to wrap or not to wrap...that is the ???


24 replies to this topic
  • ncmountainman

Posted February 02, 2005 - 08:17 AM

#1

header tape? yay,or nay ?? i've seen some people using it with the newer bikes. and the reasoning behind it is to accelerate the exhaust through the pipe(which is fact) well the new pipes are so thin i was kinda wonderin' if they would survive?, one feller' stated he's been running it on his wr for a year+ in the desert with no prob... i'm thinkin' it may even cut down on heat cycle stress. i run the stainless powerbomb,so i think it might be all right as far as the metal goes. another thing is the p-bomb works on the principle that the exhaust cools in the "bomb" and then ramps back up on exit for more flow. what might wrapping do for that? i want to wrap the whole header as i got a pretty nasty burn from it last year. i tried the carbon fiber gaurd specifically for the power bomb but it ripped off the first time i dumped on that side. one other reason is that the radiator is only 1/2" away from the header. frostbite just did a in depth article with infrared scanning and found this to be the cause of his over heating.... pro's vs. cons ??? :cry:

  • Frostbite

Posted February 02, 2005 - 08:53 AM

#2

I've got the bike running now and am going to mount the studs and ski on the weekend. I'll take the IR camera and snap some pics of the engine, rads and pipe as they warm up. I'll post the pics but may lose some image quality. The camera saves the pics in a special format that requires specific IR software to view as a picture. I've been able to transfer IR pics by printing them to Acrobat distiller and saving them as PDFs. Then I'll probably have to scan the PDF and save it as a JPEG to post it, but it should work.
The camera records lots of information about the image, so I can pull up the temp of any pixel in the picture accurate to a tenth of a degree, or I can isolate and area in the picture and get average temps, like of sections of the pipe, rads, head. I'll play with it a bit and see if I can make it interesting.
As far as wrapping the pipe goes, I don't know if it would help power or not. I do know that it'll help with the leg burning problem and may keep heat from the rad, but will it trap more heat in the engine since it won't be able to act as much of a heat sink?:cry:
One of our TT members helped me get a custom stainless steel exhaust shield with my TT name cut into it. If I had a power plate hammer like Jesse James I probably could have fit it perfectly to the compound curves of the pipe, but I did the best I could with a hammer and vice. I'll post a pic of that too.

  • Jackazz

Posted February 02, 2005 - 10:04 AM

#3

Hey frosty, another avenue (if you have a good vid card, run a reasonably high resolutiuon, & have a large monitor) is to just use the "print screen" button & then paste it into a new window in photoshop. Will most likely be 72dp1, but if you're running a 21" monitor the images would be fine for posting on TT.

  • Frostbite

Posted February 02, 2005 - 10:55 AM

#4

Hey frosty, another avenue (if you have a good vid card, run a reasonably high resolutiuon, & have a large monitor) is to just use the "print screen" button & then paste it into a new window in photoshop. Will most likely be 72dp1, but if you're running a 21" monitor the images would be fine for posting on TT.


Well, I don't think monitor size is an issue, but I don't have a print screen option.:cry:

  • ncmountainman

Posted February 02, 2005 - 11:04 AM

#5

As far as wrapping the pipe goes, I don't know if it would help power or not. I do know that it'll help with the leg burning problem and may keep heat from the rad, but will it trap more heat in the engine since it won't be able to act as much of a heat sink?:cry:

if it truly does accelerate the exhaust gas, then i guess the question would be will the faster evacuation overcome the missing heat sink effect?:cry:

  • Raistlin

Posted February 02, 2005 - 11:09 AM

#6

Well, I don't think monitor size is an issue, but I don't have a print screen option.:cry:


Alright, Im jelous!! That is to sweet!! :cry: I believe the "print screen" option is on your keyboard. Mine is right next to the "F12" key!! :cry:

  • Frostbite

Posted February 02, 2005 - 12:19 PM

#7

Alright, Im jelous!! That is to sweet!! :cry: I believe the "print screen" option is on your keyboard. Mine is right next to the "F12" key!! :cry:


I do have the key, but it no worky.:cry:

  • Frostbite

Posted February 02, 2005 - 01:21 PM

#8

if it truly does accelerate the exhaust gas, then i guess the question would be will the faster evacuation overcome the missing heat sink effect?


I’m not sure exactly how it will affect the cooling of the engine but let’s think about it a bit.

The head pipe does get very hot and radiates heat to the cooler air and things around it, like your leg, and conducts heat to things it touches, like the head, muffler, and your leg. The hottest part of the pipe would be near the head where the freshly burnt mixture is heating it, the coolest part would be the tip of the muffler.

Heat flows from hot to cold, so theoretically some of the heat from the hot pipe would flow backwards (by conduction) to the cooler liquid cooled head. As you go down the head pipe a few inches the heat would begin to flow away from the engine (by conduction) if the muffler is cooler than the head. I don’t know if it is but I’ll be able to tell you after the weekend.

Heat also flows by radiation and convection, so assuming you’re not riding through a live volcano on one of Torture Chamber’s lava field adventures, the air around the pipe should be cooler than the pipe and the head so heat flows away from the engine. If you wrap the pipe with insulation, you eliminate a lot of the air cooling (which seems to be the intent of wrapping) so now the heat transfer is limited more to conduction.

Heat flows from hot to cold. My pipe glows cherry red in the open air so I can imagine that a much longer section would be smoking hot if it was insulated. Theoretically the heat would travel backwards to the cooler head.

There are probably hundreds of other variables affecting what goes on but to think of it simply – a red hot chunk of metal bolted to your engine that was once air cooled and now is not has got to increase the engine temperature, or at least put more strain on the cooling system.

Of course, as always, I could be wrong.:cry:

  • Raistlin

Posted February 02, 2005 - 02:17 PM

#9

I do have the key, but it no worky.:cry:


You have to push either the "Ctrl" or the "Alt" button at the same time you hit the "print screen" button. Then just go to where you want to paste it and right click you mouse and hit paste!! That should do it!! :cry:

  • ncmountainman

Posted February 02, 2005 - 02:18 PM

#10

that might hold true if the heat source was stationary which part of it is from friction) but the major portion of the heat is in the form of a pressurized gas that the faster its removed away form the head (faster evacuation) the less time there is for heat transfer? i don't really know, thats why i'm asking,any FMF engineers out there? to me it seems as if a gas @ 1200deg were pushed(as it is) into a cooler pipe it would slow it down, losing pressure as it cooled forming a wall for the next wave to hit.as there is no constant flow in the exhaust, maybe making the cool part the muffler(by wrapping the header pipe) gives that cooled down wall a place to expand out of the way? thats my theory :cry: i guess one way to find out would be to try it!! thanx for the input frostbite :cry:

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  • ncmountainman

Posted February 02, 2005 - 04:17 PM

#11

well whatever theory is the right one. the research i've just done leads me to believe that its not a good idea for the sake of the header,; melts 'em down!. there are special coatings that permeate the steel and do the same thing without damage, but they make it brittle. could ceramic coat it? looks like its not worth the effort, i'll probly just throw some reflective tape on the bottom of the radiator like frostbite. :cry:

  • xcracer123

Posted February 02, 2005 - 05:53 PM

#12

Well, here's my 2 cents on this complicated issue. I do know that Scott Summers used to wrap the head pipe on his old XRs to eliminate heat from blowing back on to the air cooled head and to help evacuate the exhaust faster. I believe he does the same thing with his new CRF450. I wrapped the headpipe on my DRZ and have had the headpipe on my WR wrapped in the past. I crushed it during a race and haven't gotten a new one yet but I will wrap the next one for the same reason. To keep heat from the headpipe from blowing on to the head and from placing that much heat so close to the radiators. Hope this little bit of incite helps.

  • ncmountainman

Posted February 02, 2005 - 06:24 PM

#13

i could see it on the air cooled motor,but how much difference would it make on water cooled? seems like the radiator being on top of the glowing pipe is more the issue. did you notice any performance gains with it wrapped? faster throttle,etc.?

  • xcracer123

Posted February 05, 2005 - 10:13 PM

#14

I didn't really notice any performance gains. The bike is super fast anyway. I did it mainly to shield the radiator from the heat of the header. I suppose I could just use the reflective tape on the bottom of the radiator. I'm using Evans (Zip-Ty) coolant now. I was just worried about overheating issues. I fried the head on my DRZ and that was a nightmare, to say the least.

  • spy

Posted February 05, 2005 - 11:02 PM

#15

If preventing burns and excessive heat on some parts is the primary concern, maybe just wrap certain areas of the exhaust instead of the whole thing? :cry:
I'm intending on doing that to reduce heat to the rear shock canister.

  • ncmountainman

Posted February 06, 2005 - 06:50 AM

#16

I didn't really notice any performance gains. The bike is super fast anyway. I did it mainly to shield the radiator from the heat of the header. I suppose I could just use the reflective tape on the bottom of the radiator. I'm using Evans (Zip-Ty) coolant now. I was just worried about overheating issues. I fried the head on my DRZ and that was a nightmare, to say the least.

i just switched to evans also, wheres this stuff been all my life? the NPG-R has not even attempted to come out,even on the last mudfest i was on (which woulda left me half empty with the engine ice/water wetter blend i was using.) was still full when i checked the next day. less psi, i was running a 1.6 kg cap i've since reverted to the 1.1 (15.6 psi) but they say you can go down to 7psi !! and still keep the 400 deg boil point. i use it in conjuncture with two2cool as i did before but with the evans they seem to work better together for some reason,as my oil is looking much better now at change and the only diff was the evans :cry: :cry: ya i was thinkin' about the shock res also but frostbite just did some infra red scanning and concluded the res does not heat all that much from the exhaust. i guess every little bit helps though.

  • xcracer123

Posted February 06, 2005 - 08:18 AM

#17

Thanks for the info on the Two2cool. I was thinking about trying that out. I will order some tomorrow. That Evens coolant is incredible. My buddy/sponsor uses it in his RMZ250F and said that he didn't loose a drop all last season. Jason Raines dad/mechanic told me about it last year and I just didn't make the plunge until the end of the year. What was I thinking?!? If a factory guy tells you the stuff is incredible and is getting no kickback, you should listen.

  • Some Dude

Posted February 06, 2005 - 07:53 PM

#18

I have a 98 YZF400 I just put a Stainless FMF Powerbomb on, did a couple test rides and then wrapped with themotec. I mainly wanted to protect my leg and the rubber cooling system hoses, any performance gain would be a bonus. I had to adjust the richen the fuel screw minorly after the Thermotec and definitely noticed a gain exhaust dispersion intensity,.......meaning before the Thermotec wrap I would walk 6-8 feet behind the YZF while it was idling and I would hardly feel the exhaust, after the Thermotec wrap my posters on the wall were getting puffed around at 8 ft from the rear of the YZF. What does that mean? I think that the gases are definitely flowing better and more efficiently. Wont know if it affected primary jetting and needle position until I get it out on the trail here soon.

I have used thermotec in the past on a couple of turbo and intercooler applications and in particular on a honda 350X ATC. Granted it was aircooled, but I was running a primary jet 2 times bigger then anyone at White Bros at sea level in Florida. The only thing I did different was wrapped the header with thermotec and did some custom port and polishing, other then that everything was identical to a setup they were running in the 350B Modified class. So I am a believer in the header wrap. The biggest disadvantage to the wrap is it can retain moisture and perhaps accellerate corrosion on the headpipe of a dirtbike, but thats aruable too

  • DigilubeJay

Posted February 07, 2005 - 02:53 AM

#19

...I do know that Scott Summers used to wrap the head pipe on his old XRs to eliminate heat from blowing back on to the air cooled head and to help evacuate the exhaust faster.

Scott's father, Wade Summers, is the reason you see Scott's pipes wrapped.
I talked to Wade about this issue and his response is that at low rpm's the bike will run cooler, and at speed there is much better scavenging of exhaust gasses making for a more efficient burn.
Wade claims that wrapping is a good idea for ALL 4-stroke pipes, and has apparently done some extensive testing to come to that conclusion.
Mr. Summers is one of the most knowlegable 4-stoke guys out there, and I have to respect his opinion. :cry:

  • ncmountainman

Posted February 07, 2005 - 07:05 AM

#20

wow ,what to do?? i rectum i might have to give it a try! i would say the stainless headers would tolerate it better than Ti or plain steel. did wade say if it reduced longevity of the header? just got off the phone with thermo-tec, they dynoed a couple big blocks,gotta say the stuff puts out some serious torque gains down low and serious HP gains up high(dyno results on their website). and the new copper stuff they have out helps header longevity?? 50' is only $50 samllest roll you can get. anyone want to split a roll??? PM me if interested.




 
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