If I put on a larger intake would it effect my timing?
11-14-2005, 12:50 PM
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If I put on a larger intake would it effect my timing? I went to a Fast 90mm for the direct port features and havent had it tuned for it yet. When I had the LS6 oval intake on I would pull 26* timing at WOT with 0 or very little KR.
After the Fast 90 install I only pull 22 @ WOT with 0 KR .
Is this normal with not tuning it in?
After the Fast 90 install I only pull 22 @ WOT with 0 KR .
Is this normal with not tuning it in?
11-14-2005, 01:42 PM
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depends what adders are removing timing... not sure what software you use to scan... but if it's EFI Live or HP Tuners , they include PIDs that help determine what adder tables are pulling timing....
Also... if you're seeing 22* right after the FAST install... drive the car a little... it takes the PCM some time to determine wether you belong closer to the high octane or low octane tables (there's also a PID to determine how much the PCM is favoring high or low tables)
Also... if you're seeing 22* right after the FAST install... drive the car a little... it takes the PCM some time to determine wether you belong closer to the high octane or low octane tables (there's also a PID to determine how much the PCM is favoring high or low tables)
11-14-2005, 01:47 PM
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I would think that airflow was modified such that different cells are being used for timing since there is no KR. It could be a number of factors contributing to different timing numbers. There is also the possbility that you created an airleak which is fooling the computer as well.
11-15-2005, 02:26 PM
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If the new intake is allowing the engine to breathe better, overall airflow goes up right? The base spark table is usually set up such that higher airflow or load (shown in g/cyl on a GM) at the same RPM will yield a lower commanded base ignition advance. Check the new vs. old MAF values at WOT and compare that to where you land in the high octane spark table for load. I'd bet you're just further along the load scale now and may need to tweak the tune to keep spark advance up at higher loads. (if it doesn't knock!)
11-16-2005, 11:24 PM
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This is all good info thanks guys. Thought it had something to do with the intake/TB being a larger area.
I had just put in 92 octane so that should have been high enough gas, but it wasn't my normal station.
I drove the car about 160 miles with the new intake when did the check...should have been enough time for the computer to relearn correct?
I am scanning with just Atap V.1. So I can only see what is going on.
I am just running a mail order tune from TSP. So either I am going to have to send it down again or just make the drive to Speed INC in the spring and get a decent dyno tune. I think I would do more bad than good with EFI live in my hands.
SUCKs winter is here! And salt is out on the road.
I had just put in 92 octane so that should have been high enough gas, but it wasn't my normal station.
I drove the car about 160 miles with the new intake when did the check...should have been enough time for the computer to relearn correct?
I am scanning with just Atap V.1. So I can only see what is going on.
I am just running a mail order tune from TSP. So either I am going to have to send it down again or just make the drive to Speed INC in the spring and get a decent dyno tune. I think I would do more bad than good with EFI live in my hands.
SUCKs winter is here! And salt is out on the road.