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Anyone know the mechanical advance vs RPM curve, advance vs Vacuum specs and base and total timing for the factory SuperCharged 312? Getting ready to build a base tune for our 292 Turbo and just need a starting point to work from.
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What heads & cam are you using for the turbo application? Just curious.
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Stock 62-64 C1TE
Don't copy us. This is going to see as little boost as possible. It's just for fun. Not trying to go fast. It's a 2bbl, maybe 5psi. 215hp ish
My wife wanted her dump truck to make turbo noises. I'll post pictures in a few days when we get it going
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I thought it was an unusual combination, particularly for an F600, but I've seen stranger builds.
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“My wife wanted her dump truck to make turbo noises.”
That may be the only time I ever read a sentence like that!! Awesome!
MplsMike '56 Parklane Minneapolis, MN
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Back to your original post, the following comes from the factory Supercharger Manual. Vacuum advance: Dist RPM Deg. Inches HG 1000 0 1 1000 0-1 5 1000 1-3 7 1000 9-11 14 1000 9-11 20 Centrifical Advance: Dist RPM Deg. 300 0-1/2 400 2-3 600 8-9 1500 9 3/4-11 2000 10 3/4-12 Initial timing 3 deg. John
John - "The Hoosier Hurricane"
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Thanks John!
Am I reading that correctly, they only ran 15° total advance?
Was there any boost retard solution?
I figured this old 292 would want about 36° total before boost. Pulling 20 degrees for 9psi seems excessive. I was thinking about 4° retard at 5psi(target boost for us)?
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I’m not arguing with the F code spec, but this was my experience. 292/312 crank, 320cid. 9:1 true static ratio. 113 Mummert ported iron heads, 270 series cam (20 years ago, spec may have changed). Paxton SN2000, pulleys for 5lbs at 5000 rpm. Premium pump fuel.
I ran 10-12 initial, and 34-36 all in. The vacuum can had probably around 15 or 20 degrees in it. I used an MSD and ran 2* retard at 3 psi (manifold pressure). That came in around 3000 rpm, maybe a little higher. Hot weather, or racing with long WOT periods, I’d need less initial/less centrifugal/ more retard. Didn’t happen enough to do more than set the initial back a bit.
Your results will depend on the engine/cam specs, etc.
miker 55 bird, 32 cabrio F code Kent, WA Tucson, AZ
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The specs show 27 degrees total mechanical advance, there would not have been any vacuum at full throttle, probably about 6 pounds pressure. On my car, I'm running SN60 guts in my blower for about 12 pounds boost at 6000 RPM. I used to run 34-36 total advance, lost a lot of head gaskets. I backed down to 30 degrees total, the car ran quicker and head gaskets now live. I get 27 degrees from the specs, 12 distributor degrees times two plus 3 degrees initial.
John - "The Hoosier Hurricane"
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Hoosier Hurricane (8/18/2024)
The specs show 27 degrees total mechanical advance, there would not have been any vacuum at full throttle, probably about 6 pounds pressure. On my car, I'm running SN60 guts in my blower for about 12 pounds boost at 6000 RPM. I used to run 34-36 total advance, lost a lot of head gaskets. I backed down to 30 degrees total, the car ran quicker and head gaskets now live. I get 27 degrees from the specs, 12 distributor degrees times two plus 3 degrees initial. "Distributor Degrees"! I missed that, when reading. Thanks for the clarification. 27° sounds more like it!
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