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?

 

4 is easier to tune with than 5...6...8? With an ECU...you don't have to idle bad...and always have headroom.

 

Because a lopey, crappy idle is quite possibly the coolest sounding thing a car can do.

 

Because my car gets eleventy billion more hp each time i tell someone i swapped my injectors for ones out of a supra:gay:

 

My car is more classy now that it has Lexus injectors.

 

For some reason us turbo guys like to support our particular amount of HP with the appropriate amount of fuel. Plus the added bonuses of knock supression.

You just need a controller to run the 5th injector anyways.....

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.

 

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...

 

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.

 

Yes this coupled with the cost of a standalone like EMU &,MS, vs SS system isnt to far off.

 

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.

 

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..

 

not to thread jack but what would be ideal injectors for 215hp reilable

 

depends....using and FMU or a piggybacy or stand-alone?

 

Or a combination of two of those options?

 

for a FMU and FP i would go with some 265's
For a upgraded ecu either 330's or some 460's which ever you can support.

 

550s FTMFW
currently 54% max IJDC, probably just north of 200rwhp (and running rich)

 

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.

 

SCC wrote a good tech article on the new DISI engine from the 'speed 3,6, and CX7.

What's your question, Eva? How to best increase fuel in a direct-injection system?

 

https://www.miataturbo.net/forums/sh...ghlight=max+hp

some additional injector talk in this thread

 

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.