HONDA VTEC INFO

 KNOWING MORE ABOUT THE HONDA ENGINE

VTEC - Variable valve Timing and lift Electronic Control. At low RPM, a VTEC engine uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. The VTEC mechanism engages a high-lift, long-duration "race" cam profile at a set RPM value (i.e., ~5500RPM on the B16A) to increase high-end power delivery.

VTEC-E - Variable valve Timing and lift Electronic Control for Efficiency. This system isn't really VTEC as we know it. At low RPM, the VTEC-E mechanism effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At a set RPM value (i.e., ~2500RPM in the D16Y5), the VTEC-E mechanism engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?

VTEC-3 - This is a combination of VTEC and VTEC-E AKA 3-Stage VTEC. From 0 to 2500 RPM, the car runs 12-valve mode allowing a lean burn, decreasing fuel consumption This is the 1st stage. From 2,600 RPM the first vtec solenoid engage so engine now runs 16-valve mode. This is the 2nd stage. Now when you reach 4,600 RPM, the 2nd solenoid enggages and the wild cam (race cam) profile takes effect and this 3rd stage increases the top end power delivery.

VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs.

i-VTEC - intelligent Variable valve Timing and lift Electronic Control. This is a combination of both the VTEC and the VTC technologies - in other words, i-VTEC = VTEC + VTC. Currently, the only engines that use the i-VTEC system are the DOHC K-series engines.


Here are the list of Philippine Domestic Market that have the VTEC technology:

VTEC:
1996-2000 Civic VTI
1999-2000 Civic SIR
1996-2005 Accord Vti / Vti-L / Vti-S
1999-2003 City Type Z Vti

VTEC-3:
2001-2005 Civic Vti / Vti-S

i-VTEC:
2001- up CRV
2005 Civic DOHC 2.0 L

*IMHO:
The civic Vtec-3 has an oustanding fuel efficiency among all other competitors in its class. It has the best of both worlds, the fuel consumption of a small engine car like the corolla XL/XE / Lancer EL/GL / Kia Pride, and also has the power and acceleration of high end 1.6L / 1.8L models like the Corolla Altis / Lancer GLXi Etc. The VTEC-3 technology gives the Civic the 10 to 12 KMs/L city driving and upto 20KMs/L at the highway fuel consumption. And it is also extremely FAST! Vtec allows the engine to breathe better at high speeds extending the power curve approaching the red line.

---

Foot note
*IMHO - In My Humble Opinion
*Spelling check OK, Pak U Ian!



Posted by:    Emil Ang
Pccians_95 Blogger