[canyondancer]

Fair enough mate, I double checked the original post for his variables but didn't go through the entire thread. Still didn't feel like this massive loss of torque that I was warned about even without mapping adjustments. I did only ride for about 20mins though as the weather here is awfull and will be for the next week. I want to do a bit of timing through the EXBV range when we get a nice still day to compare some numbers to my "feelings". As I said before I don't want to trade one for the other either so removing the valve will have to have minimal effect on the low end for me to go ahead with chopping it completely. The fact that it is a weak point reliabilty wise (and the damn squeak) is my motivation, not "making the bike better". I have tuneboy so can tickle the map a little before doing anything irreversible.

Let's not get carried away now. Nobody said anything about a "MASSIVE" loss of torque.

 

[kellito]

you did say "huge" though.

J.D. tested and saw no huge dip, I know he mapped to roughly optimize fueling for both configurations, but don't you remap for any change to the exhaust? To my knowledge he is the only person to put data up before and after removal of valve, and there is plenty of people who don't have the valve and make good flat torque.

 

[[FLUX]]

I simply don't understand what the fuss is about.

People change exhaust systems all the time. It's pretty much common knowledge that any time you change any part of your exhaust system that it needs to be remapped to get the best results out of it. Isn't that common knowledge by now?

I simply don't understand why we're fighting over whether or not removal of the EXUP valve from a stock system without a remap results in a non-optimal torque curve. I would have thought that would have drawn a collective: "Well DU-U-UH!", from almost everyone with a semblence of a clue.

hordboy's tests show that removal of the valve and a subsequent remap to suit results in no torque/power loss, and it's run on the exact same dyno to remove dyno specific variables from the equation. Don't give a rats arse if someone ran a test on the same type of dyno, each dyno is different. Period. Can't compare them. Don't even bother. Don't even try. It's utterly and totally pointless, irrelevant, and confusing to even attempt do so. Once again, I thought that would have drawn a collective: "Well DU-U-UH!" from everyone with half a clue.

So what, pray tell, are we all arguing about here? I haven't the faintest idea. The EXUP valve is noise-control only. The proof is right there in the OP. It should be obvious to all but the most stubborn that if Triumph UK could have done without the EXUP valve, they would have, because it's clearly not there for any performance reasons. They simply would've ditched the valve and released the bike with the correct map instead, or are we arguing here that they wouldn't have supplied the correct map? That seems to me to be about what it boils down to, and by golly that's a pretty silly point.

 

[carpel21]

Ha ha, in a nutshell FLUX! The fresh perspective is usually the clearest. Yes I was originally under the impression that he hadn't remapped until someone pointed it out in a later post. Playing with the mapping a bit now to see if I can get it back but the weather is shite.

 

[canyondancer]

Here is Hordboys claimed dyno run with a mapped EXUP valve....and a another dyno run that is mapped without the EXUP valve. >

 

[canyondancer]

Now here is my dyno run WITH an EXUP valve and the TOR map...TOR can.

 

[canyondancer]

Now i ask you...does Hordboys dyno chart look ANYTHING like mine does? Hell no. Different dynos or not....the steepness of the hp curve and the flat torque curve on mine are completly different. In fact...Hordboys dyno chart doesn't even look like a stock Triumph 675 chart. Why is that?

In BOTH of Hordboys dyno charts....the SAME dips in the torque curve appear. That is NOT possible to acheive when disabling the EXUP valve. I repeat...not possible. Stock 675 Daytonas do NOT have those dips in them. The chart that Hordboy produced appears to be a 675 Daytona with a full system on it and all he got with a custom map that he made is 109 hp.

Just in case anybody thinks i'm fulla shit....the shop name of where my dyno run was made is right on the chart. Call them and ask if the chart is real.

Take a real close look at Hordboys torque numbers. On his chart...he gets 39 to 49 pounds torque between 7 and 12 grand. On my chart i'm getting between 49 and 51 pounds between 7 and 12 grand.
That is 10 pounds of torque difference....and i have 5 more pounds of torque at 12 k tahn he does.

So i don't know where or how Hordboy came up with that chart....but it's certainly NOT with and without the EXUP valve.

 

[carpel21]

That is an exceptionally smooth torque curve you have there CD, it must be lovely to ride.
I took mine for a nice long ride last night despite the rain, and with a little adjustment it feels much the same from 4k up now. only very small changes there, but when accelerating from 2k, it starts strong, but then a little weak spot from 3-3.5k. If I can smooth that out then I will be confident enough to get the exhaust chopped and be done with it.

 

[canyondancer]

you did say "huge" though.

J.D. tested and saw no huge dip, what do you call that dip at 5500 and at 7k? I know he mapped to roughly optimize fueling for both configurations, but don't you remap for any change to the exhaust? To my knowledge he is the only person to put data up before and after removal of valve, and there is plenty of people who don't have the valve and make good flat torque.

Show me a flat torque curve with the EXUP removed.

 

[canyondancer]

That is an exceptionally smooth torque curve you have there CD, it must be lovely to ride.
I took mine for a nice long ride last night despite the rain, and with a little adjustment it feels much the same from 4k up now. only very small changes there, but when accelerating from 2k, it starts strong, but then a little weak spot from 3-3.5k. If I can smooth that out then I will be confident enough to get the exhaust chopped and be done with it.

Thank you sir....and it was nothing but pure luck that i got the right combination of parts and the near perfect map. Not bad for a free map is it? And don't forget....that flat torque curve is only there because of the EXUP valve. The 111.78 hp came from the gutted cat. No straight through pipe either...just the cat gutted and re welded back together.

 

[canyondancer]

Mr FLUX....this is from Wikepedia and it tells the definition of an EXUP valve.

Exhaust ultimate power valve

From Wikipedia, the free encyclopedia

(Redirected from EXUP)
Jump to: navigation, search
The exhaust ultimate power valve (EXUP) is a device fitted to selected

(FZR, YZF, XV1900, R series,MT-01) that constantly adjusts the back pressure within the collector of the exhaust system to enhance pressure wave formation as a function of engine speed. This ensures good low to mid-range performance.
At low engine speeds the wave pressure within the pipe network is low. A full oscillation of the

occurs before the exhaust valve is closed, and to increase low-speed torque, large amplitude exhaust pressure waves are artificially induced. This is achieved by partial closing of an internal valve within the exhaust - the EXUP valve - at the point where the four primary pipes from the cylinders join. This junction point essentially behaves as an artificial atmosphere. The alteration of the pressure at this point controls the behavior of reflected waves at this sudden increase in area discontinuity. Closing the valve increases the local pressure, inducing the formation of larger amplitude negative reflected expansion waves. A servo motor controlled by the

opens and shuts the valve. The EXUP valve operation goes from being almost fully closed at idle speed, through to being fully open at 9000 to 11000

Please note that no where in that definition does it says it's a device to decrease noise only. It's a device to increse TORQUE at lower RPM'S. :sifone:

 

[canyondancer]

And just in case...Mr Flux...ole buddy.....this link is from Yamaha Canada explaining what the EXUP valve is. After all Yamaha INVENTED the EXUP valve so i suppose they know why they invented it right?
http://www.yamaha-motor.ca/technology/technology.php?group=M&tech=EUP

Please note....NO WHERE in that explanation does it say that they invented the EXUP valve to decrease noise. They invented it to eliminate the "flat spot" that happens with a 4 into one exhaust system....and to increse torque at low RPM'S.

You want more? :smilielol5:

 

[[FLUX]]

You want more? :smilielol5:

I'm still waiting for one single bit of information that specifically pertains to TRIUMPH Daytona 675 motorcycle engines, and NOT Yamaha designed engines.

Any time you're ready mate.

The rest of us are talking about Daytona 675's, y'know, this being a Daytona 675 forum and all, and you're here telling us all that we've got it all wrong despite entertaining your insistance that an outdated device on a completely different motorcycle engine has actual relevance to why Triumph chose to build a device that bears an implementational resemblance, but has been proven numerous times to have absolutely no functional resemblance to why Yamaha chose to implement it on some motor they built donkey's ages ago.

Triumph don't call it an EXUP valve either, so I don't know why you insist on calling it that. Triumph call it an EXBV, (EXhaust Butterfly Valve), so why do YOU insist on calling it an EXUP valve, and mistakenly ascribe the reasoning for Triumph's use of it as being the same as Yamaha's? To retain your argument perhaps?

Whenever you're ready to stop clutching at those straws and join the rest of us on the same page you're most welcome to do so. Hey, I've been wrong in the past too, hate admitting it, but I reckon I look less like a tool if I just come clean and say that what I once believed to be true across the board is now no longer relevant in a new and different modern application, rather than stubbornly hold onto outdated beliefs.

People used to believe the world was flat at one point too. No offence mate, but right now you're starting to act and behave with much the same fervour as the original round world denialists. I, for one, won't think less of you for discarding outdated beliefs.

 

[carpel21]

The original design of EXUP is irrelivant. The question is for what pupose is it installed on the daytona? When there is clear evidence that the same torque can achieved with only mapping changes, it is obvious that it is for noise control. Why would Triumph spend time and money redeveloping the EXUP to achieve the same results? Because the likely alternative was a more restrictive muffler that would stifle peak power?

 

[[FLUX]]

In fact...Hordboys dyno chart doesn't even look like a stock Triumph 675 chart. Why is that?

Here's a dyno graph of my second '07 675, absolutely bone stock intake/engine/exhaust wise as it was meant to be out of the factory. The only thing different about this bike from a stock factory bike was that I had fitted the black painted fairings to it from my BotY bike.

I'm seeing a heck of a lot of similarities between hordboy's and my graphs.

So i don't know where or how Hordboy came up with that chart....but it's certainly NOT with and without the EXUP valve.

How would you know? Do you even have a stock 675 dyno graph to compare the shapes of? You only have a single graph of a modified exhaust system from your bike, and you're the one calling other people liars because their stock graphs don't mimic yours. FFS, that's taking it too far.

 

[teriyakimonkey]

Stock 675 Daytonas do NOT have those dips in them.

Just for comparison this is mine, standard apart from TOR can and map.

 

[EvilSteve]

It might be interesting to show the stock exhaust system with a/f ratio & then do the same with the EXBV disabled. That would probably show the ratio being out & account for the variance in results of purely disabling the EXBV & not adjusting the map.

Or, I could be full of shit...

 

[hordboy]

Great, now he's calling me a liar. <yawn> :smilielol5:

Canyondancer, your comments are barely worth responding to. But I will anyway! For one thing, I assure you the charts I posted were exactly as I said they were. A stock 675, stock header, TOR can. I guess I should have gotten a Notary Public here to witness the tests? The other charts people posted sure look similar in shape to my eyes, it is very obvious. Why is that? Probably because I have a thousand or more 675 dyno runs under my belt? Probably because they are all actually 675's?

Furthermore, you can't even read your own chart. 49-51T between 7-12k rpm? I printed it out, and a straightedge says otherwise. It is 40-50 or thereabouts, as it should be. Speaking of numbers, you seem to tout this magical "111.78" a lot. Do you realize your chart is reading in a STD correction factor? Which is about 2.6% higher than SAE. And, are you familiar with the concept of graph scaling? Your graph is scaled quite differently than mine, hence your dyno curves look flatter, and smoother. I always scale mine to be as BIG as possible, to enhance the view of any portions of the curves that differ from each other. Non sense in doing science if you can't make anything out of the results, right? And that was the whole point of this exercise, to see what the results said, objectively.

I'm starting to feel sorry I posted this thread, but if I hadn't, then the 99.99% of us who are objective and have a grasp of basic scientific method, wouldn't have gotten any info. I always welcome rational discussion of any results that I post. The key word being, of course, rational.

 

[kellito]

Show me a flat torque curve with the EXUP removed.

I don't need too, hordboy's dyno shows no dip that was not there already. Maybe I just can't see it, but looks the same, which was the whole point in the first place.

Thanks jd, I for one appreciate your posts.

 

[YamRZ350]

You know what's the best thing about beating yourself in the head with a hammer?

It feels so good when you stop...


I appreciate the posts too, J.D. Thanks for taking the time to share.