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Advise... Knock, MBT, Plex V3.

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Hi Guys

Im trying to understand ignition timing steady state and ramp run styles NA or turbo principle is still the same.

Example would be

Unknown engine internals with turbo comes into shop for tune.

Running through steady state and setting up MBT with ignition timing to find its knock limited before MBT.

Say we are at 4000 rpm 2psi boost and have reached knock before MBT. Aim is 12psi

At this cell I can lower the timing 3 degrees from knock and move to the next cell.

Do I linearize the cells from start to 12psi and carry on check for knock and if there is none leave it?

My issue is.. I understand that if I tune every cell from here until I detect knock using the Plex V3 and back off 3-4 degrees im safe. (but is tuning to find knock in every cell ok to do?

If Im to put in a number I think is safe but ends up only being 1 degree off knock it leaves the potential for knock in real life driving.

Iv watched all the videos on ignition timing but this is the only part that is confusing me on how to proceed.

Also on another note,

Will using a plex v3 knock monitor pick up knock sooner and less aggressive then knock ears?

any input is appreciated

Cheers

Hi Sam

Below my personal opinion and methods that work for me. There are certainly others who could describe it better, so please do take this info for what it is worth and ask others as well.

For a start:

https://www.hpacademy.com/previous-webinars/103-setting-up-plex-knock-monitor/

..will answer many questions. The V3 will be an invaluable item to have. Although knock detection and knock control features in ECU's have developed and have become much more sophisticated as compared to when Plex KM V1 was first introduced to the market, it is still a good idea to make use of a second strategy, rather than solely relying on ECU-integrated features.

As an alternative to the V3, the LINK Knockblock works also well, although it is by no means as feature rich as the V3, obviously this is reflected in the purchase price.

________________

From initial post:

My issue is.. I understand that if I tune every cell from here until I detect knock using the Plex V3 and back off 3-4 degrees im safe. (but is tuning to find knock in every cell ok to do?

________________

I usually start with a timing map that is somewhat realistic and back off timing over a range of cells / rows (in a knock limited engine). By somewhat realistic, I mean the engine should produce some power, ie. assuming known MBT is X deg, I would not pull away huge numbers (double digits). Personally, I have found that some engines exhibit less mechanical noise once ignition is advanced and the engine makes healthy power as compared to overly retarded timing. Unlike steady state fuel tuning where most cells are calibrated individually. Extrapolation and interpolation can be applied once you get a good picture of the shape of the map, also on ignition.

Hopefully you find this useful, if others here have different opinions, please chip in.

Best regards

D

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