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Discussion Starter · #1 ·
With my limited knowledge of cars I've been wondering how the knock sensor and timing are related.

I run 98 octane which I assume advances the timing.

Does it just advance it from the set timing or is it an equlibrium type advance where if the timing was retarded on purpose and the run on high octane the knock sensor would bump it all the way back up to the previous advanced timing?

I am thinking about getting my saab specialist to check/advance my timing since I always run 98 and I want to get as much free power out of my NA.
 

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It won't work.
The EZK system advances the timing by about 1/3 of a degree each engine revolution. It retards it by about 3 degrees each time the system detects a knock. The initial setting has little to do with that.
You can't adjust how the system responds, and there's nothing to be gained if you could.
 

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Discussion Starter · #3 ·
Jim Mesthene said:
You can't adjust how the system responds, and there's nothing to be gained if you could.
I'm not sure if I understand what you mean, Is it possible for timing to be out since the knock sensor will adjust it depending on the quality of the fuel being used?

Also how advaced in terms of the amount of power is 1/3 of a degree?
 

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My understanding of EZK is that it will find the limits of knock by deliberately advancing timing until it detects knock, then back off the timing a couple degrees. If I remember right, the Bentley mentions that periodic audible knock is normal and is the result of EZK finding this limit. Check your Bentley, though, to be sure.

However, there is a finite amount of advance EZK will provide, so if you are using very high octane fuel, allowing advanced timing, you won't necessarily be able to take advantage of the octane. For example, if your fuel allows you to run, say 30* advance knock-free, EZK will only go to 22*.

There are a couple ways to get more advance. One is to remove the EZK crank sensor shutter wheel, modify its mounting holes so the shutters cause the EZK to be more advanced than it thinks it is. This is impractical.

The other way is to fit a distributor from a non-turbo 16V LH2.2 car (86-87 in U.S., dunno about Aus.) or a Turbo distributor from any 16V B202T (do not use the vacuum advance capsule, but do not remove it, either).

Both of these distributors have the Hall sensor inside, not at the crank, so you can rotate them to get whatever base timing you want, allowing you to set the base timing more advanced than Saab's 14* BTDC, thus getting more advance. (Note that you will have to deal with the wiring to get the signal from the distributor -- the signal is the same as your 89's crank sensor's.)
 
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