E90Post
 


Extreme Powerhouse
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Dead-horse: necessity of index 12s for tuning?



Reply
 
Thread Tools Search this Thread
      01-18-2019, 08:23 AM   #1
Cm452
Private
8
Rep
80
Posts

Drives: 08 335XI, stock...for now
Join Date: Oct 2018
Location: Boston Metro

iTrader: (0)

Dead-horse: necessity of index 12s for tuning?

I've got a mixed bag of injectors: 6,8,9 indexes, ~2 of each. I know the 9s are of I'll reputation, but, the car runs well otherwise. Consensus seems to be a perfunctory change up to index 12s, but I'm curious as to the actual risks of popping my motor with a tune and older injectors ?
If one of my injectors fails by leaking, I can handle that. If it fails at WOT by going super lean, that I cannot.
I guess what I'm asking is how common it is for injectors of those indexes to fail catastrophically?
I've used the search function, but there are a lot of parrot posts without any explanation aside from "just do it".
Thanks!
-Cm
Appreciate 0
      01-18-2019, 11:41 AM   #2
N54Society
Major Private First Class
N54Society's Avatar
United_States
449
Rep
1,327
Posts

Drives: 2010 E90 335i M Sport
Join Date: Mar 2014
Location: US, NA, Earth, Milky Way Galaxy

iTrader: (2)

There is no inherent risk of popping the motor with older ones. I would change them as needed. Injectors fail at random. Even index 12 injectors have failed before. Ideally, you run the latest because it has the least "shelf life" and they MAY have some kind of design change to improve the internals (just a solenoid really).

Only thing you need to consider is that if you swap in an index 12 in bank 1 (cylinders 1-3), the remaining injectors in that bank need to be 11 or 12 as well. Same goes with bank 2. Are the injectors you described new?
__________________
2008 E92 335i 6MT: FBO + MMP Silicone Inlets | Stage 1 LPFP | 335is clutch + MFactory SMFW | Custom BuraQ + MHD tune | 3.5Bar N20 sensor [SOLD]

2010 E90 335i M-Sport AT: 5" Stepped FMIC, Stage 2 LPFP - MHD V7 E60 Tune running 100% E85 - VRSF DPs
Appreciate 0
      01-18-2019, 07:00 PM   #3
Cm452
Private
8
Rep
80
Posts

Drives: 08 335XI, stock...for now
Join Date: Oct 2018
Location: Boston Metro

iTrader: (0)

Thank you for your thorough reply! I have no idea how old they are in years or in miles. I bought 'er at 90k, up to 97k now. Lots of dealer maintenance records, but they just say "fuel system service" on the carfax.
It does, every once in a while hiccup when it's cold. Carbon cleaning was apparently done recently.
-Cm
Appreciate 0
      01-18-2019, 08:35 PM   #4
Jonah335
Private First Class
54
Rep
115
Posts

Drives: 335i
Join Date: Apr 2015
Location: Florida

iTrader: (2)

Dead-horse: necessity of index 12s for tuning?

These injectors won't fail catastrophically. You will be able to see the symptoms well before it gets to a point of actual danger to your engine. mine would spit gas out of the exhaust on cold starts and ended up staining my driveway. as well as running rich and fuel smell, you will be able to see the symptoms I'm sure.

I would say put the 12's on the back burner unless you have the budget or love proactive maintenance.
Appreciate 0
      01-18-2019, 11:10 PM   #5
Chris@VargasTurboTech
Lieutenant Colonel
1930
Rep
1,531
Posts

Drives: All Things TurboCharged
Join Date: May 2016
Location: Bay Area

iTrader: (0)

Nah, just be ready to replace them if/when you see they're misbehaving. As long as logs look good, car starts/idles/decels fine without any signs of leaking (a/f doesn't immediately go to max on decel), I'd keep running them for a while.
Appreciate 0
      01-19-2019, 02:22 AM   #6
rediahad
Banned
17
Rep
115
Posts

Drives: E71, E93, E92
Join Date: Apr 2018
Location: Sacramento

iTrader: (1)

I was getting superknock in 3 cylinders. I hear thT is really bad so i swapped injectors out for 12s and im good now
Appreciate 0
      01-19-2019, 03:18 AM   #7
RnmEvo9
Banned
247
Rep
1,827
Posts

Drives: 2007 335i
Join Date: Apr 2011
Location: Pembroke Pines, FL

iTrader: (2)

Quote:
Originally Posted by Jonah335 View Post
These injectors won't fail catastrophically. You will be able to see the symptoms well before it gets to a point of actual danger to your engine. mine would spit gas out of the exhaust on cold starts and ended up staining my driveway. as well as running rich and fuel smell, you will be able to see the symptoms I'm sure.

I would say put the 12's on the back burner unless you have the budget or love proactive maintenance.
I can smell fuel out of my brothers 335i everytime he shuts off his car, where would be the best place to order index 12 injectors just in case?
Appreciate 0
      01-19-2019, 02:04 PM   #8
autoart
Colonel
344
Rep
2,277
Posts

Drives: 2009 335i e90 M/ 22 X3
Join Date: Oct 2010
Location: socal

iTrader: (8)

I thought if they start leaking fuel down into the oil, it can cause premature bearing wear.
Appreciate 0
      01-20-2019, 02:30 AM   #9
N54Society
Major Private First Class
N54Society's Avatar
United_States
449
Rep
1,327
Posts

Drives: 2010 E90 335i M Sport
Join Date: Mar 2014
Location: US, NA, Earth, Milky Way Galaxy

iTrader: (2)

Quote:
Originally Posted by RnmEvo9 View Post
I can smell fuel out of my brothers 335i everytime he shuts off his car, where would be the best place to order index 12 injectors just in case?
Could be a number of things but a likely one is this:

https://www.e90post.com/forums/showthread.php?t=1417068
__________________
2008 E92 335i 6MT: FBO + MMP Silicone Inlets | Stage 1 LPFP | 335is clutch + MFactory SMFW | Custom BuraQ + MHD tune | 3.5Bar N20 sensor [SOLD]

2010 E90 335i M-Sport AT: 5" Stepped FMIC, Stage 2 LPFP - MHD V7 E60 Tune running 100% E85 - VRSF DPs
Appreciate 0
      01-20-2019, 05:15 AM   #10
hellokitty
Brigadier General
hellokitty's Avatar
United_States
2884
Rep
3,719
Posts

Drives: '17 M3 ZCP DCT
Join Date: Jul 2010
Location: Southern California

iTrader: (2)

Quote:
Originally Posted by RnmEvo9 View Post
I can smell fuel out of my brothers 335i everytime he shuts off his car, where would be the best place to order index 12 injectors just in case?
Fcpeuro due to their lifetime warranty.

With that said, I’m tuned and running on index 9s and so far so good. Will update to index 12 once they start misbehaving.

I’d also check whether you fall under the Bmw extended warranty for fuel injectors so you don’t have to pay out of pocket.

See SIB 010215
Appreciate 0
      01-20-2019, 10:26 AM   #11
rediahad
Banned
17
Rep
115
Posts

Drives: E71, E93, E92
Join Date: Apr 2018
Location: Sacramento

iTrader: (1)

Search classifieds. I saw two guys this week selling new index 12s
Appreciate 0
      01-20-2019, 10:58 AM   #12
Jeef
Lieutenant Colonel
United_States
387
Rep
1,945
Posts

Drives: AW E92 335i
Join Date: Nov 2008
Location: San Diego, CA

iTrader: (6)

Quote:
Originally Posted by autoart View Post
I thought if they start leaking fuel down into the oil, it can cause premature bearing wear.
I've seen a motor go because of this.
Appreciate 0
      01-20-2019, 03:53 PM   #13
Silent9n54
Captain
Canada
574
Rep
940
Posts

Drives: 2007 E92 335i
Join Date: Jul 2017
Location: Vancouver, Canada

iTrader: (0)

im running index 1s at 21.5 psi for over a year with no issues

120.000+ miles
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 10:53 AM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST