Setting megajolt timing.
Turbo Mini Forums

I'm being thick this evening

I'm setting the timing in limp mode for 10 degrees at 1k rpm.

I have a snap on gun which due to it being wasted spark is obviously it reads double, and it tells you rpm and you can also factor in ignition advance to vary the strobe.

To get the timing bang on I want to set the gun to read at the tdc mark. So I take it I'll need to set the timing light to 20 degrees advance to take into account the 10 degrees for it being wasted spark and the 10 degrees to get it back to the tdc mark.

Sound about right?

The rpm will be wrong', but the advance will always read right. 10 degree advanced on no 4 is the same as no 1, it is only the cam that is in the a different position.

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Not quite right ben, if its the same snap-on light i use, the advance you enter on the keypad is guessed by the light as a function of the rpm and when the pulse is detected on the ignition. the only way to use one of these lights reliably with wasted spark is to set it to "0" degrees and it will then function like a normal timing light. you then obviously line up the pully with the 10 deg advance mark.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Damn, having just got it perfect at tdc looks like I'll be starting again!

It goes all over the place if I leave it at 0, may try with an ordinary light for now.

Just trying to minimise time spent on rolling road and if I can get the timing bang on thats more time tuning, less time doing basics.

aye just use a normal light, that way theres no chance of errors. tbo most digital timing lights struggle with false triggers on waisted spark ignition. if you use an old-school strobe there will be no error.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.