monstar
Naturally as-pirated
- Joined
- Feb 1, 2016
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- depths of Hays Inlet
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- Peugeot 207 GTi
Well good on you for denying you’d like more power 95% of your driving time, that you only need more power going over the speed limit. Potential is there if you ever change your driving habits.VVT definitely has its place like you have just pointed out. It all comes down to what you use your car for really.. if having a bit of extra torque below 2000rpm does it for you then yes maybe consider VVT.. cant say i have any problem with torque in that area, after all its a 6.2L engine! And if im wanting to hall arse im well above 4500rpm anyway. And fuel efficiency? I didn't consider that when i bought a v8, but i can still average 8.4L/100km on an open road so i have no complaints there. Money better spent else where is all im saying. I still dont understand your beef with boost?? Im guessing you got spanked by a 2L turbo and need to come up with why your NA engine is better or something..
Fuel consumption on open road with a race cam is typically around same mark BTW. I get 6.x and that’s no big deal unless you drive hundreds of km a day on the highway, agreed. But the fact it is doughy and unresponsive until say 3000 is easily fixed by tune advancing the cam to be more effective on accelerator tip-in such that tune don’t need to open the throttle body to overtake better valve timing (throttle-less operation) makes driving efficiently less of a conscious effect and more satisfying, engaging on the road.
Not just highway cruise, same with idling, WOT take-off, part-throttle, is much more efficient (powerful / less heat / economical) for everything outside power enrichment.
During PE cam of course fully advanced before MBT then straight up at torque peak then phases combustion to slight overexpansion so as to extend the torque about 500 rpm and maximise horsepower (rev out) through reduced pumping loss.
With a huge top end race cam VVT follows and constantly adjusts the crank position of overlap to maximise inertial supercharging.
So yeah, even with VVT some cam specs just don’t idle nice, and some setups are purpose-built for narrow powerband drag racing. But in Camaro and Corvette drags VVT has shown to reduce the need for bypassing poor torque delivery in the lower RPM range, like a hi-stall is designed to do.