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** All-Motor Build General Information **

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    ** All-Motor Build General Information **

    This thread was created to provide general information for all-motor or NA (naturally aspirated) engine builds.

    STATUS OF THIS THREAD: In progress....Updated 10/2/08.
    Last edited by HondaFan81; 10-02-2008, 01:07 PM.
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    Short-ram Intake: Less surface area, less airflow friction, more prone to engine bay heat in original form.

    Cold-air Intake: More surface area, more airflow friction, cooler air intake charge, more frequent filter cleaning necessary, prone to water ingestment/hydrolock.

    THROTTLE-BODY: >> Contact: Jorge

    Auto vs Manual:

    1. Automatic throttle-bodies can be used for both manual & automatic applications. The differences are in the throttle-rotors which have 2 pulleys on the automatic, one for the throttle-cable & the other for the automatic shifter linkage.

    2. Manual throttle-bodies can be used for manual applications only, as they have a single throttle-rotor for the throttle cable.

    3. Bypassing coolant lines to TB:
    > coolant warms incoming air
    > in cold weather conditions, coolant prevents TB butterfly from sticking
    > when installing Hondata or similar intake manifold gaskets, this process is included in the installation directions
    > eliminates functionality of fast-idle thermo valve (on Hseries TB's), longer engine warm-up time

    4. Tapered throttle-bodies:
    > taper helps increase incoming air velocity & helps keep some low-end
    > 3, 5 and 6 degree tapered designs available, maybe more

    5. Individual throttle-bodies:
    > increased throttle response, air travels shorter distance
    > less air friction than traditional intakes
    > more of a race-type application
    > most modify motorcycle ITBs to fit
    > expensive pre-fabbed ITBs are available such as: Toda, Jenvey, etc.
    > more difficult to tune
    Things To Consider:
    - air filtration to protect engine
    - runner length (longer = more torque, shorter = more top-end)
    - port size (volume vs air velocity)


    1. Plenum - This is the air chamber located above the runners of the intake manifold/upper-half. This chamber serves as a resorvoir of air, ready to be sucked in by each cylinder. Depending on how efficient your motor is from the factory, sometimes increasing the plenum volume helps with performance if your engine breathes well and other times it makes no difference because your engine is already maxed out on how much it can breathe in.

    2. Runners - There are many aspects to runners such as: port-size, length and geometry.

    Each engine setup has an optimal runner port-size that gains the most volume at the least sacrifice of air velocity. A taper in the runners can help balance air velocity with volume.
    In general, long runners make more torque/low-end and the shorter runners are for top-end.
    Runners should have smooth bends if you must have them for best airflow or just keep them straight as in some ITB setups. Again, tapered runners can help balance air velocity and volume.
    On the inside and cylinder head end of the runners, a semi-rough finish helps with fuel atomization and with power. Think of it as air tumbling with the fuel sprayed by the injectors, then getting sucked into the cylinders through vacuum.

    3. Intake Manifold Related Tips - Things I have learned on my F22ax SOHC NA builds.
    > if running aftermarket camshaft, block off air starting/boost valve or it will cause vacuum leak
    > run chipped P06 ECU or similar that doesn't recognize an EGR system, if you wish to block it off
    > if running aftermarket camshaft, you may need to raise your idle RPM to develop enough vacuum for consistency through engine management
    > if running aftermarket camshaft, do not be surprised if your idle screw & IACV do not help for consistent idling
    > consider replacing your IAT (intake air temp) sensor if old


    Headwork: >> Contact: Jeff Fredenburg >> Contact: Aaron Byram

    1. Portmatch - This can be done on both intake manifolds and exhaust manifolds/headers. Where the manifolds meet the cylinder head ports, the mating areas are cleaned up so they flow well into each other. Basically, this helps in getting the most potential out of your existing setup, but will not get you crazy gains.

    2. Mild Port & Polish/Clean-up - This is what most DIYs are. This involves a portmatch, but also involves going into the ports a little to clean up any flash, etc. Usually no excessive porting is done, mostly a port clean-up. This obviously will flow a bit better than a port-match, but still nothing too crazy, again most to get the most potential from your exisiting setup and remove the casting flaws.

    3. Performance Port & Polish - Now this does all the above, but they get crazier on the porting, usually enlarging the ports some, cleaning up the casting flaws, using certain grit rolls, etc. for good flow and A/F mixture. This job is usually involved with a valve-job, new valve stem seals, head cleaning and resurface and/or mill. They hit both intake and exhaust ports. Most of all, this is a black-art and that is why different companies/people have different reputations regarding their experiences and builds. Some companies/people are average and some are top-off-the-line ballz to the wall performance.


    1. Naturally-Aspirated/Nitrous - Camshafts for this application typically have more duration and more overlap for the scavenging effect to recharge the cylinders with a fresh intake of air.

    2. Forced Induction (i.e. turbos & superchargers) - Camshafts for this application typically have less overlap because with a pressurized intake you would defeat the purpose of filling the cylinders to their max potential.

    3. Valve Lift - This is the distance a valve opens from the closed position at the valve seat. Typically camshaft specifications are given with max valve lift measurements for both intake and exhaust.

    4. Cam Lobe Lift - This is the distance from the outer diameter of the cam base circle to the tip of the tear-drop shape. Typically camshaft specifications are given with max cam lobe lift measurements for both intake and exhaust.

    5. Rocker Ratio - This is the ratio number you get when you take max valve lift and divide it by max cam lobe lift. This ratio is handy if you retain your stock rocker arms on a performance build and use a performance camshaft(s) of some sort. Using this ratio, you can indirectly find the max valve lift for any camshaft(s) that you know the max cam lobe lift specifications for (which most/any camshaft companies can give you).

    6. Overlap - Amount of duration (degrees) that the intake and exhaust valves are open at the same time. This is related to the scavenging effect and on most naturally-aspirated engines can produce more gains in power, some engines are more responsive than others. Some people have found that some overlap even on turbo applications yield good power gains as well.


    Off-shelf Header: Brands like DC sports, Megan Racing, DC-S, OBX, etc. are in my opinion more for the basic bolt-on modifications such as intake, exhaust, mild camshaft(s) with low compression ratio. Most of these are 4-2-1 design. I do not recommend, based on first-hand experience, Kamikaze brand headers, as their quality is very low.

    Custom Header: Custom in my opinion are in order for applications that are extreme NA and have high compression ratio, aggressive camshaft(s), nice headwork and good flowing intake system. Bisimoto Engineering is the best for any motor they have an application for (i.e. F22ax SOHC, B-series, D-series, etc.). SMSP has nice all-motor H-series headers.


    In general, 2.25" exhaust systems for setups that require off-shelf header. I would go with 2.5" exhaust system for something more extreme NA that would require a Kamikazee or custom header.

    Last edited by HondaFan81; 10-28-2009, 01:22 PM.
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      Transaxle Swaps:

      Most, if not all H/F series transaxles are interchangeable. It comes down to what final drive do you want, what gear ratios, what type of differential and the choice of automatic or manual.

      TUNING: >> Injector Cleaning & Flow-Balance >> Wideband >> Tuning Equipment/Hardware >> Tuning Equipment/Hardware
      Last edited by HondaFan81; 07-02-2008, 12:27 PM.
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        Suggestions for oil system on F22 performance motors thread:
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