well i guess you ? is in the title. really there is no comparing a oval can to the dual ports. i mean one part is the actual muffler and the other part is were the gases exit. so i have no idea what your ? truely is.

The main difference between oval single port and dual port is obviously a second port siamesed into the can for cosmetic reasons. The big thing to note with dual port is they make LESS POWER than single port. Jorge at Renegade mentioned this to me last year so we did some testing ourselves with 3 popular brands testing their single against their dual and in all cases the dual port made less power than the single port.

To be honest there are several reasons this could be so and I didn't have the time to test flow etc and find out why but it is a fact...

what about a can like the devil SB2 which has a HUGE single outlet? how would that compare to the dual port BF cans? I guess it would have to do with the total area of the exhaust port based on what you said above. Would the single outlet increase gas velocity (due to slightly smaller exhaust exit area) which in turn would aid scavenging where as the dual port just doesn't have the correct amount of back pressure to increase exit velocity?

It's actually got nothing to do with port area - it's more about competeing negetive reversions and (I'm guessing now as I didn't have time to test) pressure variation from teh competing ports..

you need to offer an online course in exhaust technology and design. Everytime I think I got it figured out, my ignorance just shines on thru......

I am curious about that too, the SB2 can does have a huge outlet and a virtually "straight-through" design... you can pretty much stick a baseball bat through the can and out the other side!!

I wonder if the turbulence created by the inside of the can creates enough back pressure to maximize efficiency??

I wouldn't think that the obnoxious outlet port was put on there by accident or "just for looks" because the can seems to be one of the top for hp gains.......

Am I way off here???

To all intents and purposes all the scavenging effect is done in the primaries and the port at the end of the can really doesn't have that much effect as it's effectively just open air - think about a garden hose again - if you spray the water out the open hose or if you say cut the bottom off a big plastic pop bottle and stick the hose in that it makes no difference to the rate of flow or anything else - it's the diameter and length of the hose that matters not the tip (unless the tip narrows down and so restricts flow)

However, with a two tips the analogy becomes say like a sprinkler outlet - most of the flow will go through one port and so there becomes a speed differential between gas going through that port ( say the top one) and gas flowing through the other. This means that you could get suction in through the lower port as well as gas expelled so you get a vortex which then slows the over all gas speed

The alternate idea is that as you have two open ends albeit for only a couple of inches you get two reversion waves as the gas hits air which then meet again when the ports siamese... this obviously has a negative effect...

Anyway, whatever the case never buy a can with dual ports unless you prefer looks to power

Just wanting to say THANKS to the in house exhaust experts...I have learned more inthe past few days than I did in 2 years of college!

I have never understood cans really, y'all have made it very simple. I am trying to decide mine...either Jardine or Yoshimura...and just wanted to say thanks for all the info y'all teach! :mrgreen:

Anyway, whatever the case never buy a can with dual ports unless you prefer looks to power

Whooops.........well, atleast mine looks good on my bike. The Seat-o-the-pants meter says it added some power too.

How does this then translate to your underseats that have the dual ports? Does the way they are aligned create equal pressure to both outlets?

I don't know Jardine but ANYTHING has to be better than Yoshi - I used to import them to the UK and have rarely seen anything so badly made - hope that helps in teh decision

Pen, the under seat have the split in the scondary pipe not the can - so they are no different to say a 4-2-1 in terms of gas flow and power (bikes with two cans don't have a problem - just cans with two ports)

Anyway, whatever the case never buy a can with dual ports unless you prefer looks to power

Whooops.........well, atleast mine looks good on my bike. The Seat-o-the-pants meter says it added some power too.

How does this then translate to your underseats that have the dual ports? Does the way they are aligned create equal pressure to both outlets?

dam im in the same boat here. but i guess i could just plug the lower port that way i only have one so then ill have looks and better power. is there a flaw in this thought(i hope not). let me know wolf. :cheers

The flaw is that the two spouts are normally quite small to fit in so plussing one makes the outlet restricted..

The flaw is that the two spouts are normally quite small to fit in so plussing one makes the outlet restricted..

WELL DAMMIT i just cant win ohwell i like what i got so its stayin. thanks wolf for the info. :cheers

Pen, the under seat have the split in the scondary pipe not the can - so they are no different to say a 4-2-1 in terms of gas flow and power (bikes with two cans don't have a problem - just cans with two ports)

Check! Gotcha. Thanks for the info Pete.

I LOVE IT.

WOLF, YOU ARE THE MAN !!!!!!!!!!!!!!!! :werd

YODA WROTE:

"Just wanting to say THANKS to the in house exhaust experts...I have learned more inthe past few days than I did in 2 years of college! "


I feel the same way, skool for fools.

Might I suggest taking a good long hard look at the recent Sport Rider magazine Pile O' Pipes article. Please read it over, and over again. This is a credible INDEPENDENT test, and on the R6 no less, and the facts are there for all to see.

MCN did an even more wide spread test too which actually matched like for like ( unlike Sportrider ) and the latest issue of Performance Bike will have another test covering about 30 brands

The Sportrider article as I understand it pitched high against low, stainless against titanium, and even included our under seat kit against standard slip ons and then rates a twin under seat option against a ti slip on for weight and wonders why it's so heavy! (Double the cans anyone?) Still very useful though..

The dyno figures are very useful but very very odd - take teh Blue Flame - only 0.3 bhp difference between the race version fully open and the legal version with baffle and plug and only 2 db sound difference - either it aint legal (82dB being the limit) or something is wrong with the dyno figures - BF owners know what the baffle and plug system look like - do you guys think it's only going to knock off 0.3 hp?

I am of course please to see that Wolf beat 24 out of 30 for power (even though it's an under seat and not like for like with the rest - I guess it proves bends don't effect power for those who still doubted me)

Also amazed at how much they say things like the BF and Micron high mount especially, weigh - can anyone who owns one confirm this coz a Wolf slip on weights 2-3 lbs including all fittings and link pipe and I cant say a BF feels much heavier to me?