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Intake manifold mania - what really works?

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  • Intake manifold mania - what really works?

    The Feb'08 HR had an interesting test of the RPM Air Gap, Vic Jr, and Super Vic small block chevy intakes. Although the jist of the conclusion was porting your manifold can get you 13-14hp on a 600hp sbc, I was pretty surprised by how well the RPM AG did.

    My brother and I have been running the same drivetrain combo (427 sbc + TH400), with the main differences being he's 300lbs lighter, has a Vic Jr (I got an RPM AG), a down-leg 750 Speed Demon double-pumper (I got a 750 annular vacuum secondary SD), 210 AFRs (I got 210 Eliminators), and his cam is 110 LSA (I'm 112 - 3318/3319 CC lobes). My best track run (w/o N2O) was 11.8 at 114, but I easily lost 0.3-0.4sec in my crappy 2.2sec 60'. My brother has run 11.0 at 120mph (w/o N2O). I was thinking the lost 6mph could be due to the intakes, but the HR article suggests it wouldn't be worth it below 6500.

    The thing in the article that surprised me was how much cfm the air gap gained when run with the heads (it flowed more than the Vic Jr). I was a little confused why the ported version only picked up 16cfm with the heads, when it gained 75 cfm w/o heads.

    Does anyone think there would be a noticable improvement switching from an RPM AG to a single plane in a car that doesn't go over 6500rpm? Think porting the intake is worth it?
    Tampa, FL

  • #2

    Re: Intake manifold mania - what really works?

    Re: Intake manifold mania - what really works?

    Swap your 750vac for his 750dp.
    Not saying it's worth 6mph, but the better pump-shot will help you out of the hole because it will cover more throttle position.
    And because mechanical secondaries open when you say so, they expose your engine to denser atmospheric pressure that you can add more fuel to, unlike vacs that keep it in a vacuum.

    Comment


    • #3

      Re: Intake manifold mania - what really works?

      Re: Intake manifold mania - what really works?

      Im giving a professional products intake a whirl on mine,Looks very similar to the super victor edelbrock.

      Comment


      • #4

        Re: Intake manifold mania - what really works?

        Re: Intake manifold mania - what really works?

        Im giving a professional products intake a whirl on mine,Looks very similar to the super victor edelbrock.
        I'm very impressed with the one I had, a very clean casting and the carb to runner transfer area appears to be much better.

        Comment


        • #5

          Re: Intake manifold mania - what really works?

          Re: Intake manifold mania - what really works?

          Yeah, but they're made in damn China.
          The Edelbrock product employs your country-men.

          Comment


          • #6

            Re: Intake manifold mania - what really works?

            Re: Intake manifold mania - what really works?

            Yeah, but they're made in damn China.
            The Edelbrock product employs your country-men.
            I would not run a PP product simply for that reason alone, I'd much prefer a used Edelbrock to a brand spankin new PP copycat product. Just MHO, 8)

            Comment


            • #7

              Re: Intake manifold mania - what really works?

              Re: Intake manifold mania - what really works?

              The PP manifolds out of the box have made more power which is why I use it, Edelbrock needs to step up The new super Hurricane for large Cubed small blocks is way ahead now
              2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
              First to run in the .90s .80s and .70's in SBN/A
              2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
              2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

              Comment


              • #8

                Re: Intake manifold mania - what really works?

                Re: Intake manifold mania - what really works?

                Be that as it may, I'd still happily sacrifice a few ponies (and dollars) for the Yank.

                Comment


                • #9

                  Re: Intake manifold mania - what really works?

                  Re: Intake manifold mania - what really works?

                  Be that as it may, I'd still happily sacrifice a few ponies (and dollars) for the Yank.
                  We're in trouble if the only one who cares about US-made is the Aussie!!!

                  Back to the topic, if I was to switch to a dp, any suggestions for how big and what type of boosters (lower cfm downleg vs higher cfm annular)? I've been looking at the Mighty Demons and might be able to get a deal on an 850 (w/ downlegs), but I thought this might be a bit too big.
                  Tampa, FL

                  Comment


                  • #10

                    Re: Intake manifold mania - what really works?

                    Re: Intake manifold mania - what really works?

                    He's definitely not the only one, for shure.

                    Comment


                    • #11

                      Re: Intake manifold mania - what really works?

                      Re: Intake manifold mania - what really works?

                      Mark, you need one THIS BIG! :P


                      Personally, I prefer annular discharge because they begin to flow at a (numerically) lower vacuum than a down-leg. In other words, they're more responsive. This also means if you slightly over-carb the engine, an annular booster will help it work.
                      It's also said that annular boosters are capable of atomizing more fuel than down-leg. Then there are some that disagree and swear by down-leg. It's your choice but I'm suggesting the annular type.

                      I'd tend to think that an 850cfm would suit your engine size and rpm. Go to Holley.com and use their calculator to see what they suggest.
                      The Holley HP (830, 80511-1) is a good carb. I have the HP 1000 annular and it is so sensitive to changes, reliable and consistant too. I love it!

                      Try your brother's dp first before you spend the cash!

                      Comment


                      • #12

                        Re: Intake manifold mania - what really works?

                        Re: Intake manifold mania - what really works?

                        Im giving a professional products intake a whirl on mine,Looks very similar to the super victor edelbrock.
                        I'm very impressed with the one I had, a very clean casting and the carb to runner transfer area appears to be much better.
                        Thats exactly why i purchased it there was no comparison on casting compared to the edelbrock and weiand .

                        The weiand even had the ports cast in crooked.

                        Comment


                        • #13

                          Re: Intake manifold mania - what really works?

                          Re: Intake manifold mania - what really works?

                          Mark, you need one THIS BIG! :P


                          Try your brother's dp first before you spend the cash!
                          Steve - Do you have an intake for that carb? I might need to make a hole in the hood to make it fit.

                          My brother is in Chicago and I'm in FL, but since he's buried in snow I might be able to con him to send me his. Meanwhile, I ran a vacuum gauge from the engine into the car and did some WOT runs and I think it got below 3", but I had a hard time focusing on the gauge and traffic at the same time. While I'm waiting, maybe I'll try to temporarily mount the gauge by my windshield to get a better reading.
                          Tampa, FL

                          Comment


                          • #14

                            Re: Intake manifold mania - what really works?

                            Re: Intake manifold mania - what really works?

                            There may be very little difference in vacuum readings between a 750vac and an 830dp at WOT for example. However, the additional airflow and performance from 1 or 2 in/Hg might be significant.
                            In other words, you may not reveal much with the gauge.

                            I used the Holley calculator and it didn't suggest anything below 830cfm for your engine. I obviously had to guess a few details, but you try it and see what it says.
                            http://www.holley.com/applications/C...bSelection.asp

                            Comment


                            • #15

                              Re: Intake manifold mania - what really works?

                              Re: Intake manifold mania - what really works?

                              The best Carb I have owned to date was a Quick Fuel 950

                              2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                              First to run in the .90s .80s and .70's in SBN/A
                              2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                              2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

                              Comment

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