CAT delete vs free flow muffler for Monster ECU Stage 2

[UtahPete]

I'm getting my ECU Stage 2 flashed. The instructions from Wick-It recommend either a CAT delete or a free-flow muffler or both in order to maximize the benefits from the ECU flash and to reduce exhaust heat. I don't have either (my exhaust system is completely stock).

Can you ICE experts out there explain about 'free-flow' muffler and which after-market products I should take a look at? I understand about the CAT delete and I will consider that, but I'm more interested in the 'free-flow muffler' as that is easier for this tree-hugger to consider.

Thanks.

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USER NOTES:

It is imperative that stage 1 or stage 2 tuning along with specific air box or inlet modification never be mixed up or used beyond their intended development. IE: You can't run stage 2 airbox modifications with stage 1 ecu tuning. And you cant run stage 2 tuning without the proper air inlet modifications.

The dynamic tuning of the ecu allows the user the use of whatever exhaust configuration. Stock, Cat delete, free flow muffler etc in any combination. However, it is recommended to have either a cat delete or free flow muffler with the stage 2. Or both. A well flowing exhaust both works better for power and just as importantly retains less heat around the bike and engine compartment.

Stage 1 is a premium fuel 91 octane tuning. But users can use 87 octane in an emergency and follow safe engine driving habits with the fuel. (keep rpm up, use low gears, don't lug engine, stay below half throttle) Higher octane fuel can be easily used, use what works best.

Stage 2 is a premium fuel 91+ octane tuning only. NEVER use 87 octane.

Through the use of advanced logic, temperature sensors, knock sensors, oxygen sensors and torque calculations, power will be limited without ideal conditions. The use of poor fuel or exhaust configuration, or high temperatures will have power limited. Just because something works, doesn't mean its ok or ideal. Let the engine breath and feed it the proper fuel. And you will be rewarded.

[Lew L]

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A freer flowing exhaust system works better at mid to higher RPMs. An air box that has been tuned ( sized ) for the motor will actually increase power and torque as it resonates. I'm sure the large air box on the Spyder does this. Remember blowing over a longneck beer or Coke bottle and hearing it hum. The resonance of the air box does the same thing. When the pressure fluctuations (resonance) are high the cylinder filling is better. ( RE: Kevin Cameron from Cycle world) Drilling holes in the air box may change or cancel this resonance.
I've had to repair holes I've drilled into air boxes they ruined to low end/ midrange torque. Changing the intake tube for a ram effect is always a good thing.

About exhaust----- when installing free flowing headers on an auto motor, correct size ( diameter ) is very important. Too big and it kills the "backpressure" needed to give the exhaust system a little " reversion" to counter the overlap built into the camshaft timing.
I don't think a cat delete will hurt at all as the header size isn't changed. A louder muffler is--------- just a louder muffler.
Best of luck with your Stage 2 adventures, Many folks here love it.

Lew L

[Peter Aawen]

Pete, I'd suggest that for your purposes, a cat delete would give you the best bang for your bucks. Why - well, consider this... the exhaust system is there/designed to effectively & efficiently remove exhaust gasses from the engine, and the muffler part of that reduces the noise output. Sure, there is a need for some back-pressure to provide the "reversion" that Lew mentions, but I think you'd be surprised at how little is really necessary, and the muffler itself provides more than enough of that already!

But you've got a Catalytic Converter - a device inserted into an otherwise perfectly functional exhaust system to catch any exhaust emisions that it can realistically remove thru the catalytic process - but it NEEDS both extra pressure and significant heat to function (600°C + IIRC) - WAAAAYYY beyond that necessary of either for the efficient & effectively 'quite clean' (emissions wise ) running of the engine - in fact, most small (relatively anyway) motorcycle engines tuned properly get very close to passing the emission rules/requirements WITHOUT a Catalytic Converter! But as 'we've' moved further into using engines that were formerly considered 'car engines' in our bikes, ie. those engines with computer systems managing & monitoring the efficient AND CLEAN running of the engine, we've inherited a number of the controls, restrictions, & requirements that might make sense on larger less efficient (engine wise, anyway) cars; and then also, because you can't be trusted with a high power to weight ratio machine, motorbike engines are choked & restricted even more just to keep it all controlled & measured - so our Spyder engines are detuned & choked down so that they need something like a catalytic converter to clean up the mess all the induced inefficiencies make... But it's easier for the legislators to manage that way, fewer variations, and you really do need to be protected from the rush you might get if your engine truly realised its potential for power output - besides, few of the punters will ever really know anyway, fewer even understand how they're being controlled!

Consider - in a car, the catalytic converter is a substantial piece of kit with a fairly large lump of honeycomb of catalyst/special metals etc embedded in the exhaust system in a way that uses significantly extra back pressure to create enough heat & pressure to allow the catalyst material to work - they're big & heavy, because they NEED that much material to get hot enough & create enough pressure to get all that catalyst to work. In a motorcycle (&/or a Spyder) the bits that are required to create the pressure & heat are pretty much the same size as those needed by a car, but by comparison, the entirety of the catalyst material needed in the bike's honeycomb is tiny! So we get all the disadvantages of the extra weight, extra heat, extra plumbing, extra back pressure to contend with, all for a fraction of the catalyst size/volume.... and you're going to get your computer updated anyway, so it'll run your engine even more efficiently and cleaner/better than it is now!! So why keep that tiny bit of catalyst with all of its associated drawbacks for what is in effect a miniscule emissions benefit IF ANY?!?

So I suggest you toss the cat converter, lose all the extra heat, backpressure, weight drawbacks that go with it; keep the OE Muffler, or maybe go for something a little free-er flowing that doesn't produce a noise that offends you; and get the Stage II tune done to let your engine run more powerfully, efficiently, and ultimately cleaner than its previous tune.... maybe not quite as 'clean' as when it was choked down in order to produce the back pressure & heat needed to let the cat converter work well at removing the (greater) emissions that the inefficiently tuned engine produced, but it's pretty damned close - AND you get the benefits of a better tuned, more efficient, & consequently, a more powerful engine.

Or you could keep the cat converter & all its inefficiencies, drawbacks, & heat, and then when you stop banging your head on the brick wall, it'll feel good... Oh, hang on, you're NOT ALLOWED to stop banging your head, you hafta keep on banging away! It's a self fulfilling cycle . well, it is until we all go electric anyway!

[UtahPete]

Peter, that's the best explanation I've ever heard about the pros and cons of cat converters on motorcycles. I think you have me convinced (just as you and others helped get me over the reluctance to get a Stage 2 ECU flash).

I may just end up with the hot wheels I lusted after in my youth, albeit 3 instead of 4. If not now, then when, right?