Over Boost fuel cut values?.

[KeithMac]

Hello all, nice to see the flashable ecus doing so well!.

Just a quick question, is the Overboost Fuel cut set up with a table and is there anyway to find out hz vs rpm for when it cuts in?.

I'm running nitrous and need to avoid hitting it at all costs..

[Chris@Rvengeperformance]

Yes, there is a table. It is in load % though. Greg could probably give you a rough idea what % translates to HZ better than me;

500 162
1000 162
1500 168
2000 172
2500 192
3000 210
3500 205
4000 202
4500 198
5000 198
5500 198
6000 198

Due to many variables there your load vs hz may vary. I also do not understand why, but the relationship between load and hz is not constant, probably due to rpm, but here are a few samples from my logs

115 load 566 hz 2718 RPM
155 load 904 hz 3281 rpm
189 load 2000hz 5500 RPM
167 load 2154 Hz 6781 RPM

This is at roughly 15-16PSI (my logs show 13, but the gm map sensor seems to read 2 PSI lower than my defi gauge)

let me know if that helps any, I have tons of datapoints. I have peaked about 234 load so far, but I have raised the values in the table to prevent fuel cut.

[Greg E]

Load is HZ * MAF size / 65535.

Disable fuel cut by setting the timer to 10000ms.
Tune your car.
Log load.
Adjust the values in the fuel cut table to be about 10-20 load higher than your logs.
Reenable fuel cut by setting the timer back to 1000ms (or less if you prefer)

[KeithMac]

Thanks for the replys!, I'm still on my 1st gen Ecu so cant do anything about the hardcoded table but I have a Hz output table that the car is running from (via EMU) so I was after an idea of max hz for the stock system.

My max hz in the table is 2200 at 7000rpm 30psi, I basically cut the airflow in half to avoid fuel cut and make tuning the 1200s easier.