Head, Intake, Cam, Throttle Body, Fuel Injector, Compression, etc, Information

Discussion in 'Fox 5.0 Mustang Tech' started by 5spd GT, Mar 12, 2007.

  1. Head Flow Data In CFM-Source: http://users.erols.com/srweiss/tablehdc.htm#Ford

    Intake Flow Numbers:

    Intake – Average CFM

    Stock Upper -198
    Stock Upper - 192
    Stock Lower - 150
    Stock Lower - 158
    Ported Lower - 205
    Stock HO - 158
    Ported Stock HO - 200
    Saleen/Vortech - 180
    GT40 - 205
    GT40 Upper - 223
    Cobra - 205
    Cobra Upper - 271
    Explorer - 205
    Ported Explorer - 229
    Stock GT40 Lower - 219
    Ported GT40 Lower - 272
    Stock SN Cobra Upper - 248
    SN Cobra Upper - 261
    Ported Lightning Lower - 302
    Performer - 220
    Ported Performer - 231
    Performer - 209
    Performer RPM I - 230
    Performer RPM I - 232
    Ported RPM I - 277
    TF Street Heat - 245
    TF Track Heat - 265
    Trick Flow R - 290
    Victor 5.0 - 282
    Ported Victor 5.0 - 317
    Super Victor 351 - 320
    Stock Stealth 351 - 233
    Ported Stealth 351 - 263

    Thanks to Tom Moss (tmoss) for much of the intake information, he was very helpful.

    Throttle Body CFM Flow Ratings:

    Stock 5.0L 60 MM - 526 CFM
    SVO 65 MM - 540 CFM


    65 MM - 664 CFM
    70 MM - 787 CFM
    70 MM - 896 CFM (Race version)
    75 MM - 924 CFM
    75 MM - 1045 CFM (Race version)
    80 MM - 1142 CFM
    85 MM - 1322 CFM
    90 MM - 1369 CFM
    105 MM - 1550 CFM


    65 MM - 750 CFM*
    70 MM - 790 CFM*
    75 MM - 840 CFM*
    80 MM - 892 CFM*

    *Information given by Tech Rep.


    70 MM - 726 CFM

    Edelbrock, Ford Racing and Proffessional Products have no cfm information after calls/emails.

    Information to keep in mind when picking out a throttle body for your application:

    A 300 cubic inch engine (302 c.i.) flows 521 cfm at 6,000 rpm.
    A 330 cubic inch engine (331 c.i.) flows 573 cfm at 6,000 rpm.
    A 350 cubic inch engine (347 c.i.) flows 600 cfm at 6,000 rpm.

    With the above information from Accufab's website, you can see that the aftermarket throttle bodies offered flow much more than your engine can breath (302-347). Those cfm ratings are even given with NO restrictions and of course our engines all have restrictions, via our heads, cam, intake packaging. An actual running engine flows somewhere in the neighborhood of 200-400 cfm with some rough math. The aftermarket throttle bodies flow two times this amount.

    In short, be careful on picking 'too big' of a throttle body for your car. An application with boost (forcing air) allows for you to efficienty select a bigger throttle body, although N/A engines do not.

    If you've got a throttle body that delivers 100% of the peak air requirements of your engine when the throttle plate is fully open, you have control of the air throughout 100% of the throttle position range. If you go to an oversized TB that delivers 100% of the air that your engine can consume while the throttle plate is only 60% open, you have given up usable throttle-control range for no advantage.

    Stock Throttle Body and MAF sizes:

    1986 - 58 mm TB
    1989-1993 - 58 mm MAF and 60 mm TB (not Cobra).
    1993 - 70 mm MAF and 65 mm TB (Cobra).
    1994-1995 - 60 mm TB (Cobra's included).

    1996-2001 SOHC - 80 mm MAF and 65 mm TB.
    2002-2004 SOHC - 85 mm MAF and 65 mm TB.
    1996-2001 DOHC - 80 mm MAF and Twin Round 57 mm TB.
    2003-2004 DOHC - 90 mm MAF and 56 mm TB.

    Gear Calculator:


    Reference with T5 transmission/stock tire size/16in. wheel, in 5th gear cruising rpm at 70mph (Interstate Speed):

    2.73:1 - 1696 RPM
    3.08:1 - 1914 RPM
    3.27:1 - 2032 RPM
    3.55:1 - 2206 RPM
    3.73:1 - 2318 RPM
    3.90:1 - 2423 RPM
    4.10:1 - 2548 RPM
    4.30:1 - 2672 RPM
    4.56:1 - 2834 RPM

    Fuel Injector Selection:

    Injector HP Ratings: divide flow rating by .5 and multiply the result by the number of injectors. The following examples use a 100% duty cycle. These ratings are for N/A engines at the flywheel.


    19 lb injectors/.5 = 38 - 38 x 8 = 304 HP
    24 lb injectors/.5 = 48 - 48 x 8 = 384 HP
    30 lb injectors/.5 = 60 - 60 x 8 = 480 HP
    36 lb injectors/.5 = 72 - 72 x 8 = 576 HP
    42 lb injectors/.5 = 84 - 84 x 8 = 672 HP

    The preferred duty cycle is about 85% maximum, so for a safety factor multiply the final figure times .85.

    304 HP x .85 = 258 HP for 19lb injectors
    385 HP x .85 = 326 HP for 24lb injectors
    480 HP x .85 = 408 HP for 30lb injectors
    576 HP x .85 = 490 HP for 36lb injectors
    672 HP x .85 = 571 HP for 42lb injectors

    Remember that the above ratings are at 39 PSI. Increasing the pressure will effectively increase the flow rating. Example: a 19 lb injector will flow 24 lbs at 63 PSI, and a 24 lb injector will flow 30 lbs at 63 PSI.

    See http://users.erols.com/srweiss/ to get the calculators used in these examples.

    The above information is courtesy of jrichker!

    Static Compression Calculator:

    There are many factors that contribute to static compression:

    Bore, Stroke, Number of Cylinders, Combustion Chamber Volume, Piston Volume, Head Gasket Thickness, and Deck Volume for basic calculations.

    Static Compression Example using Compression Calculator Link

    Bore - 4.00"
    Stroke - 3.00"
    Number of Cylinders - 8
    Combustion Chamber Volume - 58cc
    Piston Volume - (-4cc, dished piston)
    Head Gasket Thickness - .039"
    Deck Volume - .010"

    Compression is 9.581:1
  2. Thanks DMan:nice:

    I'm editing this as I go, and adding more info and more correction...
  3. Is there some mathematic formula that can give you close numbers to how much horsepower your engine flows? I see you posted up some numbers for 300, 330 and 350 cubic inch engines and it seems they are flowing ~1.72 times their displacement. This can change alot with heads, intake, cam, etc etc. Just looking to figure out approximately how many CFM my engine will flow.
  4. According to that, my throttle body is about 2x the size that I need. I saw some dyno numbers though going from a 75mm to a 90mm throttlebody on these TFS box R intakes and gaining a decent amount of power.
  5. There are many factors to why people get gains from throttle bodies.

    They didn't match the inlet the first time and then dynoed it again after they port matched it.

    They dynoed on different days with more mileage on the engine (you gain horsepower that way).

    I have yet to see a back to back dyno with a bigger throttle body that gained power.

    One way to tell if it is the day/dyno showing the gain is if you see a gain across the powerband. That shows that it is inaccurate, because if it is showing a gain at 2,500 or 3,500 rpm it is off. Reason being is because, as in your example, a 75mm TB would flow plenty at that rpm, why would the 90mm TB gain it more horsepower if the 75mm can easily keep up at that RPM.

    I hope that made sense.

    What I would like to see, in which I have yet to see, is a back to back dyno. I imagine if any gains it would have to be in the upper rpms.
  6. Stock upper-198
    Saleen/Vortech - 180

    I'm pretty sure a Saleen/vortech intake doesn't flow worse than a stocker. At least I hope not.

    Great thread btw.
  7. Thanks, the intake flow numbers were all sourced by different testers. Numbers will vary slightly.

    Also, the intake numbers are averaged, not peak cfm flow.

    Uppers typically flow more than a lower/upper. The lower intake is usually the more restrictive of the two part intakes.

    The design is different as well, as I believe it was designed for the optional supercharger from Saleen. Correct me if I'm wrong.
  8. the stock lower is listed at 150 so the stock intake would likewise be 150, where the saleen/vortech is 180

  9. I'll have to dig out the MM&FF mag I saw it in. My guess is that it made the gains because the 90mm throttle body is the same size as the opening on the intake causing less turbulence or something. It was a surprisingly large difference though for going from one throttle body to another. I can't remember exact numbers though.
  10. You got it:nice:

    Bloodreign - I would love to see the article and then hope they didn't do any tuning after the change or I hope it was on the same day/same time (roughly).
  11. Thats because that was REAL world proof instead of internet chart theory. I too have seen gains on cars stepping up to a "bigger" tb.

    Not to ruin the thread, but when theres incorrect info given, it has to be corrected. If necessary, i'll post a thread or 2 disproving the internet chart theory. But im not getting paid for this, so maybe i'll let you guys do the work :D
  12. Post them up Grn92lx...I have no problems with that. Just keep it civil.

    Unfortunately we see to many variables that change. The track is a very inconsistent form of this.

    I have gained 3 mph by doing no changes to my car. If during that time I had a less restrictive engine and added a throttle body, it may have appeared to gain 5mph from a throttle body installation alone.

    There is not thing as such 'internet chart theory'. A chart simplifies, for us readers, the happenings in 'REAL' world testing.
  13. Damn yall thanks for the chart and info, but we did get carried away on throttle bodys. I have always edlebrock heads kick ass, but anyone ever run the Patriot Heads? Are spring pressures on the heads to soft as set up from manufacture? What should spring pressure be for an F303 cam?
  14. I agree, I've dynoed Alot of different cars at the dyno at my school and 75% of the vehicles (stock from the factory ones) will have at least 3rwhp give or take from each run back to back. My teacher said he always saw the best numbers on the second run cuz the first run gets the cylinder temps up to temp, but I believe it's more than that also. We used an inertia dyno so all it does is calculate it from how long it takes to spin the dyno rollers which are a certain weight and mass (basically a big truck rear end underground as my teacher said). so if you mash the gas at a different time or have momentum while cruising up to your start speed/rpm(when it starts calculating how long it takes to gets the rollers going) it's going to be a different reading then if you slowly climbed up to that slower start speed/rpm and then mashed it. When I dynoed mine I kept it in mind and did the exact same everything and I would have .5 rwhp+- difference back to back. Coincidence? maybe, but my teacher said he never sees a car with such consistant results everytime.
    Also before we did any runs in the morning we would run it till the oil in the differential underground would reach 106 degrees i believe it was. Who knows if that really mattered but that's we did. There's so many variables.