im more a 4 banger guy and i was lookin up on howstuffworks.com to just check out some v-8 stuff like the differences between DOHC v8’s like the northstar and regular pushrod engines, i knew internally what each was about, but the only thing the website said about advantages were gas mileages with the dohc and sohc, but not the pushrod
but power wise, why dont big name cars like the viper n vette or ford gt n such super cars besides euro cars use the overhead cams?
All you need is on the next line
LS1 > *
Ford GT is DOHC.
Corvette sticks to old school American Mentality = No replacement for dispalcement.
Pushrod motors are physically smaller and easier to package then their DOHC counterparts… so They can stuff a higher displacement motor in the same space in a Vette if its a pushrod.
Pushrod motors are cheaper to build too and they work well if the RPM’s are kept low.
Most serious race cars run OHC since its a better technology overall
my bad on the ford gt i just assumed, thanks for shedding sum light tho
Overhead cams allow for a better flowing head design.
That is the true advantage to overhead cams. Better flowing heads = more power.
DOHC is more complicated and thus more expensive. Though you can make any engine more expensive with the right parts.
its easier and cheaper to make an ohc pushrod 2v v10 and let the displacement make you power vs a quad cam 4v motor, less moving parts, less complex castings, no need for timing chain tensioners and a 293487ft long chain with multiple idlers blah blah blah. Thats why you still get great performance on these big displacement V8s/V10s with such an old design
Plus DOHC motors have more rolling mass, which makes the engine slower to spin down after revving up.
Whereas pushrod engines have less rolling mass which gives them a quicker response time.
Less mass to get moving.
so then the advantage of a sohc and dohc besides top end power and gas mileage is?..
poorly worded question. rephrase
When you are dealing with engines as large as the Vipers, moving to a DOHC would add a LOT of weight to the car, and move quite a bit of weight higher on the engine, going against the desired low-as-possible center of gravity. It is not possible to lower the Viper’s engine any more in the frame rails.
Packaging is also a MAJOR concern. The Viper’s 8.0-8.4L V-10 is not much larger than many engines half its displacement, and is light as hell for its size, allowing you to fit a gigantic engine under the hood without having to make the car bigger to accomodate it. The Viper engine, also being a 90 degree V-10, is quite wide. With the addition of DOHC, it would not fit in the current body, requiring the car be made at least 8 inches wider, adding yet again more weight. Another option would be changing to a 72 degree DOHC V-10, but the engine height then becomes an issue. All of these possibilities have actually been investegated by SRT.
As everyone else stated, simplicity. There is a reason that many quad cam super-cars are a pain in the ass, they have a ton of moving parts. Pushrod engines are bulletproof, and power the fastest cars on the planet.
HP/Liter is for wankers.
HORSEPOWER matters, who gives a shit how you get it if its usable.
when everything is said and done…euro’s use overhead cams to showcase their technology…and american’s use pushrods to avoid spending money on R&D and retooling their engine plants.
the arguement can go on all day long about which is better. you cant argue that the 4.3 liter high revving technological wonder in the ferrari f430 isnt a great v8 engine. and likewise you cant argue that the 7.0 liter monster shoehorned in the saleen s7 thats based on fords nascar powerplant isnt also a great v8 engine. both technologies have their benefits and their flaws. its all a matter of preference just like the whole import/domestic debate. i’m personally a fan of technology, but on the same token, nothing beats the sound of a large displacement pushrod v8.
Indeed. The 4.6L is actually smaller in displacement than a 302 (5.0L) but look at the size a DOHC head adds:
^^^Thats like GM’s 3400 and the older 3.4 Twin Dual Cam engine. The 3.4TDC engine took up the ENTIRE engine bay, no one liked working on that engine.
Also, food for thought…I remember reading a quote in a Hot Rod or similiar, that a GM guy…John Moss (I think) said, something along the lines of, “pushrod engines work, why mess with a good thing.”
Oddly enough the LS7 isn’t DOHC…Either is the LS6…or LS2…or LS1…
I guess you don’t need DOHC to make top end horse power… :lol:
The early 90’s ZR1 Corvettes with the LT5 were an DOHC motor 32 valve and it rocked!! one of the fastest motors ever produced. Why GM didnt stick with that technology IDK, maybe cost?
C5 Z06s are rated at 405hp, the Zr1s were rated at 375-405hp depending on year and anyone who knows the old zr1’s knows they were underrated. I saw a stock dyno of one that put down 430rwhp NA untouched.
Heres a vid, 2 old c4 91 Zr1 vettes vs c5 Z06 (incar) Top Speed run… GM DOHC > LS1, LS1 = cheaper 
http://video.google.com/videoplay?docid=-3851979797030873840&q=zr1+z06&total=57&start=0&num=10&so=0&type=search&plindex=3
i never really realized the size difference fuck
SOHC = simplicity, proven performance, performance/cost ratio high.
DOHC = more efficient or “better flowing” (BSFC), more mpg & emission “friendly” (generally), more options for OEM tuning (power band, emissions, vtec/vvt, etc)
even though the motor is pretty much useless now gm has developed some sort of variable valve system for their 3.9l pushrod v6