Knock detection with a DTA P8 pro

[slideways]

Hi all
Can anyone recommend a knock detection system that will work with a P8 Pro?


Cheers
Slideways

[anonymous-user]

The only knock detection systems i have used that i have had sufficient confidence in (see note) are those which are "crank angle windowed". This means that they analyse knock sensor input signal at a bandpass knock frequency during a determined knock window (crank angle limitation for knocking). This means that they have a suitable noise rejection outside of the angle window and the knocking frequency. For these systems to be able to do this, the system processor has to rapidly process the knock signal in the crank angle domain, which is a fairly processor intensive duty.

None of the "add-on" systems are capable of doing this (to my knowledge) because you need a very fast databus link to the processor core to do it. It also takes significant calibration experience to accurately map an engines knock window and harmonic frequency.


Note: Confidence = the ability to calibrate an aggressive ignition angle (where spark angle is knock limited (i.e. outside the MBT area) and to trust the system to properly adapt and respond to knock events in a timely and accurate manner!

[stevieturbo]

slideways said:

Hi all
Can anyone recommend a knock detection system that will work with a P8 Pro?


Cheers
Slideways

Depends on what exactly you want it to do with the P8Pro.

But as Max says, there isnt anything that will offer reliable closed loop feedback.

[slideways]

stevieturbo said:

slideways said:

Hi all
Can anyone recommend a knock detection system that will work with a P8 Pro?


Cheers
Slideways

Depends on what exactly you want it to do with the P8Pro.

But as Max says, there isnt anything that will offer reliable closed loop feedback.

Well I suppose I was hoping that there was a product out there that would detect knock and send a signal to the ecu to compensate like most OEM ecus have!

[stevieturbo]

slideways said:

stevieturbo said:

slideways said:

Hi all
Can anyone recommend a knock detection system that will work with a P8 Pro?


Cheers
Slideways

Depends on what exactly you want it to do with the P8Pro.

But as Max says, there isnt anything that will offer reliable closed loop feedback.

Well I suppose I was hoping that there was a product out there that would detect knock and send a signal to the ecu to compensate like most OEM ecus have!

If the engine is tuned properly, you have no need for such devices.

And it's only in recent times aftermarket ecu's are offering such a feature. Some work....some dont work very well.
You'll pay a lot for a system that is reliable and works well. Mostly because knock sensors pick up huge amounts of noise and they struggle to differentiate between knock and engine noise.

If you absolutely insist on wanting such control, look at J&S Safeguard.

You can retrofit this to most cars. Although again it will need professionally set up so it can tell between actual knock, and engine noise.

Even most OEM systems arent very good. They have a narrow operating range, and they will have spent millions with R&D on each specific engine.

Edited by stevieturbo on Sunday 16th January 00:27

[slideways]

stevieturbo said:

slideways said:

stevieturbo said:

slideways said:

Hi all
Can anyone recommend a knock detection system that will work with a P8 Pro?


Cheers
Slideways

Depends on what exactly you want it to do with the P8Pro.

But as Max says, there isnt anything that will offer reliable closed loop feedback.

Well I suppose I was hoping that there was a product out there that would detect knock and send a signal to the ecu to compensate like most OEM ecus have!

If the engine is tuned properly, you have no need for such devices.

And it's only in recent times aftermarket ecu's are offering such a feature. Some work....some dont work very well.
You'll pay a lot for a system that is reliable and works well. Mostly because knock sensors pick up huge amounts of noise and they struggle to differentiate between knock and engine noise.

If you absolutely insist on wanting such control, look at J&S Safeguard.

You can retrofit this to most cars. Although again it will need professionally set up so it can tell between actual knock, and engine noise.

Even most OEM systems arent very good. They have a narrow operating range, and they will have spent millions with R&D on each specific engine.

Edited by stevieturbo on Sunday 16th January 00:27

Cheers Stevie in that case I wont bother with it one less thing to buy

[Marf]

Max_Torque said:

The only knock detection systems i have used that i have had sufficient confidence in (see note) are those which are "crank angle windowed". This means that they analyse knock sensor input signal at a bandpass knock frequency during a determined knock window (crank angle limitation for knocking). This means that they have a suitable noise rejection outside of the angle window and the knocking frequency. For these systems to be able to do this, the system processor has to rapidly process the knock signal in the crank angle domain, which is a fairly processor intensive duty.

None of the "add-on" systems are capable of doing this (to my knowledge) because you need a very fast databus link to the processor core to do it. It also takes significant calibration experience to accurately map an engines knock window and harmonic frequency.


Note: Confidence = the ability to calibrate an aggressive ignition angle (where spark angle is knock limited (i.e. outside the MBT area) and to trust the system to properly adapt and respond to knock events in a timely and accurate manner!

Always enjoy reading your posts

Whatever happened to ion sensing knock control? Or pressure rings between spark plugs and the head?

A few years ago i remember reading about these as if they were going to be the technologies that would bring about closed loop ignition control.