I'm in the process of building a megasquirt for the valiant and was wondering if anyone has built the knock sensor circuit on there megasquirt? If so where on the block are you installing the sensor?
I just got the launch control circuit built, next is boost control, then the knock sensor circuit
Thanks all
Aaron

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http://www.forabodiesonly.com/mopar/sho ... p?t=126611

Anyone Lou, matt????

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http://youtu.be/2Y4i4UOLiSA

http://www.forabodiesonly.com/mopar/sho ... p?t=126611

I bought a standalone knock sensor circuit, but it will not integrate into my MSI system. I have not hooked it up yet. Sitting in trunk of turbo car in Vegas...

This is what I bought:

http://www.viatrack.ca/

Lou

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Home of Slant6-powered fun machines since 1988

The MS1/Extra knock circuit is a pretty crude one - I'd rather have a microphone clipped to the block and a set of headphones for tuning.

The MS3 add on module is a lot more sophisticated. Not quite up there with, say, the factory LS1 setup, but we didn't have the luxury of a budget large enough to blow up a half dozen engines on the dyno to develop it.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

I though mechanical valve clatter would confound a knock sensor, has the technology improved, or are you running a hydraulic cam..?

I am putting a knock sensor on the 83 D-150 (hyd cam) ,, I plan to mount the sensor in the water jacket drain plug.

And so will forged pistons because of greater tolerances......


This is for toyota engines, but gives you a basic idea of where to mount one.

http://www.lcengineering.com/LCTechPages/engtech14.html

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Well the plan is to build the circuit from the msextra manual for when I get my long rod motor together and after I get the bugs worked out or the car and install the knock sensor in the new motor. But with the fuel upgrades I made this winter donation shouldn't be much of a problem enless my tune is just way off....
Thanks always. Org
Aaron

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http://www.forabodiesonly.com/mopar/sho ... p?t=126611

I have some issues with this thinking. My 86 toyota is EFI with a knock sensor. It also has mechanical cam followers. It also has had piston slap from day one. With 378,000 miles, the pistons now sound like they are trying to swap cylinders when cold, and are still audible at normal running temps. "Back in the day" Toyota had a TSP about the slap, saying they had a redesigned piston to cure this. It was not a warentee fix, it was a customer pay repair. Toyota maintained it was just a noise issue and would not effect the running or life span of the engine. I thought the knock sensor "listened" for the unique frequency of the knock. Correct my thinking. Am I wrong?

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I think those are basically myths propogated because of difficulties some people have had. There are plenty of examples where these work with solid cams and loose pistons... Yes, you may have to play with thresholds more or do some control tests to be sure you are distinguishing knock from other things.

Lou

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Home of Slant6-powered fun machines since 1988

I have a couple of friends that are SAE mechanics for "the other brands" and are gear heads and they have stated that in the older vehicles (90's) the knock sensor was dialed into a specific set of frequencies to detect knock (probably checked by a piezo on an oscilloscope while running the test engine on an engine stand in detonation), and not cause a false alarm (say a ride down an improved fire road with lots of rocks nailing the underside of the oil pan and block-would not be good if after 10 seconds the engine management system yards out all the advance save the base timing or goes to limp mode because of it).

I also have heard that the industry has shifted to ion sensing for knock detection since for emissions purposes the manufacturer has to monitor the vehicle to keep it within govt. specs. These sensors look for a specific ion signature in the exhaust that would occur if the mixture didn't combust properly then adjust the timing accordingly. A quick search of the internet shows an interesting post by Delphi, and some traffic on the topic at DYIEFI.org on that topic (looks like Delphi goes hand in hand with coil at the plug DIS).

FYI,

-D.Idiot

Yes, you may need to limit frequency range to get knock and not other stuff. I think some (all?) of these circuits do this. Also, the threshold adjustment will be critical. You will need to induce knock (briefly) and hear it and get the sensor to pick it up, then adjust accordingly and dial the engine back in to normal operating. WOT and light throttle at the same RPM should not both produce knock, so that can help separate knock from purely mechanical sources.

Lou

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Home of Slant6-powered fun machines since 1988