Will I need a tune? De-catted stock pipe... stock mufflers & air cleaner

[bugdewde]

I'm on page 10 of Spazz's 21 page thread on FP3.......... ????

I bought a de-catted stock pipe off ebay today. B&E Performance.
I'm wanting to cool it down a bit. That cat really makes it hot on my passenger's right foot.

I'm planning on using stock mufflers, which I have opened up the left one a hair (rebar size) to try and even out the exhaust a bit.

Which brings me to now.....Will the de-catted pipe require a Tune? I'm thinking I will lean out the mixture some with the cat gone (causing heat) but will it be as bad a before with the cat?

Just wondering if there's any info/experience out there on a simple de-cat mod?????

If I have to do a tune for the de-cat, I might as well do the air cleaner too.
(really not looking to do a stage 1 as of yet)

Thanks,

 

[BluesBelly]

I'm on page 10 of Spazz's 21 page thread on FP3.......... ????

I bought a de-catted stock pipe off ebay today. B&E Performance.
I'm wanting to cool it down a bit. That cat really makes it hot on my passenger's right foot.

I'm planning on using stock mufflers, which I have opened up the left one a hair (rebar size) to try and even out the exhaust a bit.

Which brings me to now.....Will the de-catted pipe require a Tune? I'm thinking I will lean out the mixture some with the cat gone (causing heat) but will it be as bad a before with the cat?

Just wondering if there's any info/experience out there on a simple de-cat mod?????

If I have to do a tune for the de-cat, I might as well do the air cleaner too.
(really not looking to do a stage 1 as of yet)

Thanks,

The air is coming in at a rate dictated by the size of the stock throttle body and air filter. This has not changed on your bike. The stock ECM tables are in charge of things as though it's a stock bike. After the spent fuel leaves the heads is when your mods kick in. You do not need to tune until you mess with the intake which changes the A/F ratio. The thing to be ware of is changing the exhaust too much so that there is not enough back pressure affecting the exhaust, heat, and sonic pulses of the combusted gases. Eliminating the cat promotes cross talk between the 02 sensors. Think of the exhaust as a 2 into 1 on the right side with a small percentage escaping to the left side. A free flowing muffler on the right side Will loosen things up a bit.
Just my .02 after 40 plus years of bikin'

 

[Spazz]

Well stated blues...

Sent from my Note4 using Tapatalk

 

[bugdewde]

Thanks guys.... I see the relationship now. Musta been thinking old school carb jets.... lol.
Crosstalk? Because they are too close together in the '10-15 head pipes?
Assuming the one behind the cat would need to read hotter than the front one, wouldn't an O2 simulator (cant remember actual name) vary the voltage enought to please the ecm?

 

[BluesBelly]

II

Thanks guys.... I see the relationship now. Musta been thinking old school carb jets.... lol.
Crosstalk? Because they are too close together in the '10-15 head pipes?
Assuming the one behind the cat would need to read hotter than the front one, wouldn't an O2 simulator (cant remember actual name) vary the voltage enought to please the ecm?

Research .02 sensor cross talk. There are several articles at different sources. Here is a Quote from Doc. One of the best tuners in the country

"The bike will never run as good as it can with the Cat removed and the 02's cross talking....the VE's will be all over the place. I haven't just heard of it I've seen it, and proved it. Even with the cat in, the front cylinder gets a little confused from the rear cylinder gasses, however the rear cylinder tunes very well. When the CAT is removed they both go wacky because you have MORE exhaust gas recirculation......it's not a myth."

Doc

So if you are not happy with the decated header the best route for you to go right now is to invest in an aftermarket head pipe. Fuelmoto is an excellent choice but there are others as well. Fuelmoto has package deals with head pipe, muffs, intake, and tuner.
I assume you removed the cat to lower the exhaust heat. The cat is not as restrictive as people tend to believe because it is designed in the waffle fashion and actually flows quite good.

Low & Slow,

Blues

 

[losbright1]

I decatted my pipe and ran stock muffs and a/c for a while. The heat comes down some, but not drasticly..it is still hot as "f". I also got a little bit of noise, pop, decal pop when I did that mod. I recently went to V&H ProPipe system..still no a/c mod. I now get a lot of noise..still no tune. I get backfire, pop, decal pop, etc...plus my low end suffered some..hits its power at around 3K or so. I am planning on getting the FP3 pretty soon..My pipes are major HOT still even though I have no cat, and larger pipes, etc. I may be a retard, but I believe that the bike is factory tuned lean, and pipes have leaned it out even more..pushing out more air flow than they bring in..at least that is my understanding (limited).

 

[BluesBelly]

Ok

I decatted my pipe and ran stock muffs and a/c for a while. The heat comes down some, but not drasticly..it is still hot as "f". I also got a little bit of noise, pop, decal pop when I did that mod. I recently went to V&H ProPipe system..still no a/c mod. I now get a lot of noise..still no tune. I get backfire, pop, decal pop, etc...plus my low end suffered some..hits its power at around 3K or so. I am planning on getting the FP3 pretty soon..My pipes are major HOT still even though I have no cat, and larger pipes, etc. I may be a retard, but I believe that the bike is factory tuned lean, and pipes have leaned it out even more..pushing out more air flow than they bring in..at least that is my understanding (limited).

I think you need to check in with Fuelmoto. Get more air moving through the engine. They have a quality air intake system and will give you a good deal on a preprogrammed tuner. Sounds to me like you don't have enough back pressure in your exhaust system. Popping on decel is not necessarily a bad thing. Backfire is. Call Fuelmoto and talk to Jamie. He will get you straightened out

 

[Mojo]

Ok

I think you need to check in with Fuelmoto. Get more air moving through the engine. They have a quality air intake system and will give you a good deal on a preprogrammed tuner. Sounds to me like you don't have enough back pressure in your exhaust system. Popping on decel is not necessarily a bad thing. Backfire is. Call Fuelmoto and talk to Jamie. He will get you straightened out

+1 BluesBelly !

 

[bugdewde]

II


I assume you removed the cat to lower the exhaust heat.

Blues

Yes..... not looking for performance gains at this point.
Typically, I'll wait until warranty expires before tapping into performance mods.

Probably end up doing minor stage 1 stuff when that time comes. Air cleaner and tuner.... not wanting to go aftermarket on the pipes.
I wasn't too happy with my last true dual setup on the '09 SG, because it dragged on the right side badly. Will just stay stock pipes for clearance and cost.
Sad to hear the de-catted stock pipes might inhibit optimal performance.