Hey i drive a 98' HX and i was wonderin waht makes my VTEC-E engien different from the EX VTEC engine, is it just a different head? Or are there more "fuel-economical" parts elsewhere in the motor. All help is appreciated

 

Head and ecu to control the variable timing (vtec).

 

Allright sweet, is there any difference in the exhaust system cuz they have aftermarket header available for an EX but not my HX

 

The VTEC-E system is basically designed to run the engine extremely lean at low RPM (below 2500-3100). Under 2500-3100 rpm, only one of the intake valves opens. This creates a swirling effect in the combustion chamber that concentrates the "rich" part of the mixture near the spark plug and the "lean" part of the mixture towards the edges. When it fires, the rich mixture near the plug creates a fast, stable burn. This allows the engine to run extremely lean (for gas economy), yet not detonate with A/F ratios as low as ~24:1, which the oxygen sensors on the HX are designed to read. Above 2500-3100 rpm, both intake valves open and the engine operates like normal with an A/F of approximately 12:1.

I'm not sure what else might be different, but I know the head, valvetrain, computer and oxygen sensor are different on the HX.

My girlfriend has a Civic VX hatch with a D15Z1 (VTEC-E). It's slow as hell, but it averages 45+ mpg!!!

Hope this helps

 

i learned something new today

 

Headers also won't fit the HX because it uses a close coupled cat. Only the EX uses (used?) an underfloor unit