Purposely dent a Titanium headpipe?


27 replies to this topic
  • swatdoc

Posted May 22, 2009 - 08:55 PM

#1

Don't we just love it when we get something new for our bikes, go to put it on, and find that it doesn't fit?

I got the stage 3 cooling kit from PWR, which includes oversize radiators and an oil cooler. To pump the oil to the cooler, you replace the stock oil filter cover with a custom one from PWR. It's a nice machined billet aluminum piece, and it has two areas that are taller than the rest of the filter cover which have the fittings for the oil lines.

I'm sure it was designed for the stock header, whichprobably clears the extra height on the new filter cover just fine. Problem is, I have an FMF 4.1 carbon exhaust with Ti megabomb header. The megabomb area sits right on top of the oil filter cover and there is no way on God's green earth that there is enough room for the extra height of the PWR cover. I tried rotating the header up, but there's really only about 1/2" at the most leeway - not near enough.

OK - so I thought I'll just have to bite the bullet and switch out to a Powerbomb header. So, ordered that - it came in today, and guess what - still a clearance issue. I CAN force the pipe together, but the headpipe/midpipe junction is gapped uneven. I really need to rotate the header down another 1/4" to 1/2" i think.

I really hate the idea of having to have a totally custom headpipe made to join up with my FMF rear - don't even know who could do that - maybe MRD?

I'm gonna call PWR on monday to see how much meat the aluminum billet cover has in the area i need clearance - i might be able to file it down a quarter inch or a little more.

What would also help is if i could "clearance" the area of the powerbomb for some more room. It's right where the powerbomb largest diameter starts. I'm wondering if I could CAREFULLY place a long socket or something similar over the area in question and give it a whack with a hammer, only 1/4" or so inward should do it, and again, it's not on the main headpipe area, but the expanded powerbomb area.

What do you guys think? Is the Ti easy to dent you think? Will I be causing a problem like it might be more prone to cracking where I dent it? I really doubt it will affect power any cause I should be able to dent only the powerbomb area.

Thanks for your input!

  • BC3

Posted May 22, 2009 - 09:03 PM

#2

[COLOR="Blue"]Check with the manuf. of both parts and see what they recommend....I have dinged pipes before for clearance but that is an expensive dent on your pipe..... [/COLOR]

  • grayracer513

Posted May 22, 2009 - 09:44 PM

#3

I'm wondering if I could CAREFULLY place a long socket or something similar over the area in question and give it a whack with a hammer, only 1/4" or so inward should do it, and again, it's not on the main headpipe area, but the expanded powerbomb area.

What do you guys think? Is the Ti easy to dent you think? Will I be causing a problem like it might be more prone to cracking where I dent it? I really doubt it will affect power any cause I should be able to dent only the powerbomb area.

Thanks for your input!

I wouldn't think it will have any effect on power at all. You may find that the pipe is tougher to dent than you imagined, though. Denting it for clearance should not cause a problem.

  • swatdoc

Posted May 22, 2009 - 10:00 PM

#4

Yea I'll probably give FMF a call on monday too. Get their input on if this will predispose the pipe to cracking.

Gray - that's one of the things I'm wondering - just how tough this thing is gonna be to actually dent a little.

Actually what would be nice is if there is plenty of room on the filter cover, and I can file it down enough for the clearance I need and not even have to touch the header.

  • MRD RACING

Posted May 23, 2009 - 06:23 AM

#5

a dent on the mega bomb wont change perf , its just a resonator to reduce noise

  • TIG88

Posted May 23, 2009 - 07:02 AM

#6

Its gonna be pretty hard to dent. It will help if you heat it up a little with a propane torch or something. Dont get it red hot though. A small dent should not predipose it to cracking.

Ive had to squeeze SS tubing in a little, and it helped if I did it in a vice. This may not be best for you, because it will bend on both sides.

  • grayracer513

Posted May 23, 2009 - 07:38 AM

#7

a dent on the mega bomb wont change perf , its just a resonator to reduce noise

The purpose of the 'Bomb is not to reduce noise, although it does do that. Its function is to damp the shock and pressure waves that run the length of the header as the engine runs, and thus make the header seem as if it has no specific fixed length. This in turn widens the RPM range in which the exhaust system is effective.

Its gonna be pretty hard to dent. It will help if you heat it up a little with a propane torch or something. Dont get it red hot though. A small dent should not predipose it to cracking.

Ive had to squeeze SS tubing in a little, and it helped if I did it in a vice. This may not be best for you, because it will bend on both sides.

Had it been steel, even stainless, I would have recommended heating the pipe to dent it. Ti is trickier, as you are surely aware, being a welder by trade.

I don't think that heating any metal short of at least red will soften it enough to matter, so I think that would be a waste of time. Since the header can and does glow a fairly bright red under certain operating conditions without damage or degradation, I think one could carefully raise it to that state with a torch without harming it. Bear in mind, you want to stay below 1400~1500 degrees without an argon or CO₂ flood. Use this as a guide:

http://www.hearth.co...etal_glows_red/

Such work is potentially hazardous with titanium. Be very cautious. Don't try it if you aren't confident, and don't be surprised if the material still seems pretty tough when it just starts to glow, either.

The vise idea has some merit. If one were to create a form of sorts, perhaps even just some rags, to support the side opposite where the dent is desired, and a piece of pipe or whatever on the spot where he wants the dent, it could work.

  • KJ790

Posted May 23, 2009 - 08:01 AM

#8

I've seen factory teams dent midpipes to fit with the oversized shock components they were using. A dent in the bomb of a megabomb won't be noticeable.

  • TIG88

Posted May 23, 2009 - 08:04 AM

#9

I understand it can degrade it getting it red hot. It seems that individual people opnions of what consititutes red hot vary quite widely. Thats why I suggested to shy away from heating it that much. 600F Ti will be easier to bend than a room temperature piece, and if you are trying to make a small, precision dent, it may help. Either way, it couldn't hurt. :snore:

Nice link too, I've just printed it out. Some of the guys I work with need to see that :doh:

  • grayracer513

Posted May 23, 2009 - 09:05 AM

#10

I understand it can degrade it getting it red hot. It seems that individual people opnions of what consititutes red hot vary quite widely. Thats why I suggested to shy away from heating it that much. 600F Ti will be easier to bend than a room temperature piece, and if you are trying to make a small, precision dent, it may help. Either way, it couldn't hurt. :snore:

Nice link too, I've just printed it out. Some of the guys I work with need to see that :doh:

Note that the difference between red that's barely visible in low light and bright red is 900 ℉. At 600, metals don't glow visibly. I haven't done much work with Ti, so you would be more familiar with how it behaves when hot, but as I said before, even at 900 ℉, it's nowhere near melting, and it would surprise me if it were very soft at that temp, but I don't know.

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  • TIG88

Posted May 23, 2009 - 09:45 AM

#11

Right, 600 was just an arbitrary number I picked because it is not hot enough to glow. I shoudl have probably said to "heat it up till it faintly glows red" in my first post. From experience though people tend to take that too far that arent familiar with it.

It will soften quite a bit as it turns red. If you follow that guide and heat it to 975F, it will be much easier to bend or dent.

Good luck!

  • swatdoc

Posted May 23, 2009 - 01:29 PM

#12

Thanks guys - appreciate the input!

  • MRD RACING

Posted May 23, 2009 - 01:55 PM

#13

The purpose of the 'Bomb is not to reduce noise, although it does do that. Its function is to damp the shock and pressure waves that run the length of the header as the engine runs, and thus make the header seem as if it has no specific fixed length. This in turn widens the RPM range in which the exhaust system is effective.

Had it been steel, even stainless, I would have recommended heating the pipe to dent it. Ti is trickier, as you are surely aware, being a welder by trade.

I don't think that heating any metal short of at least red will soften it enough to matter, so I think that would be a waste of time. Since the header can and does glow a fairly bright red under certain operating conditions without damage or degradation, I think one could carefully raise it to that state with a torch without harming it. Bear in mind, you want to stay below 1400~1500 degrees without an argon or CO₂ flood. Use this as a guide:

http://www.hearth.co...etal_glows_red/

Such work is potentially hazardous with titanium. Be very cautious. Don't try it if you aren't confident, and don't be surprised if the material still seems pretty tough when it just starts to glow, either.

The vise idea has some merit. If one were to create a form of sorts, perhaps even just some rags, to support the side opposite where the dent is desired, and a piece of pipe or whatever on the spot where he wants the dent, it could work.


sorry but I have to disagree on that one , its a resonator , they have been used to muffle sound since the invention of the internal combustion engine , dont you think its weird that the bomb is always in the only spot they will fit on the header , how can that be the perfect spot to dampen preasure waves at the optimum tunned length ? although I dont doubt that on cirtain engine combinations it could increase power a couple tenths of a HP ( no disrespect , just my opinion )

  • TIG88

Posted May 23, 2009 - 03:04 PM

#14

sorry but I have to disagree on that one , its a resonator , they have been used to muffle sound since the invention of the internal combustion engine , dont you think its weird that the bomb is always in the only spot they will fit on the header , how can that be the perfect spot to dampen preasure waves at the optimum tunned length ? although I dont doubt that on cirtain engine combinations it could increase power a couple tenths of a HP ( no disrespect , just my opinion )


It works similarily to a 2 stroke pipe. A side effect of the pressure waves bouncing around differently does muffle the sound a bit.


http://www.fmfracing...ail.aspx?cat=44

  • KJ790

Posted May 23, 2009 - 03:06 PM

#15

sorry but I have to disagree on that one , its a resonator , they have been used to muffle sound since the invention of the internal combustion engine , dont you think its weird that the bomb is always in the only spot they will fit on the header , how can that be the perfect spot to dampen preasure waves at the optimum tunned length ? although I dont doubt that on cirtain engine combinations it could increase power a couple tenths of a HP ( no disrespect , just my opinion )


I think it does both jobs. The bomb position between an SX and an MX powerbomb is a couple inches different, and the performance difference between the two headers is noticeable. However I agree that there isn't much room to move the bomb position.

  • grayracer513

Posted May 23, 2009 - 03:59 PM

#16

sorry but I have to disagree on that one

You may if you choose to, but you may want to talk with FMF about it. As I said, it does have an effect on sound output, but that is not the primary purpose of the device. If you cut one open and examine the way the pipe that passes through it is perforated, it would become obvious that sound reduction is not what it was designed for. As to the location, no, I don't find it odd in any way that it is where it is, nor do I see it as being particularly critical as to where within the first 18" of pipe it would be located (although it might be), or as to the total volume of the chamber within a reasonable limit.

If you look at dyno charts of engines equipped with 'Bomb exhausts and compare them to more conventional pipes, what you see is that the FMF product will seldom have the highest peak numbers, but will tend to have the longest, flattest overall curve. That is the power numbers at both the extreme ends, particularly the low end, will be greater than conventional pipes.

The form factor of the damping/resonant chamber is less important than other factors that govern its function. The pipes from Akropovic and GYT-R are two examples of pipes that work in fundamentally the same way, but with resonant chambers that look entirely different from the Power Bomb series. DRD had yet a third design like this that consisted of a pipe looping out from the main header tube and then back into it farther down the header. No word on where that project went.

Either way, I will not argue that it has no effect on sound, because it does. Just that that was never its design function, but rather, a secondary effect of its operating principles.

  • swatdoc

Posted May 23, 2009 - 09:00 PM

#17

I just thought of another idea - when I talk to FMF monday, I'll ask them if they will just pull a header off the assembly line before it has had the powerbomb added to it, and see if they'll swap it out for the one I have. Worth a shot.

  • grayracer513

Posted May 24, 2009 - 06:27 AM

#18

I just thought of another idea - when I talk to FMF monday, I'll ask them if they will just pull a header off the assembly line before it has had the powerbomb added to it, and see if they'll swap it out for the one I have. Worth a shot.

I don't think that will work, but they do have their "Hi-Flo" series, which has no "Bomb" in it.

  • MRD RACING

Posted May 24, 2009 - 02:55 PM

#19

You may if you choose to, but you may want to talk with FMF about it. As I said, it does have an effect on sound output, but that is not the primary purpose of the device. If you cut one open and examine the way the pipe that passes through it is perforated, it would become obvious that sound reduction is not what it was designed for. As to the location, no, I don't find it odd in any way that it is where it is, nor do I see it as being particularly critical as to where within the first 18" of pipe it would be located (although it might be), or as to the total volume of the chamber within a reasonable limit.

If you look at dyno charts of engines equipped with 'Bomb exhausts and compare them to more conventional pipes, what you see is that the FMF product will seldom have the highest peak numbers, but will tend to have the longest, flattest overall curve. That is the power numbers at both the extreme ends, particularly the low end, will be greater than conventional pipes.

The form factor of the damping/resonant chamber is less important than other factors that govern its function. The pipes from Akropovic and GYT-R are two examples of pipes that work in fundamentally the same way, but with resonant chambers that look entirely different from the Power Bomb series. DRD had yet a third design like this that consisted of a pipe looping out from the main header tube and then back into it farther down the header. No word on where that project went.

Either way, I will not argue that it has no effect on sound, because it does. Just that that was never its design function, but rather, a secondary effect of its operating principles.


I know what they look like on the inside , it is exactly like the resonator that has been on Honda 450R midpipes since 04 , and exactly like the original resonator designed 100 years ago by some guy named Hiemholt or somthing like that , a can with a tube with a few holes in it through it , thats what a resonator is , I dont need to talk to FMF , I know the man that designed them for FMF , his name is George Luttig , he used my fuel injection systems on the racing jet skis he used to build , he is an expert engine tunner and he probably saw something when he put one on the header when he was doing R&D at FMF that he liked , but I belive it has a bigger impact on noise than power , we have a dyno too and every engine is different and not everybody will get the same result with the same part , I just think people would be more apt to buy a power bomb than a quiet bomb if you know what I mean, George also designed the CHAMBER CORE witch I dont think you can get anymore because they only work when the tip is very large and hence the pipes check loud at 20" even though they are not loud at full throttle under load , those cores produced very broad torque curves and impressive dyno charts

  • MRD RACING

Posted May 24, 2009 - 03:56 PM

#20

I think it does both jobs. The bomb position between an SX and an MX powerbomb is a couple inches different, and the performance difference between the two headers is noticeable. However I agree that there isn't much room to move the bomb position.


I dont know how much room they have to move the bomb on some bikes but I think the two headers have different dia. tube as well ( I could be wrong but I have seen some of thier headers for the same bike with different size tube ) , witch is another way to change power delivery with the header that everybody uses





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