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Author Topic: Yet Another "Help A Noob" Thread (EV14 & RS4 MAF)  (Read 12182 times)
BerkleyJ
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« on: July 12, 2013, 11:24:17 AM »

Before I start, I'd like to point out that I know how to search the forum and I know how to read and I know where the S4 Wiki is and I am not asking for someone else to tune my car.

Back Story: I bought a B5 S4 with VAST Stage 3 RS6 setup. The emissions is not properly coded out. I want to make my own tune. Hardware is as follows.

VAST RS6 Turbos
Bosch EV14 52lb injectors
Stock FPR
Walbro 255lph
RS4 MAF housing (hitachi sensor)
JFonz SMIC
3" Catless Turboback
Currently running a MBC set to about 23psi but can switch back to N75
**A bunch more irrelevant stuff**

Starting with Tony's Base Stage 3, I multiplied the MLHFM table by 0.9534948096885813
Quote
Area of 83mm = 5407.865
Area of 85mm = 5671.625
      A83 / A85 = 0.9534948096885813

For the fueling I just directly copied nehalem's values from this post to use as starting values.

Question time!
1. Is this a good start? Should I worry about implementing the RS6's right away?
2. Why are people using such different TVUB values in the EV14 thread?
3. Do you use Blocks 32 & 33 in VCDS to adjust idle and partial throttle fueling and then log your wideband to adjust for WOT fueling?
4. How rich should it get during WOT and full boost?

I'm trying to learn how to try and learn here...
« Last Edit: July 12, 2013, 03:23:09 PM by BerkleyJ » Logged
prj
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« Reply #1 on: July 12, 2013, 11:31:42 AM »

My opinion is - and this is not to put you off:
1. Learn how a forced induction operates.
2. Then go fiddling with the electronics.
3. Learning on a Stage 3 car where everything is changed from stock while asking such basic questions as "what AFR should it run" is quickest way to tears. I'd personally start on some hardware that is less expensive to blow up.
4. Copy-paste is not tuning. Injector parameters you can get, but MAF you will have to tune through logging.
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BerkleyJ
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« Reply #2 on: July 12, 2013, 03:08:08 PM »

1. I'm fully aware of how forced induction operates  Wink
2. I am fiddling around with the electronics  Wink
3. I have a stage 3 car so I will learn on a stage 3 car  Wink
4. I copy and pasted injector STARTING values  Wink

Also, I am fully aware that AFR is critical to get right on a forced induction engine. I am also aware that under a lot of boost the AFR should be around the 12:1 area depending on different factors like how well the ICs work.

Allow me to ask a different question. If this was your car, with these specifications, how would you go about getting a base file setup?
« Last Edit: July 12, 2013, 04:02:46 PM by BerkleyJ » Logged
ddillenger
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« Reply #3 on: July 12, 2013, 03:10:15 PM »

If you have an RS4 MAF, use the MAF table from the RS4 file. You can't modify a hitachi MLHFM for use with a bosch sensor, the linearization sin't even close.
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BerkleyJ
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« Reply #4 on: July 12, 2013, 03:15:28 PM »

If you have an RS4 MAF, use the MAF table from the RS4 file. You can't modify a hitachi MLHFM for use with a bosch sensor, the linearization sin't even close.
It's an Hitachi Sensor in an RS4 housing (83mm)
« Last Edit: July 12, 2013, 03:22:56 PM by BerkleyJ » Logged
Rick
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« Reply #5 on: July 12, 2013, 03:16:40 PM »

Then you have given yourself a head ache Smiley
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BerkleyJ
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« Reply #6 on: July 12, 2013, 03:20:13 PM »

Is there reason I shouldn't just scale the housing diameter as I described in the OP?
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prj
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« Reply #7 on: July 12, 2013, 03:29:52 PM »

Changing everything at the same time is not smart, you will never dial it in "quite right" at this stage if you do.
If you assume that your injector parameters are 100% right, then you can try taking the base curve, multiplying it by something to get somewhere close, and then doing fine adjustments using logs and kfkhfm.

As for fuel - if you knew FI concepts, then you would also know that the mixture is mostly a tool to combat high EGT.
There is no huge difference in power on gasoline on the 5v engines until you go below 0.8 lambda or above 0.9, although with the latter your EGT's will be sky high very quickly.

There is no "ideal" mixture. You tend to pick something that is lean enough to not hamper the engine from producing power and rich enough to keep EGT's down. Once EGT's exceed a critical point, you enrich the mixture or reduce boost - whichever makes more power.
Where those points are heavily depends on hardware setup and fuel used. This is why anyone asking for an "ideal afr" in my opinion has no idea of tuning, and I tell them to familiarize themselves better with the concepts first.
« Last Edit: July 12, 2013, 03:35:46 PM by prj » Logged

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BerkleyJ
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« Reply #8 on: July 12, 2013, 03:55:46 PM »

I simply adjusted for the for the difference in MAF housing diameter and pasted in some starter fueling values. Did I do something wrong besides having no idea what I'm doing?
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ddillenger
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« Reply #9 on: July 12, 2013, 04:06:03 PM »

I simply adjusted for the for the difference in MAF housing diameter and pasted in some starter fueling values. Did I do something wrong besides having no idea what I'm doing?

Considering this is your first experience with tuning you should start with a maf with a known transfer sheet. You're just asking to learn the hard way otherwise. Master the basics, then move on to more advanced aspects of tuning.
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prj
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« Reply #10 on: July 13, 2013, 12:47:08 AM »

I simply adjusted for the for the difference in MAF housing diameter and pasted in some starter fueling values. Did I do something wrong besides having no idea what I'm doing?

Adjusting for the difference in MAF housing diameter is never just a simple multiplication.
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BerkleyJ
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« Reply #11 on: July 13, 2013, 05:52:44 AM »

Hmm. It seems like it would be  Undecided

Do you think it would be a good idea to find a 85mm maf housing, then start with Tonys file again? One less difference to worry about.
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prj
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« Reply #12 on: July 13, 2013, 06:34:26 AM »

I would personally start with a stock file and understand every change you are making and why you are making it...

It is not hard at all to tune the MAF, but you need to LOG and then make changes based on the LOG.
Not by guesstimating numbers. You guesstimate once, then you log and see how it worked for you, and adjust the areas that need adjustment.
Rinse and repeat.
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julex
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« Reply #13 on: July 13, 2013, 07:09:49 AM »

I simply adjusted for the for the difference in MAF housing diameter and pasted in some starter fueling values. Did I do something wrong besides having no idea what I'm doing?

The reason why this is not as clear cut as you'd think is that the actual air measuring part of sensor can end up in different spot of pipe (not exact middle) which in itself changes the read out significantly. For a given total air flow in a pipe, the air moves fastest exactly in the middle and slower as it approaches walls. Placing sensor in different spots will give you different readings even though total flow is exactly the same.
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prj
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« Reply #14 on: July 13, 2013, 07:13:57 AM »

What he said.

Also, the way the intake is set up, if you have bends before or after the MAF makes a difference.
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