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Did some bench work yesterday....

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  • Did some bench work yesterday....

    Guy has a bench that draws into a clear chamber so you can inject 'smoke' and see how your intake combo works. (Something developed by Tom Hoover - father of the Hemi (some may recall him) - he lives a mile or so away and is friends with the shop owner...)

    anyways. G2 *AND* G3 intake/head combos suck for making top end power. (sorry, I know its heresey - but read on as to why)

    the problem in a nutshell is the air does not get 'turned around'

    Consider if you will the splayed valve combustion chamber - something with no changes (other than volume) G2-G3. incoming air is essentially straight and when it dumps in the intake port (which is in itself a nice hyper straight shot) the ridge on the plug side shrouds the valve, builds a high pressure zone and forces the air to 'corkscrew' into the cylinder. This is good, but the air has almost no movement getting to the intake port.

    Some might remember an intake developed in the late 60's by offenhauser called the '360' degree intake - it caused the air in the intake to swirl before it hit the intake port runner of the head - raising flow. To visualize - consider a funnel - if you pour water in the funnel, it drains faster if you pour at an angle that lets it corkscrew in vs just overloading it.

    At any rate these intake designs have been copied for the v8 land ad nauseum and of course got copied onto chevy and buick 90* V6s using carbs and TBI. For EFI, the L98 TPI was GMs first stab, ford had one for the Cobra R, dodge came up with one for the magnum. No such animal exists for the 660 motors, the G3 intakes, although improved and symmetrical vs G2, are about as tuned port as my butt. (and that upper plenum still sucks - GM would do well to steal the design off the Buick C, N and L code motors)

    And as a funsie, we tried a 4bbl edelbrock mani for the G1 and a holly 390 4bbl[1] with the throttles tied wide open - and it does what is required (which leads one to the logical conclusion that the guys in midget who build intakes and use carbs on g1,2,3 engines are on to something - they regularly circle with 300hp.

    We conducted these tests with valves installed (to do otherwise would be meaningless) we ran at .100, .200, .300, .400 and .500 lifts[2][3] (which is considered max 660 lift in most cases). On stock heads/intakes (no porting was done, they came right off motors from the bin) by .400 lift the combos were running out of steam at 28", they shined .200-.400 and we didnt conduct the test with more granularity - which confirms what I have already seen on paper - a flat ass torque curve - of course the exh performed far worse but consider, it was not heated.

    At any rate, stay tuned. Due to a previous 'discussion' on another board I am undertaking a race car project - two actually. My goal is to build a TGP and a T code as high as I can get em, the TGP of course a W body and the T code in a J or N body. I was trying to get base flow numbers before I cracked open the grinder case. In all cases I am trying to keep the EFI. Having Tom aware of this will be a boon, he did a lot of the pioneering work for AFR and should be able to guide me -these race cars will not be pollution legal or most likely streetable - with a 7000rpm redline using milled 'pink' v8 rods and the proper comp cam, it wont idle, run brakes, AC etc

    ----------------------------------------------------------------------------------
    Notes:

    1: the 390 sounds tiny, but for a 3L engine, its more than proper, in some classes, 390cfm is the max carb allowed as is 9.5:1 comp ratio and these guys are north of 700hp with basically 350 cube motors. a 390 will be more than adequate for a carb setup

    2: the guy has a tool that screws onto the stud and you adjust a wheel that pushes against the opposite side of the head and opens the valve. You just measure how much you depressed it.

    3: at .500 the heads have some serious coil bind[4]....it cant be done, you need to machine the heads to have a pocket to take roughly a 1.38ish spring - but u should get over .550 lift if you do such, there appears to be room.

    4: we removed the stock valve spring and installed a spring from a ford AOD tranny 4th gear servo lol. Neccessity is the mother of invention.
    QuadDriver.....
    go fast...run over sh....stuff

  • #2
    I need a setup like that, to push down the valve. How much to make it? I have a flowbench, have the shrouding and piping and all, but still need the mounting plate and the valve opening apparatus. I can setup the dial indicator to measure valve lift.
    Ben
    60DegreeV6.com
    WOT-Tech.com

    Comment


    • #3
      LOL, this is why I will be building my own intake for my next project, well for other reasons too.

      Which genIII intake did you test? the "small port" early 3100, or the later "large port" 3100/3400 intake? Also what heads were used for this test?

      Comment


      • #4
        Originally posted by SappySE107
        I need a setup like that, to push down the valve. How much to make it? I have a flowbench, have the shrouding and piping and all, but still need the mounting plate and the valve opening apparatus. I can setup the dial indicator to measure valve lift.
        its a homemade device....let me try to explain how it looks....

        start with a rocker arm . any style, this one is stamped steel 1.5 ratio, install it over the stud, the regular tip over the valve stem. Then there is a 'bolt' with a large flat end that wont go in the pushrod hole, onto the bolt goes a threaded sleeve with the tip of a pushrod welded on. maximum travel is perhaps .5 inch, but with the 1.5 rocker, gives .750 lift at the valve. use an offset starter wrench to turn the hex sides of the threaded sleeve - I think I have seen these in the hardware section of a home depot...in those little plastic drawers if you know what I mean.
        QuadDriver.....
        go fast...run over sh....stuff

        Comment


        • #5
          Originally posted by The_Raven
          LOL, this is why I will be building my own intake for my next project, well for other reasons too.

          Which genIII intake did you test? the "small port" early 3100, or the later "large port" 3100/3400 intake? Also what heads were used for this test?
          the Tcode was from a 92 corsica that is in for a cracked head, dont remember the cast number but the replacement they got from the heap had the same cast. stock 3.1 intake.

          the 3100 head/intake is from a 99? 00? malibu sfi 3100

          the g1 was a 2.8L head from a 80s model s10 (lets say 85 for grins) - edelbrock intake he had for a 2.8 and a carb from another motor on a stand (borrow job)

          his flow aparatus allows you to bolt the head with a seal onto a plate with a clear lexan? 'cylinder' - he has various sizes from appx 3.5" up to whatever is ina DRCE. The smoke is generated from a thing that drips oil onto a hot set of wires - like a fog machine.
          QuadDriver.....
          go fast...run over sh....stuff

          Comment


          • #6
            interesting...
            Colin
            92 Sunbird GT, 3200 Hybrid 13.99@ 95.22 (2004)
            90 Eagle Talon TSi AWD 10.54 @ 129mph.

            Comment


            • #7
              So what are your plans for improving the flow? I am hoping you are heading towards modifying the combustion chamber to unshroud the intake valve (This is what I did on my G3 heads when I ported them). Also, do you have flow numbers for all 3 gens of heads? I have seen the G2 and G3 numbers, but I would like to compare them to the G1 flows. Interesting stuff.

              Marty
              '99 Z-28 - Weekend Driver
              '98 Dodge Neon - Winter Beater
              '84 X-11 - Time and Money Pit
              '88 Fiero Formula - Bone stock for now

              Quote of the week:
              Originally posted by Aaron
              This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

              Comment


              • #8
                Originally posted by RacerX11
                So what are your plans for improving the flow? I am hoping you are heading towards modifying the combustion chamber to unshroud the intake valve (This is what I did on my G3 heads when I ported them). Also, do you have flow numbers for all 3 gens of heads? I have seen the G2 and G3 numbers, but I would like to compare them to the G1 flows. Interesting stuff.

                Marty
                the problem with the shroud around the intake is if I remove that, besides opening up a small chamber to a significant increase in size (thereby lowering compression a lot) is I lose the 'swirl port' attributes....without coming up for something on the intake side, Im up in the air right now....right now the target is to get a g2 intake to turn the air over as it flows.

                I didnt copy the flow numbers at this time....it was just exploratory to see the diff between all 3 'models', once I select the combo I will go with Ill take exacting measurements and record the data at each step. Ill probably write a webpage detailing everyting that goes on...stay tuned to this channel!

                ps - did this board change? it appears different to me
                QuadDriver.....
                go fast...run over sh....stuff

                Comment


                • #9
                  I thought about that too, but decided to unshroud them anyway. All the pictures I have seen of fully race ported gen2/3 heads have the shrouding removed, so I figured they knew something.

                  Marty
                  '99 Z-28 - Weekend Driver
                  '98 Dodge Neon - Winter Beater
                  '84 X-11 - Time and Money Pit
                  '88 Fiero Formula - Bone stock for now

                  Quote of the week:
                  Originally posted by Aaron
                  This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                  Comment


                  • #10
                    Marty, would you mind sending me those pics of the heads you mention?

                    QuadDriver; yes the board changed.

                    Ok, to clear up with the genIII parts... Did the upper intake have "ribs" with the wording "3100 SFI V6" on the top, or just writting, as in "3100 SFI"?

                    Comment


                    • #11
                      Originally posted by RacerX11
                      I thought about that too, but decided to unshroud them anyway. All the pictures I have seen of fully race ported gen2/3 heads have the shrouding removed, so I figured they knew something.

                      Marty
                      the thing is, you are correct....the v8 guys (myself included) will tell you that swirl ports make good torque - but restrict ultimate flow at high rpms - if you hung around the 80's when the 'transmaro' was big, the original 4bbl and efi motors used the swirl port heads on the 305s, but the L98 TPI option changed that later.

                      So when you cut up the head, you improve gross high end flow, but without a decent intake - you are screwed as to actually getting air to the ports. I was like you, I would smooth the hell out of the runners and unshroud valves and use larger valves - but I was not seeing the potential of the motor. every body else gets 2hp/inch on a 2 valve OHV head - cept 660s - if we did that would be 380hp under 7000rpm.

                      I dont even know where to begin to look, short of fabricating an intake by hand
                      QuadDriver.....
                      go fast...run over sh....stuff

                      Comment


                      • #12
                        Originally posted by The_Raven
                        Marty, would you mind sending me those pics of the heads you mention?

                        QuadDriver; yes the board changed.

                        Ok, to clear up with the genIII parts... Did the upper intake have "ribs" with the wording "3100 SFI V6" on the top, or just writting, as in "3100 SFI"?
                        ok ask me a hard question - I am old if you recall....lol

                        Im *pretty sure* the 'word' SFI appeared, same as they do on my 98. I wont be back there till wed to check tho. Im also pretty sure of the vehicle they came out of - original motor got dexcooled to death and got a gm 'crate'
                        QuadDriver.....
                        go fast...run over sh....stuff

                        Comment


                        • #13
                          Originally posted by The_Raven
                          Marty, would you mind sending me those pics of the heads you mention?
                          could I possibly see those pics too
                          1999 Olds Alero 2.4 to 3500 swap (running). totaled by a honda
                          1992 lumina 4 door 3500 3spd auto 15.020 @93.5 mph
                          1984 Cavalier type 10 hatch 3100 5spd!!!
                          14.96@91.47 in the 1/4
                          9.63@74.36 in the 1/8th
                          14.30 on slicks! scrapped due to rust!

                          Comment


                          • #14
                            Sure. Here's a pic from the Chevy Power Manual.

                            Marty
                            '99 Z-28 - Weekend Driver
                            '98 Dodge Neon - Winter Beater
                            '84 X-11 - Time and Money Pit
                            '88 Fiero Formula - Bone stock for now

                            Quote of the week:
                            Originally posted by Aaron
                            This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                            Comment


                            • #15
                              Here's a shot of the head from the Beretta Indy Pace Car.

                              Marty
                              '99 Z-28 - Weekend Driver
                              '98 Dodge Neon - Winter Beater
                              '84 X-11 - Time and Money Pit
                              '88 Fiero Formula - Bone stock for now

                              Quote of the week:
                              Originally posted by Aaron
                              This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                              Comment

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