K20A2: The K20A2 VTEC system engages at 5,800 RPM, whilst the VTC system is always active. The VTEC part of the system allows valve overlap to be adjusted at any moment, resulting in much greater efficiency and slightly better performance. The VTEC part of the system has two different camshaft profiles, one for low rpms, and one for high rpm. Intelligent Variable Timing (and lift) Electronically Controlled (iVTEC), is a system that combines VTEC and VTC into one unit.Īs you can imagine, combined the best of both world results in an incredibly efficient and powerful engine.
VTC is always active and adjusting valve overlap for optimal engine efficiency and power at any given RPM. Honda uses this system on the intake camshaft but not on the exhaust camshaft, as the gains from having VTC on the exhaust camshaft are minute. By adjusting the valve overlap agt different RPM ranges, effeciency and power levels are greatly improved. The variable camshaft gear allows the valve overlap to be adjusted at any RPM. Variable Timing Control (VTC), is a mechanism that allows the camshaft gear to be continuously variable. VTCīefore we jump into i-VTEC, we quickly want to cover VTC to give you a better understanding of how all this works. This type of VTEC is standard on many of the fuel-efficient Honda models. The VTEC-E design decreases fuel consumption quite a lot but lacks the high horsepower numbers that the standard VTEC produces. RELATED: What Makes the Chevy LS so Special? It does this by not allowing the second intake valve to open fully. VTEC-E does this by effectively forcing the engine to run as a 12 valve engine instead of its normal 16 valves. VTEC-E is quite different from the standard VTEC, because Honda did not design it for optimal horsepower at high RPMs, instead they designed for optimal fuel efficiency at low RPMs. This sacrifice is what causes the engine lope at idle. By designing a camshaft specifically for high RPM horsepower, you must use sacrifice how smooth the engine runs at low RPM. Muscle cars have that lope at idle because of the camshaft design. Since the camshaft spins half as fast as the crankshaft, optimum valve over-lap and timing is different at every RPM. Why does Honda impletment this system? They implement it to improve optimum engine effeciency which results in more horsepower and better fuel economy. RELATED: 1JZ vs 2JZ: Which One is Better and Why? This system is usually set to a specific RPM (5,500) and greatly increases horsepower. One camshaft profile for low RPM, providing good torque and excellent drivability, and a camshaft profile for high rpm that has greater lift and longer duration. Variable Timing (and lift) Electronically Controlled (VTEC), is a system that uses two different camshaft profiles. But what is VTEC, and what does it do? How is it any different than iVTEC? Well, first you need to understand what VTEC is. Sounds like a perfect opportunity to throw some stainless steel valves in there.Unless you’ve been living under a rock, you’ve probably heard of VTEC. Well, looks as if my car isn't so lucky Tech called and said they put the new waterpump/timing belt on and when they started the car it was backfiring real bad.and something about 2 out of 4 cylinders are working.He says bent valves :( so, they are pulling the heads tmrw and investigating further.The story about the car was a recent timing belt was put on but the shop never told me about adding a new water pump as well.so, wp went and the belt slipped off rather than actually break but still must have caught the valves while they were open.I sure the hell hope my pistions are ok.he said it's rare for them to be damaged, so if any luck is on my side that slipped belt only caused bent valves.Looking at a costly repair.wow, just before tax time.I must have some luck on my side!.LMAO what do you guys think?.just bent valves?Ĭompression and leakdown test will tell for sure, but it sounds like it.