yes this question makes it offical, i'm a (insert bad, evil comment here)
but either way what is an ef civic

 

ef is any 88-91 series civic. hatch or coupe, crx ect..... as long as it's a civic. i think that's a pretty goodd explanation

 

an EF is a JDM 88-91 Civic wich came with a B16.... USDM civics are ED7's i belive..... and the crx is a ED9 as you can see that is my user name....

 

yes sir the si hb is ed7.
other civics have their own chassis code tho.
alot of people just use ef to explain any 4th gen just for a name to call them.
same as saying eg or ek when most of the are eh and ej..
i guess its easier than saying 4th gen 5th gen 6th gen ect but those arent any kind of official chassis code since each model has its own[in most cases] and honda chassis codes are 4 letter[example E-ED7]

 

i agree with 91EDSi but i think 1st , 2nd gen and all taht is much better then EF EK and all that, LIK EU SAID every cahssis has its own code, rx7 on the other hand FB FC FD are all diff cahssis code so..

 

ed9=usdm crx 1600cc
ed8=usdm crx 1500cc