| Author | Message | ||
     Enok |
So I've been considering getting a thermal ceramic coating on the headers of my 09 1125r. I was thinking it would be a way to get the temperature down a bit on the frame. Is this a good idea, and will it work? Anyone have some experience with this? Or is just adding some heat shield to the inside of the frame a better idea. It sure is cheaper... | ||
| Stevel |
In short.....no. Frame insulation and hot air deflection is far more effective. | ||
| Panshovevo |
Stevel, short of completely redesigning the cooling system, how would you go about deflecting the hot air? Enok, ceramic coating the headers may not give the most yield per dollar as far as reducing frame temps, but I believe it will help. Given the proximity of the hot header pipes to the coolant hoses and tubes, as well as engine inlet air, I believe it will help reduce the engine temps, thereby reducing the frame temps. An additional benefit could be extended engine life. | ||
| Stevel |
I don't think the exhaust is the main contributor to fuel tank/frame heating. It is waste air from the radiators. In short the radiators are in the wrong place, that's what makes correction so difficult. This was done on purpose by Erik to keep the wheelbase short and concentrate weight more to the front wheel. These is no easy fix, but deflectors behind the radiators and tank insulation helps a lot. Please recall the Erik's race 1125s all had repositioned radiators. | ||
| Ace117 |
Precise reason why I'm doing the RX radiator conversion to my 1125. | ||
| Enok |
RX radiator conversion? Interesting, I've seen your posts with parts list and some photos Ace. Is it getting near to completion? Do you have a main thread for that conversion somewhere? | ||
| Enok |
Well, ok for now I guess I'll put heat deflectors on the inside of the frame and install a race ECM and see the effects of that. Winter is coming so its nice with some heat on your legs. | ||
| Dannybuell |
a few year back I rode for 2 hours in the middle of a hot summer day. my riding partner was riding a big twin. He had just ceramic coated his headers. When we got to the our destination and parked the bikes I gently grabbed the rear of the pipe, nothing. I worked my way towards the cylinder head, about 1.5 feet it was feeling warm. under normal circumstances, something would be melting... I don't know about ceramic coating processes, I believe his was coated inside and out. | ||
| Panshovevo |
I plan to get the header pipes of my '09 coated when I get around to pulling them off. The way I look at it, anything that can reduce engine temps will be beneficial. If you look at the proximity of the pipes to the cooling system tubing, it has to help the engine coolant temps if you can reduce the radiated heat. Edited to add that I intend to insulate the inside of the frame at some point as well. Once the pipes are coated, I may look in to diverting the fan exhaust away from the intake. The lower the temp of the intake air, the denser the air is, and the more oxygen per volume it contains. The ECM monitors the intake temp, and adds or subtracts fuel accordingly. Cooler (denser) air plus more fuel equals more power. Not much of this matters at 150 mph as the ram air is forcing the hot air away from the intake (I assume), but I don't run 150 on the street... (Message edited by Panshovevo on November 22, 2015) (Message edited by Panshovevo on November 22, 2015) | ||
| Enok |
Ok, well does anyone have experience with Jet-Hot coatings? They have the 1300 and 2500 coating. Apparently the 2500 is the best at killing radiant heat, but it is more expensive. Just curious if it could be worth spending the extra cash. | ||
| Stevel |
These coatings are not flexible and they have different expansion coefficients than the pipes, so adhesion becomes a problem as well. Not all applications are successful. If you still wish to insulate the pipes, perhaps using the fabric wraps is a better idea. This is especially so because it is inexpensive, reversible and those wraps do work well to reduce radiant heat. | ||
| Nobuell |
I used the titanium wrap on my headers before this years track season. My goal was to help eliminate fuel off gassing after a race. It seamed to help somewhat. I also carefully insulated the frame as well. If I keep the bike, I will most likely go to the 2nd generation fairings that have the radiator flow path reversed. | ||
| Albert666 |
I ceramic coated my headers, I had them done by zircotec, www.zircotec.com I wouldn't use anything else, the stuff in rattle cans is just garbage | ||
| Fresnobuell |
Hmmm. Fabric wrap. Might have to give it a try for all the reasons Stevel mentioned. Gotta do it right or it looks pretty ghetto.... anyone recommend a brand for the wrap? I haven't researched it yet. | ||
| Terrys1980 |
DEI | ||
| Nobuell |
I used the DEI on the track bike and is covered by the fairing so looks were not that important to me. However, they look nice. One word of caution, shortly after wrapping my aluminum body Barker Exhaust feel apart. It looked overheated and almost crumbled apart. Barker told me that they do not recommend using wrap with their exhaust. I do not know if it was just a coincidence, but keep in mind for Aluminum systems. I have not had issues with my Buell race exhaust. | ||
| Stevel |
Insulating the pipes will cause the pipes to get hotter. It is unavoidable. The wraps therefore work best with stainless steel, as the excess pipe temperature is a non-issue. | ||
| Terrys1980 |
Barker told me the same thing about having the mid-pipe wrapped. Basically all the extra heat kept inside the pipe eats the packing a lot quicker and the excess pressure against the end cap will eventually rip apart the muffler if the packing isn't replaced as needed. | ||
| Fresnobuell |
Packing helps reduce pressure in a muffler? | ||
| Terrys1980 |
Yes it can but maybe my phrasing could have been a little different by saying the force from the exhaust hitting the end cap will eventually break the rivets holding it together. If you've ever disassembled a glass pack you will see the exhaust flow path. The packing closest to the end cap is always depleted first. A fresh packing provides a flow path and prevents the exhaust from hitting the end cap. Everyone who has owned a Jardine exhaust knows how easily these blew apart after the packing was worn out. | ||
| Fresnobuell |
Gotcha. Is there any good way to determine the status of the packing? People say it gets louder when the packing is worn out, but it's pretty hard to tell when you ride it daily/weekly and the change is subtle over time... I do have an inspection camera. I wonder if I could stick it up in there? | ||
| Terrys1980 |
I'm not sure what could be seen. There is a perforated tube in there that the packing wraps around and likely some steel wool. Most exhaust manufacturers have their own re-packing intervals. | ||
| Panshovevo |
Copied from RB Racing's exhaust theory page.
From what I've seen, non-stainless pipes corrode under exhaust wrap because of trapped moisture, and aviation grade stainless pipes tend to crack when wrapped. YMMV... | ||
| Fresnobuell |
If there is a tube, then the packing is probably obscured....I have never had the pleasure of getting inside one of the pipes--but that might change soon.
Is this moisture just absorbed from the atmosphere in a damp climate? Or are we talking wet weather riding? I see you are in Florida. | ||
| Nobuell |
What is aviation grade stainless steel? I do not believe that stainless steel would crack due to wrapping. There would be a lot of insulated pipe and pressure vessels that would be in big trouble trouble if that were the case. The interesting thing about my failed Barker is that I repacked it two race weeks before it failed. The first weekend was at Blackhawk and could not have had more than 3 hours total race time. It actually failed at Road America during the first practice session. I assume the three wide open straights contributed to the failure. I installed the wrap at the same time that I re-packed the muffler. Barker sent me a packing kit complete with new rivets. The muffler had a nice shinny black finish when it was repacked. I did notice that the black finish had dulled considerably after the Blackhawk race but I did not pick up that a problem was forming. I do not believe that the packing disappeared from only 3 hours run time. The melting point of 300 series SS is 2750 deg F. I am not sure of the header stainless alloy, but the temperature is close. I am not sure of the aluminum alloy that Barker uses, but 6000 series is a good guess and it has a melting point of only 1220 deg F. There is a major difference between the two melting points. The important consideration is the strength of the materials. The color of the exhaust headers is generally a purple brown color. This is indicative of approximately 800 degrees F. At that temperature, the stainless has a 55.4 ksi tensile strength and a cold strength of 70.0 ksi. Compare that to 6000 series Aluminum with a 12 ksi tensile strength at 500 deg. F, 7 ksi at 600 deg F and a cold tensile strength of around 26 ksi. Based on the above, the strength of Aluminum drops dramatically when at temperature. I've not measured the surface temperature of the Barker but I would guess the temperatures could approach 600 deg F on a track like Road America, especially when hidden under a fairing. It does not surprise me that the muffler would fail when exposed to the high temperature and high exhaust pressure. I used a Barker on the street for 3 years with no issue. It was a nice exhaust for that application. | ||
| Fresnobuell |
Interesting post there Nobuell. No doubt about it, the 1125 has a pretty incredible exhaust flow. It does a nice job of blowing off the driveway as I back out. the pressure at high RPM must be out of control. Just to clarify, you wrapped everything including the muffler itself, right? (Message edited by fresnobuell on November 24, 2015) | ||
| Stevel |
Aluminum is not a suitable exhaust pipe material for several reasons like poor fatigue resistance and poor strength especially above 300C and is prone to corrosion from salt. Mild steel is used for economy and ease of bending. Corrosion also occurs much faster at higher temperatures in both materials. Chrome plating is very porous and provides very little corrosion protection. It is the copper and nickel plating that provides corrosion protection. Often 400 series steel is also referred to as stainless steel and corrosion proof. It is not. It is actually just corrosion resistant. It is the 300 series steel that offers the best corrosion protection and heat resistance, but 300 series SS also has poor fatigue resistance. There is no magic bullet here. In all cases, the fabrication methodology and design must be tailored to both the material used and intended use. Exhaust gas temperature at full throttle, if correctly fuelled, is about 600C. Not allowing the tubes to cool will cause an increase in thermal stress. The 300 series SS family encompasses several different alloys each having different performance and ease of fabrication characteristics. All of which causes increased costs. There are legitimate reasons why F1 exhaust systems cost thousands of dollars. There are two schools of thought on the value of exhaust pipe insulation in regards to performance. Some thinks it works and others do not. I'm a do not guy. | ||
| Dannybuell |
Panshovevo brought up stainless cracking. A welder I know patched my S1's SS exhaust system in the usual place. when I picked it up he mentioned that stainless gets brittle after so many heat cycles... wouldn't Ceramic on the inside inside of the pipe insulate the pipe from the heat as well? The heat would be moving out faster then, right? | ||
| Stevel |
Heat didn't cause the cracking. It was fatigue. Like I said, SS has poor fatigue resistance. That being said, the fabrication must compensate for the vibration which causes the fatigue. The most common construction fault I've seen is the use of a welded tab for a rear bolt mount and the tab failing at the weld. Correct construction should be a circular strap that supports the exhaust, which is then mounted by a bolt to the frame or engine, as just one example. Often, you see the use of coupling springs rather than solid welds. These techniques are to avoid stress concentrations and fatigue. It is the little things that differentiates the crap from quality. | ||
| Dannybuell |
THX Stevel - that explains the fatigue mystery. | ||
| Nobuell |
Stevel is right regarding the stainless material. The heat itself does not cause the cracking. It is the cyclical stresses that are a concern or corrosion stress cracking given the correct circumstances. I only had the headers wrapped up to the muffler. The muffler was not touched. I did not wrap my headers for performance. I did it strictly for insulation. The headers emit a lot of heat especially under race conditions and when somewhat obscured by the race glass. I get an extreme amount of off gas into a fuel catch can right after a race. My goal was to try an minimize the amount of off gassing. Frame insulation and the exhaust wrap did reduce it considerably. Of course this is observational only. I did not take any actual temperature measurements. I do get a chuckle after a race when somebody sees the gas bubbling up through the clear catch can hose and asks what the heck is going on! I tell them it is a Buell thing. | ||
| Fresnobuell |
Hmmm. Based on the above evidence and in the vein of "if it's not broke, don't fix it"--I have decided to not pursue the header wrap. I am sure you are all glad to know this. LOL |
