OFT Tune for GrimmSpeed Intake

[TruRace]

Originally Posted by Koa

Sorry for the lack of update! Valentine's day put a wrench (or prevented me from doing so, lol) in my final logs and tweaks. I will put out my baseline D00C bin file and MAF Scale in an excel file tonight.

It will need further refining to suit one's exact exhaust setup and to account for the variance in engines/drivetrain... but it's damn close and pulls hard!

Stay tuned

Sounds good! Did you make any other changes to the tune other than the MAF scale?

[Koa]

Originally Posted by TruRace

Sounds good! Did you make any other changes to the tune other than the MAF scale?

I have cold start disabled. Ignition Timing Post Start columns are reduced to -3.83 throughout and MAF Corr After Start tables have been rescaled. At any start-up, engine to temp or cold, rpms lock on 1400rpm and little ignition bark. It's amazing.

DTCs associated with this have been turned off so you don't throw a CEL.

Here's the MAF scale excel file and instructions to alter your own tune via RomRaider

Grimmspeed Intake + OFH MAF Scale - 91 OCT - v1.03
http://www52.zippyshare.com/v/Vt4grbCP/file.html

Here's my v2.06 D00C tune with cold start disabled, MAF scale already implemented.

D00C GSI + OFH SCALED - 91 OCT - V1.03
http://www52.zippyshare.com/v/r9S0TIIb/file.html

[TruRace]

This tune is for 93oct I am assuming right? I'm realizing the MAF scale on 93 and E85 are a tad different.

[Koa]

Originally Posted by TruRace

This tune is for 93oct I am assuming right? I'm realizing the MAF scale on 93 and E85 are a tad different.

Sorry mate, it's 91oct. Almost every station near me is 92 octane at the pump, so I round down

[TruRace]

Originally Posted by Koa

Sorry mate, it's 91oct. Almost every station near me is 92 octane at the pump, so I round down

No worries. I'm going to try it out and modify if necessary. Thanks again!

[Koa]

Originally Posted by TruRace

No worries. I'm going to try it out and modify if necessary. Thanks again!

It should ballpark you nicely Please do a log after driving around for a bit @ 60F IATs (if possible) so we can compare. I can also help if you never re-scaled your MAF before. @vgi 's program is sooo nice.

[TruRace]

Originally Posted by Koa

It should ballpark you nicely Please do a log after driving around for a bit @ 60F IATs (if possible) so we can compare. I can also help if you never re-scaled your MAF before. @vgi 's program is sooo nice.

I was fooling around with the MAF scale program yesterday and it's super simple. What I am a little unsure about is the close loop and open loop scaling process. Should I take a couple logs of closed loop driving rescale and flash ecu then repeat process with logs open loop driving?

[Cop]

Originally Posted by Koa

It should ballpark you nicely Please do a log after driving around for a bit @ 60F IATs (if possible) so we can compare. I can also help if you never re-scaled your MAF before. @vgi 's program is sooo nice.

Giving the MAF scale a try later today, I'll try to log some data over the weekend to see how it's performing. Thanks!

[mad_sb]

Originally Posted by j_Zer0

For some reason the knock only seems to happen at cruise. I've only seen it 1500 - 3500 RPM. Same behavior on 93 and E85. I'm already running a bit rich in places, so don't think I'd want to run richer. I've got 2 sources available for E85 so I need to try the other to see if it's any better. If it's not, I'd be up for learning how to edit a few tables. It's only mild, transient knock, but still.....I'd rather eliminate it. Thanks for pointing out the knock correction thread. I'll definitely be checking that out.

you might want to check for mechanical noise (exhaust clearance etc), E85 does not knock so your knock sensor could be picking up mechanical noise. You might see an occasional knock count on E85, again due to engine noise. I found cam timing in the transition area to be the major cause of tip in knock on pump gas.

[Koa]

Originally Posted by TruRace

I was fooling around with the MAF scale program yesterday and it's super simple. What I am a little unsure about is the close loop and open loop scaling process. Should I take a couple logs of closed loop driving rescale and flash ecu then repeat process with logs open loop driving?

Here's the general principle of rescaling via fuel trims in this system, as I understand it (will need @Kodename47 , @vgi , Shiv chime in and correct or clarify as I hold an elementary understanding of it all):

For each load/mafv/throttle position/rpm instance, we're trying to scale the tune to provide an AFR as close to the target as possible. The MAF scale affects more than just metering air, including load & timing (someone chime in on this), implying it is beneficial for the system of a whole to scale the MAF appropriately for one's setup and climate.

Therefore, we need to supply the program with enough data instances of these variables, including fuel trims, which is what the ECU is doing to fuel to compensate for differences between reported AFRs and the target AFR for each instance.

--

SO, the methodology is to take logs that capture both closed loop and open loop data that is indicative of every-day driving, filter the data to arrive at a true picture of what's happening in the system, and then apply the formulas to the data & current MAF scale to arrive at a new MAF scale.

There's differing trains of thought on this, but an understanding of what each variable (MAFV, throttle%, rpm, load, IATs, etc) does to the inputs to the system (engine) is very helpful. That's beyond the scope of this post, but refer to Steve99's MAF scaling threads where some very smart minds discuss these things.

The process

1. Get your car up to operating temperature, around 15-20 minutes of driving for the tranny to come up to temp. Drive towards a place where you can put constant throttle and loads in varying positions- mountain trails and interstates on off-hours are what I find best.

2. Note the ambient and Intake air temperatures before you start. This is important because you'll only want to take logs and scale data that floats around the same temperatures. There is a MAF temp correction variable that will skew your results.. try to take logs around 20-25C, or zero out your MAF temp correction table in romraider if varying temps are an issue.

3. Start logging and drive as SMOOTH as possible, avoiding deceleration/idle and working your way up the gears and rpm/powerband very slowly but deliberately. Vary your throttle and loads, remember, we're collecting data of the engine doing work. This is perhaps where the 'art' comes into play. Most tuners have their own perceptions of what is the acceptable length and variation/runs in the log.

What I do is take a 20-30 minute log of mostly 1/3-2/3 throttle/varying load closed loop driving... and near the end of the log, do 5 or so 3rd & 4th gear WOT runs, from 2k RPM to redline. I'm still trying to refine my techniques and methods of taking logs so this is an area where Kode, vgi, steve and other heavy loggers can chime in and give perspectives on.

4. Since VGI's tool makes it very easy to filter data, one could then scale open and closed loop in one go.

- You use the same log.. Load your POL fueling, current MAF scale, and log into the Open Loop section and run the program
- Copy/paste the new generated MAF scale from that section into the "current MAF scale" in closed loop section
- Load the POL fueling, and log into the Closed Loop section and run the program.

The methodology is that you take your entire log, filter out the closed loop data, and are left with open loop data. You then refine and filter it further (to get rid of tip-in wildcard and outlier distortive data) until you're left with solid open loop data that the program can then use to calculate accurate corrections to your current maf scale. Then, repeat the process for closed loop by removing the open loop data and refining it for useful info and accurate rescale material.

Awesome post by Kode that explains his VGI program settings

Here's Steve99's MAF Scaling via trims thread

Sorry it's so long, but I have had to sift through all the MAF scale threads. A month ago, I held an infintile, inadequate grasp of what these variables do and how our tune operates the system. Learned a lot here, and want to try and surmise that to help ya. PM me if you need me to help you out with any of the steps

[mad_sb]

Don't forget that rescale of the maf changes the calculated load and this the timing values at any given airflow and rpm point that is affected by the maf scale.

[Koa]

Originally Posted by mad_sb

Don't forget that rescale of the maf changes the calculated load and this the timing values at any given airflow and rpm point that is affected by the maf scale.

Stated that in first paragraph Not very eloquently of course and with a call to others for clarification.

[TruRace]

@steve99 mentions in his that that OFT uses fuel trims to compensate for the variations of %E so it is not recommend to rescale MAF. What does he mean by this?

@Koa Thanks a bunch for all the help and info. My LTFT are still a bit high, but much better after the rescale. One thing Iv'e noticed is my AFR's on my OFT when I run E85 never reflect actual AFR's. It looks as though I am running petrol, and I know E85 runs much richer. Any idea why this is so?

Edit: NVM found my answer in @steve99's thread.

[steve99]

Originally Posted by TruRace

@steve99 mentions in his that that OFT uses fuel trims to compensate for the variations of %E so it is not recommend to rescale MAF. What does he mean by this?

@Koa Thanks a bunch for all the help and info. My LTFT are still a bit high, but much better after the rescale. One thing Iv'e noticed is my AFR's on my OFT when I run E85 never reflect actual AFR's. It looks as though I am running petrol, and I know E85 runs much richer. Any idea why this is so?

when your on e85 the e% varies with season and with different brands. We are lucky in oz as we have a pump e85 that is e85 guaranteed so it just as easy to scale maf on that e85 as petrol.

with your varing e85 you would need to scale maf on an average e% that you get maybe E70 or whatever in the middle of the range and effectively end up with a compromise maf scale then rely on fuel trims to sort out the variation. You would need to get an ethanol percentage test kit and test your fuel.