Hello there all, I have a few questions regarding the engine in my 6th gen. Now I have limited knowledge on the differences between the F23a1 vs. the F23a4. I'm pretty sure that there is a small power difference due to emission restrictions, the ECU may be different/may have different settings applied to it vs. the ECU in the a1, and I believe the exhaust system may be more restricted than 6th gens with the f23a1. As you can see I'm not I'm not entirely sure, so I wanted to make sure of it what's the diference between the two and could I make my engine have just as much potential as the f23a1? Thanks

 

The only difference that I know of is that the A4 has a more restrictive exhaust manifold.

 

A4 is ULEV and VTEC. and only produces like below 150 more like 145hp or something. The A1 is 150hp VTEC. And also I have this picture of the headers. Its kinda diff. So basicly. All about the emissions

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr Wonderfull &raquo;</TD></TR><TR><TD CLASS="quote">The a1 is NOT vtec... The b1 is vtec </TD></TR></TABLE>

Que?

F23A1 = VTEC
F23A4 = ULEV-VTEC
F23A5 = non-VTEC

 

dood. Both are VTEC