philipa_240sx wrote:I raise the BS flag big time.
First off, the claims of HP, mileage, etc are totally unrealistic. I've seen and used upgraded ECU's and at most a 5-10% increase in HP might be squeezed by optimizing air/fuel ratios, ignition timing, etc and usually you have to run premium fuel.
Next the idea the engine is tuned overly rich from the factory is bogus. Modern engine controls use oxygen sensors that provide feedback and maintain the ideal stoichiometric air fuel ratio. This is necessary for the emissions systems (catalytic converter) and the engine to work properly.
Most of these so called 'tuning chips' or modules either do nothing or run the engine dangerously lean. Unless it comes from a reputable tuner who has experience (ie. Stillen or Jim Wolf Technologies), stay away!
The factory computer programming is generally about as good as it gets. Afterall, why would Nissan leave some preformance on the table in such a competitive market?
I chipped my last car, but this wasn't so much for horse power, but to remove the speed limiter (was factory set at 136) and raise the rev limiter (I used it at the track). I then had it re-programmed again when I switched out the cams to a little 'rougher' but higher rpm/horsepower set -- this was to optimize the fule/air mixture to work w/ these cams.
For a stock crossover that is designed more as an economey car then a sports car, I'd stay away from this path.