrub lots of bad stuff from your exhaust gasses which considering that prior to cats on bikes, bikes were bigger polluters than most cars.

Edit-just noticed you are in the UK. Ignore my previous statement about legality because I know nothing about UK or EU laws when it comes to emission equipment.

 

[Dave.TX]

I agree that catalytic converters nowadays are very efficient and flow very well. Of course there's always going to be some restriction with it but very little. When I got my bike it had Leo's with a cat eliminator pipe. The sound was awfully loud so I purchased a used stock exhaust, put it on and am completely happy with the stock sound and performance.

As for perceptible performance I don't notice a thing. My bike still hit 140 (indicated, 131 actual) with stock exhaust. Maybe the open pipes would have given me a few MPH more but I rarely go above 100 anyway.

If you want more power just get an R6. Open pipes are more for looks and sound, they don't do much (if anything) for power on the FZ6. The stock exhaust does emanate more heat than an aftermarket system but it isn't a lot.

When I eventually get the DB killers for my Leo's I'll put them back on and see how I like the noise increase over stock.

 

[Motogiro]

There's a lot of info on how completely reducing back pressure kills low end torque.
http://www.600riders.com/forum/garage-mechanical-help/34007-exhaust-backpressure-fact-fiction.html

This is why engineers develop exup valves. These type valve are designed for factory OEM exhausts that need back pressure to change as rpm and volume of gas changes throughout.

This is especially true with lower displacement engines. You really need to get your bike on a dyno and have it tuned once you open up the back end. Yes top end will benefit volume wise with reducing back pressure but dynos wouldn't exist if there was no need for fuel management when making large changes to the exhaust. The OEM ECU can only make minimal changes to accommodate air to fuel ratios needed to keep the motor healthy throughout it's entire range and perform properly.
Sometimes the butt dyno is good but it really doesn't confirm the numbers.

 

[Trev]

I agree that catalytic converters nowadays are very efficient and flow very well. Of course there's always going to be some restriction with it but very little. When I got my bike it had Leo's with a cat eliminator pipe. The sound was awfully loud so I purchased a used stock exhaust, put it on and am completely happy with the stock sound and performance.

As for perceptible performance I don't notice a thing. My bike still hit 140 (indicated, 131 actual) with stock exhaust. Maybe the open pipes would have given me a few MPH more but I rarely go above 100 anyway.

If you want more power just get an R6. Open pipes are more for looks and sound, they don't do much (if anything) for power on the FZ6. The stock exhaust does emanate more heat than an aftermarket system but it isn't a lot.

When I eventually get the DB killers for my Leo's I'll put them back on and see how I like the noise increase over stock.

If I was after power, I would have kept the 2008 R1 I had before my Fazer.
Did the decat to get rid of the heat, a power increase would have been a bonus.

 

[SovietRobot]

The honeycomb design is the same as "high flow" cats in cars. It's not really restrictive, compared to a regular converter.

 

[gwaihir]

I initially bought a decat pipe and fitted that with the original exhaust to firstly reduce the heat and secondly to get rid of the horrible smell when waiting at traffic lights.
I didn't notice any difference in the power output but it seemed to run smoother and sounded a touch meaner.
I've now got a pair of Scorpions and have tried them with and without the decat pipe.
Again no noticeable difference in power but the Scorpions sound 'wicked' without the decat pipe even with the baffles in.

 

[red06]

people who drill their muffler or touch their catalyst , just wasted around $600 and gained nothing lol , if you want more power , speed , acceleration , etc
it is time to move up to a bigger bike

 

[greg]

people who drill their muffler or touch their catalyst , just wasted around $600 and gained nothing lol , if you want more power , speed , acceleration , etc
it is time to move up to a bigger bike

don't think the cats sell for very much on ebay though, as there's more supply than demand

 

[DeusEx]

I bought the Leo's with the de-cat pipe. After a few months of testing with the de-cat pipe installed, I found out that the low to mid-end power was worse than with the cat on.
My current setup is with the Leo's and OEM-cat pipe still on. (yes they do fit but be careful that the pipe doesn't touch the undertray plastic)

I believe that I've got my low-mid-power back, and I'm not poluting everything around me!

 

[ChevyFazer]

people who drill their muffler or touch their catalyst , just wasted around $600 and gained nothing lol , if you want more power , speed , acceleration , etc
it is time to move up to a bigger bike

How do you figure we wasted money when we spent nothing and got the results we were looking for, sound

 

[red06]

i also gutted my cat and drilled little holes in the baffles , after that i threw it in the garbage and had to spend money to get the parts again , nothing was gained and it sounded crappy , and it ran crappy with gutted cat too.
i imagine your air box mod probably added more whistle while it destroyed the bikes proper air intake requirement .

if you can not mod the bike with high end parts , properly, dont think by punching holes and cutting things will gain anything .
everyone would be doing it if it was good, you will lose performance .my stock fz6 will smoke any of your ghetto modded fz6's any day