| quote | Originally posted by Raydar:
What I posted was only applicable to the 2.8 ECM.
With that said...
For the 4.9, I can agree with everything here, except for copying the EGR ON timing values to the EGR OFF tables. Having that amount of advance without the introduction of EGR (inert) gases will tend to make the engine ping.
I see that you recommend 93 octane, but the 4.9 wants 93, anyway. I would be inclined to do the reverse of what you recommended. Copy the EGR OFF values to the EGR ON tables. (Or just leave the EGR ON tables alone, since the chance of them being invoked are very remote anyway, considering the other parameters.)
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Its certainly true that you can run more spark advance with EGR. Yes the EGR On timing is aggressive. The answer might be to try and compensate for the additional timing and lack of EGR by running a richer mixture. By increasing the values in the MAP vs RPM VE table by 5%, we may be safe but we will never know until we try. Perhaps an average of both EGR On and EGR OFF values may be a better starting point or we could just bump up the timing by a small percentage. A while back Superchips made a performance chip that reportedly made 225HP and 300ft lbs torque by using more timing and fueling but I don't have access to that chip. There is not much out there on Cadillac 4.9L performance tuning. Not that its the answer, but the F body tuners might have a clue as to how they conquered the EGR delete..
UPDATE: After doing extensive research on the matter, I will agree that the EGR On values in the timing table are far too aggressive for an engine without EGR.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE " [This message has been edited by Dennis LaGrua (edited 05-21-2020).]
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