Why do turbos use bigger injectors?
02-12-2007, 11:20 PM
#1
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Why do turbos use bigger injectors?
I've always been curious about why turbos (Miatas specifically) all seem to use bigger injectors instead of using additional injectors?
So why not use OEM injectors and save your idle and use additional injectors to only add fuel while in boost?
So why not use OEM injectors and save your idle and use additional injectors to only add fuel while in boost?
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02-12-2007, 11:55 PM
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So why not use OEM injectors and save your idle and use additional injectors to only add fuel while in boost?
It's not like we tune to idle at 12:1 AFR....you still tune for 14.7:1 idle while adding fuel while in boost. Regardless of the injector size.
miata specifically?! ever car needs fuel per a given HP. you cannot support 400BHP with OEM injectors...it's all in the math.
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02-13-2007, 02:02 AM
#7
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save your idle? you can idle 550s like stock with a standalone ECU. A 5th injector is a very unnecessary complication, and not an ideal setup anyway.
I've always been curious as to why people try to use use ~100hp injectors to make 220hp...
I've always been curious as to why people try to use use ~100hp injectors to make 220hp...
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02-13-2007, 08:02 AM
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Unless you have a custom manifold with extra injectors bungs aimed at the runners (ala BRP or FM's old mani), then you won't get ideal fuel distribution from the one or two injectors dangling off the intake tract in front of the throttle body or wherever, either.
It's just not ideal.
It's just not ideal.
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02-13-2007, 08:38 AM
#9
Unless you have a custom manifold with extra injectors bungs aimed at the runners (ala BRP or FM's old mani), then you won't get ideal fuel distribution from the one or two injectors dangling off the intake tract in front of the throttle body or wherever, either.
It's just not ideal.
It's just not ideal.
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02-13-2007, 07:42 PM
#10
Most people (not just Miata peeps) use the increasing injector size and/or fuel pressure method. Actually, the only guy I know who had a 5th injector setup was a friend with a 96 Miata...
Besides, to run an extra injector you need the hardware to plumb the thing in and the software to control it, and it'll be an inefficient setup because of how far upstream of the cylinders it'll be. Then by the time you add up the cost of all that you might as well have bought an EMB or Megasquirt.
Besides, to run an extra injector you need the hardware to plumb the thing in and the software to control it, and it'll be an inefficient setup because of how far upstream of the cylinders it'll be. Then by the time you add up the cost of all that you might as well have bought an EMB or Megasquirt.
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02-13-2007, 09:40 PM
#11
Why???
Because Miata owners do it right the first time
I have both
305's in the Engine, 1 550cc before the TB.. Also I have a TB plate that has spots for two..
I would have preferred my PC setup to the EMB, but as already mentioned MS/EMB is cheaper then even purchasing a simple EIC. I needed more fuel. After I added the EMB, adding larger injectors was too simple... Other folks use an EMB/AFPR and larger injectors..
Because Miata owners do it right the first time
I have both
305's in the Engine, 1 550cc before the TB.. Also I have a TB plate that has spots for two..
I would have preferred my PC setup to the EMB, but as already mentioned MS/EMB is cheaper then even purchasing a simple EIC. I needed more fuel. After I added the EMB, adding larger injectors was too simple... Other folks use an EMB/AFPR and larger injectors..
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550s FTMFW
02-14-2007, 07:55 PM
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I dunno, anyone out there taken a look at the Mazdaspeed 3. I'm still trying to crack into the thing for knowledge but if they are not cam controlled (don't see why they would be) and don't require some sort of extra mounting why not use those injectors to handle the extra fuel load. I don't even see how there would be an issue with distribution of fuel between the cylinders.
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02-14-2007, 10:52 PM
#20
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You won't be controlling direct-injection injectors anytime soon in your Miata...at least not without a ECU that can process quickly enough and a cam-driven fuel rail pump that can ramp up 1,500+ PSI of pressure.
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