Injector Tuning

[SpinMonster]

Anyone have any tips on tuning for bigger injectors? I want to go from 32.5's to 42's and was looking for info on injector flow rate and/or pulse. What gets changed?...both?

[John@SDPC]

What software are you using? You will have to change the flow rate, and to determine the factor for changing that table use this formula:

New Injector Flow = Sqrt(New Fuel Pressure / Old Fuel Pressure) X Injector flow rating at old fuel pressure

Then factor = New Injector Flow Rate / Old Inject Flow Rate

If the numbers you have below are both the ratings of fuel flow at 58 psi (our normal fuel pressure), then you will have to increase the flow table by ~30% (42/32.5)

[muncie21]

Do a search on LS1Tech for injector flow spreadsheet. RHS over there has a well refined spreadsheet that calculates the injector flows. The spreadsheet is kinda setup for HP Tuners, but the flow numbers are the same regardless of the tuning package.

[John@SDPC]

You can find the injector flow sheet here. However, be careful when entering data. Some systems may use g/s, lbs/hr for the flow (although if multiplying a percentage it doesn't matter what the base units are), or the axis might be in manifold vacuum or manifold pressure. Just an FYI.