Knock Sensor Control

[TT205 42]

Was having a chat with a friend who is bonkers about MX5's and was talking about aftermarket ECU's that are available for them - they appear hugely expensive - things like 'Hydra'

 

He insists that it is the software development that has gone on to control 'knock'

 

Do DTA, Motec, Haltec etc etc have inferior knock control?

 

Cheers

 

Dave

[petert 586]

If ithe ignition advance is tuned properly, to maximise torque, you don't need knock control. Maximum torque is not necessarily the onset of knock. That might occur several degrees later. So if you've got mapping to control air temp vrs. ignition advance and coolant temp. vrs. ignition advance, and it's set up properly, knock control is unnecessary.

[TT205 42]

He is running a supercharger - would that make any difference?

[Malachy 0]

well not being funny but all a knock sensor is a microphone, this is then tuned to detect a certain frequency, when this is detected it drops the 5v signal that it is being supplied with to 0v this is then detected by the ecu as it is expecting a 5v input and has 0v and it can take appropriate actions to suit.

 

Megasquirt has had Knock detection ignition retard for a while now in both ms1+extra and ms2, Ms2+extra beta

 

http://megasquirt.sourceforge.net/extra/knock.html

 

the software behind it is very simple

 

the hardest part is finding out what frequency your block makes when it is "knocking" this can be done by using a laptop a microphone then and hitting the block with a metalic item, you can then isolate this frequency and identify it on the laptop. you then tell the knock sensor that that sound frequency = knock and the rest is easy:)

 

 

but as petert says once you have setup correctly there is no reason why the engine should knock the clttempVSign and airtempVSign should prevent this. However i still use it on my car as i am paranoid about picking up some crappy fuel and like the "safety net" it gives especially since for megasquirt the hardware change will cost you about £30 for a prebuilt unit from here

http://www.viatrack.ca/

i assume this would probably work on most other aftermarket ecus you could programme an input so that when x=0v retard by 1 deg wait y time and repeat

Edited November 13, 2006 by Malachy

[Ryan 99]

Don't forget to factor in the "jap-car markup" which adds 50%+ to the cost of otherwise identical products.

[TT205 42]

Don't forget to factor in the "jap-car markup" which adds 50%+ to the cost of otherwise identical products.

 

 

This is what I was thinking

 

More details:

 

 

HYDRA ECU

http://www.tracktive.co.uk/content.php?page=131

 

8 Sequential Injector (High Current) and Ignition Outputs

32 x 32 High resolution Fuel and Ignition tables

Switchable Fuel and Ignition tables (32 x 32)

16 User Definable PWM Auxiliary Outputs

Internal 3 bar Map Sensor (5 Bar Optional)

Dual Knock Sensor inputs for closed loop control

Dedicated NTK Wide band Lambda input

Dual Closed Loop Narrow band Lambda control

9 Auxiliary inputs

Variable Camshaft Control (up to 4 Cams)

Drive By Wire Throttle (additional cost option)

Antilag

Launch Control

Dedicated outputs for standard Vehicle Instruments

Plug and Play applications for most Japanese vehicles

 

 

Dual Knock Sensor inputs for closed loop control *** Maybe this is it?***

Dedicated NTK Wide band Lambda input *** Or this? !***

Dual Closed Loop Narrow band Lambda control *** Or this? !!***

 

??

Edited November 13, 2006 by TT205

[Scottieb 0]

looks a bit more than you need to me?

[Sandy 191]

Ears.