safe timing at max rpm for boost, or anyone have a timing map

[farmerz24]

hi all,

im running a holley commander 950 on a 3100 equipped 3rd gen cavy t3 .82 ar stage 3 turbine 60-1 compressor starting at 5-6 psi for the start.

running custom 1/58 headers, 2.5 collectors, milzy stage 1 turbo cam, 3500 intake 70mm tb, and colin's ported heads.

Anyways, im interested to know if anyone has some sample timing maps they can give me or a general starting point for max timing. also when to start taking out timing and how much i should be running at idle, part throttle (the chart is 2d map and rpm based)

i was told around 22-23 at max rpm would be safe but just wanted to know if anyone had any maps or excel charts or something they could give me.

any help appreciated.

thanks

[Joseph Upson]

Not sure of what the timing grid looks like in the Holley setup but unless the stock timing at wide open throttle is as high as 23 I would think that's a bit much. If your static compression ratio has changed that will affect it. The Turbo Grand Prix grid shows 17.9 degrees at WOT and 100 Kpa and generally speaking I would find out what the stock timing is for 100 Kpa and at 110 Kpa start knocking off about 1.5-2 degrees per pound of boost, and data log to see how much advance can be put back in before knock starts.

Since the TGP motor has a static compression well below that of the 3100 and you are using a different engine management system than stock I would error on the safe side and work my way up. I would tune with no boost first.

Take your time, impatience and over ambition destroyed two of my freshly built turbo engines a long time ago, it's no fun doing it over when you've just finished

[SappySE107]

Stock is around 24 at max RPM. I don't know what you should be running with boost but if you get tunerpro, download bfuz, and use the A1.ecu file to see the stock spark table for the latest 3.1 code GM made.

[TurboGTU]

THe usual rule of thumb is 3*-4* a psi beeing aluminum head and a fast burn. Take what you see in the N/A form from the A1 and just retard besed on boost. ON the TGP code...just run what it has and then mod as needed. THe A1 has more radical timing than the TGP does off boost. THis is due to the timming helping to spool up the turbo.