- Setting VTEC Crossover point -VTEC engagement on a stock car is OPTIMIZED. Do NOT mess with it because all you are really doing is taking away power, depsite what it "feels" like.

Now that we have that cleared up...YES, i know that bringing the VTEC crossover up or down around 500 or even 1000 rpm up or down may indeed improve your power curves. Again, this is something u can only really prove if you are on a dyno and u can see the immediate results.

So, why do you need a vtec controller? U don't, really. Unless you are using aftermarket cams, or have upped the compression, or some other internal modification that demands a shift in the VTEC x-over to again be optimized. AGAIN, something you should really be doing on the dyno, as every motor is different, not to mention weather conditions, grade of gasoline, general condition of the motor, etc....

So when you hear people say "I got a vtec controller and I set vtec to 3,000 rpm so im mad fast now", u know they're a not bright.

Why? This leads into my explanation on how vtec works but, basically on a vtec motor there is a vtec cam lobe and non vtec primary & secondary cam lobes. Those non vtec lobes are optimized for low end power delivery. However, @ upper RPM, the small lobes cannot deliver enough air nor keep the valves open long enough to continue to let the motor make power.

Hence, the VTEC crossover...where the VTEC cam lobe takes over duties in opening and closing the valves from the secondary and primary lobes. Since the vtec cam lobe is much taller, it can now provide more air and duration the motor needs to keep making power @ higher RPM.

Now think about it. What does setting VTEC at 3,000 rpm do? It makes a cam lobe designed to work well at HIGH rpm to work at LOW rpm. Conversely, setting VTEC too high will cause the motor to start dying out, then JUMP foward when the VTEC lobes take over.

If u have or do get a vtec controller, try it one day.

Set vtec to 3,000 and see how much of a pig the car is down low. Then set vtec to say 7,500 rpm or something. See how the car accelerates, slows down, then springs foward again at vtec x-over. You may think that is the car making more power, but if you were to look at dyno graphs, you would see the torque curve fall off, then rise back up @ your specified vtec cross over point. The above is also a good way to determine a starting point for an optimal vtec x-over when you have done some internal mods and u would like to set vtec @ a certain point. Take a dyno pull with vtec set low, then another pull with vtec set really high.

Overlap the graphs and where the curves intersect where power falls off and where power comes up is where you should start to mess around with a crossover point. Now, I-VTEC is VTEC, with a twist. Toyota's VVTL-i is the same thing as i-VTEC. Basically, in addition to VTEC, the ECU reads and modifies both intake and exhaust cam timing to an optimal point at every point on the RPM band. This ensures the most efficient cam timing to achieve optimal hp and torque. Infinitely Variable valve Timing and lift Electronic Control. This is why the new RSX-S motors, although only making 5 more hp than the old Type-R motors, are making around 12 more lb-ft of torque - because of i-vtec.

Also realize that VTEC and i-VTEC, although refined and marketed by Honda, is nothing THAT new. I think some Mercedes models first used variable valve timing back in the 50's or 60's...and in today's market, Ferrari, BMW, Toyota, Nissan, Honda, and many other manufacturers use some variation of variable valve timing. If you think about it, although complex and expensive both to research and develop, a variable valve and cam timing system has no competition from a fixed valve timing and fixed cam timing system. Pretty soon, all cars in the market will have variable valve and cam timing, not only does it help with making power, as I'm sure you're all concerned, but since it is more efficient, it cuts down on pollution and smog as well.