I have been tuning cars for a while and went to a friend's house to tune his new Apex'i RX6 single. I'll give you a little bit of background on the car. The turbo has been on the car and the motor popped because it was running lean (not tuned). The turbo was undamaged and the new motor went in the car. It's running the Extreme Fuel Kit and Power FC...

I tuned the map so that we were around 11.5 afr based on a few other maps and light tuning for his particular car. All of a sudden at 4000 rpm and 4psi, the car goes from 11.5afr to 14.8... Nothing changed on the log except the afr.

Is it timing? Is it the new motor? Coils? All the sensors are within spec, and I have no idea what it could be. Any ideas?

Thanks.

 

Check the fuel cells around the affected area which can be determined from the log. If the log contains the advance functions, check the values for the injectors.

Also check for boost spiking.

 

The fuel map is very smooth and I read from the log that the Secondaries are coming on and there are no boost spikes... the Power FC part looks good, as far as following the map and not jumping around and having a solid map to start from... The issue looks to be mechanical I think. Any ideas?

 

I'll restate my response from your thread in the Single Turbo section:

Did it ever go thru that spot previously without going lean? If not perhaps his secondaries are not 1680 or maybe they are not coming on at all. I set transition at 40% and 0.996 with a 0.4 lag on the 1600's. These settings would apply more fuel at transition but I don't know if it would be enough to cause the lean condition you are seeing.


Try the PFC forum if your friend's car has a PFC, there are several of us there that have done alot of tuning. Perhaps not experts but we have done quite a few and we don't mind sharing.

 

try and verify stable fuel pressure throught the rpm/boost range