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Dept store Quartermaster
Join Date: Jul 2001
Location: I'm right here Tati
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Exhaust before and after
Thought some might be interested in a before and after comparison on my exhaust. The before is the exact condition I sent them off to jet-hot in. They take care of the stripping and blasting.
Before  after 
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Cornpoppin' Pony Soldier |
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04-04-2003, 06:39 AM
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911 + 129 = JOB
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WOW!!!
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1989 911 Carrera Coupe 3.2 2012 BMW 135i M Sport "It is not how much power you have, it is how much you have left to spare!" |
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04-04-2003, 06:40 AM
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Bandwidth AbUser
Join Date: Nov 2001
Location: SoCal
Posts: 29,522
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That looks great. If you don't mind my asking, how much did that set you back, lendaddy?
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Jim R. |
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04-04-2003, 06:53 AM
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Location: Long Island, N.Y.
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Very impressive. How long did they have it for? I wish I saw those pics during the long winter layover!
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'88 930 '04 Cayenne S |
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04-04-2003, 06:59 AM
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Dept store Quartermaster
Join Date: Jul 2001
Location: I'm right here Tati
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It took about 3-4 days each way for UPS, and it took them 2-3 days to process. The cost was $240
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Cornpoppin' Pony Soldier |
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04-04-2003, 07:06 AM
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Location: Long Island, N.Y.
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lendaddy, any pics of the muffler? I think your pictures show the headers only.
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'88 930 '04 Cayenne S |
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04-04-2003, 07:19 AM
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Can you explain the functional improvement (if any) of the jet-hot coating? Is it for appearance or is there a cooling effect? What about long term appearance--does it discolor or wear off over time?
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1980 911SC Targa 3.6L |
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04-04-2003, 07:23 AM
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Not Quite Banned
Join Date: Dec 1999
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The effects are that the ceramic coating tends to 'extract' heat from the combustion chamber.
We used Jet-Hot coating for years on all our Sprint Car headers (clay tracks) and they held up perfectly. The coating is extremely durable but did become slightly dull with the constant blasting from the sand. Of course, my bad driving usually involved accidents where the headers were mangled before the coating appearance actually started becoming a distraction. But, that is another story... Summary - Jet Hot is a great product and the people there are very easy to deal with.
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Thomas Owen 1972 911T 1972 911S |
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04-04-2003, 07:31 AM
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Dept store Quartermaster
Join Date: Jul 2001
Location: I'm right here Tati
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I did not do the muffler, That is a stock unit and I have a stainless Monty dual-out that I will be using. As far as why, of course the look is part of it, as well as anti corrosion properties. The finish may dull in my application as I will be real close to the temp limits of the coating. They tell me it will not "fail" but would only change in appearance. Also it should help keep temps down in the engine compartment. They claim it will last virtually forever if you dont get it over 1400 degrees F. My dad did this to his ultralite exhaust years ago and it never changed its look at all.
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Cornpoppin' Pony Soldier |
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04-04-2003, 07:32 AM
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On a typical not Porsche, jet-hot header application you coat both the inside and the outside. It brings the temp coming off the exterior of the header down hundreds of degrees. Many opt for stainless headers just to find out that the heat transmission to the engine compartment is greater than the originial cast iron manifold setup. Mild steel headers coated inside and out are very desirable...Matthew
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04-04-2003, 07:44 AM
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Banned
Join Date: Jun 2002
Location: Chapel Hill, NC
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thats sweet, looks like another task on my restoration, at least my heat exchangers wont ever rust off.
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04-04-2003, 08:24 AM
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Location: Omaha, NE
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Another question--could I jet hot coat my 993 headers (which I think are stainless steel) and my 993 cat (which I also believe is stainless steel). How hot does a 993 cat get? Thanks
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1980 911SC Targa 3.6L |
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04-04-2003, 08:28 AM
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Hmm, don't wanna ruin the party, but I don't understand how such a coating can lower the temps of anything. Scientifically, heat is given off 3 ways:
1) Conduction. After coating, nothing changed structurally, so conductive heat transfer is unchanged. 2) Convection. There's no increased air flow over the surfaces. Further, the heat transfer coefficient of the metal surface is unlikely to be any higher. Lower perhaps (not good) due to the smoother surface. 3) Radiation. I'd think that the rough uncoated surface would have greater emissivity than the coated one. May be wrong, but "flat black" for example is the best and this coating seems to be moving in the wrong direction. Thus, I don't see any radiative heat transfer improvement. Sorry but I need convincing. Otherwise, looks GREAT!
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1995 993 C2, speed yellow. Protomotive Stage 1 twin turbo. JRZs, RS parts, DL1 logger, etc. |
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04-04-2003, 08:57 AM
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Dept store Quartermaster
Join Date: Jul 2001
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Basically the ceramic coting is a poor conductor of heat. Therefore the heat stays in the exhaust gases till it exits the system. I think you are assuming that the header tubes are the source of the heat when it is actually the gasses inside.
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Cornpoppin' Pony Soldier |
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04-04-2003, 09:48 AM
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WOW - that looks awesome!
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04-04-2003, 10:00 AM
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Excellent!!
Looks really nice!
/J
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Jocke Andersson Reach me on ICQ - 317860713 Porsche 930 -77 SOLD Modified, one of a kind in Sweden. Check out my car @: http://members.cardomain.com/jocke |
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04-04-2003, 10:50 AM
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Location: Texas
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Good stuff!
lendaddy is correct as far as I have heard on the temp - ceramic coating (both inside and outside) that does not conduct well so the heat goes out the tailpipe. Or through the turbine in this case. You can polish Jet-Hot with a non-abrasive metal polish (like Wenol) and it will shine even more. |
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04-04-2003, 10:58 AM
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Join Date: Jan 2003
Location: Chicago, IL
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Ok, I'll buy that. Man, those things look nice!
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1995 993 C2, speed yellow. Protomotive Stage 1 twin turbo. JRZs, RS parts, DL1 logger, etc. |
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04-04-2003, 11:59 AM
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I had the complete system on a stock 91 vw vanagon done ( Vanagon exhaust used to be very expensive)...lasted about 2.5 years...Vanagon exhaust gets HOT...2.1l pushing a brick. Burned the nice pretty JetHot off at the 90 degree turns. They replaced it under warranty with the new "extreme coating"...It has been on the van for about two years...I can send you a sample...from my driveway...
 lsg
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Scott 1982 911 SC 1962 sunroof bug 1991 WE Vanagon CARAT WRX conversion |
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04-04-2003, 01:15 PM
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1989 Porsche 911 3.2
1977 Porsche 930 3,0L Turbo
1982 Porsche 911SC
