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  • NISMO Heads $$$

    Do they work with whatever cams? Anyone know?

    Just pipe dreaming...
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

  • #2
    I believe they used the same cam blanks as the production heads.

    Nismo heads would be a complete waste of money in my opinion. As I am sure I seem very fond of saying... the electramotive GTP cars used production cylinder heads. They were extensively modified and used with solid lifters, roller rockers, oversized valves and whatnot. I have a bunch of pictures of this stuff I will upload and post when I get time.

    Ther's a lot of gain to be had on the stock heads even with a pocket porting. Expect 20% overall for both intake and exhaust, then tack on the gains at low lift from a better valve grind and you will start to see where it can really add up to make for some good flow numbers. I was considering disconnecting the wastegate actuator to see how much power my current engine could put down with no (or at least very little) boost. I speculated that the modified heads and cams I am using caused a 50-60whp gain and was criticized by some for making such large claims. I don't doubt my assessment at all, I only doubt their experience with VG heads and automotive performance in general (which is actually none).

    8.3:1 with stock heads and 18PSI made 383rwhp/373rwtq
    7.8:1 with modified heads and 15.8PSI made 418rwhp/389rwtq


    same 93 octane fuel, lower compression, less boost, yet more HP and torque. Both were reading about the same MAF voltages, which means at ~16PSI I am moving as much air as it was before at 18PSI with the same turbo
    .

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    • #3
      Yes, their cost outweighs any serious consideration, unless I win the lottery or rob a bank or something.

      Did you use SAE, Standard, or uncorrected values from those dyno runs?
      BLOZ UP.com
      It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

      Comment


      • #4
        SAE on everything, but it's suprising how little correction it was over the uncorrected values put out by the dynapack.

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        • #5
          A little bird or two told me that uncorrected is the way to go with supercharged vehicles.
          BLOZ UP.com
          It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

          Comment


          • #6
            BLOZ UP wrote: A little bird or two told me that uncorrected is the way to go with supercharged vehicles.
            Well... It also depends greatly on the type of dyno being used; there are whole books on the subject.

            My car makes about 4XXhp to the wheels either way. I can't say one car (even if they were both VG30ET Z31's of the same weight and gearing) will be faster than another by looking at dyno graphs taken from different dynos anyway, so I never consider anything to be exact to begin with.

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            • #7
              In other words you doctored the graphs... sheesh. :roll:
              BLOZ UP.com
              It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

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              • #8
                lol, funny man.

                then they are "doctored" to be less than actual?

                I can always take the car to another shop some time in the future to see it put down another 40whp on a dynojet

                :lol:

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                • #9
                  Jason84NA2T wrote: lol, funny man.

                  then they are "doctored" to be less than actual?

                  I can always take the car to another shop some time in the future to see it put down another 40whp on a dynojet

                  :lol:
                  Ha, I guess so.

                  Hey, make sure your tires are filled to the MAX each time! Makes buttloads of a difference, I swear. I asked a mustang dyno owner at hybridz, and he confirmed it, and ive just reconfirmed it at work.
                  BLOZ UP.com
                  It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

                  Comment


                  • #10
                    May i ask what the difference between corrected and uncorrected valves are?

                    Terrible idea putting those wheels on...

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                    • #11
                      WaZZ300 wrote: May i ask what the difference between corrected and uncorrected valves are?

                      The uncorrected values
                      are straight from the dyno. They are strictly what the Engine RPM vs Dyno Drum Acceleration result in horsepower and torque. SAE and Standard (and whatever other standards) add in Air temperature, density, humidity, etc into factoring those power numbers. Uncorrected will usually yield lower numbers, corrected yeilds higher numbers.

                      For turbo/supercharged cars, I have just recently heard that uncorrected is the way to go, to get "consistent" dyno results from various dyno days. Since the air is pressurized and such the initial air temp reading doesn't matter (as much).

                      I still have a few grievances against using uncorrected (like, pressurized air temp DOES depend on initial air temp, etc. -- to what degree, I don't know for sure), but I'd like to try it before I knock it, and possibly research it more.
                      BLOZ UP.com
                      It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

                      Comment


                      • #12
                        haha values....sorry, the white backround is very bright

                        Terrible idea putting those wheels on...

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                        • #13
                          if you could keep the heat soak down somehow I could see uncorrected being consistent

                          you'd need a lot of ambient temp airflow over the i/c and rad however, or each run would need a significant cooldown period... or ice water ?

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                          • #14
                            G-E wrote: if you could keep the heat soak down somehow I could see uncorrected being consistent

                            you'd need a lot of ambient temp airflow over the i/c and rad however, or each run would need a significant cooldown period... or ice water ?
                            I don't like doing cool down periods between runs. Letting it return to idle temp is fine, but turning it off for an hour between runs just isn't realistic, it's just trying to get the highest numbers possible.

                            I let my whole car warm up: engine, tranny, and diff by cruising on the dyno. I make a couple runs and let it idle for a while. I like to have as many control variables as possible. Now, if it really is heatsoaked beyong where it would be when im, say, cruising down the highway, ill turn it off and leave it for a while.

                            Unfortunately, all of our customers just want the biggest numbers, so I have to do whatever they want.
                            BLOZ UP.com
                            It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

                            Comment


                            • #15
                              BLOZ UP wrote:
                              I don't like doing cool down periods between runs. Letting it return to idle temp is fine, but turning it off for an hour between runs just isn't realistic, it's just trying to get the highest numbers possible.
                              I agree. I did not allow my engine to cool for a long period between runs. Just enough to get the temp back down to what it would be at idle or driving around on the street. Heatsoak is going to happen on the street about like it's going to happen on the dyno...

                              GE: The dyno does NOT correct for heatsoak! The dyno only corrects for ambient air, humidity, baro... and each correction is really only a very small factor most of the time. Bloz up noted that it's probably best to remain uncorrected for forced induction vehicles because the intake temp does not mean as much as the charge/inlet temp (after compression)? Interesting, because according to the laws of thermodynamics, the colder your intake charge is going into the compressor, it will be that much colder and then some coming out. IE: if I have a 60 degree inlet temp and a 230 degree outlet temp, I might have a 200 degree outlet temp if that drops to a 50 degree inlet temp. (I forget what the exact eq. is but you get the idea). Then throw the charge cooler efficiency, pressure drop and heatsoak into the equation and you have a gobbleygoop of a thermodynamics puzzle to figure out! The uncorrected values will take just that ambient air property out of the equation and depending on the actual properties of the air the engine is using, it could display both lower or higher in power output (but usually very slightly lower).

                              So my question is... what does it really accomplish to use uncorrected if you are tuning the car on the dyno?

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