Anyone know the stock Vortech timing? When does it start and how much is retarded up to redline?

 

Gil

I looked at a stock timing map . The timing up to 10psi is as follows
5000rpm = -1 degree's
5500rpm = -2
6000rpm = -4
6500rpm = -6
7000rpm = -10
7500rpm = -15
8000rpm = -15
After 10psi = -1 , -2 , -4 , -8 , -10 ,-15 , -15

Remember....The SS box pulls an additional 1.5 degrees from just being hooked up . From signal delay

 

Thanks.

My J and S setup is .5 degrees per 1 psi starting at 3 psi and then an additional 4 psi taken out between 5 and 6k rpm for a total of 8 degrees retard at 6500 rpm. I'm usually at 5 psi by 5k, so upon seeing what the stock Vortech timing is, I can actually take out .5 psi per 1 psi starting at 1 psi and then 4 psi from 5k to 6k.

 

Important to correlate after intercooler temperature [in plenum temperature] with ignition advance............using psi alone without temperature correction [density] is pretty inaccurate.

1% per 11F.

You really need an under spark plug [peak pressure sensor/electronics] sensor to measure the peak BMEP to optimize timing to allow max cylinder pressure at 16-17 degrees ATDC. AS the flame speed varies with both temperature and PSI.

http://www.optrand.com/fliers/psiplug_%20060201.pdf
http://www.vehicular.isy.liu.se/~lar...ects/main.html

http://www.streetrodstuff.com/Articl...tion/index.php

 

Q45tech
Would you happen to know how the engines knock sensor and the ECU work together ? Meaning....the signal sent to the ECU is in volts . It shows 2.53 volts all the time [ no knock ] at what volts would the ECU consider it to be knock and retard timing ? Would slight increases or decreases be considered as engine noise [ say ] 2.29 to 2.63 volt range be just engine noise . And any thing [say] over 3 volts be considered as knock and the ECU retard timing ?

 

Think you are seeing the [microphone aka knock sensor] bias voltage.
Knocks are ac components superimposed on this voltage and passed to amplifier thru a capacitor to block this voltage. A frequency band pass filter shapes the response to that of the knock spectrum to block out other engine noises. This works ok up to a certain rpm above that rpm the engine creates too much noise to discriminate knocks from noise.

Knock sensor frequencies typically range from 2kHz to 8kHz.

The KS IC creates a noise base line based on the average of the preceeding 12-24 cycles and responds when the thresho;d is exceeded, first reducing the advance by 3 degrees[listening] then 6 degrees or 10 if necessary.

Once the knock has decreased it slowly increases advance in 1 degree steps per 2-4 cycles [4-8 revolutions] until the previous desired value is achieved.


This might help:
http://www.intersil.com/data/an/an9770.pdf
http://www.intersil.com/data/fn/fn3601.pdf
http://pdf.rtkcomponent.com/pdf/p19e6.pdf
http://www.luxtron.com/pdf/AN88-EAS100-A9.pdf

http://www.directignition.com/pdf_files/tec3r.pdf

 

Thanks....very much over my head , thought it might be a little easier to determin knock just from the volt signal sent to the ECU.
I tapped the knock sensor and log the volts coming from it . It stays right at 2.53 until 6000rpm and then goes up and down [ 2.29 to 2.63 ] and stops around 6500rpm's . The first time I logged it , I had the same readings , except one good spike to 3.6 volts . I took that as knock and retarded timing by [1] degree and I have yet to see a spike like that again

 

Bill,

Contact this guy. He makes the Safeguard and should be able to answer your question concerning knock. As you know, the J&S senses knock and retards timing, so it must have parameters set to do so.

jpizzuto@jandssafeguard.com

 

Schematics of typical IC and circuits used in designing KS were provided in pdf format above. This is the kind of question that requires and deserves at least 8 hours of detailed study. Everything you need is in the websites links above.