Horespower Gain from just a tune??

Discussion in '2005 - 2009 Specific Tech' started by satinleafct, Aug 30, 2009.


  1. ski

    ski Member

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    According to the referenced article, the C&L intake manifold flows no less than 317 cfm per port. That calculates to no less than 2536 cfm for the entire manifold.

    WRT the BBR article, it does not state whether the 225 cfm flow is for one intake valve port, for the 4 intake valve ports in each head, or for the 8 intake valve ports in both heads. However, the following article shows a flow of 156 cfm per intake valve port for the 92-98 4.6L 2-valve heads.
    4.6 liter Ford Engine Cylinder Heads
    Hence, one can intuitively deduct that the 225 cfm flow in the BBR article is also per intake valve port, or 1800 cfm total flow for both heads.

    Hence it's quite apparent that the flows of the heads and the intake manifold vastly exceed the flow of the stock air intake, and thus calling them bottlenecks is a gross error.
    #41
  2. grngt50

    grngt50 New Member

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    thank you sir :nice:


    -J
    #42
  3. Ken04

    Ken04 New Member

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    the sucking factor is huge, huge. It's way up there in value in many things,,,,,
    #43
  4. grngt50

    grngt50 New Member

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    excellent bang for the buck lol
    #44
  5. TGJ

    TGJ New Member

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    Really?

    No matter how you cut it, what it all boils down to is the fact that the air all bottlenecks down to an intake port on the head. What I have said is in fact correct.

    It is funny how around 10 years ago, on Modular Tech Community which merged with Modular Depot years ago. A Ford Engineer behind that was part of the team that designed the Modular Engines went and scientificlly proved how much a CAI was worth. In the scientific experiment, a CAI gained 1.2 RWHP over the stock airbox on a 650 RWHP Vortech Supercharged 4.6 2V Mustang. He got tired of dealing with the internet experts.

    That Engineer was a big part in my N/A 2V car. That car is still the one of the most powerful N/A 2V Auto's on this board. In full street trim, it made 348 RWHP on 91 Octane fuel and it did it with it's stock airbox which flows less than the S197 Mustangs. The car's best Dyno run is 363 RWHP with the above setup except that the exhaust is dumped behind the X-Pipe and the Power Steering is bypassed, and that to was on 91 Octane on the same tune that made 348.

    I am done with this board. I will let the new experts who have no numbers of any kind to back their claims up deal with this from now on...
    #45
  6. ski

    ski Member

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    The numbers that you stated in your post, in of themselves, are correct. What's incorrect(and the main reason for my post) is your misleading implication of what these numbers depict(that the stock intake's total airflow capacity exceeds the stock heads' total airflow capacity) in an attempt to prove your claim that the 3V heads are the bottlenecks in the S197 GT engine.
    And while it's true that engine airflow bottlenecks down to an air intake port in the head, you conveniently forgot to mention that there are 8 air intake ports in the S197 GT engine.

    I can't say that I'll miss you, because I have absolutely no respect for anyone who calls another person dumb. There's no justifiable reason for doing that on these boards.
    #46
  7. grngt50

    grngt50 New Member

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    :cry: haha he got all butt hurt when he was proved wrong. You shouldn't leave the board, it's obvious you know a lot about cars. Just don't make it a point to turn a debate into a personal attack, that's all.

    -J
    #47
  8. gmantheman

    gmantheman Member

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    I have dynoed my car with an 87 canned tune w/o an intake and bamas 87 per tune with a jlt. At the time I dynoed the 87 bamatune, I had 91 octane in the tank because I was going to dyno the 91 tunes as well. With 87 canned tune I was at 284RWHP 298 RWTQ A/F was around 13.4. Bama's 87 tune w/JLT RWHP 293.75 RWTQ 305. A/F was around 13.4.
    #48
  9. tug3

    tug3 New Member

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    Just a quick question, how many of the intake valves are open at any given moment?
    #49
  10. grngt50

    grngt50 New Member

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    and those numbers are pretty much in line with what Doug had told me. Thanks for your input

    -J
    #50
  11. danGtheTman

    danGtheTman New Member

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    Go with the CDC shaker system and plumb it into the stock airbox. I can tell that my throttle is more crisp with the cooler outside air going into the stock airbox. A CAI will suck hot engine air.
    #51
  12. grngt50

    grngt50 New Member

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    not according to my datalogs with my Predator.......IAT's at their HIGHEST temps were in line with the ambient temperature.

    -J
    #52
  13. ski

    ski Member

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    2 are open at any given instant in time, 4 open during 1 crankshaft revolution, and all 8 open during 2 crankshaft revolutions.
    However, it must be remembered that only 1/8 of the total volume of air that's flowing into the engine thru the air intake reaches each intake port, because it's channeled thru 8 individual runners in the intake manifold that feed each of the 8 intake ports. And since each runner's airflow capacity exceeds the airflow capacity of each intake port, and the 8 intake ports' total airflow capacity exceeds the air intake's total airflow capacity, it's thus quite obvious which one is the bottleneck.
    #53
  14. ski

    ski Member

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    +1000
    #54
  15. ski

    ski Member

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    That CAI made a big difference in the engine's power output when compared to the stock intake. :nice:
    #55
  16. ski

    ski Member

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    Did you datalog the IAT's only when the car was moving?
    If so, then see if they're considerably higher than ambient when the car is standing still for at least a minute with the engine idling after it has reached normal operating temperature.
    The IAT's on my 05 GT with a C&L Street CAI and heat shield were also approx. ambient(82 F) when the car was moving. But they increased quite a bit when the car was stopped for any extended amount of time, e.g., traffic light. However, they quickly cooled back down to approx. ambient after the car started moving again for about 1/4 mile.
    #56
  17. grngt50

    grngt50 New Member

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    honestly all my data logging was done at night, so most of the time the Stang was in motion. I will take some time this Sunday and data log the temps in stop in go around town and then report back with my results.

    -J
    #57
  18. ViperNuge

    ViperNuge New Member

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    Thats music to my ears!! And has value IMO.

    Thanks guys.

    patrick
    #58
  19. 40oz

    40oz Member

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    holy crap, why don't people learn what they are talking about before arguing?

    A different than factory MAF will require a tune because it returns different numbers than the factory MAF. A factory MAF installed into a larger tube requires a tune because the *sensor* is seeing a different rate of flow across the sensor than the factory system.

    A MAF sensor measures airflow by measuring changes in the resistance of a wire. The wire changes resistance depending on the mass of air that passes over it. More air, less resistance; less air, more resistance. "More air" can mean either cooler, denser air or air travelling at a higher velocity. In a tube of known cross-section, this gives an accurate measurement of the mass of the air flowing down the tube. Since it can't actually measure the mass of all the air in the tube at a time, the system has to make certain assumtions about the tube the sensor is in.

    When you install the factory MAF in a larger tube or when using an aftermarket MAF, the engine is still inhaling the same amount of air, but since the intake tube is bigger the air is travelling slower. Less air is flowing past the MAF sensor for a given throttle opening/engine load situation. The engine is actually getting the same amount of air it was getting before, but due to the larger diameter tube, it travels slower down the tube. The MAF sensor is reading low compared to the factory system under the same conditions. Since the engine is getting more air than the sensor would imply, the ECU ends up not giving enough gas, hence a lean condition.

    This lean condition is NOT an indication of a CAI "working." It's an indication that you've increased the diameter of the MAF tube, causing the ECU to underestimate the air mass and deliver less gas than desired for efficient combustion.

    Knowing that, it's no surprise that people who put the CAI systems to a scientific test see no gains. And it's obvious why a tune is necessary for a CAI that changes the MAF tube diameter. You might see power from the tune itself, but you'd see the same power from a tune on the factory system.
    #59
  20. grngt50

    grngt50 New Member

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    thanks for the essay on how a MAF sensor works :shrug:

    The original debate was whether there were any additional gains to be had by adding an aftermarket CAI to a vehicle that ALREADY HAD A TUNE using the stock airbox.
    #60

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