Hi folks! I recently acquired an OBDII diagnostics tool that is capable of programming fuel injectors on the R53. Until now, I did not know that “injector programming” is a thing. For the benefit of the uninitiated, it involves feeding a code (printed on each injector) into the ECU, thereby telling the ECU the exact maximum flow rate of the component; that is, whether a “550cc” injector flows at 550cc/min on the dot, or 545, or 553. The ECU then uses this data to calibrate its fuel delivery.

This raises a question. I have a set of Bosch 550cc injectors that I want to install instead of my stock 340cc. Until now, I’ve understood that I’d need to flash the ECU to allow it to compensate for the higher flow rate. But is that still necessary if I can now program the new injectors myself? In other words, does “flash the ECU for larger injectors” = “program the new injectors”? Or are they two distinct things, each equally necessary?

Thanks in advance for your insight!

 

Check out this helpful link: https://injector-rehab.com/knowledge...or-duty-cycle/

Also, viewing your current mods I doubt you'll be able to efficiently use those 550cc injectors without a cam swap. Jumping to 380cc with a re-tune is probably what you need (without the higher lift cam).

 

Yes, they are the same thing. You have to account for the difference in flow and injector dead time.

I thought codes on injectors were a direct injection thing though?

 

I'm in agreement with cooper48 WRT 550cc injectors seemingly being too large for the engine mods stated in your sig line. With mods (if any) to my own cylinder head unknown, I chose and installed OEM JCW 380cc injectors in combo with a remote tune performed by Adrian (forum member adriancl in Romania) to optimize efficiency rather than maximize peak power. I fully achieved my objectives but question whether you'll have issues with AFR and LTFT with those 550cc.

 

In reality those injectors being "too large" just isn't a thing.
you can run 1000cc injectors on a stock engine as long as they are scaled properly, you just won't use more than 33% of their potential, and they would have to be able to handle the minimal pulse requirements. (Cheap injectors sometimes can't)

They just have to be scaled properly.
But that involves more than simply figuring out there proper percentage of maximum flow, they need to be scaled for the entire rpm range since percentage of flow varies under not only rpm but demand under conditions as well. (Esp torque demands)

It will take an actual tune, not just a simple overall calculation and change.

 

I doubt a diagnostics tool can modify the ECU software for bigger injectors using the part number of injector.This procedure is used on most modern diesel engines, but we talk about high pressure injectors . over 23000Psi, not for 4 bar injectors.Even your tool can rescale for bigger injectors, is not enough, because bigger injectors have a different latency time than stock, will need to modify also fuel map for cruise and for WOT., also ignition maps.And that is not enough.

 

I think you would have to admit that scaling 1000cc injectors to 33% efficiency is a waste of both time and money, therefore they are "too large" for his application.

 

Thanks for the link, I’ll check it out! Also, thanks for alerting me that my signature was out-of-date. I had a RMW/Newman street camshaft installed last year, and a Milltek header & cat last month. I’ll add those to my sig now.

 

Given the cam and exhaust mods you've mentioned it's likely that 550cc injectors would a nice addition. When you have them installed contact adriancl on this forum for a remote tune via your laptop & OBD II connection. He knows R53s inside and out and has performed hundreds of tunes, many for members on this forum, including me. Adrian is in Romania so you'll need to adjust for the time difference.

 

I figure I ought to close the loop on my original question here, lest any readers be confused or led astray.

TL;DR: Fuel injector coding does NOT apply to the R50/R52/R53, and therefore one will indeed still need to reprogram the ECU if they install larger-than-stock injectors.

To elaborate on this, as was mentioned above in other members’ posts, injector coding applies to direct-injection engines (common in diesel and newer gasoline engines), which involve very high fuel pressures and tight tolerances. The R50/R52/R53, however, uses the older method of port injection. Port injection involves much lower fuel pressures than direct injection, and this presumably negates the relevance (or maybe even the possibility) of fine-tuning each individual injector.

Thank you, everyone, for helping to get me on the right track!