I have a set of bosh injectors. I think they are 40lbs. The # is 0280150803. My question is: what do I need to do if I want to use these? I have tunercat but I do not know what table to change.

 

Open up your file, click on tables then on the ecm constants table, then change the fuel injector size constant to 40 lbs. You may have to adjust the injector offsets table, but I would suggest you drive the car, collect some data to see where your fuel trims are before making any offset adjustments.

 

On my ecm constants all I have is injector flow rate. I do not have a injector size constant table.

 

they are rated at 40# but thats probably not at the same fuel pressure of our cars so the 40# may or may not be accurate. you have to find out at what fuel pressure they are rated to #40 and figure what the true lb/hr flow rate is. then you can change the injector flow rate of your constants table. its also a good idea to adjust the injector offsets too. do a search for injector offsets and youll find some offsets that should be close the the injectors you are running. the only chart i am aware of however is made for LT1edit which shows the flow rate in millisec so youll have to adjust them accordingly for tunercat.

 

How do you find out the injector flow rate of that bosh injector?

 

You would divide the fuel pressure rating used by GM (43) by the Bosch rating (usually 39.5), then take the square root (1.04).

Then, multiply that by the flow rating of the Bosch (40) and you get your corrected constant (41.73).