Subaru GC8 exGrA trackcar

[DenisAlmos]

Hi all,

I'm working on an old rallycar and wanting to use it of tracks.

Here is the setup: EJ205 with Wossner forged pistons, stock heads and VF34 turbo

I went to a mapper and had to pay him before seeing the car becouse he also was the transporter.

I discovered that the all boost table is at 10% so I'm unsure about his work. Can anyboy have a look and give me a feelback about this tune? What do you think this tune worth?

https://drive.google.com/file/d/12XZaGnFIjnQUx_5tUUcxqRASKQ_uCI3W/view?usp=sharing

[DenisAlmos]

To give you some news, the mapper answered “yes” every time I asked something but with no surprise, he did nothing to help.

I tried the car and found out it was 14% rich.

These is 2 raisons I see for this difference; the mapping as been done on a hot summer day, and I want on mountains to test in without seeing the cops, so air temperatures and atmospheric pressure were much lower. I measured 85KPA for BAP.

What would be the best to do?

Could changing the main fuel from MAP to MGP solve this out?

 

Can you guys have a look? @Adamw @koracing @Vaughan@Confused

[koracing]

Do you have datalogs of the car running at close to sea level and datalogs of it where the BAP is 85kpa?  You could easily switch the MAP to MGP and run a second test to see if the fueling is closer in line with what one would expect.  I downloaded and saved a copy of the tune and I'll take a look when I get some time to do so.

[koracing]

What fuel is being used here?  How is the ethanol content verified?  I do see several basic setup issues.  Fuel density, and temperature coefficients are set up for 99% ethanol, but the stoich ratio is set up for 85% ethanol.  Injector dead times seem wrong based on my own experience - at the very least this was not verified to be accurate, fuel pressure is monitored but not used in the model, there is no charge temp approximation table set, IAT mode is being used, oil pressure is monitored but not used for any type of failsafe, the PID values for closed loop boost control are suspiciously low and the target table is rather large but the target values aren't changing all that much - I'm unsure what is trying to be accomplished with that, cranking enrichment and post start enrichment tables are zeroed out.  The main fuel table has a large wedge in an area you aren't likely to ever hit, but just "looks" bad.

[DenisAlmos]

@koracingSorry for the late replay but my Google Drive was full so I couldn’t upload the logs.

1 – The information you asked

You can found in this folder a log from July the 9^th which is the log from the mapper and a log from August the 2^nd which I’ve done static in my backyard.

The mapper did the dyno runs during hot summer near sea level so I guess BAP was over 100KPa. The second log is also near sea level and BAP was 98KPa and it already had a CL lambda correction about 4%.

I don’t have a log during testing in the mountains but I’ve manually adjusted the fuel map to match my Lambda target while CL lambda OFF. You can found this tune “after testing” in the folder and calculate the error by comparing the changed values. I remember subtracting 13 to 14% on the fuel map.

 https://drive.google.com/drive/folders/12QvmVxBooMJm385VUDnnn_vKtDrUil1a

 

2 – Replay to your observations

The fuel used is pump ethanol, so yes it can vary on ethanol %. Unfortunately, the car didn’t had ethanol sensor at the time of the mapping. Thank you for pointing the fuel density and temp coef are wrong. The car now has a sensor but is still using the same mapping. What would be the best thing to do in your opining?

Yes, he changed the injector dead times, I replaced the data from Injector Dynamics website. The mapper said Injector Dynamics are china’s renamed products …

I use a fuel pressure regulator and I’m not confident in sensor wiring so I prefer it to be logged only for now. What would be your recommendation on fuel pressure usage? Do you recommend ”FP Sensor“  mode in this case? What does it change if the fuel pressure regulator gives the right fuel pressure difference? [My decisions before mapping, he changed nothing]

I installed the IAT sensor in the manifold, is the charge temp still relevant? [My decisions before mapping, he changed nothing]

You are right, I installed the oil pressure sensor just before going to the mapper and he didn’t set any protection on this parameter. I’ve now set it up myself.

For the boost setup, I assume he did something because I can see boost dyno runs on the logs. Has the air temp was too high he probably deleted the boost setup and told me he can finish tune as soon as I put a front mount intercooler. I’m not going this route because of lag so I installed a much bigger scoop, I called the tuner every week for months but I’ve never had another appointment. He said yes every time but did nothing.

If I understand, in your opinion I should not trust the mapping at all and restart everything? If the fuel map could not be trusted, nothing could be trusted right?

[koracing]

You would have to monitor your logs and see if differential fuel pressure is truly constant or if it fluctuates at all.  If it is always constant and the settings are correct with your MAP referenced tune, then there should be no issues running the car that way.  I usually use FP Sensor as this will use the changes in pressure as part of the fuel model calculation.  

Overall I've seen worse maps from professional tuners, so it isn't *horrible* but I would correct any known issues and see if the mapper is amenable to retuning or addressing the issues you're having.  The fuel table requiring 14% less fuel seems odd - unless the car was only dyno tuned and not street tested afterward and thus had different loading in use versus while being tuned.  Ideally you will road test the car while it's near sea level to see how much that affects the fuel tune.

If your ethanol content varies, I always recommend doing a pump gas tune and ethanol tune with known values of ethanol and use modelled-multi-fuel.  Depending on the change in ethanol content from one fill up to another you can see quite a swing in reported AFR values.