Larger injectors?

[LeBaronMike]

Hey,

I have an 87 2.5L turbo I converted to Turbo II so I am running 33pph injectors right now. ECU is stage 3 from fwdperformance. I have my boost set above 15psi but i rarely ever hit 15 and no, the wastegate doesnt open to stop the boost. Do I need larger fuel injectors? What do larger injectors even do? I know the obvious, more fuel, but more technical. And yes, I have read the article about installing larger injectors to support more boost on donavons dodge garage. I have a narrow band a/f gauge and when in boost it is 3/4 rich. Any advice/help is appreciated thanks!

[turbovanman²]

Did you put the 2.5L in? Is the cal for the 2.5? Stock injectors, which you have, are good for stock boost levels, usually anything above 15 psi you need larger injectors. If you staying at 14 psi, then you don't need to go bigger.

If you want to go higher in boost, +40's are the best bet as they will support a lot of HP, but you'll need another calibration and a 3 bar map.

[LeBaronMike]

yes i put the 2.5L in and the cal is for a 2.5

[turbovanman²]

Ok, then see above, lol.

[LeBaronMike]

okay what if I use 804 injectors?
Also, so no matter what Ill need a FPR? What else?

[tryingbe]

Stage 3 computer uses 2 bar map sensor, which means the computer will not see boost over 15psi. The computer will give the same amount of fuel regardless if you're at 15psi or 30psi. You will blow your engine if you continue with your plan.



Set your boost BELOW 15PSI and leave it or

Go Stage 4, 3 bar map sensor, wideband, bigger injectors, adjustable fuel pressure regulator or

Go DIY tune, 3 bar map sensor, wideband, bigger injectors.



I have my boost set above 15psi but i rarely ever hit 15 and no, the wastegate doesnt open to stop the boost.

Fix that before you think about adding more boost, unless you like replacing pistons.

[turbovanman²]

okay what if I use 804 injectors?
Also, so no matter what Ill need a FPR? What else?

804's are 33 lb/hr, same as stock. Either go big or go boom, :eyebrows:

[LeBaronMike]

Alright that makes sence! Well I am going to be honest, I dont no anything about map sensors. Is there step by step info on how to turn 2 bar to 3 bar?

[tryingbe]

Alright that makes sence! Well I am going to be honest, I dont no anything about map sensors. Is there step by step info on how to turn 2 bar to 3 bar?

With the car off,
Replace 2 bar map sensor with 3 bar map sensor.
Replace calibration for 2 bar map sensor with a calibration for 3 bar map sensor.
Replace whatever injectors the new 3 bar map calibration is called for.
Install a wideband to monitor a/f ratio
Set boost to 7psi

With the car running.
Up the boost 2psi at a time and keep checking a/f ratio, adjust calibration and/or adjustable fuel pressure regulator, keep repeating until you hit your reach your desire boost level.

Enjoy.

[turbovanman²]

With the car off,
Replace 2 bar map sensor with 3 bar map sensor.
.

The connector is slightly different, you'll easily see that the 3 bar has slots in different spots, just use a knife to match the notch's in the connector.