header insulation

[Jim Steck]

>> I'd like too insulate my exhaust header down to the O2 sensor so it won't 
cool off and get better gas mileage( that's my theory anyway) Does anyone 
have a simple recommendation for something effective? I've thought of the 
asbestos muffler wrap stuff but I don't think it will retain the heat in 
very well. This for an 81 528i BMW. <<

Don't wrap any carbon steel exhaust pipe or you'll end up replacing it much
sooner than you planned.  Besides the higher temperature, the wrap traps
moisture when the car is not running.  I suggest one of the ceramic coatings
like Jet-Hot.  It does a fair job of insulating and keeps the pipe from
corroding.  

-Jim Steck
AutoComponenti

BTW, it does make a couple extra horsepower on the dyno with a tuned open
exhaust (ask Smokey about the theory) . . . but I don't know about a system with
a CAT and mufflers.