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Thread: Bigger injectors=more power NA?

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    Idling - Listen to it purr... alexlula's Avatar
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    Question Bigger injectors=more power NA?

    alright i feel stupid asking this but here i go... i bought some red tops RX-7 460cc injectors and a RX-7 afm last month and i had a quick discussion with a friend of mine and he told me that adding both of these on a naturaly aspirated engine would give me a minor power gain now i know that the afm has a minor torque gain in the 7k rpm but would the bigger injector make a difference ?

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    3,000 rpm - starting to feel the power BoBo's Avatar
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    The stock injectors should be adequate for non turbo engines. I don't think there's any gain on HP just by adding bigger injectors on a naturally aspirated motor. It might cause your engine to run rich and loose hp, but if you add a turbo kit and a standalone ecu, those 460cc injectors will gain you substantial HP since the turbo will pump more air into your combustion chamber.
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    3,000 rpm - starting to feel the power freedomgli's Avatar
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    Short answer is no, not really. You are not fuel limited and so bigger injectors won't give you more power.

    Re: RX7 AFM, you're right, you might see a small hp bump at peak rpm. But IMO, it's not worth it these days unless you can get one really cheap and have low expectations.

    http://www.solomiata.com/airflowmtr.html

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    Bigger inhectors actually take longer to ramp up and down and if you don't have forced induction to take advantage of the added fuel, it's all really pointless.


    No todo que es oro brilla.

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    4,000 rpm - entering the fun zone Hyper's Avatar
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    if you want more power increase the timing to 14 degrees and use higher octane fuel, make sure your intake gets cold fresh air and install a vent to atmosphere catch can to avoid recirculating hot valve cover gases back to the intake manifold
    Last edited by Hyper; 02-27-2015 at 02:13 PM.

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    First, thanks for asking the question! There are no stupid questions here.

    The RX-7 used to be considered a good mod, but it takes some finesse to get it to work correctly. The injectors won't work and the car probably won't run more than a few seconds with them. The _is_technically a way to make them work, but nothing you are running, n/a, would support them, so no, they won't add power.

    The best way to add power to a b6 engine is forced induction, or swap in a BP4 from an NB.

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    4,000 rpm - entering the fun zone wannafbody's Avatar
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    I have a RX7 Meter on my 99 1.8 swap. it works but the idle is a bit funky in the cold. It's not a daily driver so I can live with it.

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    2,000 rpm - light wheelspin, no bog here! ADOBOMiata's Avatar
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    If you want more power for a NA vehicle. Tuning with a megasquirt and deleting the maf (using a gm IAT sensor-etc) will definitely do the job.

    BorgWarner EFR 6758, Built 1.8, mspnpv2

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    Idling - Listen to it purr... alexlula's Avatar
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    Quote Originally Posted by Hyper View Post
    if you want more power increase the timing to 14 degrees and use higher octane fuel, make sure your intake gets cold fresh air and install a vent to atmosphere catch can to avoid recirculating hot valve cover gases back to the intake manifold
    im kinda new to this, how do i advance timming on the mx-5 and i am currently building a turbo kit

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    2,000 rpm - light wheelspin, no bog here! ADOBOMiata's Avatar
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    Quote Originally Posted by alexlula View Post
    im kinda new to this, how do i advance timming on the mx-5 and i am currently building a turbo kit
    ️️Timing light, adjust the CAS (that large circular part that connects to the exhaust can.)

    BorgWarner EFR 6758, Built 1.8, mspnpv2

    295whp, 271tq @14psi



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    3,000 rpm - starting to feel the power freedomgli's Avatar
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    ^^ you forgot to mention jumping the pins in the diagnostic connector.

    See this link for a basic explanation. Also get a factory workshop manual and some other supplemental workshop guides (Rod Grainger's "Enthusiast's Shop Manual"; Keith Tanner's "How To Build a High Performance Mazda Miata," "Mazda MX-5 Miata: Find It, Fix It, Trick It" and "Miata Performance Projects" just for starters).


    Also go to Miataturbo.net and read the DIY FaQ - ALL your answers in one big post and then spend about 40 hours reading the DIY Turbo Discussion forum before buying anything or asking any questions. There are more ways to mess up a Miata than to improve it when you're talking about turbocharging. It is a very deep rabbit hole that has swallowed, chewed up and spit out many wishful Miata owners. Good luck!

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    3,000 rpm - starting to feel the power BoBo's Avatar
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    Quote Originally Posted by alexlula View Post
    im kinda new to this, how do i advance timming on the mx-5 and i am currently building a turbo kit
    If you are building a turbo kit don't bother with timing advance. If you advance ignition timing you will have to worry about pinging on very hot days and the extra expense on using higher octane fuel. Not to mention the added load you will put on your pistons for 1hp who knows unless you use a dyno to know your gains. Your best friends will be a Standalone ECU and a tuner whether you go Turbo, Supercharge or Naturally Aspirated because the hp improvement you will get is so much greater than a timing advance.
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