Printable View
loving this! my voice might get a bit sore from always shoutingQuote:
Originally Posted by aaronng
http://www.geocities.com/tyrome87/vtec.jpg
nice work aarong.. i was wondering why there wasnt a big vtec kick during full bore acceleration... now i know why.. its always on, yo!
no cams r better :) but if u must... DOHCs r "better" not because u can have wilder cam profiles or durations... because u can have the same in sohc engines... u could even have an extremely wild cam in a buried motor "pushrods" fastest drag cars in the world use 1 cam :P and make 7000hp+ but for street and tunability and probably cost.. dohc is the way to go.. oh and btw.. they dont rev harder.. thats the dumbest thing ive ever heard
For low rev applications, SOHC is more efficient because of lower valvetrain resistance (only 1 cam rotating). But at high rev of above 6000rpm, the larger mass of the valve rocker arms have too high an inertia requiring much stronger valve springs to compensate. Rocker arms used in DOHC engines are much smaller as the cam sits directly on top of the valve, so there is less inertia and it is more reliable at high RPM.Quote:
Originally Posted by Silver_EH
The reason why everyone says DOHC for wilder cam profiles is because when you use wilder cams, you need a higher RPM limit to take advantage of pushing the peak torque up higher in the RPM range. DOHC for high RPM reliability :thumbsup:
so basically sohc low end power and dohc lil low end power but lotsa high end power
no his wrong in both aspects... both cams can be used for either application
u can rev the shit outta any car, doesnt matter how many cams it has. like i said earlier under my fiances nick... the fastest, most powerful cars arent twin cams.. they use 1 cam... and the rev to 10k+ and make 7000hp+ :)
sure twin cams make things easier and possibly more efficent but rev harder and wilder cams r just a myth... btw do u work on cars aarronng?? as a profession???
god damn...when did you learn all that stuff aaronng???
Be an engineer and all things mechanical are interesting.
i too am an engineer.. mechanical engineer @ that and im also an automotive technician :) Neither cam will rev harder than the other or make more power as a total if money is put into it. the thread was meant to be which vtec is better... sohc or dohc.. in the case of a honda dohc is better because it makes more power and revs higher but not because it has an extra cam, but because the head itself flows more air. the cam also has a higher lift and duration than its sohc counter part. The bottom end is also better balanced and has stronger internals than the sohc which allow it to rev higher. depending on how much money u spend on a design, in almost any case.. a DOHC head will flow more than a SOHC head. In almost all cases also, a SOHC will not make more power than a twin down low either. In any case... having no cams at all r even better from a mechanical loss point of veiw ;) lol