[forrestking]

Allright... I have a 1991 Cabriolet with Digifant and a knock box (of course). Digifant is the same as Motoronic for all of you haters.
If I understand correctly, the knock box retards timing to prevent knocking. How far can the box retard the timing? if i set my timing to 30 BTDC will it fix it for the situation (not for real, i'm just trying to grasp the system). If it has a limit, what is it? Does it restore (advance) the timing at any point? if i run 87 octane in my car it would of course retard the timing, so if i run 93 after some 87 will it advance to the highest setting the 93 can sustain or will it stay back at the 87 setting? Where should i set my timing to get the best performance without trashing the engine or sacrificing much fuel mileage?

 

[ABA Scirocco]

Re: Knock Box Timing (forrestking)

The knock box does much more than retard the timing to prevent knocking, it completely replaces the mechanical and vacuum advance mechanisms found in a conventional distributor. To get technical, the knock box doesn't control advance, it controls retard only, if you were to bypass the knock box and run the ignition straight off of the distributor you'd find you'd probably have about 50 degrees of advance at idle speed the knock box programming calls for about 44 degrees of retard resulting in 6 degrees of advance at idle. As the engine speed picks up it calls for less and less retard.
The knock box has no way of knowing what fuel you are using, it has a pre-programmed ignition map and that map is the same whether you are running 87 or 93 octane . It only alters that map when it detects knocking it retards the timing a little, just enough to eliminate the knock when the knocking stops, it reverts to the pre-programmed map and the cycle repeats.
.

 

[GTIZRX]

Re: Knock Box Timing (ABA Scirocco)

I have a old vwp magazine that explaned it that the knock system advances the timing until it detects knock then when it does it redards the timing in 3 degree increments until the knock has stopped then starts advancing the timing in 1 degree increments until knock is detected again and then the whole process starts over again. This was a article on a 16v scirocco. I am recalling from memory and there are probably more qualified poeple than me who can give you a better explanation.

 

[eurotrashrabbit]

Re: Knock Box Timing (ABA Scirocco)

Well you are wrong about Moronic being the same as Digifuct. Moronic CIS-E does not use pulsed infectors like Digifuct but it does incorporate the ignition and fuel maps in one computer. The Moronic Pulsed system uses a trigger wheel for the ignition the digifuct does not. And yes the knock box does control advance and retard to a point it will not advance the timing like a mechanical advance system if the Pezoeletric(Spelling?) sensor senses detonation or a certain frequency it retards the timing in 2 degree increments but it does also bring it back to where the dist is set at if no detonation is occuring.

 

[forrestking]

Re: Knock Box Timing (eurotrashrabbit)

not to be too much of a dick, but you are wrong. I have seen the input that you bring to this list and think you are a pretty knowledgeable guy when it comes to these cars, but I must disagree with these drunken statements you have made

. Motronic is different from KE-Motronic or LH-Motronic. KE-Motronic was a CIS system, But there are like 2 other motronic systems that aren't, and KE-Motronic happens to be the only motronic system that is CIS. See? Motronic in general was a pulsed sysytem. first introduced in 1981 as an "engine management" setup. Soo.. the system that Bosch calls 'Motronic' is pulsed

and Digifant is the same as a Motronic system except that it uses a simpler ignition map, developed by VW. Digifant II, incorporates a knock sensor and brings a bit more finnesse to the situation. Digifant is, in essence, a Bosch licensed VW modified Motronic system. Thanks.
And thanks for answering my question. it is good to know that the knock box is running at a Big Retard

.

 

[eurotrashrabbit]

Re: Knock Box Timing (forrestking)

It is still not the same the later moronic uses a crank trigger which gives input to the comp and gives that signal to the injectors

 

[forrestking]

Re: Knock Box Timing (eurotrashrabbit)

Motronic DOES NOT EQUAL KE-Motronic. KE uses the crank trigger, and is a CIS system. Motronic (not KE) is a pulsed system. And AFAIK the fuel mapping changed pretty frequntly as each upgrade was made to the existing systems.

 

[eurotrashrabbit]

Re: Knock Box Timing (forrestking)

KE motronic does not use a crank trigger wheel. Don't make me get the Bosch infection bible

 

[forrestking]

Re: Knock Box Timing (eurotrashrabbit)

/me quits. I am too unsober to argue effectivley, but at least i got my timing question answered.

 

[eurotrashrabbit]

Re: Knock Box Timing (forrestking)

I was about to say the same thign let me drink my alckohol in peace. Posting just provakes mehave a

on me I knewthe the PVW post would get loked after I posted onit

http://****************.com/smile/emthdown.gif


[Modified by eurotrashrabbit, 1:11 AM 2-14-2002]

 

[Big CADDY]

Re: Knock Box Timing (eurotrashrabbit)

I guess I'm [email protected]@hole.... I'll drink to that

we were playing a..hole right?