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weird problem on GT86

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I`ve already done a few mapping on Toyotas GT86 by using BrzEdit from Epifansoft but I recently had the following problem the second time and just analyzed my Datalogs and Dynoruns to find the root cause of it but cannot find it ;-/

The Car is performing normally with the stock rom (verified by Dyno), I uploaded my Basemap for this model and the result are as expected, a little gain overall and about +7-10Hp peak performance (Mods are just Catback and replacement airlifter).

but at my second or third version (normal at this step I just adjust the AFR or Ignition a bit) and then the performance starts to decrease about 10-20HP less than STOCK, car feels on the street very laggy until the port injection is active then it feels better but still making less power than stock. Feels like 50% throttle until 4500rpm... torque curve is also very low before 4500rpm and than increases (not the same shape as the stock or remapped curve).

When I switch back to the Basemap it is performing great.

the changes between this versions are very small, about 1° Ignition or changing AFR from 12.5 to 12.7.

when I compare my Datalogs they show nearly the same... about 1-2°C different in Coolanttemp or Intaketemp, so I don`t think there is a compensation for it. Ignition is nearly the same, maybe 1° Ignition at high rpm.

I also tried to drive a few minutes to cool down everything but no change in performance.

IAM is at 1.0 after refreshing (set in the Basemap)

anyone had this problem too?

any specific Log-Parameter to watch for?


I haven't used BRZedit, however is there any torque management tables to be altered?

Sounds like the ECU is detecting the increase in power, and heavily curbing the tune to suit.

Have you logged throttle angle, and cam angle to ensure it isn't curbing your power/torque that way?


I checked some other stock and stage2 maps compared to my stage1 and the torque table does not seam to be a limiting factor... Also the regions that start so much laggy were not altered in my v2/3 compared to my v1 ;/

No my datalogs I have saved are without cam and throttle.

I've only tuned the 86 platform on EcuTek and the Motec M1 so I'm not overly familiar with BRZ Edit. I would be logging your ignition trims during the runs as well as your final ignition timing. If the power is fluctuating then there is something changing to cause this. If your ignition timing, AFR, cam position and throttle position all remain identical between runs then you would also rightly expect the power to be consistent.

The knock control system is quite active on these engines and I've also found them to be quite sensitive to engine temp. The IAM doesn't tell you the full story though so in your logs compare the fine correction during the run as well as the final ignition advance - This is what is actually being delivered to the spark plug. I've also found that in N/A form the engine power is quite sensitive to oil temperature and for consistency I always try and start my runs with the same ECT and oil temp (perhaps 88-90 deg ECT and 100-105 oil temp).

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