b16 cams
- Thread starter new2me93
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LS_VTEC
you get the BRAKE
you know what... when the engine is finished, i wanna have a special video-taped dyno day just for you showing the comparisons of vtec crossover with different types of cams... ill even use my engine to do the R&D.
All jokes aside, im serious about this Blanco. It will be interesting...
All jokes aside, im serious about this Blanco. It will be interesting...
LS_VTEC
you get the BRAKE
Personally, I don't give a rats ass about peak horsepower numbers. I care about the power curves. It's not worth picking up a five peak horsepower to lose 15 throughout the rest of the powerband. So video tape all you want. I won't be looking at the peak, I'll be looking at the entire graph.
All you have to do is get a little theory with your practical application. When you go to school for these things, they don't just throw you into a bay with a bunch of tools and tell you to have fun. No, they make you go through the book work, too. That way you know the reasoning behind things. I haven't been to school for this, but the people I've learned from have been. A powerband should never dip inward (concave) with proper tuning, it should be either straight or curved outward (convex). There's never a point to riding the cam profile past the point where it makes power and there's no point in riding the high cam more than a 1000rpm +/- past the peak power. Doing so may make your peak horsepower figure more impressive, but it makes the engine slower than it could be.
The engine being built for a powerband of 6000-9000rpm, as an example, doesn't mean jack when it comes to VTEC crossover. That means that that's where the engine makes the most power, by design. The head work, header design, intake manifold design, and cam profile were all done to optimize flow at high RPM, so flow at low RPM won't be as smooth. So, quite obviously, you're going to feel more power in that 6000-9000rpm range than you will in the lower RPM ranges, regardless of what specific RPM your crossover is set to.
Lastly, there's no reason to launch below VTEC crossover in drag racing and if the crossover is set too high you'll have a much better chance of coming out of VTEC on the shifts. Unless, of course, you're riding your cams way past where you should be shifting.
I'm not as much of a newbie as you think I am. Being a bookworm full of hot-air isn't why I get respect on the technical forums here.
Very well put... I agree with you 100%. Infact, Im going to run the itr cams WITH a different range of power. peak torque in LS/VTEC is roughly around 6500-6800 rpm. When we tuned it with vtec it didnt concave whatsoever with it set at 6800rpm BUT it would be nice to make more mid-range to go with all that torque down low. SO im going to try different crossover points and the such. but most importantly, I am going to set vtec @ 7400rpm and test it on the dyno to see exactly what rpm it flattens out/falls off at. and from there its all tuning =) Hope it works well....the old set made the 204whp @ 7800rpm climbing the whole way up to it. So maybe if i stretch it out a bit, and lower the redline to say 8400rpm I can make a significant increase in my mid-range and have a broader powerband...