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Discussion Starter · #1 ·
Guys,

Took the GTR for a quick blast yesterday and noticed on full throttle I was getting a bit of hesitation, and a couple of flickers on the CEL. I've got a PFC, so I'm assuming this is the PFC detecting knock and retarding the timing? I'm also assuming this is due to the warm air (or poor fuel maybe?). EGT/oil/water temps are all fine.

Is there anything I can do from datalogit that will help with this? Or should Ijust pull the boost back a little? I've not had it before in over a year of owership and I whilst I'd like a full remap, the bank balance is saying "no" at the moment.

ta
 

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it's detecting knock but NOT RETARDING TIMING!! very important! how bad were the flickers - what was your peak knock? It's far better to read knock in graph mode; you can see overall trends and if the graph is smooth or jagged in general.

What's causing the knock, you need a wideband to see if you're running lean. Datalogit is enough to fix it - that's all I'm using to remap my car. That and the wideband, but not only am I digging into the airflow meter calibration and water temp corrections, there's ignition retard versus temperature and revising my entire injector map. Every single car is different, you may have to revise ignition timing as well.

A stopgap if you're engine is pinging is to retard timing overall in the Settings menu. But you have to do this every time you start the car, and it's a global correction, meaning that you'll be sluggish in the parts of your map that are ok as well.

I'm going through a tedious remap at the moment to get the car knock free and powerful enough for the summer; if you think a remap is hard on the wallet, try rebuilding an entire engine. Trust me, I know this from personal experience.
 

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Discussion Starter · #3 ·
So if it's not retarding the timing, what's the hesitation I'm feeling? :eek:

I've not got a hand commander (old PFC that needs an FCC-NT, or alternatively a hens tooth) hence the datalogit so I didn't have the graphs.

The flickering wasn't bad at all - maybe once or twice for a tenth of a second and that was it - it was hardly noticable, but when you're as paranoid about your car as I suspect most GTR owners are, you notice EVERYTHING :)
 
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