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I'm looking at tuning an 2017 LT4 Camaro that's having a supercharger put on it. The owner uses the car for track days and circuit races the car exclusively. It will only be running about 5-6psi of boost, however my concern is keeping everything in check on the 20min lapping sessions as it heats up.
Since the car is N/A from factory I was going to pull a few degree's out of the boosted sections of the map, and run it at 11.3 AFR's as my target as I dial in the fuel (I'm hoping that's rich enough to keep things cool).
I'm more curious about how much timing I should leave on the table. Too little timing and the EGT's will likely be very high? too much and the car may start knocking once the IAT starts heating up..etc. To top it all off, its a DI car, which I haven't tuned before so I'm looking for some advice on how to approach it.
My main concern is keeping the factory bottom end intact lap after lap.
my advice would be to use the ect and iat enrichment and spark retard tables instead of removing from the main table,
keep in mind the lt4 uses direct injector so it should be ok running really lean but not sure for how long, i think 11.3 would be too rich for direct injector for low boost, i personally would try 11.8 with mbt timing but retarding timing at peak hp and torque,
you could retard the timing above 230f coolant and 140f iat aggressively to act as spark limiter so the owner knows to let it cool down
keep in mind increased egt temp is from moving the combustion to the headers so your engine isnt really running hotter its just your engine bay
I didn't realize that about the AFR target on a DI car, good to know. I'll have to look into those modifier tables that make more sense. And great Idea about the coolant and IAT retard function.
I appreciate the advice. Thanks!
You'll almost certainly end up encountering knock before you get to MBT timing with a supercharger so it will be a balancing act. Ultimately you're going to be best to log some data from an actual track session and see what's going on in terms of knock activity. You can correlate that to IAT and modify as necessary. For 5-6 psi I'd be starting in the 11.5:1 vicinity and see how the engine responds. Fahad is correct that often DI engines will happily run at a leaner AFR than a PI engine however a richer mixture still removes heat from the combustion charge temp which isn't going to be a bad thing.
Thanks for the response Andre, I'll keep that all in mind.