What you need to remember about headers is that although they add power up top, they also introduce some lag into your system... This is most likely why ESX don't use one... Their turbo is most likely already big enough with monster lag that they don't want even more lag being introduced into the system by headers...WRX_Wagon said:
There's anecdotal evidence about the E-Street (?) 9 sec WRX with practically the entire engine replaced/rebeuilt but merely a port-matched OEM header.
So if I follow you, getting the coating inside is to keep the heat of exhaust in, velocity up, etc, getting it coated outside is most likely for cosmetics (or, it can't be avoided in the process of coating the inside). If the coating on the inside is doing its job, there shouldn't be much for the outer coating to do.NJSubieTech said:
This is the key - you have your headers coated. If the place was good itll be coated inside and out. If not tell me and Ill tell you where you can have it done for about $150. The purpose of coating or wrap is that you assume that heat passes through the metal quickly - so when you put a barrier on the outside - it keeps it from leaving the exhaust gases. Its not the header you want hot really - its the gases. And youre not going to keep any more heat in than you already have with your coating.