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  • 8000 rpm or bust!

    I just scored an AMAZING deal on some Carrillo Pro-H (H-beam) rods for my turbo 3200 destroker build (in a Fiero) and it's got me crawling all over in excitement again. These rods will handle anything I can throw at them. In fact, my whole car will explode into a blazing fireball of glory then entirely disintegrate off the face of the earth before these rods will fail on me.

    So... 8000 rpm or bust!
    Rods- check
    Can WOT Tech's best give me the rest of what I'm after?

    It'll be a turbo "3200" destroker using:
    3500 block (bored about .020)
    Diamond pistons for a 3400 (.100 over) w/all the goodies
    5.85" rods
    Gen II 2.8 crank (or maybe the billet 3" crank that my friend will sell me if it has the 2" journals, just will need the external crank trigger with that)
    That gives a 1.95 rod/stroke ratio, relatively low peak piston speeds, and more overlap in the rod journals (vs. the 84mm stroke), it'll just beg for RPM's.

    The current shortblock has a 3400 top end bolted to it with a 180 degree rotated upper so I'll need to keep the upper as is, but probably ported and with a 62 or 65mm TB. I'd rather keep the whole top end but with ported heads/intake, but if there's a better reason to use 3500 heads/LIM than ported 3400, I'll do that instead.

    The exhaust has 2.25" primaries into 2.5" logs/crossover then into the .82 a/r T3 turbine housing w/a Borg-Warner S282 turbine wheel and compressor side, followed by 3" pipe (or 2.5" when I feel like using the muffler, I have a variable bypass in there controlled by a switch in the center console) into dual 2.5" tips. This will flow plenty enough for 8k.

    That leaves the valvetrain, the real limit in most pushrod engines. Here's where I'm not so sure, considering what's available.
    The Street/Strip Turbo Cam sounds about right for this based on the description, but I've never been great at spec'ing out cams. Keep in mind that a 3.2 is about ~5% smaller than a 3.4 (3.35) and ~9% smaller than a 3.5 (3.499) so it'll rev a little bit higher with the same cam. I'm worried about going bigger than this anyway because bigger = more load on the rest of the valvetrain at a given RPM. I don't want to make peak power at 8k, just enough to keep it going strong so I can be in the right range going into the next gear (better area under the curve that way).
    So for all you 60V6 cam guru's, what thinks you?

    From what I gather, the best as far as the rest goes is this:
    Double roller timing chain (of course)
    Manley titanium retainers and keepers (lighter is better)
    PAC 1518 springs
    Manley SS valves (are these any lighter than stock? Needed for the power level anyway)
    Stock lifters with the TCE LS springs

    Do you think this would handle it? Are there any better options available? Are there any full roller rockers available for Gen III's?

    As for the tranny, an F23 5-speed is going in with a Quarter Master twin-disk and this combo should breeze through 8k shifts based on what has been done with the cars it came in.
    OBTW, don't try to talk me out of the 3200, we've been there and done that. Please just help me get 8000 rpm so I can post lots of 8000 rpm videos for you!
    Last edited by ALLTRBO; 04-17-2011, 06:29 PM.

    '88 Fiero GT - Project MIDTRBO
    '10 Camaro LT/RS
    The rest of my cars are for sale (Click here)
    There's no replacement for turbo placement

  • #2
    Your right the valvetrain will be the limit. For a cam as specialized as your looking for I would just call COMP cams when you have all your specs in order. With a turbo you also need to calculate the expected pressure between the exhaust valves and the turbo. The pressure differential between the exhaust and intake side is critical when picking the right turbo cam.

    You can use narrow body aluminum rocker arm for a small block chevy and install them with a set of ARP conversion studs. When your given a spring spec after getting your cam get yourself setup with a beehive spring. It will reduce the mass of the spring and you will have a lighter retainer compared to a straight spring. Your also going to need some strong pushrods which are easy to get once you know the length you need.
    1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
    1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
    Because... I am, CANADIAN

    Comment


    • #3
      Don't forget you will need to modify the rockers to fit under the LIM, and you will need heat treated pushrods and guide plates to use the floating rockers. The roller tips will be nice for high rpm, but not sure about the extra side to side movement and friction from the guide plates. I'd be most worried about that and the timing chain.
      '97 Grand Prix GT 3800 (sold)
      '00 Grand Am GT 3400 supercharged
      13.788 @ 103.73 mph, 320whp 300 ft/lbs
      Gotta love boost!

      Comment


      • #4
        Yea some rocker may work without modification. Harland Sharp has a set that look like it is much smaller profile in the back and may work. When I put a set of Cranes on a 3400 the LIM was all that needed clearancing.
        1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
        1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
        Because... I am, CANADIAN

        Comment


        • #5
          My cranes on the other hand still wouldn't clear the LIM without modification. I sanded right through the bottom of the intake runners trying to get clearance, and ended up having to put a small radius on the nose of four of them. Same thing with the Scorpion SBC rockers I have now, which are much thicker and heavier duty than the cranes where. The nose of the rocker (on the pushrod end) won't clear the bottom of four of the intake runners. I put the same radius on all my Scorpion rockers and weighed them all on a digital scale so they would be balanced.


          On a side note, I still have the cranes if anyone wants them.
          '97 Grand Prix GT 3800 (sold)
          '00 Grand Am GT 3400 supercharged
          13.788 @ 103.73 mph, 320whp 300 ft/lbs
          Gotta love boost!

          Comment


          • #6
            This sounds a lot like my previous plans for my De-stroked 3500 build. It was to hard to get the machining work done here in houston, so I opted to keep the 84mm stroke and 5.7i rods. (same as a 3400). Im using modified 327 , H-beam rods and L19 bolts. I can get away with a safe 7500rpms without consequence. (which coincidentally, my cam grind has a peak power at 6500-7000rpms. Works out pretty nicely)

            My car is a bit heavier than your fiero so I think that I can benifit from the added low-end torque of the higher displacement. (3500 w/ .020 overbore + 84mm stroke. I think that it comes close to 3.6l). In any case, Ill keep an eye on this thread. Keep us updated.
            Last edited by Driver_10; 04-21-2011, 12:47 AM.
            Took a break from working on the car. Got some better tools, got a better shop, got a better job... Its time to burn metal!

            Comment


            • #7
              Sound nearly identical to the 3400 build I was planning.

              I'd use the new comp cams steel rockers.

              I know someone who has run an ironhead turbo to 8200 rpm.

              The stock intakes flow @220 on a set of gen III heads. If you run the formula for flow solving for CFM you get: 220*6 = 1320 CFM. So for a 3.2L that's 195 CI. So the required flow for 8000 rpm is CI*RPM/(1728*2) = 451 CFM @ 100% VE. The flow restriction isn't in the heads. It'll be valve train since the power and flow are direct functions of RPM. In theory to flow enough air to use the full head flow capacity you'd need to spin the engine well beyond 20K. Certainly not possible.

              Comment


              • #8
                Originally posted by NateD4 View Post
                The stock intakes flow @220 on a set of gen III heads. If you run the formula for flow solving for CFM you get: 220*6 = 1320 CFM. So for a 3.2L that's 195 CI. So the required flow for 8000 rpm is CI*RPM/(1728*2) = 451 CFM @ 100% VE. The flow restriction isn't in the heads. It'll be valve train since the power and flow are direct functions of RPM. In theory to flow enough air to use the full head flow capacity you'd need to spin the engine well beyond 20K. Certainly not possible.
                When are all 6 valves open .500" at the same time? Never. I will never understand why people use that formula short of advertising to the general public. "omg 1300 cfm heads!"
                Ben
                60DegreeV6.com
                WOT-Tech.com

                Comment


                • #9
                  It doesnt matter really as each cylinder has it's own port. The point is the engine's capacity is RPM limited. 195 Cubic inch at 8000 rpm is only 450 CFM. Divide that by 6 and you have @75 CFM/cylinder. If you have a 220 CFM port you can easily fill the cylinder. It becomes a question of cylinder dynamics, And transient dynamics.

                  The point is you are mechanically limited to 450 CFM independent of the head flows. Unless you use boost of course.

                  Comment


                  • #10
                    I disagree. If you have a 220 cfm port, you can easily flow 220 cfm at 28" of water without the intake manifold or throttle body bolted down. Ignoring all those dynamics just turns me off of the discussion completely and really doesn't help the OP.
                    Ben
                    60DegreeV6.com
                    WOT-Tech.com

                    Comment


                    • #11
                      That was my whole point though. The heads flow enough to supply 450 CFM. I'll try to post more detailed numbers with the dynamics accounted for.

                      However with boost there really is no discussion or argument required the engine will rev to 8000 even with cast Iron heads.

                      The question is at what pressure and what will it's characteristics be.

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                      • #12
                        I wouldn't use hydraulic lifters for an 8k rpm motor. You can, but solids would be much more stable.
                        Ben
                        60DegreeV6.com
                        WOT-Tech.com

                        Comment


                        • #13
                          Thanks for the advice and info. Sorry I'm slow to reply, there is a whole lot going on lately (but I wanted to get back... I hate it when someone starts a thread and disappears).

                          I suppose a custom grind would be the best option, I just didn't know where to start. The car will be back in my hands next Saturday (Finally! 2 years!) and I've got to figure out why the current engine has a valve tap (TGP 3.1 shortblock with a 3100/3400 top end) but once I get it going and dialed in some I'm going to gather some exhaust pressure info among other things... and thinking about it, even though an 8000 rpm 3200 is a different animal, it'll be a huge leap ahead in helping out with having a cam designed because the turbo setup will be the same and the top end will be close or the same.

                          I once knew about the SBC rocker setups then forgot, but hadn't looked into great detail anyway.
                          So then there is no problem using floating rockers on the heads designed for pedestal mounts? The thought of guide plate friction at 8k does kind of worry me, but I'll have to research more to see how much of a worry it is in reality. Clearancing a tiny bit is no problem.

                          Nate, if you know someone who has run an ironhead turbo 60V6 to 8200, can you give me the details?

                          Ben, you mentioned solid lifters and I thought "Huh? on a non-adjustable valvetrain?" and that's when I put two and two together. With floating rockers comes adjustability, heh. So are there solid roller lifters that'll fit the Gen III's? If so, I've heard of some issues with FI engines picking up false knock from solid's, how accurate is that info? I've no experience in that regard.
                          Are these custom cams able to deal with the aggressive ramp profiles long-term?
                          I'd rather use hydraulics for the 'set it and forget it' factor but if I had to (and if it's possible), I'd highly consider using solid's to reliably get 8k. I just don't want to ever have to semi-regularly check the lash under all this (on the front bank anyway). The completed swap is not nearly as clean as I expected. Either way, that's a lot of stuff to dig through.


                          '88 Fiero GT - Project MIDTRBO
                          '10 Camaro LT/RS
                          The rest of my cars are for sale (Click here)
                          There's no replacement for turbo placement

                          Comment


                          • #14
                            Originally posted by Driver_10 View Post
                            ...Ill keep an eye on this thread. Keep us updated.
                            Sure thing, here's my abbreviated build thread on here, that's where I'll be updating things. I'm waiting to get it back and a few things finalized before I post another update here.

                            '88 Fiero GT - Project MIDTRBO
                            '10 Camaro LT/RS
                            The rest of my cars are for sale (Click here)
                            There's no replacement for turbo placement

                            Comment


                            • #15
                              Wait a sec, the question was cam selection and no ones suggesting a solid roller?? I dont think you'll get a hydro cam to 8000, Im not saying it cant be done but if you want to hold that rpm for any given period of time, a solid cam is a must.
                              The whole theory about smaller motors should rev higher?? Im not convinced. Ive been driving around in a 95 240sx with the RB20DET in it and it only revs to 7200. The guys at the shop here say with the right cams, maybe 8000rpm. Maybe?? Huh, a 2 liter inline 6 cant rev to 10K?? But they want to sell me a RB26DETT that can rev to 12K with the right cams. Bigger motor rev higher?? I even remember guys running stroker 502's with solid cams, a blower, and noz run to 10K at the track all day. I dunno, but my suggestion would be a solid cam will be a good starting point if anything.

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