Hey guys,
I just thought I would add my two cents to the thread.
First off:
Regarding the ECU
The ECU 'de-tunes' a motor indirectly. The ECU knows what numbers it should see from the various OBDII sensors on a stock Prelude. Adding intake, headers, exhaust, etc. will always modify these numbers some (depending on which mod you've done ).
In the case of a CAI, the air temperature and air:fuel ratio changes because of the added intake pressure. In this case, the ECU will notice a consistent change in the curves of your A/F. After a while it will richen the mixture to keep the motor from lean conditions, and pre-mature wear and tear. So, what happens is your car is taking in more air still, but the fuel ratio has been brought back up to compensate. Therefore you lose a large portion of the horsepower you gained before.
I hope this explains some questions.
I would recommend you check out the
OBDII Workaround mod at
http://www.ntpog.org - I have done it, and it works wonders. I have a fairly complex stereo setup, and disconnecting the fuse for the radio once a week is just NOT acceptable to me. The mod requires about an hour, and some patience, but it's not particularly hard. Once done your car will run like always before, and you simply have a switch you leave off. The premise is simply that you disconnect the 'memory' wire, or battery lead from the ECU so when you turn the car off, it forgets anything it may have learned that particular trip out. Then, if you were to throw a trouble code (check engine light) - you can flip the switch back ON so that when you turn the car off it will remember - and you can diagnose the problem. Please note that the mod does not DAMAGE your car in anyway, and will not CAUSE any trouble codes (a common mis-conception).
Second off:
Regarding the Air Conditioner
It is ALWAYS a good idea to turn of the A/C BEFORE you jump on the throttle. Most A/C compressors have a clutch assembly so that when a car is put under strenuous load (such as full throttle), the compressor will temporarily shut off so that it doesn't over compress and burst. It's not a good idea to put your faith in that clutch assembly however.
I've never heard of it happening on a Lude, but the 1998 Camaro z/28/ss LS1 motor was NOTORIOUS for bursting compressors. I've seen fiberglass damage from this - thankfully the car was still under warranty.
Third:
Regarding Cam Gears, V-AFC, Timing Parts
Anytime you change parts that are related to either the air/fuel ratio or the timing (such as cams and cam gears), it's highly recommended that you have facilities such as a dyno at your disposal to tune. Often the theory behind certain changes to ADD performance can cause loss of performance, or even lean conditions that are potentially harmful to your car.
Finally:
Regarding SS 5G Preluds
It does depend what car you came from before on how sporty the Prelude will feel. Sport shifts have a tendancy to feel MUCH less responsive (even though, as w0rdie said, they really aren't that much), and likewise, the Lude has a tendancy to take some spool up time for the first 4000 rpms in first gear (in either transmission) simply because of the nature of the high-revving 4 cylinder motor - once you get moving into VTEC however, the car shows its colors.
I hope this information found some people well - good luck finding your performance problem!
R.J.
Linear Mode
