Porting will change everything. 1-1/2 pipes could work better when your head is flowing well. But it may only show improvement on the top end. The Maney 2 to 1 pipes should show the best mid range. But twin pipes will probably have more top end. I'm talking racing megaphones - not peashooters or mufflers.
Exhaust dyno testing
- Thread starter Fast Eddie
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Fast Eddie
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Ok guys, I just may have found the reason for the 'mystery power loss' ... you ready for this ... Ignition timing was out. Schoolboy error or what? FFS !!
I'd like too say 'it slipped' but we all know that's not really likely!
I corrected the timing and went out for a road test with the Maney system. Fan-bloody-tastic!
Now to the next step, I hope to re-visit the dyno again before removing the head, to get the firm baseline. Then either change or re-work my existing head before re-testing. This will be really nice to see the back to back results.
As Jim S said earlier, porting changes everything, so the different pipes may well work differently. But, based on yesterday's dyno results and today's road test, I cannot currently imagine anything beating the Maney system.
Will keep y'all posted.
I'd like too say 'it slipped' but we all know that's not really likely!
I corrected the timing and went out for a road test with the Maney system. Fan-bloody-tastic!
Now to the next step, I hope to re-visit the dyno again before removing the head, to get the firm baseline. Then either change or re-work my existing head before re-testing. This will be really nice to see the back to back results.
As Jim S said earlier, porting changes everything, so the different pipes may well work differently. But, based on yesterday's dyno results and today's road test, I cannot currently imagine anything beating the Maney system.
Will keep y'all posted.
"Sounds like you are on a sales commission from Steve Maney !!" 
Good thread and glad you found the culprit.
Good thread and glad you found the culprit.
lcrken
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Dances with Shrapnel said:"Sounds like you are on a sales commission from Steve Maney !!"
Good thread and glad you found the culprit.
It would be hard to get much commission from Steve Maney, since he doesn't have any of the exhaust systems to sell. With all the interest here, I'm surprised he hasn't decided to make another batch, but he did have some issues with them breaking when used on Commandos. Might have something to do with faulty installation by customers. They seemed to be much more reliable on rigid mount frames. Never had a problem with the one on my wideline. I think he just didn't want the hassle, and that's why he passed the remaining systems off to Minnovation, and got out of the business.
I recently looked into copying his system in titanium, and I'd have to sell the system for at least US$1000, and probably more, just to break even, much less earn a profit, so I've dropped that idea (one of many of my ideas that end up that way).
Ken
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Hi lcrken.
Re your: "...Might have something to do with faulty installation by customers. They seemed to be much more reliable on rigid mount frames...".
It can't be the customer if it works on one model but not another: perhaps an unresolved design issue to do with vibration frequency and amplitude.
Ta.
Re your: "...Might have something to do with faulty installation by customers. They seemed to be much more reliable on rigid mount frames...".
It can't be the customer if it works on one model but not another: perhaps an unresolved design issue to do with vibration frequency and amplitude.
Ta.
Brooking 850
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Hi ken , I have to agree with that comment about the cracking, a vertical brace between the two where the pipes fist state to straighten out and run parallel seems to work.
Also keeping the bends all one piece instead of a series of welded 'U's seems to hider the cracking as well.
Will post progress pics and results as they come to hand, probably ithe back end of September due to work committments out of the country.
Regards Mike
Also keeping the bends all one piece instead of a series of welded 'U's seems to hider the cracking as well.
Will post progress pics and results as they come to hand, probably ithe back end of September due to work committments out of the country.
Regards Mike
Fast Eddie
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The Maney system is quite thin wall, as one would expect really from a race system.
The trouble is, it seems very easy to install the Maney system under stress. There is not as much 'wiggle room' as with the stock independent two pipes set up.
I find it very easy to imagine a racer rushing the installation in the paddock and fitting the system under stress, resulting in a later breakage.
The trouble is, it seems very easy to install the Maney system under stress. There is not as much 'wiggle room' as with the stock independent two pipes set up.
I find it very easy to imagine a racer rushing the installation in the paddock and fitting the system under stress, resulting in a later breakage.
Fast Eddie
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lcrken said:Dances with Shrapnel said:"Sounds like you are on a sales commission from Steve Maney !!"
Good thread and glad you found the culprit.
It would be hard to get much commission from Steve Maney, since he doesn't have any of the exhaust systems to sell. With all the interest here, I'm surprised he hasn't decided to make another batch, but he did have some issues with them breaking when used on Commandos. Might have something to do with faulty installation by customers. They seemed to be much more reliable on rigid mount frames. Never had a problem with the one on my wideline. I think he just didn't want the hassle, and that's why he passed the remaining systems off to Minnovation, and got out of the business.
I recently looked into copying his system in titanium, and I'd have to sell the system for at least US$1000, and probably more, just to break even, much less earn a profit, so I've dropped that idea (one of many of my ideas that end up that way).
Ken
Ken, please re-launch your titanium exhaust idea. They would be a stunning statement !
The Maney system was well over £1000 with VAT etc ($1600 ish), and is no longer avilable, so there would be no need to aim at a $1000 sales price Ken.
Also, it was not well publicesd just how good they were. A few Internet posts showing awesome back-to-back results would create big interest I think. Especially in the current Cafe Racer renaissance area.
Go Ken !!
SteveA
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Chris said:Hi Eddie
Glad you liked my Maney
Fortunate find brand new in Ireland half price & Gerry went halves on postage. Steve did'nt have them in stock at the time. Dave Watson had one made by NRP but Gary was'nt happy with it. Until it was redone. Steve A has had one done for his Rickman & is now pleased with it. Still not sure they are in stock with Steve Maney.
Hopefully at Donnington.
Chris
Nope....I am on separate 1 1/2" ID (1 5/8" OD) pipes...from NRP but I am happy with those...they are similar to the pipes Dave Watson had on his 750 short stroke (270 crank). But these are working with a Fullauto.
I sort of disagree that Steve Maney's system was under publicised, most people who used it rated it and a lot of race bikes have used it, or copies of it.
It is true that Dave Watsons NRP system was reworked, but I understood they were happy with it then, and on a dyno it was close to Steve's baseline.
Racing Pipes, twin megaphones and velocity stacks are generally tuned for wide open and above 4000 RPM.
And many racers want to work around 6000+ RPM. The peashooters are really just an extension of the header pipe because they don't have an open chamber like a racing megaphone - So you end up with a very long pipe instead of a header pipe leading into a megaphone chamber. What works for the track won't be ideal for the street. Whatever you're doing - have fun with it and don't be disappointed if it leads to whats already been worked out.
And many racers want to work around 6000+ RPM. The peashooters are really just an extension of the header pipe because they don't have an open chamber like a racing megaphone - So you end up with a very long pipe instead of a header pipe leading into a megaphone chamber. What works for the track won't be ideal for the street. Whatever you're doing - have fun with it and don't be disappointed if it leads to whats already been worked out.
Fast Eddie
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I was wondering how it sounded on the road test with that system ?[/quotecjandme said:
Crisp and sweet!
And not overly quiet...
SteveA
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jseng1 said:
The need for silencing to 105 drives away from megaphones as such these days, the pipe steps up through the silencer section but its not a 'real' mega.
But with long inlets, and the separate pipes, I really love the power delivery from 6000 to 7000, with the odd tripp to 7500 so far, suits the ratios in the boox well. Would just be better if it wasn't tipping it down like it was yesterday!
Its not a road set up!
lcrken
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It is possible to construct race exhausts that still use megaphones and also meet the sound limits, but they get kind of bulky. Ron Wood developed such a system for his Rotax powered singles racer to meet AMA regs a decade or more after the original development of the bike. For the twin cam single in 676 cc configuration, he built this 2 into 2 system, with reverse cone megas followed by his own design silencers.
His design used a typical perforated, glass packed core, but it was in a sort of zig-zag path, not straight through. That was one of the reasons the can was so large, to accommodate the crooked path. He said that was the best design he'd found, meeting the sound specs without significant performance loss. It certainly worked well. My last dyno run, on Phil Darcy's conventional hydraulic load cell dyno, gave 80.2 rwhp at 8500 rpm, and still met the AMA sound spec.
I'm sure you could build a similar system for a Norton, but it would be large and bulky, as well as (according to some) ugly. I had quite a few people ask me at the track why I used such a large silencer.
For comparison, this is the system on the bike when it was still using a single cam 600 cc engine, only making 62 rwhp, and running in club races with no sound restrictions. Quite a difference. And did I mention the stylish rider? I think this picture is from somewhere around 1988 or 1989.
Ken
His design used a typical perforated, glass packed core, but it was in a sort of zig-zag path, not straight through. That was one of the reasons the can was so large, to accommodate the crooked path. He said that was the best design he'd found, meeting the sound specs without significant performance loss. It certainly worked well. My last dyno run, on Phil Darcy's conventional hydraulic load cell dyno, gave 80.2 rwhp at 8500 rpm, and still met the AMA sound spec.
I'm sure you could build a similar system for a Norton, but it would be large and bulky, as well as (according to some) ugly. I had quite a few people ask me at the track why I used such a large silencer.
For comparison, this is the system on the bike when it was still using a single cam 600 cc engine, only making 62 rwhp, and running in club races with no sound restrictions. Quite a difference. And did I mention the stylish rider? I think this picture is from somewhere around 1988 or 1989.
Ken
ewgoforth said:
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