New motor is in- need some advice on tuning...
07-22-2006, 06:33 PM
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New motor is in- need some advice on tuning...
I put my new crate motor in and need some general advice from you all.
This new motor is the old-fashioned GM Goodwrench crate motor with iron heads. It is the 260hp 350 motor, and I bolted on a new Holly Projection intake and my GM TBI unit with 55lb injectors running at the stock pressure (for now - more fuel will come soon). I'm also running ceramic-coated headers with 2-1/2" duals into Jegs turbo mufflers. I have a heated o2 sensor. No cats. The engine specs are:
Hydraulic flat tappet cam, (.383''/.401'') and a 112° lobe separation
Cast iron cylinder heads with 76cc chambers
8.5:1 compression ratio
Where would you guys set your base timing and generally, what kind of advance would you start with? How about VE for this setup?
I tweaked my old bin file to try to get it close but it did not like my adjustments. So I downloaded a stock 350 TBI pickup truck bin file from the late 80's and loaded it. It does idle like a dream but anything over 1500 RPMs it just bogs. I didn't have my ALDL cable plugged in but the computer was hunting all over the place with fuel and timing. The timing advance values are really high compared to my old bin, with alot of bias in the cool advance table. I zeroed all the spark adders and biases and tweaked it down. It seems a little better but I'm not experienced enough to get this thing dialed in. I am going to put in a permanent fuel press guage just to make sure my pump didn't go out, but it has never had a FP problem. Any advice?
This new motor is the old-fashioned GM Goodwrench crate motor with iron heads. It is the 260hp 350 motor, and I bolted on a new Holly Projection intake and my GM TBI unit with 55lb injectors running at the stock pressure (for now - more fuel will come soon). I'm also running ceramic-coated headers with 2-1/2" duals into Jegs turbo mufflers. I have a heated o2 sensor. No cats. The engine specs are:
Hydraulic flat tappet cam, (.383''/.401'') and a 112° lobe separation
Cast iron cylinder heads with 76cc chambers
8.5:1 compression ratio
Where would you guys set your base timing and generally, what kind of advance would you start with? How about VE for this setup?
I tweaked my old bin file to try to get it close but it did not like my adjustments. So I downloaded a stock 350 TBI pickup truck bin file from the late 80's and loaded it. It does idle like a dream but anything over 1500 RPMs it just bogs. I didn't have my ALDL cable plugged in but the computer was hunting all over the place with fuel and timing. The timing advance values are really high compared to my old bin, with alot of bias in the cool advance table. I zeroed all the spark adders and biases and tweaked it down. It seems a little better but I'm not experienced enough to get this thing dialed in. I am going to put in a permanent fuel press guage just to make sure my pump didn't go out, but it has never had a FP problem. Any advice?
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