SOHC vs DOHC | Autotechlabs 

But the info is mostly wrong. Clear, but dead wrong.

Ryan Nugroho. 💪😎👍..

Yup

Library?

True.

😊👻

You don't really understand something unless you can explain it to your grandmother.

​@@mauj.2409😮

Came here to make the same comment, also a number of SOHC Engines featured VVT like some honda engines and Mitsubishi's 4g69 Mivec engine. But yeah great explanation and animations.

@@jake.g1 An excellent point, one I had forgotten

Exactly! My imported 1990 Accord 2.0si exclusive coupe came with a F20A DOHC and it had rockers and 4 valves then i swapped over my ported and cammed superior flowing 4 valve SOHC F22A head just because stupid people think 2 cams gives them twice the power of a SOHC haha!

Mitsubishi 6a13 engine uses a SOHC valve design while having 4 valves per cylinder

@@remi009340maybe not twice the power, but definitely more power...

bouaaaah

No my sohc is a beast

@@josephrebensdorf9844 yea, for drag racing

well not really, dohc gets implemented to all modern engines now even economy daily driver cars gets dohc

@@josephrebensdorf9844 and cheaper to maintain.

@Gibbon when life was better 😕

Go for QOHC. V engines with 4 cams haha

But I still don't get why SOHC produces less power than DOHC??

Douglas Healy also, how do sohc produce low end torque?

Honda used sohc while toyota and other manufacturer used dohc

@@JohnKickboxing Basically like they said; SOHC are usually fitted with less valves per cylinder due space constraints. It's not really due to having 2 cams instead of one, it's more of a side effect thing. Another example: a DOHC car almost always have the spark plug right in the center of the cylinder for better an more uniform combustion and that simply isn't possible on SOHC unless they offset the camshaft and use longer rocker arms on one side. @Burcey B That once again has mainly to do with with valve count and lift which effects performance. Usually on low rpm you actually want a slight vaccum to occur because you won't be using all the air that is coming into the cylinder anyways. You will be compressing air that in turn will not be used up in the combustion event (3rd stroke) with the fuel therefore you are losing power (torque). This is all compromise game. You give away something to gain something. Of course that VVT and other systems reduce this compromise and pretty much give you the best of both worlds but at an increased cost and complexity.

Also , there are DOHC engines with 2 valves per cylinder, old Alfa Romeos for example .Better performance in the low to middle RPMs range of two valves engines is because of the larger squish / quench area in the combustion chamber which is impossible to be replicated in four valves chambers . The larger squish area generate strong turbulence even from very low RPMs and this lead to faster completion of air/ fuel mixture burning. DOHC on two valves chambers allows for precisely adjusting and varying of valves overlap which is impossible with SOHC . Poor video on the subject overall!

Right. It depends on the design.

DOHC provides greater performance from my experience

Likely due to cost.

when the cost is down? everything is about cost.

Never, mechanical components have better reliability than electrical therefore in everyday use we will always have camshafts.

Likely in this decade, due to new pollution norms inside the EU. It's hard already to respect Euro 7 with current engine tech, most likely there will be steps in adopting Koenigsegg FreeValve like tech on mainstream cars. This would improve efficiency a lot, and also could lead to a more easier fix using firmware update to enhance vehicle usability in the latter of it's life and so it's likely to use a car for more of it's life at the same standards of pollution. Yes, might not be what the car producers wants, but it is what they need to do.

It’s already been done, look up Koenigsegg no cam engine

With dohc you have 2 cams and 2 camshafts. With sohc you only have 1 camshaft and 1 cam.

@@tommieboi707 but in SOHC you have to produce at least 3 extra rocker arms (for 4v/cyl setup) with bearings inside each of them, plus the rail where you place your rocker arms. this makes the number of parts higher and you have more stuff to assemble. why would the DOHC, which has 1 extra cam but less parts overall and no assembly of rocker arm system required (they can simply run bucket tappets), be more expensive?

@@sepg5084 exactly

@@sepg5084 And the more websites I see saying the same thing without actually questionng it, the madder I get 😆

The f22 and f23 as long as you keep oil in em they'll keep on chugging along

It's clear that DOHC 4VALVE has more power on high rpm, the air flow are better because the cam are directly touch the valve, not like SOHC need to use a ROLLER ROCKER ARM SOHC 4VALVE is good for stop & go because it has more torque on lower RPM DOHC 4VALVE are less power & torque on lower RPM But if you on highway definitely DOHC 4VALVE are better But if you driving in the city SOHC 4VALVE is better choice, Especially if the traffic is heavy & forece the engine to STOP & GO also run on lower RPM

Yeah, and nowadays I say, you don't need any valve overlap. 4 valves allow for enough air anyway. Instead of internal exhaust recirculation to throttle an engine, just start with a downsized one and get power on demand from turbo.

Not all D series engines lacks low end torque, what I realised is that USDM Hondas have less powerful engines than Europe or Asia. Here (in Europe) we have d series engines were the torque figures surpasses the hp figures and those cars have good low end torque. Where are you from?