Got to 183whp - cant get more
 

So I spent the day at the dyno yesterday trying out various map changes. I started with Shivs Stage 2 1.42b map and the car baselined at 181whp. I then did the following tests and in each case I started out with Stage 2 1.42b and did the stated modification:


T1: Leaned out Primary Open Loop Fueling by 3% to compensate for trims
T2: Modified the Intake VTC by advancing in the higher rpm range (see photo)
T3: Retarded ignition timing by eliminating the advance in the Knock Correction Advance table, basically removing 1.76 advance (see photo)
T4: Flashed Shivs Stage 1 1.42b map


Ok so the results, in T1,T2,T3 the dyno graph was a near mirror image of the baseline Stage 2 1.42b map. In T4 there was a slight gain uptop from 6750 to redline




At this point I am happy with the 183whp but what is bothering me is why the changes I made had no impact on the dyno results. I am starting to think that I ran into a bottle neck that needs to be resolved before more power can be made. I am thinking the up pipe and midpipe are the only stock pieces I am running so they could be causing a bottleneck. My next tests will be with mid pipe replaced.


Attached is a dyno sheet of the baseline Stage 2 1.42b and the best result I got which was with Stage 1 1.42b.

Dyno looks good and you are making good amount of power. Your secondary cat cud be restricting some flow tho!

You're planning on replacing the wrong pipe! The oem front (up) pipe is much more restrictive than the mid-pipe due to the oem cat in the front pipe. According to Nameless and Super Sprint the gains from replacing the mid-pipe are slight.

Some questions if I may,

1. 4th gear?
2. What fuel?
3. 3% leaned out where?
4. Why the change with intake AVCS only? and also why the reduction?
5. Why did you you removing timing?

You need to change out your exhaust up front. Stock exhaust is restrictive.

1. Yes 4th
2. VP Motorsport 103
3. In all rev range in the 0.9 to 1.3 load range
4. Testing to see the effect of such changes. None observed.
5. Same as above

On 103, you should be able to add more timing without knocking, not sure why you are reducing them.

As for the 3%, it looks on the lean side between ~4900rpm to ~6500rpm.

The reduction in intake AVCS, this would take some playing around which I have not done as yet, perhaps try advancing and play with exhaust side as well since you changed the header which is more on the exhaust side?

you adjusted the fueling targets to compensate for fuel trims? you should adjust maf scaling to eliminate the trims to begin with, or set the high af learning bucket to 61g/s so they won't apply in open loop. you shouldn't ever have to change the fueling targets if everything else is right.

What do you think is the reason why tuners change fueling target?
Some of the dynos/logs I've seen shows AFR of up to ~13.5 recently, do you think it is because they haven't scaled the MAF correctly?

yes. fueling targets are just that: targets. they will be hit assuming that airflow estimation is correct (ve if sd, maf if maf) and fueling calibration is accurate (di flow rate, port injector scaling, latency, etc.). if the ecu is making fuel volume calculations using inaccurate values, the end result will be off and you'll see fueling error.

some folks change targets to hit the afrs they want to see. that's fine, but your just masking a fueling error issue, and you'll chase your tail until you resolve that.

you made 181 on the stage 2 but 183 on a unedited stage1??

I believe he is just running a drop in filter, would that warrant maf scaling? Didn't think it would deviate much from stock by just the filter.

I was able to achieve 183 whp on my invidia catback and injen intake on the dynoet as well. When you free up the front pipes and overpipe you see more gains

i think @mad_sb did some testing where he found the stock maf scaling to be pretty bad even with all stock components.

Without putting your car on the same dyno on the same day the numbers aren't really comparable at all.

I can't disagree on the front pipe though, definitely need to replace the stock one!

i don't remember his post on maf scaling but remembered this one:
http://www.ft86club.com/forums/showp...&postcount=338

I think @jamesm is referring to this one.
http://www.ft86club.com/forums/showthread.php?t=30418

that is correct

i think something is wrong if you are on vp 103 !

Quick FYI: your posting results with SAE correction which is fine. But most of the results posted up here on the forum (including the one that I think you are comparing your results to) are displayed in STD correction. If you view your run in STD correction, you will probably pick up 3-5whp.

Also, as others have mentioned, if you are running VP103 you want to advance (not retard) timing. On that fuel, I would start adding 2 degrees of advance everywhere and then seeing where it helps and where it doesn't. Where it doesn't help, take it back out. Where it does help try putting more advance in in 0.5 deg increments until you stop gaining power. From my more advance will help up above 5000rpm where the tune, on pump gas, is knock limited.

shiv


Edit: my eyes must be playing tricks on me because your dyno results are STD corrected:bonk:

As mentioned above stop playing with the target AFR to attempt to compensate. You need to scale your maf. this is easily done on street. Do this on the street prior to going to the dyno and only fine tune if needed. Start by only shifting the entire maf scaling small % at a time. Then fine tune as you go along.

Before going into "tune mode" I recommend disabling LTFT so that way no trims are affecting open loop. To do this you need to set your closed loop afr targets to 14.7, or set the bucket to 61g/s as per @jamesm.

If you do not do this your LTFT will be "swaying" your AFR. Attempting to get your targets lined up first, then tune the car, then re-enable your LTFT if so desired. Dont tune with them on as you will need to pay attention to your logs and compensate in your head every time you adjust.

I also do not see why you are removing ignition timing for VP 103 fuel. Could you shed some light towards us as to why you are doing this? If it was simply confusion this is easy to fix, you should be advancing for non-pump fuels over your standard pump. adding 1-3 ignition advance in loaded regions (e.g. 0.8+ load) and then incrementing at 0.5-1.0 at a time and monitoring your FLKC and other KC values closely if you do not have det cans.

i agree with the above aside from two points:

first you'd never set closed loop targets to 14.7:1 to turn off long term trims. this would only do that as a side effect of effectively negating short term trims, which isn't a good way to go about it. do it with min/max values or af learning buckets. i agree it should be done for tuning purposes as it eliminates another variable. very much like setting initial iam to 1 while tuning timing, this should probably be reverted to stock (or at least re-enabled in some reduced capacity) after you're finished.

the other thing is with regard to timing, i would be sure to only add 0.7deg at a time at most. as always, the key to not blowing your car up (and thus eventual success) is in taking baby steps and following best practices.

Also to add if your not gaining power or the gain was very minor compare to another ifnition advance pull it back a tad. If you aren't gaining power from advance you would likely be pushing past MBT increasing cylinder pressure for little to no reason. And if the gain was smaller than the previous gain than you are likely near or at MBT and should consider pulling back to make the tune more conservative and less stressful.

Also @jamesm knows more on the subaru platform than me on open loop mechanics. Not to mention the fact his method is significantly easier to do than what I said which involves restoring the table later. I would go with his recommendation for LTFT. :)

Thanks to all for all the helpful comments. My next reply to this post will include results of yesterdays 3 back to back tests of 1. Baseline running fresh flashed OFT Stage 2 1.42b 2. Removed Tomei 60s catback and went back to stock 3. Removed secondary cat. Very disappointed with the results. Watch the next post.

How much have you spent so far in tuning and high octane fuel so far? Have you considered just going FI?

Ok so I spent Friday afternoon on the dyno to try out the BRZ without the Tomei 60s exhaust (was too loud for me after header install), so I did the following:


Run #1 Fresh flashed OFT 1.42b Stage 2 with Tomei 60s (Dyno run #9)
Log here: http://datazap.me/u/brn12345/log9


Run #2 Removed Tomei 60s and installed stock exhaust (Dyno run #10)
Log here: http://datazap.me/u/brn12345/log10


Run #3 Removed secondary cat and continued running stock exhaust (Dyno run #13)
Log here: http://datazap.me/u/brn12345/log13


If anyone wants actual CSV or DRF files, feel free to ask me for them.

your tq has dropped on dyno #2 & #3, and if you look you are looking at a fair bit richer on both of these. When testing mods like this you want to make sure LTFT is not affecting your AFR's. Also verify that the oil, coolant, and IAT temps are near the same between pulls. Verify your ignition timing is near the same, if not look into why. Did you play with ignition tuning this time around? When you remove the OEM header and install a new cat-less one the EGT temps tend to drop allowing more aggressive tuning.

From what i am seeing here you just removed parts and made no tuning changes between so the changes will be minimal. With the secondary cat removed you should work on getting your AFR's close to your commanded AFR first. Then once the ecu is doing what you tell it to you can start working on timing and actual afr's.

- Tuning is free as I do it myself (Also thanks to Shiv for the free OFT maps)
- Dyno is free for me on Fridays and sometimes during the week when no one is booked
- I have 180litres of VP Motorsport 103 left over from last seasons circuit racing (I race in the local 2000cc championship) so that's free too
- Not really interested in FI

Very useful info thanks. Moving afr was something I didn't know how to tackle, so thanks for the advice on disabling it. Thanks to @jamesm as well. Will try disabling next time.


I didn't play with the tune at all in this case. Will try fiddling right after I get a resonated mid pipe. I gutted the secondary cat and the car sounds really bad.


In the meantime Ill probably review logs and review maf scaling as suggested.

I noticed that in your last run the AFR is going very rich according to the dyno like 10 on 4500 rpm. on the log, it is reading 12.17.
Can any one help in explaining why is that happing.


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Looks like his OEM wideband is not calibrated. OEM calibration only reads around that low. You have to re-write the axis on the tune to lower it and make it readable. However below ~12AFR the oem sensor is not terribly accurate and its update frequency is fairly low.

The dyno wideband is a little more reliable. However if you remove a cat on the car the dyno will start to read more accurately. So it might start to look slightly richer at the tail pipe.

Wideband != narrowband

The OEM front AFR sensor is a Denso limiting-current wideband. Not a narrowband.

http://www.ft86club.com/forums/attac...1&d=1359633652

The denso sensor just simply doesn't read much below 12 AFR, and below 12 its accuracy is not quite as good. Compared to my LC-2 and the LM2 we were using on the dyno (with the bosch from my LC-2 wired into it) it was fairly close on AFR's. Mind you I have calibrated mine though. Although below 12 AFR the accuracy drops off a bit. And the oem wideband updates much slower than my innovate does. So the detail I get in my logs are more precise on the innovate. However it is not always necessary unless doing very fine tuning to use more advanced wideband especially on pump gas.

Wonder why it targets around 10 for AFR with the stock ROM for high rpm and load when it is so inaccurate under 12?
Can't remember off the top of my head how far out it was for @jamesm when he did the compensation map for full close loop setup.

@8686 I am aware of the OEM sensor has a floor of 12.17 but I assumed that if I changed it to read lower it would mess up part throttle etc. I am assuming the stock map limits it to 12.17 for a reason. I am going to install a standalone wideband that will then be plugged directly into the OP2 for direct logging. I believe this will have much more consistent and real results.

Understanding open loop fueling is the key here and is why MAF scaling (or fueling table corrections) are important. When on open loop, the ECU uses the MAF to calculate g/s of air entering the engine and then calculates how much fuel is required to hit the target AFR in the fuel map. The output of the O2 sensor is purely for you to monitor the output and is not used by the ECU in these conditions.

My O2 has been scaled to read as accurate as possible after time spent on the dyno using the wideband to calibrate it as above.

As with all sensors, you choose where you want resolution. Actually the stock sensor is good at lambda 1 which is where you spend most of your time in cruise and part throttle. I'll see if I can dig out my O2 scaling as a reference as well as one by a previous tuner, both are different but have worked well.

Yeah, I know about it.
You didn't actually answer the question though.

It did kind of explain it though. The map can still target those values as at high RPM and loads it's not using the O2 sensor to validate what it's achieving, it's in open loop so is calculating the output AFR from the MAF sensor reading and fuelling accordingly. That is also why there is LTFT as it works them out in closed loop when the O2 sensor is within good working ranges and then applies them in open loop when it's not.


Remember the O2 sensor is only used for fuelling in closed loop.

The ecu doesn't need a wideband to verify its AFR targets. The AFR traget is created based off the maf calibration and other tables combined. The car in open loop can run completely with out a af sensor. The car does not need to know if it is more than say... 1AFR off for adjusting fuel trims, so there is simply no reason to spend the time calibrating it from the factory as it literally does nothing for the ecu. We however are using this sensor to verify our target AFR and as it is only calibrated from the factory for closer to stoich levels... we need to extend this to see further.

The region in which you would be in closed loop with the factory tune is pretty much all 12+AFR. Once you dip into areas in the 11's the car should be in open loop on the factory tune. Open up the fuel table and you will see what i am talking about.