Exhaust ponderings......

[Anonymous]

I was daydreaming ahead to the summer commutes ahead, when I got this bright(??) idea. Back in my old hotrod days, we had a product called Thermotec Header Wrap. You would wrap it around the header pipes and it kept most of the heat inside the pipe and made for additional horsepower by more forceful exhaust scavenging. Now... being the deductive monkey I am, would any of you GS geniuses think it would create problems for the bike if we used this product on our bikes? The NASCAR teams use it and on street racers, they get anywhere from 5-25 more HP with more efficiency and power. Why not us????

[Anonymous]

I think header wrap would start to look nasty pretty soon kinda like "The Mummy". I also would worry about the rusting that header wrap is known to create. I would think you might get 1-3 horses out of this and if you are after the "road warrior" look, that might be a good first step before you get your crossbow. All the evidence I have seen suggests that coated headers (Jet-Hot, et al) do a much better job than header wrap and prolong header life. It is a lot more expensive, but also seems to be much more effective. Try to get some hard before and after data, like dragstrip time slips, that will tell ya if you're making more power. Header wrap won't add enough to measure via butt-o-meter.

Good luck! Bob

[Anonymous]

I have heard of rotting issues with header wrap. I have sseen it in use on bikes though. I guess rott is not an issue if you dont expect or care if your exhaust lasts for 5 years or not. Personaly I do not know and may use it myself. I have no personal experience using it, yet.

[Anonymous]

Part of the underlying issue for me is that, being the owner of a GK model, I get really toasted in the summer from the heat directed to me from the fairing. It seems that if you eliminate all the heat coming from the pipes, you would, theoretically, only have the head heat to deal with.

[Anonymous]

I was under the impression that keeping the headers cooler would increase the flow, thus improving HP. Wouldn't header wrap actually increase the temp of the headers (not allowing air to cool them). I like the idea of ceramic coated (inside and out) headers, cooler headers plus no rust and better durability. When i get some $$ I'm going to get my V&H's blasted (they are ugly and rusty) and ceramic coated. Are your headers already rusty or are they in good shape to begin with?

[Anonymous]

actualy mookie, acording to physics, heat is energy. in terms of exhaust and headers, the more heat(energy) that is transferred out of the exhaust system then the less energy is left in the system to move the exhaust. Ceramic coatings work the same way in that they keep the heat in the exhaust system rather than transferring it to the air, and nearby parts.

krash

[KrazyKarl02]

header wrap

I think some of the gain from header wrapping (at least in cars) is that it removes heat from the engine compartment. That is why it is just the headers that are wrapped and not all the way out to the end of the tail pipes.

[Anonymous]

Yeah, I think you are right about keeping the exhaust gasses hotter.

"MORE POWER?Applying JET-HOT to the interior and exterior
of headers contributes to net power in a number of ways.
Because the coating acts as an insulator, it keeps heat inside
the headers and out of the engine compartment where lower
temperatures permit more dense fuel/air charges to reach combustion
chambers. At the same time, demand from power-robbing
accessories is reduced. Also, by retaining heat within
headers and smoothing header bores, the coating increases
the velocity and reduces the turbulence of exhaust gases, leading
to more effective scavenging of cylinders."

however I'm not quite sure I follow the logic of this :

in terms of exhaust and headers, the more heat(energy) that is transferred out of the exhaust system then the less energy is left in the system to move the exhaust.

I thought Heat was wasted energy, so wouldn't you want less heat to be produced in the 1st place? Does increasing the heat of the exhaust produce some extra vacume effect somehow? what is the underlying principle that says... increased temp of gasses=increased flow, or something to that effect?

ps- this place http://www.performancecoatings.com/pci.htmlsays they will blast and ceramic coat inside and out for $110 plus shipping. thats Much cheaper than i was anticipating.

[Anonymous]

Mook, you're right about the heat and improved scavenging. It works to reduce under the hood temps, which when coupled with a cool box to improve the induction density, provides a denser intake and hotter, thus faster and more complete exhaust. I was wondering this because even tho we don't have hoods, per se, if you improve and cool the air flowing past the heads by keeping the heat off the headers from adding to that hitting the heads, then you should have cooler air entering the box behind the block. Just trying to have my cake and eat it too. You guys are too good!!

[Dink]

Both header wrap and ceramic coating achieve the same things, both reduce what is called "laminar airflow"which is heated air that is slow moving because it is transfering its energy into the walls of the pipe.
Both methods help to reduce this laminar airflow, there by reducing the amount of heat conducted through the walls of the pipe and increasing flow by retaining heat in the exhaust gases, this increases the exhaust outflow rate and improves scavenging on the cylinder slightly.
However the header wrap retains moisture and dirt angainst the pipe damaging them ( and it looks ugly IMHO) whereas ceramic coatings preserve the pipe and look as good or better than new.
Dink

[Clone]

I read a page link from one of the other postings about exhaust scavaging and a thought occured to me. What would happen if the crossover between the two headers was sealed off? Would this improve the performance of the stock 2-1? :?
Anyone applied the ceramic coating to a set of old headers? what did you so to clean the insides?

[Anonymous]

I used the wrap on my GSXR stock exhaust. The pipes are stainless steel so rusting wasn't an issue. It did help keep the heat inside the fairing down.
I've tried headers bare, wrapped, and coated and the e.t. difference was so minute couldn't say for certain that one performed better than the other.
Never had a problem with it getting too dirty, but my wet condition riding time was usually minimal. If you run the engine long enough to burn off the moisture, rusting shouldn't be a problem. And if i remember correctly, Thermo-tec also sold a sealer that sprayed or brushed on.
But as the others have pointed out, the ceramic and aluminized coatings do look better and are a little easier to maintain.
Mike