Initial Tuning on My First Blower Car
09-09-2004, 08:41 AM
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Initial Tuning on My First Blower Car The car is a 98 SS m6 with shorty headers, granateli maf sensor, and a borla exhaust, everything else is stock. The Super Charger is a ATI ProCharger P1-SC pushing 8lbs (supposedly) through a six rib setup (no boost gauge was installed).
The car is running on the stock 28 lb/hr injectors.
Before we drove it at all I added 10 percent across the power enrichment table as we are not using the fuel management unit which I was told by the shop owner that all it does is add fuel pressure.
Part throttle cruzing resulted in posative 10 to 4 ltrms and 14.7 to 15.0 air fuel ratios (verrified with my wideband) and a .5 to 1 degree of knock retard about every 5 minutes (no audible pinging). Wide open throttle generated a 10.8 to 11.5 a/f ratio and posative 8ish ltrims and knock retard in the 2-4 range between 4600-5200 rpm. I have the stock timing values in the car which greater then .6g/cyl is 28 ish to a dip of 26-23 in the 4200-4800 range and back up to 28. Could this KR be false as the 98s do have overly sensative knock sensors? Injector %s as monitored with EFI Live were in the 121 range maximum which I would deffinatly not think is good even though the car never went lean.
I retuned the car by adding 10 % to the ltrms and adding 8% to the power enrichment table to offset the loss of added fuel by zeroing out my ltrms. The same results were had at part throttle except for the ltrms were now in the 6 to 1 range. Wide open was now around 10.5 to 11.2 a/f ratio, posative 3-1 ltrms, and kr in the same range as before. My injector duty cycle percentage was now 149 percent max (as a result of the richer wot mixture).
First thing I did was to recommend larger injectors were put in the car and 42 lbs/hr Racetronix were ordered from Thunder Racing. Second, as stated before could the 98's overly sensative knock sensor by causing problems, I don't see how the car could be knocking with only 8 or less pounds of boost, a 10.5-11.5 to 1 a/f ratio, and 28-23 degrees of timing.
Any suggestions would be appreciated but get ready for more questions.
The car is running on the stock 28 lb/hr injectors.
Before we drove it at all I added 10 percent across the power enrichment table as we are not using the fuel management unit which I was told by the shop owner that all it does is add fuel pressure.
Part throttle cruzing resulted in posative 10 to 4 ltrms and 14.7 to 15.0 air fuel ratios (verrified with my wideband) and a .5 to 1 degree of knock retard about every 5 minutes (no audible pinging). Wide open throttle generated a 10.8 to 11.5 a/f ratio and posative 8ish ltrims and knock retard in the 2-4 range between 4600-5200 rpm. I have the stock timing values in the car which greater then .6g/cyl is 28 ish to a dip of 26-23 in the 4200-4800 range and back up to 28. Could this KR be false as the 98s do have overly sensative knock sensors? Injector %s as monitored with EFI Live were in the 121 range maximum which I would deffinatly not think is good even though the car never went lean.
I retuned the car by adding 10 % to the ltrms and adding 8% to the power enrichment table to offset the loss of added fuel by zeroing out my ltrms. The same results were had at part throttle except for the ltrms were now in the 6 to 1 range. Wide open was now around 10.5 to 11.2 a/f ratio, posative 3-1 ltrms, and kr in the same range as before. My injector duty cycle percentage was now 149 percent max (as a result of the richer wot mixture).
First thing I did was to recommend larger injectors were put in the car and 42 lbs/hr Racetronix were ordered from Thunder Racing. Second, as stated before could the 98's overly sensative knock sensor by causing problems, I don't see how the car could be knocking with only 8 or less pounds of boost, a 10.5-11.5 to 1 a/f ratio, and 28-23 degrees of timing.
Any suggestions would be appreciated but get ready for more questions.
09-09-2004, 11:20 AM
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The only thing that I am thinking is that if you buy the FMU with the kit then they say you don't need any computer tuning. That is why I didn't back down the timing. I will try to back the timing down and see what happens. Thanks.
