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Can you get high compression rods?

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    #1

    Can you get high compression rods?

    I.e....if I wanted to bump up my compression w/o changing pistons, could I just get H22 OEM rods and put them on the stock pistons?

    *EDIT* Yes, by George, I can: http://www.honda-tech.com/zerothread?id=1482111
    Last edited by gloryaccordy; 02-26-2006, 05:23 PM.


    Originally posted by lordoja
    im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral
    Tags: None
    #2
    you dont need to change your rods. with bumping your hp by compression, your rods wont be the weak link. just make sure your rings and pistons are good for our stock sleeves and make sure you install a new oil pump!
    To have loved and lost is better than to have never loved at all #CB7Life

    Comment

      #3
      Originally posted by SoySauceCb7
      you dont need to change your rods. with bumping your hp by compression, your rods wont be the weak link. just make sure your rings and pistons are good for our stock sleeves and make sure you install a new oil pump!
      I meant as an alternative to buying new pistons and having the sleeves machined.

      Rod lengths:
      H22A = 5.633 (143.0782mm)
      H23A = 5.572 (141.5288mm)
      H23A1 = 5.572 (141.5288mm)
      F22 = 5.572 (141.5288mm)

      Hmm... .155cm of cylinder height is pretty significant...if you multiply that by the area of the piston face (56.75cm^2 * .155cm), that's 8.8cm^2 more piston coming into the combustion chamber. Considering that the combustion chamber is only 62.5cm^3, that's a huge difference. 550/53.7= 10.24, which means switching to H22 rods with stock pistons would bring you up to 10.24:1 compression, which is PRETTY FLIPPIN AWESOME if you ask me. Stock H22 rods go for ~$400...get some new rod bearings and get the pins pressed and you're looking at $500-600 for higher compression, better geometry and all in all MORE POWER!!!! Dammit I'm a flippin genius!!!
      Last edited by gloryaccordy; 02-26-2006, 06:10 PM.


      Originally posted by lordoja
      im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

      Comment

        #4
        hmmm . . . interesting. I wonder if F23 rods are somewhere in the middle . . . that could be a nice medium ground if someone wanted a low boost turbo setup as well.
        -Mark-
        CB7
        CD5


        And if i could swim I'd swim out to you in the ocean
        Swim out to where you were floating in the dark.

        Comment

          #5
          F23 rods have different bearing sizes. If you could snag some H23 rods that would work too...RaceEng has some for sale for $699 a set.


          Originally posted by lordoja
          im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

          Comment

            #6
            I think for this question you'll have to show your work.

            Cylinder volume at BTC before and after rod change?
            Cylinder volume at TDC before and after rod change?
            2003 Maxima SE Titanium Edition
            Polished Titanium ext, heated black leather int, heated leather steering wheel, HIDs, 255bhp, 6 speed, 15% tint.
            1993 Suzuki GSX1100F 136bhp

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              #7
              I think piston speeds might change with the new rods ever so slightly, but the rhyme and reason behind this is the fact that with the new rods the piston is occupying 1.55mm of combustion chamber space that it wouldn't be with the old rod. Regardless of anything, at TDC with the H22 rods the piston occupies 8.8cm^3 more space within the combustion chamber than it did before.

              I'd really have to look into engine dynamics and all that to get a more accurate answer, but just going on static compression specs that's the number I came up with.

              Here's what I did again, quickly:

              H22 rod length- F22 rod length= 143.0782mm - 141.5288mm= 1.55mm->.155cm
              F22 piston area= pi*8.5cm^2/4= 56.75cm^2
              Additional height*piston area (aka the additional space the new piston takes up)= .155cm*56.75cm^2= 8.795cm^3
              Orig. FULL combustion chamber size: (2156cc/4)/8.8= 61.25cc
              NEW combustion chamber size: 61.25-8.795= 52.455cc
              NEW compression ratio: (2156cc/4)/52.455= 10.27:1 <----mad H22ish son!!!

              This takes into account the old piston's wrist pin height and everything. Literally, the new rod is pushing the piston further into the head further than the old one. I'll admit I'm unsure of the effects the new rod length will have at operational speeds, but I'm 99% this is the right calculation for the static compression ratio. Just a heads up for everybody.


              Originally posted by lordoja
              im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

              Comment

                #8
                yo gloryaccordy i thought u were going turbo?

                Old Ride-New Ride

                Comment

                  #9
                  ask hondafan
                  Shift_BOOST

                  BOOM!

                  Comment

                    #10
                    Originally posted by Mike
                    yo gloryaccordy i thought u were going turbo?
                    I'm going back and forth with it...I dunno what I wanna do. It'll cost the same either way, but I really like all-motor vs. turboing. Turboing is a lot easier though. I was turned off the all-motor thing when I learned that I'd have to get my bores honed for high compression pistons, but this new discovery has kind of brought me back. 170whp is the goal...and it's definitely doable all-motor...

                    Actually now that I think about it, H22 rods+Delta cam+OBX I/H/E would definitely be less than a legit turbo kit (turbo+manifold+intercooler+piping+tune) and be a hell of a lot safer, especially in the summer. I plan on selling the car this summer anyway though so it doesn't really matter, even if I get the 6th gen I plan on getting...
                    Last edited by gloryaccordy; 02-26-2006, 09:02 PM.


                    Originally posted by lordoja
                    im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

                    Comment

                      #11
                      I'm going to post this without reading and then I'll go read and I'll edit if need be. If you change your rod length to a longer rod, you're just putting your piston closer to the cylinder head on BDC also. So explain to me how your're compressing more air. True the piston is closer at the top of the throw, but it's that very same distance further, down low. It just moves the stroke, it doesn't change its value.

                      Now think of it this way. In theory, shouldn't you be able to change rod length the exact distance you can safely mill your head? Can you mill your head that far? No. I would guess that it would hit your head, and by a good bit.
                      Last edited by Jarrett; 02-26-2006, 09:53 PM.
                      My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!

                      Comment

                        #12
                        Originally posted by Jarrett
                        I'm going to post this without reading and then I'll go read and I'll edit if need be. If you change your rod length to a longer rod, you're just putting your piston closer to the cylinder head on BDC also. So explain to me how your're compressing more air. True the piston is closer at the top of the throw, but it's that very same distance further, down low. It just moves the stroke, it doesn't change its value.

                        Now think of it this way. In theory, shouldn't you be able to change rod length the exact distance you can safely mill your head? Can you mill your head that far? No. I would guess that it would hit your head, and by a good bit.
                        If you get high compression pistons, isn't it exactly the same thing? The only thing that worries me is that the piston isn't domed...that+ valve clearance with higher lift cams makes me bite my nails.

                        But whether you get high compression pistons or change the rods, they both end up providing the same effect- taking up more space in the combustion chamber (the space above the piston at TDC). The ratio of the SWEPT volume (the space the piston covers from TDC to BDC) to the space above the piston at TDC= your compression ratio...changing the rod has nothing to do with the displacement.


                        Originally posted by lordoja
                        im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

                        Comment

                          #13
                          A high compression piston doesn't do it with height but with dome volume. It's in the center of the piston as far away from the valve angle as possible. I didn't make a comment about displacement. You might be right but I don't think your going to have accurate volumes without measuring it actually installed. I still think it's going to hit the cylinder head. I guess there's only one way to know.
                          My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!

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                            #14
                            it would be easier to just shave the head a little. later.
                            Avoiding dirt at all costs

                            Comment

                              #15
                              Yeah, 0.05 off and you're set.
                              My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!

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