Aftermarket Knock detection

[harry b]

Any body have good experience with an aftermarket knock detection unit.
And I don't mean the simple amplifier boxes with a gain knob.
A good one which can be calibrated for engine speed or in the rotation window where the detonation occurs.

Phormula, Plex, Gizzmo, Mlabo etc.

Ideal would be with a visual aid, logging and headphone exit.
Can't really find good test reports on these units and don't like to throw money at something I don't know the level of quality

[Vixpy1]

We like the Phormula units

[stevieturbo]

harry b said:

Any body have good experience with an aftermarket knock detection unit.
And I don't mean the simple amplifier boxes with a gain knob.
A good one which can be calibrated for engine speed or in the rotation window where the detonation occurs.

Phormula, Plex, Gizzmo, Mlabo etc.

Ideal would be with a visual aid, logging and headphone exit.
Can't really find good test reports on these units and don't like to throw money at something I don't know the level of quality

The only one that meets those requirements is the Plex

http://plex-tuning.com/products/plex-knock-monitor...

Virtually all others are simply audio only units.

None of them will relate to an actual crank rotation window unless they have that information, but realistically the only setups that will have that...are those integrated with the engine ecu.

I got the Plex recently, and although I havent had a chance to use it on a car yet, the quality of the product is superb.
You can use it as a standalone unit, or hook it up with the laptop and view/record everything on the laptop so it's very versatile in that respect.

Via either a coil or injector trigger it uses this to identify which cylinder any noises and potential knock are coming from. It also takes rpm from this same trigger and you can add an additional load parameter to get a very good picture of when and where any issues my be.

Edited by stevieturbo on Monday 21st September 13:16

[anonymous-user]

The problem with all these systems is that there is no way to validate the actual knocking pressure against the structure born vibration level and frequency content. i.e. the only way to set a sensible maximum knocking pressure is to run with more and more knock until the engine fails, and then turn it down a bit!

[harry b]

Max_Torque said:

The problem with all these systems is that there is no way to validate the actual knocking pressure against the structure born vibration level and frequency content. i.e. the only way to set a sensible maximum knocking pressure is to run with more and more knock until the engine fails, and then turn it down a bit!

Sounds like a solid plan,.............but thanks, I'll stick to something more careful.
I normally use headphones, but doesn't always work optimal. Special when doing fine tuning on the road in mid range levels where the torque just starts to pick up. Too many things to watch for. The logger function is in that case very handy to adjust the ignition timing.

[harry b]

stevieturbo said:

The only one that meets those requirements is the Plex

http://plex-tuning.com/products/plex-knock-monitor...

Virtually all others are simply audio only units.

None of them will relate to an actual crank rotation window unless they have that information, but realistically the only setups that will have that...are those integrated with the engine ecu.

I got the Plex recently, and although I havent had a chance to use it on a car yet, the quality of the product is superb.
You can use it as a standalone unit, or hook it up with the laptop and view/record everything on the laptop so it's very versatile in that respect.

Via either a coil or injector trigger it uses this to identify which cylinder any noises and potential knock are coming from. It also takes rpm from this same trigger and you can add an additional load parameter to get a very good picture of when and where any issues my be.

Edited by stevieturbo on Monday 21st September 13:16

That's the thing I also have on the top of my wishlist, but as said, before I throw roughly £700 to the unit I would like to know some on hands experience.
By the way, love that 9 seconds granada.

[Vixpy1]

harry b said:

stevieturbo said:

The only one that meets those requirements is the Plex

http://plex-tuning.com/products/plex-knock-monitor...

Virtually all others are simply audio only units.

None of them will relate to an actual crank rotation window unless they have that information, but realistically the only setups that will have that...are those integrated with the engine ecu.

I got the Plex recently, and although I havent had a chance to use it on a car yet, the quality of the product is superb.
You can use it as a standalone unit, or hook it up with the laptop and view/record everything on the laptop so it's very versatile in that respect.

Via either a coil or injector trigger it uses this to identify which cylinder any noises and potential knock are coming from. It also takes rpm from this same trigger and you can add an additional load parameter to get a very good picture of when and where any issues my be.

Edited by stevieturbo on Monday 21st September 13:16

That's the thing I also have on the top of my wishlist, but as said, before I throw roughly £700 to the unit I would like to know some on hands experience.
By the way, love that 9 seconds granada.

The Plex stuff is very good, many of my pro tuners use their stuff

[stevieturbo]

harry b said:

Sounds like a solid plan,.............but thanks, I'll stick to something more careful.
I normally use headphones, but doesn't always work optimal. Special when doing fine tuning on the road in mid range levels where the torque just starts to pick up. Too many things to watch for. The logger function is in that case very handy to adjust the ignition timing.

TBH from an audio point of view, the plain old simple DIY stethoscope type ear defenders really are bloody good. Sounds are quieter than some electrical based setups, but if you can hear and know what to listen for, they are very very sensitive.
But yes it lacks the ability to record and pinpoint exactly when it's happening.

Some of the very good standalone knock devices...you're almost halfway into the price of a good ecu with knock control built in. ie for double the price of the Plex, you're into Syvecs S6 territory which then gives you the listening, recording, and of course proper cylinder identification and control corrections

Anyways, download the Plex software/manual for a nosey

http://www.plex-tuning.com/support

[harry b]

Thanks Stevie. I will have a look at it.
You're correct about the built in knock detection ECU units. It gets very expensive, and I can't take it out on another car to tune. I would primary need it to fine tune my C20XE engine which is very sensitive in the mid range.
My other car has a busa engine I would like to dress up with either a turbo or compressor. Not clear yet what to do.

[stevieturbo]

harry b said:

Thanks Stevie. I will have a look at it.
You're correct about the built in knock detection ECU units. It gets very expensive, and I can't take it out on another car to tune. I would primary need it to fine tune my C20XE engine which is very sensitive in the mid range.
My other car has a busa engine I would like to dress up with either a turbo or compressor. Not clear yet what to do.

Often compared to the price of an engine the car etc etc, a good ecu represents excellent value for money as it will serve you for many years. It's just a big initial outlay

But yes it doesnt cover the help with tuning of multiple vehicles though

[PeterBurgess]

Hi Stevie

Thanks for the heads up on the Plex, I have ordered a single pickup version so we can use it on our Olde Worlde MGBs, Midgets, V8s and Trs! At 58 my ears cannot hear detonation properly anymore, my stepson is now 47 so we thought we would give the Plex a try out. I like the idea we can 'see' which cylinder, if only one, is pinking, we can then drop the CR on that cylinder only

Peter