[ton]

Hey J.D.

i'm sure canyondancer would be willing to pay you for the dyno time to do the exact experiment he describes to put this debate to rest permanently. prolly better to use his bike though, just so that the variability in dynos is taken into account.

-mark

 

[YamRZ350]

From what I can tell, there's only one guy here going on about the merits of the exhaust valve and power delivery.

No matter what you show him, or tell him, he will just continue to argue his version of reality.

 

[mb66l79]

hordboy - would it be possible to run the same test on the same bike with the TOR tune instead of the stock tune (that is assuming it had the stock tune in the first place). I would think that should settle this, unless the cat would really affect it that much which I'm afraid it would. Just thinking out loud here.

 

[hordboy]

Why? That would be a test of the tunes and not of the valve. All I am interested in is the valve's effect on power delivery, and that's the only variable I tested in this case.

 

[mb66l79]

Why? That would be a test of the tunes and not of the valve. All I am interested in is the valve's effect on power delivery, and that's the only variable I tested in this case.

Based on what CD was saying, the only thing I could think of is if removal of the valve affects (or lack thereof) different tunes in different ways. I wouldn't think that it would, but I'm no expert on this subject.

Either way, nice work on your testing, I think you convinced me to unhook my valve. I have the TOR can and tune with the cat gutted, I'll have to see what my butt dyno says on the difference.

 

[hordboy]

Well, I'm sure CD would be right, removal of the valve would have a different result with different tunes. That's why I removed the variable of the tune, and made sure the mapping was roughly optimized for each testing condition of the valve. I guess I'm assuming everybody realizes that, and I shouldn't be. Again, simply running the bike with one tune and the valve hooked/unhooked, doesn't give you any meaningful data on the valve. The same way modifying your engine and running the stock tune wouldn't give you any meaningful data on the engine mods.

And, for the record, I'm not saying everybody should go out and disable their EXUP valves. I just wanted to find out if the valve itself provides power enhancement. It seems not to.

 

[carpel21]

I'm likely taking the exhaust off to the fabricators next week but still undecided whether to remove just the cat or cat and EXBV. Mine has never seized even with riding in the UK spring/autumn and being stood up through the winter. If I leave the EXBV on, then no need to remap (20109 +3 degrees ignition for standard can) and I could always just cut the cables and leave it open if it does seize. The cover bolts are mush though so I'd need to drill them to set a seized valve open. If I do remove both, then how much will the fuelling be off under 7K? I have Tuneboy so could trim it up but would it run richer or leaner without the valve?

 

[canyondancer]

Based on what CD was saying, the only thing I could think of is if removal of the valve affects (or lack thereof) different tunes in different ways. I wouldn't think that it would, but I'm no expert on this subject.

Either way, nice work on your testing, I think you convinced me to unhook my valve. I have the TOR can and tune with the cat gutted, I'll have to see what my butt dyno says on the difference.

So what did the butt dyno tell you? Let me guess....loss of torque under 5k....right?

 

[mb66l79]

That's why I removed the variable of the tune, and made sure the mapping was roughly optimized for each testing condition of the valve.

So what did the butt dyno tell you? Let me guess....loss of torque under 5k....right?

I haven't had a chance to test it yet, but hopefully this weekend. I'll post up my thoughts after I actually do it.

If I understand hordboy correctly, the tune was different for the runs with and without the valve. My conclusions from this are that the valve is worthless if you dyno tune the bike, which is nice to see some hard evidence behind this. :thumbsup:

From what I've read on this subject in other threads, I understand the main question as whether or not removing/unhooking the valve without changing the tune has any effects on low end torque. For myself, and I would assume the majority of other people, this is what I would like to know as I'm not ready to spend the money on dyno tuning. I've read lots of people arguing this both ways but haven't seen any definitive evidence like hordboy's test, unless I missed it. I'm afraid that until someone shows evidence solving this question one way or the other, like hordboy did with his test, this topic will never die.

 

[shaunthesoundguy]

With the stock tune and removing the exup, the bike will undoubtably suffer in the RPM ranges that the valve was meant to be functioning.
Hordboy proved that the exup itself provides no power gains, but a retune is necessary if you remove it, as our stock tune obviously is mapped to have it there. And essentially after removing it the only gains are losing 1.5 pounds and no more fussing with it.

 

[canyondancer]

From what I've read on this subject in other threads, I understand the main question as whether or not removing/unhooking the valve without changing the tune has any effects on low end torque. .

Of course you lose low end torque when removing the valve. THATS WHY TRIUMPH PUT IT ON THERE. It doesn't matter what tune you use. What is more important here is the torque curve. You don't ride your bike on the dyno at 12 grand all day. You ride on the street and what you want is the flattest torque curve you can get. You remove the valve...you lose some torque down low and you get a dip in the torque curve.

It's not possible to make a fuel map to correct the loss of torque. The EXUP valve reverses exhaust waves and that creates torque. No map can do that.

 

[mb66l79]

Well I did some testing of my own today. I have an 06 with the early TOR tune, TOR can, and gutted cat.

By unchecking the exbv box in tuneedit, the exbv no longer functioned. I made sure it was in the wide open position for the test. The first thing I noticed was the much improved sound of the exhaust at low rpm's, it was much louder too, I fell in love with it immediately. According to my butt dyno, I feel like there was less torque in low rpm's. I feel confident enough in that result that I am leaving the exbv hooked up as I prefer the increased performance over the improved exhaust melody. I am disappointed as I wish I could have it both ways.

Since I was already doing testing with tuneboy I decided to try out the madas tune with my setup to see how it compared to the TOR tune. My butt dyno was not calibrated well enough to notice a difference between the two, which surprised me. I will continue to run the TOR tune however.

I may at some point this summer try out some of the other more popular tunes that can be found in the massive tuneboy tune thread, just to see if I can find one that will be better with my setup. I think canyondancer has the exact same setup as me, and I would think there are others as well, so if/when I do, I'll post up my thoughts.

It would be nice to run these tests on a dyno, but until I have that much extra money, I have no evidence for my results. I think I answered the question for myself, but I don't expect anybody else to accept any of this as fact.

 

[canyondancer]

Well I did some testing of my own today. I have an 06 with the early TOR tune, TOR can, and gutted cat.

By unchecking the exbv box in tuneedit, the exbv no longer functioned. I made sure it was in the wide open position for the test. The first thing I noticed was the much improved sound of the exhaust at low rpm's, it was much louder too, I fell in love with it immediately. According to my butt dyno, I feel like there was less torque in low rpm's. I feel confident enough in that result that I am leaving the exbv hooked up as I prefer the increased performance over the improved exhaust melody. I am disappointed as I wish I could have it both ways.

Since I was already doing testing with tuneboy I decided to try out the madas tune with my setup to see how it compared to the TOR tune. My butt dyno was not calibrated well enough to notice a difference between the two, which surprised me. I will continue to run the TOR tune however.

I may at some point this summer try out some of the other more popular tunes that can be found in the massive tuneboy tune thread, just to see if I can find one that will be better with my setup. I think canyondancer has the exact same setup as me, and I would think there are others as well, so if/when I do, I'll post up my thoughts.

It would be nice to run these tests on a dyno, but until I have that much extra money, I have no evidence for my results. I think I answered the question for myself, but I don't expect anybody else to accept any of this as fact.

Yep we both have the same year bike...same setup. It would be great if you could afford the dyno run and see if it puts out the same power and torque as mine. I know dynos are different...but it would at least show two of us with nearly the exact HP and torque curve. I don't think there is any need for a dyno run with EXUP disconnected. We both know the noise is louder and the torque is less. I'm kinda suprised no one has made a map specific for our setups yet. I think with a disconnected EXUP valve....you could recover a little of that lost torque down low with a custom map....but i'm pretty certain that big dip in the torque curve would remain. That's why i havn't pursued it. I love that flat torque curve.

 

[carpel21]

How is it that Hordboy's dyno graph is conflicting with your butt? I tried this also and noticed no power loss but fueling felt a little off. There must be an explanation that will satisfy all. Is it possible that the valve, under high pressure (WOT) could be held further open than it's intended angle? This would give the noise reduction and slightly higher torque at smaller throttle openings, but tie in with Hordboy's full throttle graph that shows near identical power curves?

(my post in another thread):-
I want to get shot of it, but not at the expense of grunt up to 7k so I decided to do a bit of home testing. Got to thinking that Tuneboy has a check box "exhaust valve fitted" in the tune constants so I unchecked it, downloaded, turned off/on and voila, no squeek on startup tests! Exhaust note had changed for the better too though not as much as I thought it would. Took it for a very short blat out of town and back again and my feelings were this:

Not noticably weaker in the lower rpm, but the response was a little fluffy, like it was running rich, though not to the extent of pausing before pickup.
Where off/on throttle transitions at around 3k used to make the bike "kick", it was now noticably smoother and easier to navigate in city, like small roundabouts, junctions and slow moving traffic.
My setup by the way, is standard can, BMC raod filter, and 20109 final dyno tune by Tuneboy.
This was a very preliminary test (around 20 mins) and when the weather settles down I'm going to do some roll on runs in 6th gear from 3-7k, and time them with the onboard lap timer, then activate the EXBV again and repeat.
So far, while I completely agree with Canyondancer in theory on this, my personal opinion is leaning towards the torque curve not being affected to any noticable degree, even without a remap as Hordboy's dyno results implied also. Sorry CD:itsok:

 

[canyondancer]

How is it that Hordboy's dyno graph is conflicting with your butt? I tried this also and noticed no power loss but fueling felt a little off. There must be an explanation that will satisfy all. Is it possible that the valve, under high pressure (WOT) could be held further open than it's intended angle? This would give the noise reduction and slightly higher torque at smaller throttle openings, but tie in with Hordboy's full throttle graph that shows near identical power curves?

(my post in another thread):-
I want to get shot of it, but not at the expense of grunt up to 7k so I decided to do a bit of home testing. Got to thinking that Tuneboy has a check box "exhaust valve fitted" in the tune constants so I unchecked it, downloaded, turned off/on and voila, no squeek on startup tests! Exhaust note had changed for the better too though not as much as I thought it would. Took it for a very short blat out of town and back again and my feelings were this:

Not noticably weaker in the lower rpm, but the response was a little fluffy, like it was running rich, though not to the extent of pausing before pickup.
Where off/on throttle transitions at around 3k used to make the bike "kick", it was now noticably smoother and easier to navigate in city, like small roundabouts, junctions and slow moving traffic.
My setup by the way, is standard can, BMC raod filter, and 20109 final dyno tune by Tuneboy.
This was a very preliminary test (around 20 mins) and when the weather settles down I'm going to do some roll on runs in 6th gear from 3-7k, and time them with the onboard lap timer, then activate the EXBV again and repeat.
So far, while I completely agree with Canyondancer in theory on this, my personal opinion is leaning towards the torque curve not being affected to any noticable degree, even without a remap as Hordboy's dyno results implied also. Sorry CD:itsok:

Sorry for what? Put it on the dyno and see how much torque you lost under 5k. When you do...you'll see a huge dip in the torque curve under 5k too. I've seen a few charts with the EXUP removed and they all have a huge dip. It gets worse with a full system.

 

[mb66l79]

How is it that Hordboy's dyno graph is conflicting with your butt?

Not noticably weaker in the lower rpm, but the response was a little fluffy, like it was running rich, though not to the extent of pausing before pickup.
Where off/on throttle transitions at around 3k used to make the bike "kick", it was now noticably smoother and easier to navigate in city, like small roundabouts, junctions and slow moving traffic.

In hordboy's test he used different fuel maps, they were tuned to be optimal with the valve and without the valve. He proved that the exbv makes no measurable difference with a custom dyno tuned map.

In my "test", I did not change the map, proving to myself that removing the valve for the TOR tune has a loss in low end torque.

Where you say the response "was a little fluffy" and the bike doesn't "kick" and is smoother, I noticed the same thing; confirming my results. This is the loss in torque that I said I found, and that canyondancer has been saying all along.

The two tests can not be compared as they are testing two different things.

 

[carpel21]

In hordboy's test he used different fuel maps, they were tuned to be optimal with the valve and without the valve. He proved that the exbv makes no measurable difference with a custom dyno tuned map.

In my "test", I did not change the map, proving to myself that removing the valve for the TOR tune has a loss in low end torque.

Where you say the response "was a little fluffy" and the bike doesn't "kick" and is smoother, I noticed the same thing; confirming my results. This is the loss in torque that I said I found, and that canyondancer has been saying all along.

The two tests can not be compared as they are testing two different things.

Where does Hordboy say he remaped for the missing valve? He's actually PM'd me suggesting +5% fuel from 6k down as a very rough guesstimate which makes sense, but the fueling didn't feel far enough out to have a noticable loss of torque. Only delivery felt softer from OFF/ON throttle but when WOT from idle, pull felt just as strong to me. I'm not saying it hasn't lost ANYTHING, but not to a degree that I noticed. I'd really need a dyno run to tell for sure, but maybe i've just got numb-nuts!:laugh:
I really couldn't sense this "massive torque dip". I do weigh 63kgs without gear though so maybe I just wouldn't notice it as much, but I thought if anything, my lack of weight would increase the degree to which power/weight ratio affects low grunt.
When the high winds die down here, I'm gonna do some roll on tests through the EXBV range to see if it slows the times down at all.
Don't get me wrong, I'm not out to prove the valve is useless, but my cover bolts are seized and it's only a matter of time before the valve jams, so if I can get rid of it without too much, if any torque loss, then I can get it chopped out with the cat.

 

[carpel21]

Sorry for what? Put it on the dyno and see how much torque you lost under 5k. When you do...you'll see a huge dip in the torque curve under 5k too. I've seen a few charts with the EXUP removed and they all have a huge dip. It gets worse with a full system.

CD, were these charts of bikes that had been remapped to compensate? Also, full systems are optimised for maximum flow all the way through, so they can't be expected to hold any back pressure increasing low end. My bike still has the stock muffler and cat currently, which must be increasing back pressure further.

As for put it on a dyno and "you'll see a huge dip in the torque curve under 5k too", isn't that exactly what Hordboy has just done and found the torque curve to be largely unaffected on a bike with only a TOR can upgrade?

 

[mb66l79]

Where does Hordboy say he remaped for the missing valve?

Well, I'm sure CD would be right, removal of the valve would have a different result with different tunes. That's why I removed the variable of the tune, and made sure the mapping was roughly optimized for each testing condition of the valve.

Unless I'm understanding that wrong, but it seems pretty straightforward to me.

 

[carpel21]

Unless I'm understanding that wrong, but it seems pretty straightforward to me.

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.