Fuel Mass to PW Conversion
From SCT SRT Wiki
Under Section: Fuel Injector
Name: Fuel Mass to PW Conversion
NOTE: When altering this table, it is advised to alter Convert PW to Fuel Mass along with it
Description: Converts Fuel Mass into Injector Pulsewidth
Values: Cyl. Charge to Injector Pulsewidth based in microseconds
Use: To allow the tuner to tune in a bigger or smaller injector size.
Directions:
- Calculate the flow of your new injectors for 58psi. Most aftermarket injectors are rated at 43psi. 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]
Common Injectors Sizes:
03 SRT-4 Stock Injectors -- 527 cc -- Rated @ 58 psi
03 SRT-4 'Stage1 Injectors' -- 577 cc -- Rated @ 58 psi
04 SRT-4 Stock Injectors -- 577 cc -- Rated @ 58 psi
04-05 SRT-4 Stage 2 Injectors -- 682 cc -- Rated @ 58 psi
04-05 SRT-4 Stage 3 Injectors -- 682 cc -- Rated @ 58 psi
RC 650cc Injectors -- 650 cc - Rated @ 43.5 psi
RC 750cc Injectors -- 750 cc - Rated @ 43.5 psi
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.
Related Tables:
Screenshot:
