86-93 MUSTANG Throttle Body Bypass Kit +8HP

[Jeff Chambers]

Coolant loop to the TB is not for cold weather operation. Think about it, when the car's cold, the coolant is cold so there is no 'choke' effect. Coolant is routed to the TB to purposely raise the intake air charge temperature for emission purposes. By raising the air charge temperature, the NOx emissions are reduced. NOx is the most harmful of the products of combustion.

Eliminating both the coolant loop and EGR function are of good benefit for all-out performance. As someone else mentioned, both of these work to increase the intake temperature and thereby reduce air charge density and resulting HP. If you're not too emission/EPA-minded, block the coolant path and completely remove the EGR for added performance. Also install a phenolic spacer and use freeze plugs to block the EGR ports between the upper/lower intakes. All this will lead to a cooler intake plenum and result in a more dense intake charge and increased HP. The EGR valve is closed at WOT, so it's not dumping exhaust stream when you're on it, but the rest of the time it is partially open and heating your intake up while you cruise around town, up to staging or back from a run. Eliminate EGR all-together. Have a chip burnt to shut the EGR function off in the computer and you won't get the related codes when you check them.