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  • pro charger/sbc questions...

    So lets say I took my 350 dropped the compression to around 8:1 and dropped a non-innercooled d1sc in, what could i expect for relaible pump gas power? Heres the criticals on my motor. This is somthing im considering in the future. Its either this or a 434ci or somthing of that nature. The 350 runs hard but its kind of getting boring for me
    -350ci 4340 crank and H-beams, splayed main caps w/oliver front cap
    -BrodixRR200's
    -296/302, 258/[email protected] .562/.562lift on a 108
    -Team G, probably be a super vic by then
    -750 mighty demon, I know a need a blow through carb
    -1-7/8"x 3-1/2" super comps

    Right now with my 116mph trap speed and my 3500 lb race weight the motors somwhere in the 450-475 hp range i think

    any pro charger experts here? Discuss...

  • #2

    Re: pro charger/sbc questions...

    Re: pro charger/sbc questions...

    I've done more Vortechs than Prochargers. An advantage to them is that they use a carb enclosure, so you can use your current carburetor. Take the money you save by not having to buy a carb and throw it into a 3.750 crank. You're buying pistons either way, and you can reuse your old rods (IMO, don't get convinced that 6-inch rods will matter much). So you'll have a 383 that will run decent with all your other parts. I'd do it at 9.0:1. You should make abut 675hp on 94 octane, in my estimation.

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    • #3

      Re: pro charger/sbc questions...

      Re: pro charger/sbc questions...

      do you think he'd run into detonation problems at that power level on pump gas without an intercooler?


      V10Mercury on here works at Procharger, I'm not sure what kind of input he'd have. Might be worth sending him a PM too. I know a lot of people run the D1 without intercoolers, at less-than-max boost, they're very efficient...

      -scott
      www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

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      • #4

        Re: pro charger/sbc questions...

        Re: pro charger/sbc questions...

        I wouldn't call myself a Procharger expert since I've only played with one, but I would tell you that you do not need a new carb -- just like DF said. Even if you don't use a box, just set up your existing carb a little rich to start (like 4-6 jet sizes front and back) and go make some pulls on a chassis dyno with a wideband AF sensor so you can get the tuneup in the ball park. (see Scott ;) )

        We did an F1R on a 383 and the 850 annular Mighty Demon wanted about 6 jet sizes over stock for a 12.0:1 AF ratio. I also knocked the power valve protection out of the base plate so there is no chance of that little check ball making the power valve stick shut under boost. If your AF ratio gets weird on you (especially if it wants to stay lean) you may want to take a hard look at your bowl vents -- air blowing across them can actually pull a suction on the bowls. Some guys put tubes on the vents and run them back into the hat so they get full boost pressure in the bowls. Beyond that, there is nothing fancy about a blower carb -- you do not need to boost reference on a blow through setup.

        One last thing -- whatever cam you use, make sure you have enough spring pressure. Boost pressure on the back of the intake valves makes the valve act "heavier" and consequently springs that are "just enough" on an NA motor will float on a boosted motor. We added 45 psi seat pressure on the 383 we built to keep the valves under control.

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        • #5

          Re: pro charger/sbc questions...

          Re: pro charger/sbc questions...

          Some guys put tubes on the vents and run them back into the hat so they get full boost pressure in the bowls. Beyond that, there is nothing fancy about a blower carb -- you do not need to boost reference on a blow through setup.
          Really? Every hat I've seen encloses the bowl vents. And if they are enclosed, or if the vents uses hoses to the hat as you suggest, then you DO need boost referencing. With the vents exposed to inlet pressure, 7 psi of boost on top of 7 psi fuel pressure equals zero fuel flow. The fuel regulator should be referenced to the hat or enlcosure, not to the intake manifold.

          As for detonation without an intercooler, I think it would be fine at around 7 psi. The carb itself acts as an intercooler. In my tests, I've seen inlet temp drop 100 degrees across the carb.

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          • #6

            Re: pro charger/sbc questions...

            Re: pro charger/sbc questions...

            Let me clarify Dave -- maybe the way I worded my post was a little confusing.

            Float bowls: depending on the height and design of the hat, the vent tubes can have high velocity air blowing across them. When air blows across a tube you can get negative pressure (relatively speaking) in the tube due to the venturi effect. This lowers the pressure in the float bowl and as a result you have less fuel flow. Sooooooo . . . the fix is to put a tube on the bowl vent (leaving it all inside the hat) and put the other end (the end not connected to the vent tube) at a different location in the hat. You have to put it in a different position so you no longer have air blowing across creating suction.

            Power valve: Does not need to be boost referenced in a blow through setup. The main reason for boost referencing a power valve is in a draw through setup in a situation where the blower is big enough to draw a vacuum on the bottom of the carb potentially closing the PV. In a blow through setup, the PV does not need to be boost referenced, but the blow out protection should be knocked out of the base plate because it is designed to close off (thereby protecting) the power valve in the event of positive pressure (like a backfire).

            Pressure regulator: Agree. The pressure reg definitely needs to be boost referenced for a blow through setup. In my personal opinion tapping the boost reference line into the hat is better than below the carb, but either will work.

            Sorry if I confused anyone!

            Comment


            • #7

              Re: pro charger/sbc questions...

              Re: pro charger/sbc questions...

              So you guys think with my current motor @ 9:1,200cc RaceRites and a non intercooled D1SC, i could be looking at 675 hp on pump gas @ 7 psi? Holy shizzle. That would be low 10's if I could hook it at all.....So whats the deal with supercharger cams? Would I need to increase my L/S to a 110/112/114? Would my current cam run smoother with the forced induction? Get a completely different stick?

              Comment


              • #8

                Re: pro charger/sbc questions...

                Re: pro charger/sbc questions...

                No need for me to reply with DF and Eric posting on here, they both really know their stuff. If your motor is 450-475hp then 7psi should put you around 675hp. Most cars see around a 50% power gain with 6 or 7psi. You could get away with 10psi on a non intercooled carb motor if you wanted to, but with the 9:1 compression then 7lbs of boost would be safer with pump gas. Our sales manager at ProCharger has a 69 Chevelle with a D1SC on a sbc and I am pretty sure it makes around 700hp (at the wheels) with 91 octane pump gas, his name is Carey feel free to give him a call 913-338-2886. I am sure he would be happy to talk to you about it.
                From what I understand on a blower cam the only thing to be concerned with is keeping the L/S around 112.

                Comment


                • #9

                  Re: pro charger/sbc questions...

                  Re: pro charger/sbc questions...

                  So you guys think with my current motor @ 9:1,200cc RaceRites and a non intercooled D1SC, i could be looking at 675 hp on pump gas @ 7 psi? Holy shizzle. That would be low 10's if I could hook it at all.....So whats the deal with supercharger cams? Would I need to increase my L/S to a 110/112/114? Would my current cam run smoother with the forced induction? Get a completely different stick?
                  I was assuming 675hp with a 383. For pump-gas centrifugal setups with decent heads and cam, I generally presume around 1.75 hp/ci (then wiggle it 10 or 15 hp either way depending on boost, how much timing you can run based on chamber design, etc...it's just a bench-racing guess). So your 355 should make around 620 hp. And, yes, I'd change the cam to 112 LDA.

                  Comment


                  • #10

                    Re: pro charger/sbc questions...

                    Re: pro charger/sbc questions...

                    Really? Every hat I've seen encloses the bowl vents. And if they are enclosed, or if the vents uses hoses to the hat as you suggest, then you DO need boost referencing. With the vents exposed to inlet pressure, 7 psi of boost on top of 7 psi fuel pressure equals zero fuel flow. The fuel regulator should be referenced to the hat or enlcosure, not to the intake manifold.

                    [/quote]

                    The vent tube extensions he is talking about go from the bowl vent to the inlet of the carb hat. This is done with 5/16 brake tubing inside the carb hat. It moves the bowl vent to the high velocity airstream at the inlet and actually seems to add a little pressure to the bowls which really helps feed the engine. After adding these tubes guys are dropping around 10 jets front and rear to get a safe afr.

                    A good carb hat is a must, Extreme Velocity and CSU both make a hat that works very well. As for the carb I run a CSU and a buddy has a C&S. Both work very well. If you feel like doing it yourself take a look at this:


                    http://www.theturboforums.com/smf/in...&topic=51153.0


                    Personally I would not go with the box. Its too bulky and make jet changes a pain. I also hear that it costs alot of power versus a hat. Freiburger seems to have done pretty well with it though.

                    Like Freiburger stated the carb makes a great intercooler. Even better on e-85. My intake temps at 25 psi are around 90*. That was in Vegas where the outside air temp was 88*

                    Comment


                    • #11

                      Re: pro charger/sbc questions...

                      Re: pro charger/sbc questions...

                      Excellent info Jesse! I am interested in hearing more about your ride. What is the rest of your combo? (if you don't mind me asking).

                      25 psi on E85 and no intercooler sounds killer -- that combo ought to be wicked fast on 25 psi.

                      Comment


                      • #12

                        Re: pro charger/sbc questions...

                        Re: pro charger/sbc questions...

                        Personally I would not go with the box. Its too bulky and make jet changes a pain. I also hear that it costs alot of power
                        I've done the A/B o the box vs hat and not seen big swings. Also witnessed a test of multiple hat styles. Some were a MESS.

                        I know I'm way outside the norm and admit that I may not know what I don't know, but I still feel that boxes are easier to deal with, especially in tamer applications. (Though I've made 1,000-plus rwhp on a 408 with a box). You can usually drop a Holley right out of the packaging, dyno it to find the jetting, then do fine tuning with bleeds so it does not have to come out of the box again.

                        Comment


                        • #13

                          Re: pro charger/sbc questions...

                          Re: pro charger/sbc questions...

                          Eric68,

                          My newbe post is on page 20 of the hello thread in the general discussion area. There is a few links to info and some pics. I forgot this one:

                          http://www.youtube.com/watch?v=U6wY_m6dEPc

                          That was 16 then 19 psi and pushing through the converter really bad. Chad Reynolds was there but mostly you hear the other guy.

                          The car has gone [email protected] That was with a 1.72 60ft, no trans brake, tailpipes, 4070lb race weight,and on radials. I have a trans brake now so I'm looking to pick up some time there. Its tricky to launch right now, I got a 1.51 60ft once but I forgot to trigger the boost controller > Still went 9.24 with only 8 psi for over 1/2 the pass. If I ever get my poop in a group it should be fun



                          Freiburger,

                          Like I said that what I heard, I really don't have any experience with the box. I will say that the carb from CSU was really close out of the box on gas. This e-85 conversion took a bit of messing around though.



                          www.theturboforums.com has an entire section dedicated to blow-thru. Lots of good info.

                          Comment


                          • #14

                            Re: pro charger/sbc questions...

                            Re: pro charger/sbc questions...

                            This slightly differs from your basic combination but, I thought I'd offer info to give you an idea of what a similar setup has done.

                            I've ran a D1 Procharged 355 with basic blower mods. This combination was reasonably tame as a street driver as well. We used a 8.8:1 static w/ Comp Solid Roller - 248/254 @ .050 on 114LSA. Dart Pro1 215cc moderately ported to about 225cc. This used Holley single plane EFI which didn't have the best intake design, and 75mm throttle body through an elbow. As stated, the carb should cool the charge better than the intercooler we used at the time.

                            On the dyno, it made 725hp @ 19lbs using 110 fuel. 24* timing and intake air temps were in the 230* range. This setup @ 3200lbs on 26x10 tire footbraking went 9.83 @ 138mph on race fuel and 9.95 @ 134 on pump gas (less timing). 60ft's were in the low 1.40's

                            Before I decided to run a turbo setup, I pulled the engine and re-dyno'd it for some testing. Our initial pulls were pretty much right on at 720hp. We had a used snow on an a/a intercooler to cool the charge down to a moderate temperature of 140* and power improved dramtically. Right to 800hp with the addtion of fuel with the cooler charge. Now it would tolerate more timing (2*) netted 20hp at peak and 16avg (26* total). Another 2* (now 28* total) netted another 20hp at peak and 18hp average. We were now besting 847hp @ 6700 rpm with 720ft lbs @ 5500rpm. We ran out of fuel pump and injector so addtional testing wasn't an option. The springs were pretty well going away so I expected it fell a few hundred rpm short as well.

                            What I'd suggest is to spend some $$$ on those heads. Have them ported and a quality valve job goes a long way. I'd suggest a Vic Jr w/ CSU carb/hat. As stated, the cam needs to match the application accordingly. Comp's XR stuff is pretty decent. You can have them widen the LSA on a catalog grind to work with the blower. I prefer not to spin the heck outta the stockers, I had Oliver splayed caps and they showed some signs of movement although it regularly saw 7300rpm with 19lbs of boost. As DF indicated, the boxes work well on the lower boost stuff. It keeps things pretty simple for the carb mods. I've done some testing with both and feel the bonnet is a better option above the 12lb mark.

                            Comment


                            • #15

                              Re: pro charger/sbc questions...

                              Re: pro charger/sbc questions...

                              Also, to address the NA 434ci buildup versus the blown 355, my guess is you'll have a more streetable combo with the blown 355 and will probably make more power.

                              Comment

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