Search Index: (Jet-Hot, ceramic, coating, headers, excessive heat, hot) I received an estimate package from Jet-Hot with a color brochure and a video. In the brochure is a picture of a heat comparison that Car-Craft performed between a Jet-Hot coated header, and a non-coated header. See the picture below. It speaks for itself. It also occured to me that the crossover pipe for the fuel tanks is very close to the headers. I measured mine, and it's about 4". I blieve my car may have originally had an additional heatshield, but it is no longer present. Yours may be missing too. And in any event, I don't think a simple heat shield can provide the same kind of protetion that the cramic coating will. So I'm also sending that pipe off to Jet-Hot with my headers. If (as indicated in the picture) the header is over 500 degrees while running, I have to wonder, "What might be the temperature inside that thin little crossover pipe? And how hot is the gas?" That's a frightening thought! Even inside the tanks, it must be close to 200 dgrees or even more. And I think that could be very very dangerous. Ferrari's "are" after all, known for burning. And anything you can do to prevent that is (to me) a "must have". With that in mind, I think it makes 'having' vs. 'not having' the ceramic coating a simple saftey issue. And one that should probably not be ignored, except at ones own peril. The excessive heat in my engine compartment has also finally taken it's toll on my starter solenoid. A gentle twist of large nut (see 2nd pic below) on the solenoid, broke the ceramic casing to which the stud is attached. And although it has it's own heatshield, the alternator is also surrounded by the headers. It's only a matter of time before the heat does it's destructive work there too. And hopefully Jet-Hot will buy me a lot more of it! Time that is. Just my opinion of course. Image Unavailable, Please Login Image Unavailable, Please Login
Thats very interesting David a 223 deg. difference thats alot of heat reduction. I was wondering, does Jet-Hot also coats the inside of the headers? and is it necessary to put back the heat shields back on after Jet-Hot?
Yes. and they coat the inside too. They call it being "flow-coated", and it's supposed to increase cylinder scavaging, incerase the effeciency of the header and also produces a mild and demonstrable increase in horsepower. They also strip and clean the header with high-quality aluminum oxide (only) prior to applying the finish. So no, sand, glass, acron nuts, or any other debris or residue is left imbedded in your header, as would be with sandblasting. I also suspect that coating the crossover pipe and reducing the temperature of the fuel entering the engine, as well as reducing the termprature of the engine compartment in general, will also allow a denser fuel mixture to enter the carbs (carbs on my vehicle, anyway) and thereby produce an increase in performance as well.
If I may ask, how much does the treatment cost for the headers? If you don't want to answer, I fully understand. Thanks
excuse me if i'm out of line... but is the point of this thread informational or advertising? fwiw, on my fiat i have HPC coating on the headers, that's inside-out and all that gear... extractors on a 4banger cost $300AUD. http://www.hpcoatings.com.au/pages/hipercoat.htm
Mike, With that kind of reduction in heat, I'm not sure you'd need to replace the heatshield. Although, there are several reasons you might want to anyway, including: -Keeping your F-car as close to original as possible. -Anything you can do to reduce heat, would (I think) be good. -I think an insurance company might be able to deny a claim if they suspected that the shield has been modified or removed. Tillman, The inital quote I got from Jet-Hot stated: "We'd charge $299 to coat your headers in the Sterling finish. Add $20 for the flat black, blue or grey finish. We'll need them here for 5 days plus shipping time back. If the parts are chrome or nickel plated, add $40 to the total and 2 days for stripping. Return shipping would be about $31. I will send you our full information package to get you all the coating benefits in greater detail." But that does not include the crossover pipe. I have to call this guy Todd to get either an additional estimate, or have them send me a new one that has the pipe included in the price. I don't suspect it'll cost too much though. And by sending it all-at-once, I'll save on shipping too. ashsimmonds, Excused. But only because you have...what?... Whoa! 6000+ posts??? Yikes! <chuckle> Excuse me instead! <sheepish grin> The above response to Tillman should answer your question. You can (almost, humor excepted) always take what I say, "at-face-value". My life is an open book, and I have no hidden adgendas. BTW: My grandmother was from Melbourne. Where are you?
yeah, no offense, it's just first i noticed the search index optimization, but figgered you might be a geek like me. however for the rest of the first post in this thread it seems, well, like an ad! complete with ad-like imagery. post count means jack, just have something dumb to say 7.77 times a day for 2 1/2 years and you too can be as great as me check aussie section to see how much everyone hates me i'm in adelaide, about 500 miles from melbourne, but that's ok because i'm not sure i've ever met someone from melbourne who wasn't homosexual.
Yeah, I'm a computer geek. I think everyone posting something they think might be useful to someone else, should include a search index in thier threads. It makes you think of what/how other people might be looking for the solution to some problem, and in the end, it willl make the whole site a lot easier to use. And I can assure you my grandmother wasn't a homosexual. And I'm livin' proof mate! Although now that I.... GAAAAKKKKK!!!!!! It, gives me the willies just to think about it!
What about just wrapping the headers and crossover pipe with header thurmo wrap? The product that I was looking at claims "up to 70% engine compartment heat reduction". Any pros / cons on this?
The headers and crossover pipe can be "cooked" inside the thermal wrap, even more so if the wrap becomes wet with precipitation, and the pipes crack up and deteriorate quickly. NOT recommended. The Jet-Hot temperature reduction does not parallel our experience, although there is an improvement. -Peter
That's what I heard too. I was hoping to 1) make it cooler, and 2) make it a little quieter (for my wife). I still think the thermal wrap might be good "after" the Jet-Hot, to achieve some sound deadening. And hopefully with the Jet-Hot, the corrosion issue should no longer be an issue. Lolaman, Any thoughts on that?
I can't remember when F-cars went to SS tubing on the exhaust manifolds. IIRC, all the early 308's (up to QV) had mild steel and that seems to be the big problem. The mild steel is more susceptible to heat cracking, but look at the F355 headers! <grin> I think the first SS header I saw was a Euro 308 QV, but I can't remember. Incidentally, it was that Euro QV header that was cracked near the flange on the forward bank. On all of the pro-built cars at the highest level, they don't use header wrap. I appreciate what you're trying to do, but I wouldn't use that stuff to do it. -Peter
Have a 1985 Euro 308GTS here and the heads were plain. Had them Jet-Hot coated as she is tracked a lot. Yes the heat seems to have lowered and the headers should also last longer.
DavidDriver, The readings shown in your photo are quite impressive, but I think not quite correct. I assume you are using an IR gage. Are the displayed units degrees C or degrees F? If degrees F, then the coated headers are at a temperature less than the boiling point of water, extremely low for a header. Even 201 C is quite low for a header temperature, therefore the temperature of the coated headers is suspect for this case. Assuming the same warm up method for both the cases, similar ambient air temperatures, and measurement point, the biggest potential source of error I see is that the slightly rusted surface may have a vastly different emissivity than the ceramic coated surface. The slightly rusted surface will have a relatively high emissivity and the clean shinny surface a relatively low emissivity. If this is the case, and it likely is, the ceramic coated surface will appear cooler than it really is to the IR measurement device. I'm not saying that the jet hot coat doesn't result in a cooler outside surface, just that it is likely not as cool as it appears. At work we use a 70K, FLIR IR camera. If we are looking at modest temperatures (usually less than 100 C), we often times prep the target surfaces with a piece of electrical tape, or of all things, Desenex foot spray powder. The prep ensures an emissivity approaching 1.0. The temperatures of different surfaces can then be directly compared at near steady state conditions. As a control, we usually bond a thermocouple to a representative surface and read its temperature as a check. One of the funny things you find out, if you are trained in the area of IR imaging, is that a reflective surface such as a clean metal, will reflect the local ambient air temperature to the camera. Indeed, we often use a small patch of shiny aluminum foil in the view area to document the local air temperature. I recently reviewed close up photos of some 2512 chip resistors, these measure about 0.25 by 0.12 inches in footprint, and were newly soldered to a printed wiring board. Well, the resistor body was made of plastic, the printed wiring board was made of GFG (an epoxy fiberglass matrix), both with a fairly high emissivity, and both surfaces appeared quit hot. The solder joints, on either end of the resistor, were quite shinny and in intimate contact with the resistor body and the printed wiring board, so we knew the the solder temperature had to be somewhere between the that of the resistor body and the printed wiring board. Yet the IR camera showed the solder to be much cooler, which it was not. The lesson here is that one must interpret the images with all available information and knowledge. I'm sure the jet hot coating provides some real temperature reduction benefits because cramics are pretty good insulators. A coated inside surface will reduce heat transfer to the header pipe and the coated outside surface will reduce heat transfer to the local air, because it is an insulator, and to surrounding surfaces because the header tubes are clean and shinny, therefore limiting radiation heat transfer to surrounding surfaces that have a direct view of the header tubes. I hope this discussion sheds a little light on IR imaging and some of the more common pitfalls. Bill
Check with the Jet Hot coating people before having a gas pipe coated. I do not know if the coating is ok with gas - if it weren't, you might have bits of ceramic in your tanks. I have no reason to think that it is not compatible, but it seems good to check. Also might be good to check with the JHC people regarding wraping the pipes, they probably have experience with this and have an opinion about longevity or efficiency. Looking forward to having mine done when i can group the maintenance items in that direction. I would still install the heat shields, just in case the header failed, Nothing good has ever been reported about hot exhaust hitting gas tanks, pipes or hoses. I have also seen pictures of mufflers being coated. Considering the oven that the 308 trunk becomes, this sounds like a good idea as well. Did they give you a cost to coat a muffler?? Does anyone have experience with this?? hth, chris
It's been done. Chris Marsh had his whole system coated by Jet-Hot. He seemed to like it. http://www.ferrarichat.com/forum/showpost.php?p=135337316&postcount=43
David Driver, While I'm on a roll here, I'd like to discuss the cross over pipe situation a little if you don't mind. The cross over pipe is quite low in the engine compartment. As such it sees different air than if it was placed higher up in the engine comparment. Remember that warm air rises to be replaced with cooler air from below. Even when sitting on hot asphalt, the engine and headers will be hotter than the air beneath the car. Bouancy of the resulting hot air will create convection air currents so the lower fuel containers are never likely to get into temperature trouble. The aluminum connecting pipe is further bathed in fuel, which sloches around in normal driving, and even when the car is stationary, there would be internal flow of the fuel by convective processes where warm fuel, due header heat exposure down low in the crossover tube, would be replaced by cooler fuel in the system. The surface temperature of this pipe is never much different than the fuel temperature because aluminum is a pretty good heat conductor. The connecting rubber hoses are not a very good conductor so even though the insides are in contact with the fuel, the outside surface could be a good deal hotter than the insides. But these connecting hoses are further away from heat sources, so the heat flux on them will be lower. The gas tanks are in general even more removed from heat sources. It's interresting to note that electronic engine controls on fighter jets are cooled with jet fuel before the fuel is recirculated back to the tanks or used for combustion. The factory heat shields should be replaced if they are not in position. By observation on my 308, they look pretty good to my professional eye, so I suspect no additional temperature management is needed and yes, they actually pay me to evaluate these kinds of things for aircraft applications. If factory pieces are missing and unobtainable, an aluminum heat shield between the exhaust header and fuel container would be a very good solution for the cross over pipes, but heat shield fitment would likely cut down on lower engine access. Insulation wraps are probably not as good a solution, especially if they are tightly wrapped and subject to water and other contaminants, so external corrosion of the connecting pipe is more likely and more difficult to detect. I hope this helps. Bill
Bill, Please pardon me for being very frank. But, I didn't post this information to put myself in a postiion of having to: 1) Defend some product. 2) Have to write replies such as this. But.... FWIW, the test was done independently by Car-Craft Magazine, (and everyone else please forgive me for taking the time to clarify this, and "no" <again> I'm not a mole for Jet-Hot!) using at Raytek handheld digital pyrometer, whatever the heck that is! The US Army uses it on their armored vehicle exhausts. The US Navy uses it on aircraft carrier catapults. It's received good reviews from, Car-Craft, Hot Rod, National Dragster, NHRA Today, 4-Wheel & Off-Road and NASA. But I'm impressed also that you have your A&P. I wish I had mine. My son (currently a crew chief on C130's) will be testing for his in a few weeks. Chrismorse, Yes. I intend to ask them about gas before I have them re-do the order. And certainly before I run so much as 1oz., of gas through the pipe. But, they also do ceramic coatings for intake manifolds, inside and out. So it's probably okay. But I am going to check with them first. And, no. I did not ask about the muffler. But that is a VERY good idea! Thank you for the suggestion. My car (a GT4) is new to me, so I have yet to experience the negative aspects of having a hot trunk. I suppose that because the heat is being transferred out through the muffler, instead of through the headers; Doesn't it seem logical that the muffler might get even hotter than it does now? Hmmmmm...... Ya know, I'm trying very hard NOT to get upside-down with this car. <chuckle> Oh well. <giggle> Maybe I can justify it as a reason not to get a Tubi, and then declare it a cost savings! Yeeah.... Roight.... That's the ticket!
DavidDriver, Please don't misunderstand my posts. I try to be very clear on subjects like this because I often have to write reports for a varied audience. Not everyone likes the results all the time, especially if the subject is complicated, not generally understood, and contrary to a desired outcome. There are often a lot more things happening than are fully appreciated. There is no reason to have to defend the IR instrument you are using. I am not criticizing it. It's probably working fine and I might get one myself. I just wanted to point out some of the limitations of this technology that not only affect your instrument but also the very high-end instruments I occasionally use for work. Emissivity of the target surface is a property of the surface itself, not the instrument. Tabulated surface emissivities are available and vary from a very low (0.02) for highly polished silver to a very high (0.95) for candle soot. Perfect black body enclosures have an emissivity of 1.0. This property affects both classes of IR instruments in the same way, but not necessarily to the same extent. An IR instrument doesnt know what it is looking at but some can be told how to interpret the information they are receiving via an emissivity adjustment feature, either in real time or in post processing of the raw data. Its up to the user to make this correction and/or to interpret the results accordingly. As an absurd and unrelated example, consider a 308 on a chassis dyno that puts out 200 bhp on a hot day. The owner insists on polishing the exterior of the car to see what power improvements will result and has the car retested the next day. All else is the same except it happens to be very cool. Well the dyno says the car is now putting out 220 bhp, so polishing improved output by 20 bhp? No. Is the dyno wrong? No. Results need to be normalized (adjusted) to a standard set of conditions to see that there has been no benefit. The real issue is that one should critically challenge the readings of all instruments and apply knowledge and experience to properly interpret the information the instruments are providing. By the way, I dont have an A&P license, which Id love to have, but I am a degreed mechanical engineer, specializing in the temperature prediction, management, and validation of aircraft electronics. I analyze, improve, and test these products. Enjoy your tool, Bill
As Bill has already said, the surface finish has a huge amount of effect on the reading of an IR pyrometer like the Raytek. I use a Raytek at work all the time. It will have a much higher reading on a black radiator, than the chrome metal coolant pipe that feeds the radiator even though both are at the exact same temperature. I would recommend taking a direct temperature reading off of the surface using a thermocouple type instrument if you want an accurate measurement. Brian
This topic is interesting, as I have been considering refinishing a used equal length system before installing it on my 79 308gtb. Has anyone here used the Tech Line ceramic coatings? They are apparently selling their coating material for home diy as well as professional powercoat shops. Some of their coatings are applied and cured on the car, while other require an oven bake. I am sure thorough metal cleaning is mandatory for good results but might be worth it for lower temps and longer lasting results compared to paint.
DD jethot is a good way to go to reduce temps in the car . If your old alum. insulation is shot then doing the jethot is good. I do think you are over reacting though because in normal driving with OEM insulation and shields you should not have a heat or fire problem. Most Fcars this old with no normal maint. on fuel hoses usually cause the fire problems. Also the ceramic brakage is due to age so if you take a 1980 car who's starter bat mount is 26years old its gone a brake. So get the starter rebuilt and you'll get another 26 years before it breaks again. Also there is a small shild on the fuel cross over pipe and at times when i'm under the car with it running checking everything out you can grab the fuel pipe and it won't burn you. So jethot is great and someday if my stock insulation goes due to age I'll get it done. Thanks for the pricing information.
