Advance settings on Crane HI-4TC

Thunder90 said:

I am doing an engine upgrade on my 2005 Thunder Mountain Custom. It came with the 95 inch kit already, flat-top pistons, SE203 cams, stock heads. I'm having the heads ported/flowed and he's also going to deck the heads to bump up CR north of 10:1. I'll be installing a set of S&S gear drive cams (probably 570s)......and it's a carbureated motor.

I bought the Crane HI-4TC adjustable ignition module as well.

Question is: what should the initial and advance settings be (given that I'm bumping up compression and going with the bigger cams)? I plan on having my local shop dyno-tune it where they will adjust the ignition timing to get it to run at it's best......but what should I set the initial settings to after completing the build (using the dial knobs on the module itself) while breaking in the motor?

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You say you are bumping compression up above 10 to 1....well how far? The crane canned maps are very agressive down low in the rpm band. For a long time, I tried to stay close to that 5 initial...usually running -1/-2 initial and an advance of 3/4...but whenever it got above 80* ambient outside, I had pinging problems. Daytona Twin Tec recommends no more than 30* advance at 5000 rpm for motors with 10.5 compression; which is what I run. I finally struck on a combination that works well for my build without pinging...and I hope to get it on a dyno this spring and see if it shows on the dyno.

The settings I came up with for 10.5 compression, is -5 initial timing with a curve of 6. This way you are starting out lower, for the lower rpm ping zone of 2500-3500 rpm...but because the advance curve is more agressive, it catches back up as the r's climb (These settings put the advance right at 30* at and above 5000rpm as DTT recommends). If you're not going as high as 10.5, I'd suggest starting at -2 or -3 initial atleast for starters with a curve in the 4-5 range.