Vems knock detection, is it good?

[A80Avant]

i am planning to use the knock cable from marc to reset the knock settings on vems, but i dont like the idea of being a guinea pig either... we'll see...

[GazzaG60]

everythings to be tested. just dont do anything stupid with timing.

test the sensor reaction first. wack one with a spanner but not hard and the engine should stumble.

[Jamo]

Is knock configuration worth it then on VEMS or is it a throw away afterthought?

[pnanassy]

Get that stroker running first!

The one im making is now running on 1.8bars,but we run out of fuel pump capacity!

Peter

[GazzaG60]

for me its almost irrelevent. maybe a person who is more interested in this aspect can give opinion.

my opinion is unless knock is used to set optimum timing like in some oem systems its not worth worrying about.

personally id get it running first. map in some boost, then try to get idle good. cruise will be there by then hopefully too. then id look at things like knock and optimising the vems boost control.

maybe marc or peter can add something here on thier opinions of knock systems in general. surely the number of knocklink type warning devices is an indicator to the usefullness of knock systems?

[pnanassy]

I would be happy to see a datalog where small and or brutal knock was registered by the VEMS and it retarded the timing,effectively saving the engine.I wish i had the oportunity to test these subsystem,unfortunately my offer was not good enough for the Creator.The plan was to go to the dyno and let the engine ping/knock a little while hearing it with conventional earphones,and then setting up the vems to handle it.

Something like this:

http://www.motec.com.au/filedownload.php/SKM%20and%20OKM%20User%20Manual.pdf?docid=2811

[GazzaG60]

what would you use to simulate it though.

1. correct timing and lower octane fuel?
2. exagerated timing?
3. leaner mix and timing?

surely this could be tested/setup on a throwaway 8v golf or something? now i know they work as my mate had one with the timing a mile out and when he put some 95 in it stumbled all over the place until i set the timing correctly.

wouldn't want to test such a thing on a built stroker like jamo has.

[pnanassy]

Every setup needs its own knock settings,so i would use a 5 banger,maybe a NA,that i use on the streets.Or my lowbudget 10VT,which can be easily pinged all the way

If there would be enough interest,and at least my expenses could be recovered without any profit, that would be awesome.But hey,then everyone will use it...

Maybe one day.Or is there enough interest to make it happen?

Peter

[Bram]

Well, if it really works so I do not have to worry about engine explosions when doing a WOT on dubious fuel I would be interested

Off course I always try to avoid bad fuel, but still.

[nervas]

Functions like CLC wideband and knock control are there to make corrections due to some unexpected or long term change (engine wear). They are not for fixing bad tuning.

[Jamo]

Who said anything about fixing bad tuning? The OEM ecu wasn't released with bad tuning and runs with knock sensors

It's a safety feature which if it could be gotten working is a very good one at that.

[A80Avant]

i think even if you try to look for knock with a cable and then try to configure vems for it, it wont work properly as it will inadvertenly mistaken noise for knock as well. Then you would have to increase the timing to compensate and in the end you may end up with bigger problems.

a different solution is to get some 95 octane fuel in and tune the timing with that fuel consumption, save a map with that, and have the ability to change from one to another in case you fear you have a bad batch of fuel in the car OR you manage to hear some knock.

Now that i heard some mild knock in my engine, i know what it sounds like and i can look out for it.I am not sure that vems can be configured fine enough to sense it. If i have time i may give it a go, but i doubt that this will have a great effect.

[diesel des]

Did anyone get any were with vems and knock control?

[A80Avant]

A lot of people. The firmware is out there and it's been said it's working very well. I haven't got round to it yet

[diesel des]

http://vems.hu/vt/help/v3/v3_knock_control.html Seems promising