vtec

**ej_saiyajin4** · February 16th, 2009 01:47 PM

sa anong rpm nag eengage ang vtec ng ph16a(96 civic vti)?

**ejaydpogi** · February 16th, 2009 05:01 PM

ph16 vtec is actually vtec-e. it doesn't have different came lobes. it just switches from from 12 valve to 16 valve operation. cut-off i think is 3500 rpm (don't count me on this).

**v6dreamer** · February 17th, 2009 05:07 AM

VTEC is great.
HERE IS HOW IT REALLY WORKS:
There are two can lobes for each valve, one for low RPM and one for high rpm.
#1, high lift at idle and low engine speeds actually causes the car to be slower. Why? because instead of creating a suction and swirl to mix the gas and air it would blow through and out the exhaust.
All engines are different, B series are 5000 RPM , yes, but my accord 2005 v6 is 3500.
Once it hits this point, the solenoid opens up and uses the vehicles oil pressure to lock the lifters into the rocker that rides on the higher lift and overlap cam lobe, greatly increasing engine power.
This is the same technology Ferrari used on their engines in the 70, but they did it by retarding the exhaust valve to get a last extra push out of it.
DOHC VTEC engines use the VTEC on the intake and exhaust valves, the SOHC VTEC usues it on the intake only.

**oj88** · February 17th, 2009 08:39 AM

Originally Posted by ej_saiyajin4

sa anong rpm nag eengage ang vtec ng ph16a(96 civic vti)?

Since VTEC-E is not performance oriented, the VTEC cut-over is much earlier on these engines.

VTEC-E Valve Timing Change Conditions are:
Engine Speed : 2,500 RPM minimum (3,500 RPM typical) - Determined by engine load (MAP sensor output)
Vehicle Speed : 5kph (3mph) minimum
Water Temp : -5.3 C (22 F) minimum

**ejaydpogi** · February 17th, 2009 08:45 AM

Originally Posted by v6dreamer

VTEC is great.
HERE IS HOW IT REALLY WORKS:
There are two can lobes for each valve, one for low RPM and one for high rpm.
#1, high lift at idle and low engine speeds actually causes the car to be slower. Why? because instead of creating a suction and swirl to mix the gas and air it would blow through and out the exhaust.
All engines are different, B series are 5000 RPM , yes, but my accord 2005 v6 is 3500.
Once it hits this point, the solenoid opens up and uses the vehicles oil pressure to lock the lifters into the rocker that rides on the higher lift and overlap cam lobe, greatly increasing engine power.
This is the same technology Ferrari used on their engines in the 70, but they did it by retarding the exhaust valve to get a last extra push out of it.
DOHC VTEC engines use the VTEC on the intake and exhaust valves, the SOHC VTEC usues it on the intake only.

this is the performance vtec. the local vtec (ph16) is vtec-e which optimizes fuel economy and doesn't have 2 cam profile (20 lobe d16/d15 vtec sohc).