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VTEC vs iVTEC: What's The Actual Difference?
1 00:00:00,0 --> 00:00:04,600 Unless you've been living under a rock forever. You've probably heard of VTEC 2 00:00:04,600 --> 00:00:08,160 It's one of the defining features of Honda engines and it's one of the reasons so many people love it 3 00:00:09,559 --> 00:00:13,629 Without VTEC Johnny Tran probably wouldn't have smashed Jesse's Jetta. 4 00:00:14,320 --> 00:00:17,129 What's up guys, my name is Bryce with Dust Runners Automotive Journal 5 00:00:17,130 --> 00:00:21,29 And today I'm gonna tell you everything you need to know about VTEC and iVTEC. 6 00:00:30,500 --> 00:00:37,349 Variable valve timing lifts and electronically controlled also known as VTEC is a system that uses two separate cam lobes to 7 00:00:38,660 --> 00:00:44,860 Optimize engine efficiency it does this by using a cam lobe for low rpm and a cam lobe for high rpm 8 00:00:45,590 --> 00:00:48,239 By using two separate cam lobes you can optimize valve overlap 9 00:00:49,760 --> 00:00:52,320 lift and duration for two separate sets of rpms 10 00:00:52,320 --> 00:00:56,680 So you end up with more low-end torque and more high-end horsepower 11 00:00:56,750 --> 00:01:00,789 But you still have great drivability and great fuel efficiency 12 00:01:00,789 --> 00:01:04,869 this kind of a system is usually set to engage at a set rpm say 13 00:01:05,629 --> 00:01:08,978 5500 rpm it will engage the second cam lobe 14 00:01:08,470 --> 00:01:13,839 So Honda implements the system and so do many other car manufacturers now 15 00:01:13,479 --> 00:01:16,749 to improve overall engine efficiency 16 00:01:17,960 --> 00:01:22,439 since the camshaft spins half as fast as a crankshaft, you can really only optimize it for one set of 17 00:01:24,710 --> 00:01:30,970 Rpms now by having two different lobes you can optimize it for two sets if you had three lobes you could optimize it for three 18 00:01:30,970 --> 00:01:31,470 Sets and so on and so forth 19 00:01:31,470 --> 00:01:35,99 But two is pretty much all you need to optimize it for low end and high end power 20 00:01:36,530 --> 00:01:39,0 If you ever wondered why the muscle cars have that really lopey idle 21 00:01:39,0 --> 00:01:45,209 It's because they're using an aftermarket camshaft designed for high end power now designing it for high end power 22 00:01:45,280 --> 00:01:48,449 It's designed to have duration and lift and valve overlap 23 00:01:49,299 --> 00:01:55,19 Specifically at higher rpm that means that low rpm is basically it's not designed for low rpm at all 24 00:01:55,20 --> 00:01:57,20 And that's what gives it that choppy idle 25 00:01:57,430 --> 00:02:01,599 Before I tell you what iVTEC is, let me tell you what vtec-e 26 00:02:01,790 --> 00:02:05,559 Is because that's a different kind of VTEC that not a lot of people even know about 27 00:02:06,500 --> 00:02:13,319 Vtec-e is different in that it is not designed for power. Basically at all. It's designed solely for fuel efficiency and nothing else 28 00:02:14,260 --> 00:02:19,170 Vtec-e gets such great fuel economy by turning your 16-valve 4-cylinder 29 00:02:20,810 --> 00:02:26,890 Engine into a 12 valve four-cylinder engine what it does is it doesn't allow one of the intake valves to fully open 30 00:02:27,620 --> 00:02:32,399 By not allowing the second intake valve to open all the way combustion chambers swirl is improved and so is fuel atomization 31 00:02:33,10 --> 00:02:38,560 This allows Honda to use a leaner AFR and ultimately improve fuel economy 32 00:02:39,590 --> 00:02:44,340 Another thing we quickly need to talk about before talking about iVTEC is VTC which is known as variable timing control 33 00:02:45,890 --> 00:02:50,919 now variable timing control is typically a mechanism that you'll find on the end of an intake camshaft and it allows 34 00:02:50,200 --> 00:02:57,820 it's essentially cam phasing it allows the intake camshaft to be continuously variable so that the overlap between 35 00:02:57,160 --> 00:03:01,869 The intake and exhaust cam can be infinitely adjustable 36 00:03:01,209 --> 00:03:07,719 Throughout the RPM range. this kind of system can be used on both the intake and exhaust camshaft 37 00:03:07,720 --> 00:03:11,770 But for the most part it's only used on the intake camshaft because that's where you're gonna find the greatest gains 38 00:03:11,230 --> 00:03:18,90 Intelligent variable timing and lift electronically controlled which is a massive mouthful is a system that combines 39 00:03:18,370 --> 00:03:20,19 VTEC and VTC 40 00:03:20,19 --> 00:03:27,29 Into one system as you can imagine combining VTEC and VTC or best of both worlds into one system 41 00:03:27,370 --> 00:03:30,450 Results in a really efficient and really powerful engine 42 00:03:31,850 --> 00:03:37,109 The VTEC part of the system has two different cam lobes one for low rpm one for high rpm and the VTC system 43 00:03:37,110 --> 00:03:45,760 It's constantly adjusting valve overlap to be optimized. So throughout the power band. You pretty much have optimum valve overlap 44 00:03:45,280 --> 00:03:49,570 timing and duration throughout the entire rev range 45 00:03:50,510 --> 00:03:53,309 Unfortunately Honda made this really confusing by having two different kinds of iVTEC. 46 00:03:54,860 --> 00:03:59,399 So in the case of the K20A2 which is the performance oriented K20 that we got in the u.s 47 00:04:00,530 --> 00:04:02,949 that combines VTEC and VTC. 48 00:04:02,470 --> 00:04:06,359 By combining those two, Honda got a lot of power out of that little engine 49 00:04:07,0 --> 00:04:12,940 Where this gets really confusing is with the K20A3 which combines vtec-e and VTC. 50 00:04:12,459 --> 00:04:16,499 Now combining vtec-e and VTC, you still get great power, but it's not 51 00:04:17,109 --> 00:04:23,949 Performance oriented like iVTEC in the k20a2, it's still good, but it's designed for fuel efficiency 52 00:04:24,620 --> 00:04:26,399 It's really annoying that Honda decided to use iVTEC 53 00:04:27,670 --> 00:04:32,710 As the name for both the k20a3 and the k20a2 because really they're different systems 54 00:04:32,440 --> 00:04:39,29 Now how exactly VTEC increases horsepower can be kind of confusing if you're new to the whole automotive world 55 00:04:40,520 --> 00:04:45,579 Now horsepower is just a measure of torque times RPM. To increase torque 56 00:04:45,580 --> 00:04:50,949 You need to get more air into the engine and with more air you can add more fuel this results in a larger 57 00:04:50,80 --> 00:04:56,370 combustion more downwards force and more torque by opening the valves further and for longer at 58 00:04:57,590 --> 00:05:04,569 Different Rev ranges you can ultimately increase torque and low rpm and increase torque at high rpm the VTC system 59 00:05:04,640 --> 00:05:10,349 optimizes how much air is being sucked into the engine at low rpm and high rpm by constantly adjusting the cam timing you might be 60 00:05:10,350 --> 00:05:16,260 Wondering why Honda didn't just use more cam lobes in their VTEC system instead of just two cam profiles 61 00:05:17,750 --> 00:05:23,340 They could use three or four cam profiles and the answer is simplicity the gains from three cam profiles would be so miniscule 62 00:05:23,440 --> 00:05:29,369 That it really wouldn't be worth it. Especially considering it would vastly increase the complexity of the system ultimately 63 00:05:30,310 --> 00:05:34,810 Decreasing reliability down the road because you have more moving parts. 64 00:05:34,850 --> 00:05:38,219 The easiest way to remember all this is that iVTEC is the same as VTEC, except it has 65 00:05:38,380 --> 00:05:42,730 VTC included in the system to further improve efficiency 66 00:05:42,730 --> 00:05:45,179 I hope this helped you guys understand the difference between VTEC and iVTEC better 67 00:05:45,180 --> 00:05:49,170 If it did be sure to hit that thumbs up button and subscribe and I'll see you guys in the next video
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