HSTuners - View Single Post - i got smoked by a nissan se-r spec v

05-06-2002, 05:01 PM

I told the salesman that he was a fool, of course. I also pointed out on the Prelude SH that I test drove that the VTEC crossover can be distinctly felt at 5200 RPM.
A VTEC controller would only, in my opinion, be usefull if your heavily modifying your drivetrain (cams, cam gears, valves, valve springs, retainers, pistons, rods, crank) so that the engine can rev much higher than the factory setting. The most effective use of the VTEC controller is actually RAISING the VTEC crossover because you'll get a more effective kick that way.
If your engine is modded (NA) to rev to, say, 9 or 10K RPM, then that means you most likely have more aggressive cams, which might actually cause you to run a slower 1/4 mile should the VTEC crossover happen at a relatively "low" 5,200 RPM. You'd probably want to raise the crossover by at least 1 or 2K RPM. Lowering the VTEC crossover on a more or less stock VTEC engine might actually cause you to run slower because your switching to a cam grind with higher lift and duration, meaning your sucking in more air and not doing much with it at lower RPM.
That's why VTEC was invented, for less aggressive cam grinds down low for bottom end grunt, and higher lift, higher duration cam grind for the top end when that extra O2 will actually benefit.

If I were to lower my VTEC crossover, I'd only lower it to 5,000 RPM which shouldn't make too much of a difference, but no more than that.

05-06-2002, 05:01 PM	#22
Incubus Posts: n/a	I told the salesman that he was a fool, of course. I also pointed out on the Prelude SH that I test drove that the VTEC crossover can be distinctly felt at 5200 RPM. A VTEC controller would only, in my opinion, be usefull if your heavily modifying your drivetrain (cams, cam gears, valves, valve springs, retainers, pistons, rods, crank) so that the engine can rev much higher than the factory setting. The most effective use of the VTEC controller is actually RAISING the VTEC crossover because you'll get a more effective kick that way. If your engine is modded (NA) to rev to, say, 9 or 10K RPM, then that means you most likely have more aggressive cams, which might actually cause you to run a slower 1/4 mile should the VTEC crossover happen at a relatively "low" 5,200 RPM. You'd probably want to raise the crossover by at least 1 or 2K RPM. Lowering the VTEC crossover on a more or less stock VTEC engine might actually cause you to run slower because your switching to a cam grind with higher lift and duration, meaning your sucking in more air and not doing much with it at lower RPM. That's why VTEC was invented, for less aggressive cam grinds down low for bottom end grunt, and higher lift, higher duration cam grind for the top end when that extra O2 will actually benefit. If I were to lower my VTEC crossover, I'd only lower it to 5,000 RPM which shouldn't make too much of a difference, but no more than that.