I thought it would be good to post the proceedure for Injector Nozzle Tuning. There has been alot of speculation as to what this means and the easiest way to set the record strainght is to post it for all to see. If you would like the data sheet send me an e-mail with "Nozzle Tuning" in the subject line. The sheet is important so that your data can be collected in a uniform way to be e-mailed or faxed to an injector shop. Don Riveria, Air Flow Performance can inturpt the results of the data and suggest what nozzles to change.
The basis of nozzle tuning is to get each of the cylinder EGT?s to peak at the same fuel flow. Your aircraft must be equipped with EGT information on each cylinder and fuel flow information. A digital flow meter is preferred.
To gather correct data for nozzle tuning, set a cruise power setting. Typically 24? MAP and 2400 RPM. Set the mixture to be 0.5 GPH richer than peak on any cylinder. At this setting record all the EGT?s for each cylinder. Lean the mixture 0.2 GPH and record all the EGT?s again. Lean the mixture an additional 0.2 GPH; record all the EGT?s again. Continue leaning the mixture 0.2 GPH and record the EGT?s until all the cylinders have peaked.
An alternative method although not as accurate is to lean each cylinder to peak and record the fuel flow at that point. You will get the same data, but since the EGT reacts slower than the leaning process you may go past the peak and not know it. This is especially true if an engine monitoring lean find function is used. We get more accurate data taking the EGT data manually. If you use an automatic data acquisition function, allow 30 seconds or so at each fuel flow setting so the EGT value can stable out.
After the data is taken, we determine which nozzles to change to get all the cylinders to peak at the same time. You will notice that the EGT number at peak may not be the same for each cylinder, THIS IS NOT IMPORTANT. The cylinders that peak first (higher fuel flow) are the lean ones; the cylinders that peak last (lower fuel flow) are the rich ones.
Getting all cylinders to peak within 0.2 GPH is ideal.
Injector Nozzle Tuning Procedure
Linear Mode
