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I'm new to this forum thing but this has been bothering me for quite some time now.. as we all know (for those of you who actually take time to look under your hood) we 7th gen's have SOHC D17A motors.
Single OverHead Cams.
Now as opposed to hearing about many DOHCs around there...can anyone say B series..
what is the difference between SOHC and DOHC.. disadvantages? advantages? i need help.. thanks
well, just to warn you, you sort of came off as having an attitude, which is prob gonna get you some undesired responses. I cant help you out too much except to send you to www.howstuffworks.com and read about the engines and dual cams and single cams, that may help you more than anything else
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dohc's in the long run will be able to rev higher due to the fact that their rocker arms, and valve train have shorter parts. in a dohc setup, generally one cam is for the intake side, and the other for the exhaust side. (meaning the intake valves and exhaust valves)
so obviously in the case of two is better than one, dohc and sohc are no exception.
there's a ****-ton more detail you can go into on it, but howstuffworks.com will give you a good rundown as well.
Not only that, but when you come in with an attitude, you should at least get all of your facts straight. "Single OverHead Cams" -> WTF?? Single indicates ONE overhead CAM.
thats why its called SOHC. and i wasnt copping an attitude.. sorry if thats how you received it but thats not how i meant it to be.. anyways thanks.. ill check the site
yep + in the case of cars with VTEC both the intake and the exhaust valve performance in maximized with the DOHC. Were with the SOHC only the intake valve performance is maximized. This creates a VTEC that is a hell of alot more noticeable.
The only advantage that I know of on a SOHC engine over a DOHC one is less moving parts.
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sohc- is less rotationing mass, which means your would be able to make it so that this engine design to be able to make very high rpm's with the right amount of tuning. single cam engines have been some of the most powerful its just takes money.
dohc- has more potential to make power there for its most likely the better choice. the problem with dohc designs is that there is more rotating mass involved so it takes more power to make those parts move, also there is double the chance that something may break because there is 2 of them instead of one. but overall this is the better choice because of honda's setup with their dohc designs you are able to change the the advance/ retardation of the cams as stated earlier.
I'm new to this forum thing but this has been bothering me for quite some time now.. as we all know (for those of you who actually take time to look under your hood) we 7th gen's have SOHC D17A motors.
Single OverHead Cams.
Now as opposed to hearing about many DOHCs around there...can anyone say B series..
what is the difference between SOHC and DOHC.. disadvantages? advantages? i need help.. thanks
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sohc- is less rotationing mass, which means your would be able to make it so that this engine design to be able to make very high rpm's with the right amount of tuning.
just to point out.
yes less rotating mass, since there is only one cam, rather than two.
however, they are NOT as good for high rpms as a dohc.
due to the fact that the cam rocker arms, etc, must do BOTH intake and exhaust valves, they are longer and do not do well at higher rpm.
To hell with all SOHC, DOHC, pushrods, rocker arms, lifters......Rotary is infinitely more effecient and simple. If my memory serves me correctly, I belive a standard wankel rotary only has some 3-4 moving parts where a standard V6 has around 200. It's too bad though most companies don't think outside the box and can realize the benifits of such an engine.
To hell with all SOHC, DOHC, pushrods, rocker arms, lifters......Rotary is infinitely more effecient and simple. If my memory serves me correctly, I belive a standard wankel rotary only has some 3-4 moving parts where a standard V6 has around 200. It's too bad though most companies don't think outside the box and can realize the benifits of such an engine.
Let me clarify.
1.0-1.3L rotaries have 3 moving parts. Two rotors and an eccentric shaft (similar to a crankshaft.) The 20B (2.0 L) has 4. Three rotors and the eccentric shaft.
The main reason why other companies don't use them is because in the beginning, they gave up early. In the late 60's Chevy experimented with the idea of a rotary Corvette, but ditched the idea. They couldn't make it work. The engineer at Mazda (sorry I really don't know his name) who still designs rotaries today, was under the direct tutelage of Dr. Felix Wankel...the Father and inventor of rotaries, a German engineer.
The reason why the other companies don't use them now, is because Mazda has copyrighted much of the progress they've made in rotary development. Plus the fact that Mazda has established a niche with a rotary market, and it would be very hard to compete.
yep + in the case of cars with VTEC both the intake and the exhaust valve performance in maximized with the DOHC. Were with the SOHC only the intake valve performance is maximized. This creates a VTEC that is a hell of alot more noticeable. 
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