Pages: [1]
Author Topic: Max "safe" DI injector ms?  (Read 2402 times)
vwaudiguy
Hero Member
*****

Karma: +53/-37
Offline Offline

Posts: 2024



« on: May 25, 2020, 01:28:28 PM »

I assume it varies a bit by injector, but does anyone have any details to share? Question is directed @ MK6/7 VAG. How high has anyone seen? I assume running with higher ms will decrease injectors life?
Logged

"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
gman86
Hero Member
*****

Karma: +45/-128
Offline Offline

Posts: 705


« Reply #1 on: May 25, 2020, 02:45:22 PM »

I assume it varies a bit by injector, but does anyone have any details to share? Question is directed @ MK6/7 VAG. How high has anyone seen? I assume running with higher ms will decrease injectors life?

I wouldn't be so worried about reducing injector life but more about running out of injection window. In the midrange, where fuel pressure is starting to ramp in properly, you don't want any more than 8-9ms. Slower engine speed means longer window to spray. At 7k, you want to be sub 7ms for healthy margin, sub 8 for safety. 9ms is the injector almost flat out and 10ms is approaching misfire territory. A strong K04 car with 130bar rail pressure will run 6s.

On the EA113, the injectors are sensitive to over-pressure. They're designed to run 110bar but stage 2/2+ setups will run up to 134-136bar. For hybrid turbos, 155-165 and even 175bar rail valves are used but it's at these levels that the filter baskets start to break up and injectors generally fail. If you're having to run more than 150bar to fuel the setup, you want to swap to a better injector.
Logged
gman86
Hero Member
*****

Karma: +45/-128
Offline Offline

Posts: 705


« Reply #2 on: May 25, 2020, 02:46:57 PM »

I wouldn't be so worried about reducing injector life but more about running out of injection window. In the midrange, where fuel pressure is starting to ramp in properly, you don't want any more than 8-9ms. Slower engine speed means longer window to spray. At 7k, you want to be sub 7ms for healthy margin, sub 8 for safety. 9ms is the injector almost flat out and 10ms is approaching misfire territory. A strong K04 car with 130bar rail pressure will run 6s.

On the EA113, the injectors are sensitive to over-pressure. They're designed to run 110bar but stage 2/2+ setups will run up to 134-136bar. For hybrid turbos, 155-165 and even 175bar rail valves are used but it's at these levels that the filter baskets start to break up and injectors generally fail. If you're having to run more than 150bar to fuel the setup, you want to swap to a better injector.

All IMO of course. Others may be more comfortable leaning on them harder.
Logged
vwaudiguy
Hero Member
*****

Karma: +53/-37
Offline Offline

Posts: 2024



« Reply #3 on: May 25, 2020, 04:29:16 PM »

Thanks for your input. One reason I ask, is because we had an injector failure, and I remember seeing 11/12 in the logs 6 months ago, the last time I saw the car (not my tuning). Car also had 100k miles, so multiple factors. Maybe ms was high because the inj were old/partially clogged. Have to find the log(s).
« Last Edit: May 25, 2020, 04:32:04 PM by vwaudiguy » Logged

"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
gman86
Hero Member
*****

Karma: +45/-128
Offline Offline

Posts: 705


« Reply #4 on: May 26, 2020, 01:23:48 AM »

Thanks for your input. One reason I ask, is because we had an injector failure, and I remember seeing 11/12 in the logs 6 months ago, the last time I saw the car (not my tuning). Car also had 100k miles, so multiple factors. Maybe ms was high because the inj were old/partially clogged. Have to find the log(s).


Fuel trims will tell you if the fuel system was struggling. Anything over 10ms is asking for trouble at the top end. Maybe more tolerable in the midrange where you have far more time to spray. The injection time isn't per cylinder though, it's median. So a failed injector won't have enough clout to cause the rest of the injectors to go high as their cumulative extra fuel would far outstrip any lean AFR caused by a failed injector in one cylinder.
Logged
Pages: [1]
  Print  
 
Jump to:  

Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Page created in 0.014 seconds with 16 queries. (Pretty URLs adds 0s, 0q)