[Megahurtz]

I think I would prefer the DEI Titanium header wrap over coating the header as long as the header were quality stainless steel. The wrap would be superior to coating the header at minimizing underhood temps. The wrap isn't cheap either. Probably $150 worth or wrap needed to do both headers correctly.

[LibertyHill]

Yes that seems to be the wrap of choice and I like the look, but it seems to hold in too much heat and the increased temps the SS is then subjected to reduces its lifespan. What about wrapping only the first 6" or so?

[Megahurtz]

Originally Posted by LibertyHill

Yes that seems to be the wrap of choice and I like the look, but it seems to hold in too much heat and the increased temps the SS is then subjected to reduces its lifespan. What about wrapping only the first 6" or so?

I don't think wrapping 6 inches will do much help. I guess a reduced lifespan depends on how long we are really talking. The newer wrapping isn't the same stuff as the old school stuff they used back in the 70s and 80s. I probably won't keep my car more than 5-6 years before I get into something new. So even so it would only have to last me that long. I still think the quality wrap would hardly shorten the lifespan of quality SS headers. At least not in my part of the country. We don't have road salts or anything to get trapped in the wrap. Only rain.

[2000form]

http://www.hotrod.com/articles/hrdp-...gine-coatings/

[oldman]

Originally Posted by LibertyHill

I went uncoated and now wish I had given it more thought. Wraps seems like a bad idea even on SS, but the semi-rigid insulating blankets over the top seems like they may be worthy of consideration to insulate from some of the radiating heat. Any thoughts on those?

wrap is a bad idea IMO, the header has to breath or it ejects or bakes the carbon out of the matrix and falls apart even SS will do this over time. I DO absolutely like shields. Acura made a beautiful twin shield for the JDM Type R 4 to 1 header:


Radiated heat on this setup is way down.

[oldman]

Originally Posted by Megahurtz

I think I would prefer the DEI Titanium header wrap over coating the header as long as the header were quality stainless steel. The wrap would be superior to coating the header at minimizing underhood temps. The wrap isn't cheap either. Probably $150 worth or wrap needed to do both headers correctly.

Even SS will bake the alloying agents out of the metal matrix when wrapped. OK on race car but not for DD... two or four metal shields or metal / fiberglass shields would be more than adequate.

Here is some food for thought:
Carbon the black coat that forms for free is a VERY good insulator.
Ceramic is a good insulator but we are talking .002" thick here are we not? From a straight black box mind project, constant heat source ie engine running, a constant sink air, the 4 oz of coating, magic whatever, will reach the SAME temp soon after nominal conditions or reached as the rest of the part the 800" square inch header. Thermal transfer deltas (note the constant source and sink) do not even take part in this.

The only way the header temp is going to be lower is if the thermal transfer of the header is significantly reduced in relation to the quench or air sink i.e. the air moving over the header is taking heat away from the header faster than heat can move thru the header, so yes absolutely with air flow the coated header can run cooler and retain more heat, I'm just pointing out with air flow I would want cooling fins on my header when hooked to an exhaust cause heat and velocity equal backpressure when we are talking about a closed exhaust system. The exhaust system for the most part is nothing more than a energy dissipation unit. aka heat sink.

In a NO airflow environment ( I''ll leave the thought extrapolation to you for low air flow). A constant heat source 4OZ of anything is not going to stop the system from reaching nominal heat conditions given a constant heat source (running engine).

Heck air itself is very good insulator, the only problem being is it is light ie little mass is it heats up instantly... moving air oh yeah good insulator (not in high energy heat cause it is transparent in those ranges). You can arc weld 30,000 degrees bare hands sure you will get a sun burn but air's insulation properties means you ain't going to spontaneously combust. My closest spark plug wire at its closet point is say 1/4 from the header rubber burns at 500 degrees right? The rubber still looks good just saying. Air makes a good insulator, even gm covered the factory headers with shields making use of air as an insulator. Look at it this way, GM had say three complicated shields on each header with maybe 8 bolts, Yes some of that is for noise control, but IMO most of that is heat control. If GM could spend at the OEM level $20 bucks per to coat the header and get the same result wada you think?


My prediction is that in the future you WILL see high end mfg of headers actually design air shielding for their header. Here is the JDM Yonoka header:



This can take factory shields or aftermarket Benson shields.

quick and dirty:

[glenB]

I've never seen an increase in HP by coating headers, but under hood temps have been lower in normal street driving and time, meaning not hours tooling around. The coating helps reduce temps, but only goes so far like most temp reducing mods. Eventually, over time, the temp will match non coated temps, but this does require extended driving such as trip. The other benefit is you can pull a plug within 10 minutes of shooting the engine off.

I've tested the temps by using a typical temp probe mounted to the master cylinder and an AC line on the other side, AC not running, wired to a Fluke meter so I'm confident of my results.

[oldman]

Originally Posted by glenB

I've never seen an increase in HP by coating headers, but under hood temps have been lower in normal street driving and time, meaning not hours tooling around. The coating helps reduce temps, but only goes so far like most temp reducing mods. Eventually, over time, the temp will match non coated temps, but this does require extended driving such as trip. The other benefit is you can pull a plug within 10 minutes of shooting the engine off.

I've tested the temps by using a typical temp probe mounted to the master cylinder and an AC line on the other side, AC not running, wired to a Fluke meter so I'm confident of my results.

What were the average deltas?

I wonder how good the factory heat extractors on the hood are?

[glenB]

Originally Posted by oldman

What were the average deltas?

I wonder how good the factory heat extractors on the hood are?

I don't recall, I tested this on an '87 Monte Carlo SS years ago. They had more open space under the hood.

The difference was enough to convince me to move my CAI that was pulling fresh air low behind the bumper, but would heat up significantly at stops due to its proximity to the ground. It would heat up enough that it took blocks to get the IAT temp to drop.

I relocated the CAI to the top and back of the engine by the cowl and fixed my problem.

On my SS (vf) chassis, I used a roto-fab CAI. I insulated the box adjacent to the engine and reduced the time it took to cool down the IAT. I used a relocated sensor kit from Vector MS. I had uncoated headers at the time. Had the headers coated locally and my IAT temps at a light never went over 10* ambient. So I know that the coatings work for temp reductions.

[oldman]

10 degrees very believable at light.

[glenB]

Originally Posted by oldman

10 degrees very believable at light.

It was going 30*, easily hitting 120*- 130* during the summer