Vtec Vs Non-vtec & Sohc Vs Dohc

[B00STd_FoeDoe]

I've always wondered what the difference was. What are the pros an cons. Why is having vtec an essential. Same questions apply to a DOHC. I've heard tuning a DOHC motor is more beneficial because you can retard the timing making it the intake side of the motor stay open longer..?

[thepowderblue]

I like a good flowing non vtec heads, All vtec does is put your car into pussy mode under so meany rpms. I want a good cam profile from the start!

[cbscandal]

I like a good flowing non vtec heads, All vtec does is put your car into pussy mode under so meany rpms. I want a good cam profile from the start!

Those are opinions.

[thepowderblue]

Those are opinions.

No its not. vtec is 2 cam profiles. One is to make your engine purr and be all economy and the other is to oven the valves more after so meany rpms.
If you can bypass that economy cam profile and have a good normal profile all of the time you will have more power off the bat.

[B00STd_FoeDoe]

So sohc cams are more aggressive then dohcs.???!!

[cbscandal]

No its not. vtec is 2 cam profiles. One is to make your engine purr and be all economy and the other is to oven the valves more after so meany rpms.
If you can bypass that economy cam profile and have a good normal profile all of the time you will have more power off the bat.

That's better.

I like a good flowing non vtec heads, All vtec does is put your car into pussy mode under so meany rpms. I want a good cam profile from the start!

You like good flowing non-VTEC heads. You think VTEC just puts your car in "pussy mode". And you want a good cam profile from the start.

Those are opinions/preferences. I'm not going to argue with you.

To OP: I prefer the simplicity of SOHC. And VTEC is to provide a good cam profile for high RPM, while also a providing one for low RPM driveability. I, personally, think VTEC is overrated.

[turbo90accord]

it really just depends on the setup. I personally love the single cam mainly because of the bottom end which is more conducive to higher torque than the DOHC variety.

All of the cam tuning stuff that people say is a pro to being dohc, can be had with the properly designed camshaft for a single cam.

[pike0825]

hopefully no one gets pissed of my oppinion. DOHC i better than SOHC and v tech is better than no tech lol

[owequitit]

No its not. vtec is 2 cam profiles. One is to make your engine purr and be all economy and the other is to oven the valves more after so meany rpms.
If you can bypass that economy cam profile and have a good normal profile all of the time you will have more power off the bat.

I'd be careful before you speak mistruths, especially in the beginner section where you could detrimentally affect someone's initial learning.

1) VTEC is not necessarily designed for engine purring and economy. What it IS designed to do is make the engine more flexible over a broader range. Luckly, low RPM torque and response happen to be created by the same things that make the engine purr and be all economy, because the camshaft is efficient at those engine speeds.

Then, to avoid the typical non-VTEC compromise of either having to tune an engine for low RPM response OR top end power, it has the second set of cams that takes over at high RPM's, which allows it to breathe well in the top end, which is coincidentally what is needed to make good power up top.

In the end, you end up with MORE bottom end torque and power AND more top end power, which is something you can't do with a conventional cam to the same degree. It is by virtue of function less of a compromise.

When you stuff that big badass cam in your street F22, you lose bottom end. Or, if you size it reasonably for around town driving power, you sacrifice top end power. Either way, you have to make a choice with the cam you choose. There are a lot of variables beyond that, and you have to optimize a lot of stuff, but ultimately, the VTEC cams allow less compromise when doing so.

2) You are aware that a "pussy" H22 out of VTEC is pretty much identically strong as an F22 right? About the same torque, slightly better curve shape, and then when it hits ~5500 in stock tune, it does something that the F22 can't, right? So essentially you get an F22 with a huge top end kick.

[thepowderblue]

That's better.



You like good flowing non-VTEC heads. You think VTEC just puts your car in "pussy mode". And you want a good cam profile from the start.

Those are opinions/preferences. I'm not going to argue with you.

To OP: I prefer the simplicity of SOHC. And VTEC is to provide a good cam profile for high RPM, while also a providing one for low RPM driveability. I, personally, think VTEC is overrated.

Vtec is good for a dd. I think vtec is nice because You can be in"pussy mode" and not be working your car hard and saving gas but when you need your car to have balls it kicks in... Get what I am saying? I wish there was a switch in your car to turn vtec all of the time or off.

[thepowderblue]

I'd be careful before you speak mistruths, especially in the beginner section where you could detrimentally affect someone's initial learning.

1) VTEC is not necessarily designed for engine purring and economy. What it IS designed to do is make the engine more flexible over a broader range. Luckly, low RPM torque and response happen to be created by the same things that make the engine purr and be all economy, because the camshaft is efficient at those engine speeds.

Then, to avoid the typical non-VTEC compromise of either having to tune an engine for low RPM response OR top end power, it has the second set of cams that takes over at high RPM's, which allows it to breathe well in the top end, which is coincidentally what is needed to make good power up top.

In the end, you end up with MORE bottom end torque and power AND more top end power, which is something you can't do with a conventional cam to the same degree. It is by virtue of function less of a compromise.

When you stuff that big badass cam in your street F22, you lose bottom end. Or, if you size it reasonably for around town driving power, you sacrifice top end power. Either way, you have to make a choice with the cam you choose. There are a lot of variables beyond that, and you have to optimize a lot of stuff, but ultimately, the VTEC cams allow less compromise when doing so.

2) You are aware that a "pussy" H22 out of VTEC is pretty much identically strong as an F22 right? About the same torque, slightly better curve shape, and then when it hits ~5500 in stock tune, it does something that the F22 can't, right? So essentially you get an F22 with a huge top end kick.

Very true.
I know some vtec heads will cut power like on the F SERIES

[djcaz_aom]

Pussy mode? My H22 didn't come with that.
I bet if I managed to stay out of vtec, or in pussy mode as you call it, I would still stomp your f series.

And then a beautiful thing happens ...

The heavens are stirred, creatures silenced, as the roar of the motor opening up and vtec engages leaves you in awe.

Of course you speak of the h the way you do, as you don't own one.

Single cam vtec f series, was a sales pitch.

Dohc h series vtec, a thing of genius.

I still don't think you understand the whole vtec thing. It isn't a button you can push for a surge of power like the Knight rider car. You want that, get nitrous.

You can't have it all the time, because you will either give up top end or low end. Essentially a non-vtec motor.

So, don't concentrate on the finger or you'll miss all that heavenly glory.

[cbscandal]

Pussy mode? My H22 didn't come with that.
I bet if I managed to stay out of vtec, or in pussy mode as you call it, I would still stomp your f series.

And then a beautiful thing happens ...

The heavens are stirred, creatures silenced, as the roar of the motor opening up and vtec engages leaves you in awe.

Of course you speak of the h the way you do, as you don't own one.

Single cam vtec f series, was a sales pitch.

Dohc h series vtec, a thing of genius.

I still don't think you understand the whole vtec thing. It isn't a button you can push for a surge of power like the Knight rider car. You want that, get nitrous.

You can't have it all the time, because you will either give up top end or low end. Essentially a non-vtec motor.

So, don't concentrate on the finger or you'll miss all that heavenly glory.

Well said.

[deevergote]

Scott, thank you for chiming in here. I don't have the desire to type all this stuff out, and the idiotic things already said in this thread make me want to delete it.

In regards to the H and F series motors that are most commonly used in our cars:
VTEC is not essential. It does, however, provide two cam profiles in one. The powerband is widened considerably with VTEC as opposed to a cam with only one profile.
SOHC VTEC and DOHC VTEC differ. The SOHC VTEC engines only have VTEC (for the sake of simplicity) on the intake valves, and are not performance oriented. DOHC VTEC engines have secondary cam profiles on both the intake and exhaust cams.

Aside from the VTEC difference, the only real benefit to DOHC is being able to adjust the timing of the intake and exhaust valves separately with an adjustable cam gear. With a SOHC engine, you have to adjust both at the same time, the same amount, unless you get a new cam.
However, the SOHC engines, non-VTEC especially, have a much simpler and lighter valvetrain, which has benefits.





thepowderblue, please do some research before typing. I won't hesitate to ban you for spreading terrible information. If there was a switch in your car to have VTEC on all the time, the car would barely run under 4000 RPM.

[KB7]

I like a good flowing non vtec heads, All vtec does is put your car into pussy mode under so meany rpms. I want a good cam profile from the start!

this reminds me of a past thread