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Thread: Base Timing Question

  1. #1

    Default Base Timing Question

    I'm hoping to get a little better understanding of the Base timing setup. I have a mild N/A SBF with Holley HP, TFI & SEFI. I used the MPFI, up to 409 ci cam 216-225 base tune with 25° idle and 34° WOT to get it up & running. The Base Timing Table ranges from 25° at idle to 44°. I'm still in the early stages of tuning and learning, but with this timing table, it starts, idles, and runs OK. I recently looked at the base tunes available with the Terminator X, and there's a base tune TFI_NA_SBF_MPFI, which I'm guessing is designed to get someone with a 5.0L up and running quickly. When I look at the Base Timing Table for this setup, it's very different than the one I'm using. 12° at idle, 36° at cruise and 31° at WOT. This seems more traditional to me. Wondering which is a better starting point to evolve from.

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    25,470

    Default

    Remember, the only thing this EFI system self-tunes, is the Base Fuel Table, via the Learn Table.
    You're responsible for everything else, especially the Target A/F Ratio Table & the Base Timing Table.
    A dynamometer is the only real way to determine the optimum ignition timing for your performance engine.
    Most people research it, or just "know" what their engine needs or likes. Especially if it's a popular engine.
    https://forums.holley.com/showthread...8640#post88640 (Target A/F Ratio Table & Base Timing Table Reference)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  3. #3

    Default

    Timing at idle depends on how big the cam is. Timing at WOT depends on how good the cylinder heads are. Timing at cruise is dependent on vehicle weight and gearing as well as engine design.

    12° at idle is for a stock cam, 25° at idle is for a race cam. Your engine sounds like it is in-between those extremes. 31° at WOT seems low but it depends on the heads and CR. 34° at WOT should be safe with most wedge heads. 44° at cruise might be a little high, 36° at cruise seems low to me. For your engine I'd go 20° at idle, 34° at WOT and 40° at cruise.

    You understand that you can drive the car and make changes real time correct? Hook up the laptop and have a buddy drive your car while you sit in the passenger seat and adjust the timing. You can adjust the timing while you drive down the freeway and watch the fuel flow to see if you're making the engine more efficient or not.

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