My build thread is getting way too long so I thought I'd follow the trend and make a separate thread for my Chrome ECU tuning experience.
Here are the specifications of the relevant parts on my car:
- Stock boost solenoid
- Evo 560 injectors (INP-401, 4 nozzle version using short latencies)
- Supra fuel pump (hotwired ~14v)
- Montero 482 MAF
- AEM rail mounted FPR
- Stock eurospec 11b turbos
- Gene SMIC's
- CX Racing 2" pre-intake and intercooler pipes
- AEM 30-2310 Inline Wideband UEGO
- GM 3 bar MAP sensor
- Stock ECU boost solenoid
- 3" exhaust and downipe with a single large catalytic converter
- Precat eliminators
- Stock engine and heads
I've spent the last couple of weeks fine tuning the VE table trying to get the car to run like stock and with good trim values and accurate AFR values. I now have a tune that runs fine under all conditions except very low engine loads and engine braking where I experience some stutter/hesitation.
Today I decided that the low engine load hesitation problems can wait until later and instead I started upping the boost. I followed the instructions in this thread and updated the following tables in my ROM:
Setting all values to zero in the load error correction table made my pulls much smoother. Previously the ECU would start pulling back my boost after about 3 000 RPM since I was overshooting the stock load values. This made it feel almost like driving into a wall halfway through the pull.
Here is how the boost curve looked with the stock boost values (3rd gear pull):
This is how it looks with the new values (3rd gear pull):
Much smoother and steady all the way to redline holding about 11 psi.
However when I made a pull though 2nd, 3rd and 4th gear I got a very different boost curve with boost increasing a few psi each gear peaking at 17 psi and giving me single count of knock. The chart is cut a bit short because I didn't want to pull 4th gear all the way to redline
Whats the best way to tackle these boost spikes and slight boost creep?
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