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Old 04-17-2024, 12:06 PM
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R 70 Judge R 70 Judge is offline
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Join Date: Mar 2002
Location: San Diego, CA
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Great info in here!

Okay so upon reviewing my ignition parameters I think I need to do some work. My car runs great midrange and full throttle but is hard to start. It used to start okay on race gas but since switching the E85 its a pain. A few things I've noticed when looking at how mine is set up.
  1. Inductive delay is set to 100.00 usec (which from what I've read is probably fine)
  2. Timing offset is 12* (A video I watched said it shouldn't be more than 5*, and if it is I need to move the pickup on the crank trigger)
  3. Crank sensor is set to digital rising and cam is set to digital falling (I believe they should be the same, preferably digital falling)
  4. My Holley smart coils P/N 556-112 have the dwell set to 5.0 msec (See Holley's instructions below)

"Dwell Setting:
- For street cars below 1.5 HP per cubic inch, the dwell should be set to 4.0 msec.
- For cars that exceed 1.5 HP per cubic inch, the dwell should be set to 4.5 msec.
- For high boost, maximum effort drag race engines, the dwell can be set to 5.0 msec."

My engine is on E85 and is not a traditional "street" engine, but I do drive it on the street. Its got a ton of compression (13.8-1) and a healthy cam (272-283 .726" int .696" exh on 109LS). According to timeslip MPH I'm under the 1.5hp per cube mark though.

I'm thinking the dwell time is fine for my application but wouldn't mind input on the subject.
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1970 Trans Am

Spotts Built 484" IA2, Highports, EFI Northwind
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