Tuning 900cc/min

[Longuy]

Hello,

We have bought DW 900cc/min injectors for our 2016 BRZ.

First, The technician claimed there wasn't a “flow chart” included with the injectors for the tune. Is everything needed to calibrate the injectors included in:

https://www.deatschwerks.com/sites/w...0Settings.xlsx

Second, application of the injectors:
ECUTEK
MAP 2.5 bar
DW HO fuel pump
Jackson Racing C38 supercharger system with small pulley
Tomei Header
Invidia over pipe
Invidia High flow Catted down pipe
Nameless axle back muffler delete

The technician claimed the injectors are to big for the application. Will the technician be able to scale the injectors to meet the application? (max duty cycle 35%)

We are trying to work with what we have. Tuning is expensive and don't want to pay, to not have the car tuned because the injectors were to big

Thanx

[dholloway543]

This is a little complicated but the injectors run on PWM (https://en.wikipedia.org/wiki/Pulse-width_modulation)


I'm not an expert in the matter but. From what i understand, the bigger you go on injectors the more the flow scale is stretched out.
So the car has a set frequency that the injectors run at meaning there is a defined range that the injector can squirt. The ecu can only step the frequency be a predefined step because of said frequency. Increasing the injector size means the ecu has the same scale to work with but the values of injector squirts are now more spread out. If I had to guess the frequency of the injectors would have to be some multiple of the rpm such as (250hz * RPM) to keep it in sync.

long story short the bigger the injector the harder it is to get the right amount of fuel in the idle areas because each percent increase on the injector is a big jump in fuel.

This only matters during startup because I think the frs ecu is set to use port injectors for cold start but after it warms up it only uses the direct injectors to idle.

If your planning on pushing more boost and you need more injector though its better to have more headroom on your injectors as you wont run lean by running out of injector headroom and your injectors might last longer due to not being run so hard.


I believe that pushing more fuel in a shorter amount of time. IE bigger injectors lets more gas enter the chamber and mix more even. Where as smaller injectors held open longer might have the valve start closing and have more gas hit the valve. But who knows I might be wrong

As for the tuning aspect of the situation IDRK if that is all the information you need.

[Longuy]

Thank for taking the time to comment, it expanded my understanding.. im new to this.

The injector box was open when I got home. idk what paper is missing that the tuner needs

[dholloway543]

The paper would look something similar to this.

[tomm.brz]

Better to use the right datasheet as every injectors have their own specs
Also deatchwerks injectors are a bit bad at low width pulse compared to others so it needs attention, and 900cc are actually 1100cc in this car

For example, DW 900cc have non-linear fuel delivery already under 3ms of opening
Fuel Injector Clinic 900cc are more linear at low pulses... big difference in quality!


so from the DW datasheet on their website (not the excel with suggestions, that's rubbish), try your tune like this:



the sheet is here: https://www.deatschwerks.com/sites/w...%20Summary.pdf

If it jerks, try rising minimum opening time to 3ms and remove some %PI at lower loads

[Longuy]

Thank You all !!

Very Helpful