Dominic Sorresso

Two years ago, I replaced my failing Accel #21 injectors w FIC for my LT5. Supposedly, the FICs were rated at 1% +/- for flow. On a hunch I had them flow tested and found they weren’t close to that. The LT5 uses 16 injectors w what is a valet key to allow use of all 16 injectors. The paired injectors allowed me to get improve the cylinder to cylinder balance from > 10% to within 2%.
The difference in how much smoother the motor runs and accelerates is pretty amazing.
However, even tho I got some “ballpark” Injector Bias values from FIC, based on how the VE tables, I have that “well” or pit in the idle and small PW area of the VE. I’d like to find someone who could test the injector and get the proper IB values if possible.
Anyone know of a vendor who would do this? Unfortunately, the place that did the flow testing for me locally does not do the Injector latency testing.

RBob

iTrader: (1)

Dominic, these folks may be able to do it for you: Injector Dynamics:

http://injectordynamics.com/

RBob.

Larry

Another is https://deatschwerks.com/pages/injector-services

Dominic Sorresso

Thanks for the suggestions. May check w both of them. As stated with my initial post, a “well” appears in my VE table in the area for idle which is suggestive of incorrect IB. However, a question for anyone that may want to answer. As my LT5 has Stage 2 intake and exhaust cams, I have lowered the O2 voltage biases for the 0-15gms/msec due to increased overlap. Would that also affect VE in the idle area(creating the “well”) given that I am commanding the ECM to run a bit leaner in that part of the table?

Dominic Sorresso

As an update, I sent a couple of the FIC injectors to Deatschwerks for their IB testing. I provided them w the voltages that are used in the calibration and they graciously provided the offsets using those voltages. No interpolation required. Very kind of them.
After plugging those values into the table, I was a bit surprised by the extent they impacted the overall VE tables. I was expecting perhaps changes to idle and decel, but the changes to the VE were much more extensive than that. Pretty much up to around 2800rpm and in all 4 VE tables found in the LT5 calibration. Starting the motor for the first time, I was struck by how much quieter the motor was. The following datalogs really showed how the change in IB “leaned” out the mixture. In some cases, the IB was 40% shorter than what I had been using, so the VE needed to be increased in order to compensate. But overall, the motor appears to run smoother than before.
The combination of using the correct IN and having preciously balanced the cylinder fuel delivery has really changed the characteristics of the motor. Idle is very steady altho the motor is cammed. No hint of the motor shutting off on freewheeling decel, which is a common complaint among ZR-1 owners. Especially if using a lightweight flywheel.