DOHC is not as good as it gets, quad cam is. As a general rule the more cams an engine has the more top end biased it is for hp and torque assuming similar engines and state of tune.

 

How about this, we just quit useing cams alltogather, instead we will use electric solenoids to operate the valves. the PCM could use various inputs such as RPM, engine knock, engine load, wheel spin, etc etc, to vary the valve timeing, of each cylinder individually, for optimum power in every situation. i`m not say`n ur gonna see it on a quad, but cars, hmmmmmmm.

 

well, lets see here, TOHC, well, there is a TOHC motor, but not for quads or passanger vehicles, some big rigs have a 3rd camshaft that opens and shuts the fuel injector...

 

...someone has been reading up on jaguars i see

 

I think your confused. A "quad cam" engine IS a DOHC motor, with two cylinder banks. (such as a DOHC V6 or DOHC V8)
Quad cam = 4 cams... yes, but not over EACH bank of cylinders. 4 total.

And as far as general rules, usually DOHC motors are tuned for higher peak HP, but have lower TQ down in the lower RPM ranges. This is why some people think that SOHC motors have more torque. Its not that they have more torque, It is that they are tuned for lower RPM torque to make up for their lack of high RPM capability, and higher RPM HP.

 

There are (or at least were at one time, I dont keep up on this well) engines that were labeled DOHC that contained 2 banks of cylinders and one cam over each.

And as far as general rules go, yours sounds awfully supporting of mine.

 

There is no general rule. Its how the engines are tuned. A DOHC Honda 4 cylinder makes very little torque down low compaired to the same SOHC 4 cylinder Honda.
(but much, much more high RPM HP, and a 1K RPM higher redline)

DOHC Ford V8's make loads of low RPM torque, as the GM 4.2 DOHC I6 does too.

The application is how the manufacturers determine where they want a motor to make power/torque. Theres no general rule.


Also, there was never a motor that was labeled DOHC that only had one cam per bank. That would be a SOHC motor. ONE camshaft PER HEAD.

Example: Toyotas 3VZE 3 litre V6. (88-95 4Runner V6 and pickup V6) A SOHC motor, 150Hp, 180 ft lbs of torque.
Toyotas 5VZ-FE 3.4 litre (96+ 4runner and tacoma) is a DOHC motor, 190HP and 220 ft lbs of torque. And the topper,
our 97 4Runner 4X4 with the 3.4 litre gets about 23 MPG on the highway with the AC on and has loads more power than the 3.0. (vs the 15-17MPG my old 3.0's got)

Im sure there is other technology there, but the fact that it is DOHC probably has something to do with it.

Maddog, try to think of the name of the car/maker that you remember the DOHC stamp was on.

 

I think I heard theyve been able to make these kind of motors for a long time, problem is making it usable in a car. One of the poblems I heard was that it snaps the valves shut too hard so it clacks.

 

oh, so it sounds like every 4 cylinder chrystler motor. hey, since i have a dodge stratus 4 cylinder, does that make me the man of the house? or do i need the v6?

 

another 400 cubic centimeters,fuel injection, better designed, oh and thats 240hp at the base