Changing Fuel Injectors
From SCT SRT Wiki
Basic Tuning: Changing Fuel Injectors
Maps altered:
Description: The following steps explain how to modify the pcm to run larger/smaller injectors. These directions are for a static fuel pressure of 58psi. If you are using a 1:1 RRFPR, then you will need to set that up described on this page.
Directions:
- Calculate the flow of your new injectors for 58psi. Most aftermarket injectors are rated at 43.5 psi. This is done by taking the square root of the new pressure divided by the old pressure and then multiplying by the original flow rate.
- Divide the new injector's new flow rate by the stock injector's flow rate to achieve a ratio.
- Multiply all values in the "mg/charge/cylinder" by this ratio.
- Make sure that both tables are updated.
Example:
- 650cc injectors are rated at 43.5 psi. At 58psi, they flow 750.56cc. (sqrt(58/43))*650
- 750.56/577.1= 1.30057
- multiply all values by 1.30057
Here is a calculator that will aid in this conversion for you:
[Fuel Conversion Calculator:http://www.rearsync.com/calc/fuel_cal.php]
Flow rates for mopar injectors:
03' stock = 527cc
04' 05' stock, stage1 = 577cc
stage 2 = 682cc
Flow rates for RC Engineering injectors converted for N-Heptane flow specs:
RC 750
750 cc/min at 43.5 psi using RC Engineering test fluid.
712.05 cc/min @ 43.5 psi using N-Heptane test fluid.
822.2 cc/min @ 58 psi using N-Heptane test fluid.
RC 650
650 cc/min at 43.5 psi using RC Engineering test fluid.
617.11 cc/min @ 43.5 psi using N-Heptane test fluid.
712.58 cc/min @ 58 psi using N-Heptane test fluid.
It is important to use the RC injectors converted to flow using N-Heptane for your calculations of "Convert PW to Fuel Mass" and "Fuel Mass to PW Conversion" If you do not your calculations for "Power Enrichment Above Stoich FA Ratio" will be off and you will have to adjust accordingly.
Screenshot: These are stock maps
