john banks

Often a knock related active green LED will turn into an orange or red when you get the car really cooking, but it would be nicer to have a clearer early warning system. If it doesn't develop ever I reckon it is fine, but you have to read the knocklink more cautiously in the midrange than at the top end it seems.

When a car is appropriately knock correcting in the midrange it often gets rid of a lot of this green flickering.

This is in the accessory position just behind the factory knock sensor, have also tried the factory knock sensor position. I found the TMIC bracket was far quieter on my car - big red at 4000 RPM on the block was only a flickering bottom green on the TMIC bracket.

[Edited by john banks - 10/3/2003 9:42:12 AM]

john banks

On maximum sensitivity on a typical UK engine, the knocklink barely registers mild knock at say 4000 RPM with just a slight flicker of the bottom green LED. Good going det in a few suspicious places on a typical UK engine doesn't even illuminate the orange LEDs.

How about increasing the gain in areas where the engine is quieter? That way you would see detonation as a spike above normal background levels?

You could do it with analog components if you are clever, I think this would be easier with an inexpensive microcontroller.

Leave out the shallow knocklink bandpass filter, rectify the signal, put it through an ADC on a uC. Reduce the 12V pk-pk RPM pulse to 5V with a few diodes and put it into a logic input to the uC and measure the frequency. Then divide the knock sensor signal by RPM or make a lookup table of thresholds by RPM.

I've not got the time or inclination to do it, but just thought I'd share the idea. The RPM based threshold is not new - used in most high end knock detection systems, and on posher aftermarket ECUs and no doubt the factory ECU, but the latter is so tied to a standard engine it doesn't work well with modifications.

I think you'd get a lot further with this method than with steep bandpass filters personally.

Floyd

iTrader: (9)

I was just thinking along the same lines. Get your phase inverters and route the power relays through the fusion coils to the anti -matter injectors. Quite simple really, glad that's all clear now.

F
PS whats a knocklink?

john banks

You muppetise my post and I drill holes in your pistons when you are not looking

T-uk

I've not got the time or inclination to do it

well it is after half ten on work night, do it on your next day off

WREXY

Hi John,

I get the bottom green flickering around those revs, however Delta Dash shows no knock correction. Is it safe to say that it's just engine noise on my car then?

Cheers,

George.

Scoobydick

Whatever you do, don't cross the beams

*Sonic*

Im a Doctor not an auto electrician

Jolly Green Monster

iTrader: (4)

Sounds like you are rewriting the ECU's software...

Just email me a copy when you have finshed..

Cheers

Simon

dowser

Where are you mounting the sensor though? I moved mine around a lot until I found the noisiest place - it wasn't under the tmic but on the right hand (looking at engine) tmic mounting bracket.

Richard