IIRC Jason Cramer (RJC racing) posted , where he measured header temps with Jethot and a spot where the Jethot had been grinded off (for a repair). Hardly any temp difference.
The heat-insulating properties of jethot seems highly over-rated. I would look at it mainly for providing high-temperature, rust-resisting, cosmetic qualities.
I found the thread :IIRC Jason Cramer (RJC racing) posted , where he measured header temps with Jethot and a spot where the Jethot had been grinded off (for a repair). Hardly any temp difference.
I suppose YMMV ...... There is a section on the headers of my personal car that we had to sand blast the thermal coating off to do some repair. Now i have an uncoated section and a coated section side by side in the same header. This is a perfect way of measuring the effectiveness of the coating. Using an infrared pyrometer you can measure the temp of both sections. The result? Not one degree difference....
... even though we have just everything under the hood coated on our cars. We tried to measure the difference and could not find any reduction underhood temperatures reguardless of manufactures claims...
Very good point.Also, if the headers were coated inside and out and the coating was only ground/sandblasted away from the outside then it still has a ceramic coat on the inside which is still providing insulation. Just a thought.
I respect what Jason has contributed to our sport, but I don't believe he is an authority on ceramic coatings. As for his testing, he states the coated and ground areas were side by side. This could definitely allow radiant heat from the uncouted area to influence the "infrared pyrometer" readings over the coated areas----who knows. Bottom line, coatings do work. I have experienced this first hand for many years. If guys don't believe, than that's OK. As for me, I'm sold. My engine bay is cooler, it's that simple!