Slip-On vs. Full Exhaust

[bmccrary]

If you can find that image that some one posted of the full system (headers and cans) you will see where the gains are made.

On our system all 4 header pipes merge into one at the same point. This system works, but is not the most efficient for our small displacement. If you notice on full systems the exhausts will go from 4-2-1 as opposed to the 4-1 we have now. This allows for a less turbulant flow and disruption at the collector. In turn, allows the exhaust to evacuate they cylinders quicker, ie makeing for a more effiecent charge.

Fact: When the motor goes through the exhaust stroke, the cyclinder does not completely discharge all of the burnt gasesm, it is not a perfect system (Nothing is). There for the engineers at Yamaha set up the fuel system to release enough fuel to each cylinder, accounting for the amount of burnt gases that remained from the last cycle. So by having a more straight through exhaust you are able to evacuate the cylinder faster which allows more to escape and leaning out your mixtures.

To compinsate, adding a bit more fuel and having a cleaner charge results in the power gains.

Hope this helps.

-bryan

 

[Gilo-FZ6]

If you can find that image that some one posted of the full system (headers and cans) you will see where the gains are made.

is this the one you mean

 

[bmccrary]

Yup thats the one. See how there are three collectors instead of 1. That and the space between the first set of collectors and the last. This give the gases time to settle before being met with the others.

-bryan

 

[Hellgate]

The stock system is a 4-2-1. For the '07+ there is a CAT in each 2.

The full Devil system is beautiful however, aside from weight reduction and major cool factor points, I don't think it will add much more hp than a CAT back system, about 2 to 2.5 hp. A full system may get 3ish...maybe. How do I know? I don't, only the fact that none of us can get above 100ish hp. I think the heads, cams, air induction system and FI are the gating factors.

But it is a way cool exhaust system and if someone would buy me one I'd gladly give them my Akro in exchange.

 

[Gilo-FZ6]

problem is this isnt a fz6 system..its just a generic pic..terrible shame..i read earlier on some forum while searching that r6 headers are compatible..they are slightly wider diameter, and give better top end. this seems like a pointless exercise tho as most of us want better torque through the midrange..the 100bhp threshold is a great target for those of us that want the power,and it will be interesting to see how this pans out over the next year (Que the "why dont you just get an R6" brigade)..lol

 

[bmccrary]

The stock system is a 4-2-1. For the '07+ there is a CAT in each 2.

The full Devil system is beautiful however, aside from weight reduction and major cool factor points, I don't think it will add much more hp than a CAT back system, about 2 to 2.5 hp. A full system may get 3ish...maybe. How do I know? I don't, only the fact that none of us can get above 100ish hp. I think the heads, cams, air induction system and FI are the gating factors.

But it is a way cool exhaust system and if someone would buy me one I'd gladly give them my Akro in exchange.

???

Pete,

Every picture on Yamaha's site shows the same exhaust where all four tubes collect at one point just before the swing arm. I havent seen the exhaust you are refering too.

Even if the power numbers on a dyno do not reflect change, the length of those head pipes before the first set of collectors will change where the power is made on the motor. Those on the devil are much shorter than those on stock header. Which, IMO, will result in a more top end power curve. However like you said, to get full gain out of them many other changes will need to be made. Out heads , cams and FI system are far to restrictive to make any significant power gains. But I do believe a full system along with a tune like you got from AF1, you would see some better numbers, and power gains in different RPM ranges. In additon to this, with the pipes seperating, you could potentially change the pipe length to move the gains to your desired area. At this point through, you would be better with an R6...

-bryan

 

[Stumbles06]

I'm not sure of any significant gains in a full system, but I saw a full Titanium Akro system on a Kawasaki Z1000 the other day, looked sweet, and knowing the guy, he likes his power on the bike, so I'm guessing there were gains there.

Next time I see him, I'll find out what he knows.

Would have to get a significant weight gain by going to a full Titanium system too, how much do the stock headers weigh???

 

[Gilo-FZ6]

i just copied this from antother forum

I would go for a 4 into 1 recently fitted full titanium Akropovic to mine and the figures were exactly as per there dyno charts. Have a look at there site and compare charts 4into 2 does nothing for torque whereas 4into 1 fills in the flat spot.

so depending on if this guy knows what hes talking about, the usalble power will come from our existing header configuration i guess this only leaves bore size/flow rate as a factor to make gains

 

[nimzotech]

Slip-On Exhaust is about 1/2 the price of the full system and adds about 3 horsies of power - not to mention the awesome sound and improved throttle response

Full System is way more expensive and most likely adds way more horse power. If I was a race track racer I would opt for the full system. For day-day street riding the slip-on system is more than sufficient.

Cheers

 

[Hellgate]

???

Pete,

Every picture on Yamaha's site shows the same exhaust where all four tubes collect at one point just before the swing arm. I havent seen the exhaust you are refering too.

Even if the power numbers on a dyno do not reflect change, the length of those head pipes before the first set of collectors will change where the power is made on the motor. Those on the devil are much shorter than those on stock header. Which, IMO, will result in a more top end power curve. However like you said, to get full gain out of them many other changes will need to be made. Out heads , cams and FI system are far to restrictive to make any significant power gains. But I do believe a full system along with a tune like you got from AF1, you would see some better numbers, and power gains in different RPM ranges. In additon to this, with the pipes seperating, you could potentially change the pipe length to move the gains to your desired area. At this point through, you would be better with an R6...

-bryan

Hey Bryan - Yup its a 4-2-1. Can't post a photo right now but you can see the header on the fiche.

Stadium Yamaha | Kymco OEM Parts | Yamaha OEM Parts

 

[Gilo-FZ6]

just call me the image whore

 

[FZ6OZ]

I have a custom exhaust bike shop near by, i might hit them up and see what it would cost to get a system made up

 

[MarinaFazer]

yea, that Devil Racing Replica exhaust (reading from the website) looks saweeeet. Hmmm...looks like I'm stuck between Devil, 2 bros, and Leo Vince they all seem so dope and sound good too!

 

[OZXJR]

Leo's mate............no contest :thumbup:

 

[bmccrary]

Ok Pete, thanks to Image Whore, you win. I could see the that detail from the images from Yamaha. The Microfish has it better detail. I stand corrected.

However, the aftermarket headers will flow better since those cats arent there, lol.

-bryan

 

[Hellgate]

Ok Pete, thanks to Image Whore, you win. I could see the that detail from the images from Yamaha. The Microfish has it better detail. I stand corrected.

However, the aftermarket headers will flow better since those cats arent there, lol.

-bryan

That's okay, we'll still talk to you Bryan. :Flash:

I agree, a real exhaust would help with the overall flow, no doubt.

 

[MarinaFazer]

However, the aftermarket headers will flow better since those cats arent there, lol.

-bryan

So then you'd see same gains with Cat Elim with new pipes then? So far it's sounding like that's the best bet...although I don't really want to eliminate my Cat (tree huggin' sonofabich - yet drives a Jeep occasionally lol)

question: does eliminating the CAT change the pitch of your cans?

 

[bmccrary]

Yes. It will make it sound rather raspy.

Honestly man, I mean its your money, but I really wouldnt spend the $$ on a full exhaust for the FZ. Its going to be very pricy and you really wont see enough gain, unless you are really trying to do some serious track time. In that case I would recomend an R6, lol.

-bryan

 

[Bruce McCrary]

Not FZ6 specific, but more sport bike in general;

When looking at full systems be sure you know what your getting into, do some research. Most stock systems are made of titanium, only the more expensive aftermarket ones are. If you replace a ti system with one made of steel you'll gain weight. Then you have to ask yourself if the gains (if there are any) are worth the extra weight. Most aftermarket systems and many mid pipe replacements will do away with the variable exhaust valves (Yamaha's EXUP for example) in favor a straight flowing pipe. True, these are good for making dyno numbers and allows the engine to breath better at ultra high RPM's, but they kill bottom end and mid range power.

The stock cans on 99% of the sport bikes built have more than enough flow capabilities for the stock engines state of tune. So the only reason to replace them with an aftermarket slip on is for looks and to make more noise. Any nominal gain in hp is more than offset by the increased db's and the average rider will hardly ever be able to tell the difference in power anyway, but may find himself shuffled to the back of the group when riding with friends. Right Josh?

I can't tell you how many times I've seen someone think they are smarter than the engineers that designed the bike replace stock pieces with aftermarket ones only to find that in the end the bike was heavier, made less power and gave up ride-ability to boot.

Any time you change something in your engine you effect more than one area or part of it. The big picture has to be considered...

Bruce

 

[icesurpher]

I have been looking for aftermarket exhaust for some time for my FZ 6 but i am not serious enough about needing the extra power to drop big cash on it. I just wanted better sound more than anything. So a buddy and I got together (both engineers) and designed a custom exhaust for my bike and did it for much less than the average market price. I have been extreamly pleased with the results. Great throaty sound, much less weight and increased low and mid range power. We decided to make some extras and see if we could sell them. Here is a link for our listing on e-bay if anyone is interested. eBay Motors: Yamaha FZ-6 FZ6 FZ 6 FZR 600 Performance Exhaust 04-08 (item 290293878915 end time Feb-10-09 11:33:31 PST)