Announcement

Collapse
No announcement yet.

VERY in depth article about why 4 valves ARE better!

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • VERY in depth article about why 4 valves ARE better!

    Now I know that most of us here run SOHC myself included. I love my engine. BUT I am no fool to assume that four valves are no more superior than two. The following article is a very good write up of WHY four valves are superior to two valves. It even touches on five valve heads a little bit. It is very long so if you are not truely interested or dont really care to learn the truth then dont even bother.

    http://www.billzilla.org/2v4v.htm#friction
    85 Z31 6.0 LSX turbo 766whp/792wtq
    04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

  • #2
    I can't say that I've ever been in a multi-cammed car that had sack off the line like a 2v does (z32 included). It seems that they all come in and make power at higher revs.
    vg33et -blew some chunks outta it, then gave it all away.
    2009 370z touring/nav/sports

    Comment


    • #3
      Driven a 4v cobra mustang and many 2v Gt Mustangs...I have to say the biggest differ is the sounds. 4v's sound a bit meaner and yeild more upper end horsepower...yet I've always felt the greater torque came from the single overhead 2v's.

      Basically, it's all in preferece to me. I enjoy the old 2v 5.0's rather than the 4.6 liter cobra 4v's. With Nissan's I couldn't say, but I could assume the same outcome.
      2008 BMW E92 335i 6MT

      Comment


      • #4
        The article was not meant to say what the preference was. It was meant to prove WHY 4 valve is superior than 2 valve.

        This is examples of performance oriented engines but, thats what we are here at z31PERFORMANCE.com
        85 Z31 6.0 LSX turbo 766whp/792wtq
        04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

        Comment


        • #5
          grahfz wrote: I can't say that I've ever been in a multi-cammed car that had sack off the line like a 2v does (z32 included). It seems that they all come in and make power at higher revs.
          This is exactly the point. Are you going to spend your entire z31 project redlining at 6k or do you want I high reving high horspower monster?

          Torque is good but it will only get you so far. 5252rpm's to be exact LOL
          85 Z31 6.0 LSX turbo 766whp/792wtq
          04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

          Comment


          • #6
            Signal 12 wrote: Driven a 4v cobra mustang and many 2v Gt Mustangs...I have to say the biggest differ is the sounds. 4v's sound a bit meaner and yeild more upper end horsepower...yet I've always felt the greater torque came from the single overhead 2v's.

            Basically, it's all in preferece to me. I enjoy the old 2v 5.0's rather than the 4.6 liter cobra 4v's. With Nissan's I couldn't say, but I could assume the same outcome.
            The cobra's actually have a butterfly valve in the intake that closes off a tract at low rpm's.. my roomie has one, and we had to replace the motor .. spun a rod bearing. Exact same engine out of a lincoln mark 8, if you ever need one..

            Overall, for supposing to have '300hp', it's not fast.. the 5.0's feel FAR faster, and they're dirt cheap to make badddd :twisted:
            vg33et -blew some chunks outta it, then gave it all away.
            2009 370z touring/nav/sports

            Comment


            • #7
              [quote]SATAN wrote:
              Originally posted by grahfz
              I can't say that I've ever been in a multi-cammed car that had sack off the line like a 2v does (z32 included). It seems that they all come in and make power at higher revs.
              This is exactly the point. Are you going to spend your entire z31 project redlining at 6k or do you want I high reving high horspower monster?

              Torque is good but it will only get you so far. 5252rpm's to be exact LOL
              I'm all about the torque, I view hp as just another way of saying "torque @ RPM" because that's all it is anyways.
              vg33et -blew some chunks outta it, then gave it all away.
              2009 370z touring/nav/sports

              Comment


              • #8
                [quote]grahfz wrote: [quote=SATAN]
                Originally posted by grahfz
                I can't say that I've ever been in a multi-cammed car that had sack off the line like a 2v does (z32 included). It seems that they all come in and make power at higher revs.
                This is exactly the point. Are you going to spend your entire z31 project redlining at 6k or do you want I high reving high horspower monster?

                Torque is good but it will only get you so far. 5252rpm's to be exact LOL
                I'm all about the torque, I view hp as just another way of saying "torque @ RPM" because that's all it is anyways.
                Dammit man! did you even read the article? :shock: Torque is good yeah but.... read the damn article!
                85 Z31 6.0 LSX turbo 766whp/792wtq
                04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                Comment


                • #9
                  for one motor to be superior to another, they have to compare to each other.

                  example. why are top fuel and pro mod drag racing cars not using multi valve heads? 16 seems fine to them, to 5000hp or so
                  Nearly all men can stand adversity, but if you want to test a mans character make him a moderator.

                  Comment


                  • #10
                    I did read it, it's just that I like 2v motors..

                    if I had gearing that dropped me more than 1500-2000rpm, than I'd be worried about it.
                    vg33et -blew some chunks outta it, then gave it all away.
                    2009 370z touring/nav/sports

                    Comment


                    • #11
                      aceman wrote: for one motor to be superior to another, they have to compare to each other.

                      example. why are top fuel and pro mod drag racing cars not using multi valve heads? 16 seems fine to them, to 5000hp or so
                      You mean compare like the vg30E to the VG30DE? hmm which one makes more power with the SAME DAMN BLOCK.
                      Uh, maybe because nobody make at one million liter 32 valve engine? :shock: Now just imagine what they could make in power if they could rev higher and have more flow.

                      BAH nevermind I'm wasting my time on ignorance. This is an example of why people piss me off. They refuse to learn.

                      I supply FACTS
                      and people ignore them and say things like "what about pro mod drag racing cars... seems fine to them...." Why dont more F cars run 2 valves then? because they understand the advantages.
                      85 Z31 6.0 LSX turbo 766whp/792wtq
                      04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                      Comment


                      • #12
                        I thought the writeup made some good points. Friction wise there is no doubt an advantage to four valves per cylinder. Another would be lower valve mass reducing valve float at higher rpms. But I was surprise by the low rpm gains in torque though. I imagine some portion of the power increase is a result of being a newer designed/better flowing head even if it only had two valves. Good find. (gotta give the Devil his due) :wink:
                        86 Turbo

                        Comment


                        • #13
                          just so we seperate the sohc/dohc from the 2/4 valve argument, you can have more than two valves per cylinder with 1 camshaft...

                          Comment


                          • #14
                            This guy is right on base with most of his information as I have read it so far. Thanks for the link. I need more time to actually read and digest the whole thing before commenting though.

                            Comment


                            • #15
                              G-E wrote: just so we seperate the sohc/dohc from the 2/4 valve argument, you can have more than two valves per cylinder with 1 camshaft...
                              I suppose you could, but what engine has 4 valves with one cam? I dont think I know of one. Which example are you speaking of?

                              Generally the two go hand in hand tho. :?
                              85 Z31 6.0 LSX turbo 766whp/792wtq
                              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                              Comment

                              Working...
                              X