i have a F23A4 engine in my 1999 Accord LX. The engine is ULEV which was started on my year car. Before ULEV their was LEV which was on the F23A1. Which was on the 1998 Accord. The A4 has a stock hp of 148hp and the A1 has 150hp. I wonderin if smaller exhaust manifold holes and smaller intake manifold have anything to do wit the 2hp difference. my car isnt ULEV anymore wit my exhaust and air modifacations. but i was just wonderin y the A1 has more hp and torque than my engine.

 

LOL does your muffler have two resonater thing?
well..if you dyno two car one with a1 and one with a4
maybe there's a 0.000564484 whp difference.

 

I do not know specifically what was changed to drop the HP from 150 to 148, but you are probably close. The cat might be closer to the manifold, the cat might be more restrictive, the exhaust piping might be alittle smaller etc

 

that would probaly gain more hp. i still thinks its smaller exhaust manifold and intake manifold holes. and restrictive cat.

 

no, it wouldnt.

its most likely a combo of a cat and ECU adjustments

Its an emissions reduction primarily, they didnt just cut HP and leave emissions alone.

 

It is 100% a difference in electronics/sensors. the A4 and A1 have sligthly different programs on the ECU, and a few of the sensors are different. in fact, it's only the O2 sensors that are different, otherwise all stats are the same.

A1 was available in 99 for sure. mine is it's a 5-spd. don't know if that makes a difference

edit: my build date is dec 98 though. may be a calender year, not a model year thing.


[Modified by jweller, 10:20 PM 12/22/2002]