slip on, or full system

ok, i kno this topic has most likely been posted b4, im sorry... looking at doing some mods to my 06 636.. want more sound so a pipe, power comander III , air filter..
i kno full system is most likly the way to go>> but alittle out of my budget, wondering if a slip on pipe, would do .. and maybe , put the rest of the system on later, and would the power comander adust to full pipes>?? was looking at the Akra , yoshi RS-5 SERIES - Undertail, or two brothers pipes>>
any help would be great... thanx>>
carlos

uh

yes to all. Most full systems consist of the headers, link pipes (if appropriate) and slip on

For example, the Arrow slip ons on my RSV can be mated to Arrow headers later if I choose. In fact, MOST of the RSV slip ons will mate up to the Arrow headers.

Just as long as the diameter of the header pipes match the diameter of the link pipe, you won't have a problem.

Also, I have no idea where the cat is on that model, slip ons might not eliminate it, but a full system will.

The PCIII changes the fuel maps sent from the ECU to the injectors. For best results, it should be dyno tuned. You can dyno tune it again once headers are added.

If you just want noise, slip on, PCIII and air filter are all you need. To extract every last ounce of power, the headers will give you a bit more (5hp at most).

And I LOVE the look/sound of the Two Bros systems!

cool, thanx for that... just gotta save alittle cash... see wat i will get>> keep you posted..
Carlos

Don't bother with the air filter change..just remove the plastic mesh from the stock one

a mesh air filter like a BMC or a K&N will change the induction noise slightly

Plus they do usually flow a little more freely than stock paper type filters.

Having said that, they can let in a little more particle matter, so it's 6 of one 1/2 dozen of the other...

I don't know if the 6 has one, but the 10 has a powervalve in the headers. Looking at dyno graphs, a full system will give a few extra donkeys at the top end, but loses a lot in the mid range (no power valve). This change is great if you're racing and no good if you road ride. But like I said, I don't know if the six has a powervalve in the exhaust.

I don't know if the 6 has one, but the 10 has a powervalve in the headers. Looking at dyno graphs, a full system will give a few extra donkeys at the top end, but loses a lot in the mid range (no power valve). This change is great if you're racing and no good if you road ride. But like I said, I don't know if the six has a powervalve in the exhaust.

The 05/06 does have an exhaust flapper valve. As for removing them costing midrange on any bike which comes with them stock, I remain to be convinced. On bikes with a catalytic converter, losing that by fitting a full system is going to more than make up for any power losses caused by the removal of the flapper valve.

As for the OP's dilemma, if all he's after is noise and pose value, there'd be no need to even fit a filter or a Power Commander. No bike objects to swapping the stock pipe for a straight-through. Even with full systems, remapping mostly just maximises the exhaust's potential rather than filling out anything that might be lost compared to stock.

Mid range power is boosted by back pressure. Remove the cat (slows the gas and causes some pressure) and the valve which activates for the mid range and you have no back pressure at mid range. The free flowing exhaust will allow far more horse at peak revs, but the mid range will be very weak. It may be the same or a little lower than stock, but with a raised peak power feels like a flat spot.

Mid range power is boosted by back pressure.

Would this be an opportune place for a moan about what a hideously misleading term "back pressure" is.

Remove the cat (slows the gas and causes some pressure) and the valve which activates for the mid range and you have no back pressure at mid range. The free flowing exhaust will allow far more horse at peak revs, but the mid range will be very weak.

It's, really, not that simple, and, in some ways, it's off the mark. Exhaust flapper valves serve one purpose; to enhance and/or alter the pressure wave dynamics in the exhaust and thus assist tuned cylinder filling. They don't so much *add* power as *smooth* the power out. As the engine moves through its rev range, exhaust gas speed and temperature interact with header lengths and collector box design so that the interference in the cylinder between exhaust gas pressure waves reflected back from the collector and pressure waves in the incoming mixture changes from constructive to destructive and back again. At some points in the rev range, the interference is beneficial to the operation of the engine and the engine breathes better there and makes more torque. At others, the interference is detrimental, and the engine makes less torque.

Exhaust flapper valves change this wildly-varying interference to something more uniform to give a flatter torque curve.

However, their presence can't but increase the exhaust's flow impedance, meaning the engine has to do more work to pump its waste gases out. This is work which doesn't end up going to the back wheel to drive the bike forward.

To make an engine produce more power through altering its exhaust, there are two options; lower the total flow impedance of the exhaust so the engine doesn't have to work as hard pumping out its own waste gases, or alter the exhaust tuning so the pressure waves reflecting from areas of varying local flow impedance assist in cylinder filling. The former has a positive effect throughout the rev range and can be huge (40%-50% lower flow impedance for one exhaust vs another), the latter has an effect only at some points in the rev range and is relatively minor.

A full race system is going to have *much* lower flow impedance than a stock system (just compare the sizes of the header pipes; the bigger the pipe, the lower its flow impedance), especially one with a catalytic converter, and it's going to have a better collector design than a stock system, for better tuning.

Racebike builders everywhere bang on about how important it is to give a bike a good spread of power. If exhaust flapper valves really *increased* midrange power, we'd be seeing them on GP bikes instead of the dump pipes they mostly run.

"Exhaust flapper valves boost midrange" is another piece of bike journo intellectual shorthand which has crept into common use.

The common opinion (and I know what that is worth) is that the exhaust valve on the 10 is more about noise reduction than mid-range power

My flapper valves sit on the bench, right next to the flux capacitors and the flange oscillators..........

My flapper valves sit on the bench, right next to the flux capacitors and the flange oscillators..........

I thought it sat at the back of your Y-fronts blublublublub

My flapper valves sit on the bench, right next to the flux capacitors and the flange oscillators..........

OK, I.K. will probably have my guts for garters for this!!!! But i disagree with his statement that the exhaust valve removal will rob the bike of bottom end or midrange. I know from dyno graphs (Before and afters) on both a mates ZX6R (05), and Dangerous Dave's R1 that removal of the valve did nothing to rob any bottom or mid, in actual fact on the R1 it picked up on both. Then once a set of fufflers was fitted, it increased again along with an increase in peak power.

As for mufflers for the 636, and Akrapovich is one of the best I have seen. When Gavin cosway first built Shris Seatons bike in 05, he couldn't get hold of a full Akra, and used a slip on for the first race. When the full system was put on it, it made 2 more HP, right at the top with no noticeable diference anywhere else. I would be inclined to just stick an Akrapovich muffler on it. And FWIW it also made a little more power througout the rev range than a couple of other systems that they tried.

wow ..ok, that just went mental... you guys sure kno alot of stuff... ok.. my 636 will be mainly used for road... track... maybe..but not really... heard putting pipes plus pcIII will smooth out the reve range and make it more controlable.....
stiil dont kno wat to do...... ! confused>>>?

As long as we are getting technical can someone explain how the flattened part of my Micron serpent headers work.
I assume its to maintain velocity at low revs while providing no restriction at high but what I-K wrote has opened my eyes a bit.