I’m tuning a 7747 on a Crossfire Vette using TunerCat and WINALDL. I have been through the archives and past posts and am still unclear about how some of the tables relate.

My question has to do with tuning WOT and these three tables.

%TPS Threshold Vs. RPM for PE Mode
Main Fuel Table #2, % Volumetric Efficiency Adder
PE Air Fuel Ratio Vs. RPM.

How do these 3 tables interact or do they?


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Dan

 

1) depending on application and driving style you'll want the engine to get up and go at different ranges at different throttle openings. With a loose converter you'll want early (low % TPS PEs) to get enough fuel and timing to get the car moving.
I tun something like
400 rpm 10%
1200 rpm 20%
2400 rpm 60%
3600 rpm 80%
Now if I tell you this is a turbo motor with a loose converter do things make sense?

2) When you first enter PE how much fuel does the motor need?. Enough to stop stumbling, and lean enough not to bog.

3) At WOT what air fuel ratios do you want as what rpm?.
Again, min reads
10.6
11.2
11.6
11.6
At lower rpn I run a slightly retarded timing, and dump fuel into the pipe, the exhuast temps drive high, and spool the turbo. As we get boost and the engine is off and running we back down to 11.6.
In a N/A car you won't want that rich thou
HTH

 

Thanks Grumpy

In an over simplified description would it be in line to say that %TPS Threshold Vs. RPM for PE Mode and Main Fuel Table #2, % Volumetric Efficiency Adder are like the accelerator pump in a carb and the PE Air Fuel Ratio Vs. RPM similar to Main jets and WOT?

Sorry for the carburetor digression/comparison. Its just that I have worked with carbs for 30 years and just started efi tuning. Its a blast but a little confusing.


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Dan

 

Ya kinda sorta,
once ya soend some time on the EFI stuff it will get ALOT clearer.
There are so many things similiar, yet more specific. You can compare the VE table to an emulsion tube, and then the various limiting devises to jets, but remember not to get too huge up on comparing the two.

Best thing is just to get in there and start making changes, and NOTE everything you do.
Then often reveiw your notes.
After a couple hundred chips you'll really understand what you know and dont know. <G>