Author Topic: knock sensor?  (Read 1002 times)

Offline jordan

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knock sensor?
« on: March 16, 2017 - 12:09:38 AM »
I just came across a product from www.jandssafeguard.com called the safeguard.  It is a knock sensor that retards individual cylinder timing based on inaudible knock.  It can also retard timing for easy start up and then go to a baseline timing at idle.  And many other features.  I have never been totally happy with my distributor, and the ability for my engine to knock at random.  I think this can help me from slowly destroying my engine, but is it really just a band aid for my improper tuning of my distributor?  Does anybody have a source for a distributor spring kit, so I can do like Jas did last year, and replace and test the springs and tuning?  I feel like I want this product, and would like to save the money to put towards FI, but I blew my budget this past winter on a new dirt bike for ice riding (13" crf 450), and a killer newer snowmobile (15"polaris indy 800: 150hp and 450lbs!!).  So the Fi is on the wish list, but I really want to fix my detonation issues.  I suppose one way or another, I just have to learn, and know how to fix and tune the timing.  And the safegaurd will cover my butt if I screw it up.  Does anyone have any experience with the Safeguard?
« Last Edit: March 16, 2017 - 12:11:29 AM by jordan »
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Offline cudabob496

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Re: knock sensor?
« Reply #1 on: March 16, 2017 - 03:57:05 AM »
why not just slowly turn your distributor to reduce initial timing, until
the pinging goes away.
Also, run 92 octane gas.
what kinda dist do you have?
what engine?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline GoodysGotaCuda

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Re: knock sensor?
« Reply #2 on: March 16, 2017 - 05:41:32 AM »
Knock circuits are very complicated and sensitive to change.  I think some level of a retrofit will be hard to execute well and consistently. I have EFI and factory Hemi knock sensors and will still have to dial in knock control quite a bit.  The "universal" magic box gives me doubt.

Focus on getting a good tune on the car. It will be more beneficial than throwing the timing all over the place on false positives, missed knocks, etc.


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1972 Barracuda - 5.7 Hemi + T56 Magnum

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Offline jordan

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Re: knock sensor?
« Reply #3 on: March 16, 2017 - 09:40:33 PM »
I have a stroker 520" 6 bbl with 440 source heads with big valves and 11:1 compression pistons., roller rocker, roller lifters.  I have  a stock type distributor set up by FBO.  My basic understanding it that I want to get as much advance with out detonation.  I only have so much degrees to work with to get it started and to get it fully advanced at higher RPM.  If I pull out advance, then I am losing some on the higher RPM, but I can get it to start easy.  If I advance it so it runs out, then its hard to start.  Am I wrong?  If I change my springs, then I am only changing the RPM at which it starts to advance, right? Different springs can let me start the advance a little earlier or a little later in the rev range?  Am I supposed to match it to when my outboard carbs open up?  Or just before?

This controller is set to allow the car to start with little advance, and then moves to normal at idle.  As RPM comes up, it knows which cylinder is the one that is predetonating, then retards the timing on that particular cylinder until the ping goes away.  At that point, it increases the timing again per cylinder. Not overall.   Its ability to "hear" the ping is adjustable.  I have read some about it, and have heard great things, and I hear from the nay sayers. 

I would love to get it set up where it just runs perfect all the time, but weather, temperature, gas, and weight in the car all change the dynamics of the timing.  But the vintage distributor is set to where it is set.  Sometimes it is perfect with just me in the car.  Then if I grab a buddy and go for a beat run, it starts to run like crap because I needed to retard the timing a degree or two because the car now weighs 200 lbs more.  I am not going to do that every time I want to run it hard.  I was hoping the computer could help me out, and save my pistons, and bearings from a beating when it isnt just perfect.  Plus, I want it to run hard when it can.  I could set the all in at 33 degrees, but I feel like I would be losing out on the power that a couple extra degrees could give.  I not afraid to try to fix the distributor, and I would love to have somebody make some recommendations on settings.  First I need to know where to get an assortment of springs?  My settings are close, just not perfect for every situation.  My car isnt totally out of tune and I want this to save me from making it better.  I just want it better than a stock type vintage distributor can do for me. 

Hey Goody, if you have knock sensors and have to dial it back, why do you think that this unit won't do what the factory system you are using is doing?    I am sure there is noise in my engine, but I was hoping my roller valve train my take some of the noise out.  This unit is programmed to listen for a knock just after each cylinder firing.  And it is adjustable to noise sensitivity. 
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Offline GoodysGotaCuda

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Re: knock sensor?
« Reply #4 on: March 16, 2017 - 09:54:29 PM »
I have a stroker 520" 6 bbl with 440 source heads with big valves and 11:1 compression pistons., roller rocker, roller lifters.  I have  a stock type distributor set up by FBO.  My basic understanding it that I want to get as much advance with out detonation.  I only have so much degrees to work with to get it started and to get it fully advanced at higher RPM.  If I pull out advance, then I am losing some on the higher RPM, but I can get it to start easy.  If I advance it so it runs out, then its hard to start.  Am I wrong?  If I change my springs, then I am only changing the RPM at which it starts to advance, right? Different springs can let me start the advance a little earlier or a little later in the rev range?  Am I supposed to match it to when my outboard carbs open up?  Or just before?

This controller is set to allow the car to start with little advance, and then moves to normal at idle.  As RPM comes up, it knows which cylinder is the one that is predetonating, then retards the timing on that particular cylinder until the ping goes away.  At that point, it increases the timing again per cylinder. Not overall.   Its ability to "hear" the ping is adjustable.  I have read some about it, and have heard great things, and I hear from the nay sayers. 

I would love to get it set up where it just runs perfect all the time, but weather, temperature, gas, and weight in the car all change the dynamics of the timing.  But the vintage distributor is set to where it is set.  Sometimes it is perfect with just me in the car.  Then if I grab a buddy and go for a beat run, it starts to run like crap because I needed to retard the timing a degree or two because the car now weighs 200 lbs more.  I am not going to do that every time I want to run it hard.  I was hoping the computer could help me out, and save my pistons, and bearings from a beating when it isnt just perfect.  Plus, I want it to run hard when it can.  I could set the all in at 33 degrees, but I feel like I would be losing out on the power that a couple extra degrees could give.  I not afraid to try to fix the distributor, and I would love to have somebody make some recommendations on settings.  First I need to know where to get an assortment of springs?  My settings are close, just not perfect for every situation.  My car isnt totally out of tune and I want this to save me from making it better.  I just want it better than a stock type vintage distributor can do for me. 

Hey Goody, if you have knock sensors and have to dial it back, why do you think that this unit won't do what the factory system you are using is doing?    I am sure there is noise in my engine, but I was hoping my roller valve train my take some of the noise out.  This unit is programmed to listen for a knock just after each cylinder firing.  And it is adjustable to noise sensitivity.

The problem I see is that it is not without fault. It has to knock for it to pull timing, and then it will try it again to get closer to the target timing. This is similar to a factory setup but that has been known to be the death of current engines as well. Just look up how much Subaru owners care about ensuring their engine never knocks, responding to a knock is not good enough.

I do not have a factory ECU, I have a standalone Megasquirt. If I implement the knock sensors, I will do so after the car is shaken-down and I can play with it on a dyno [or the like]. The Megasquirt builders and tuners have very specific cautions that it is not a plug and play system, making adjustments to something you cannot always hear is not without fault.

If you are after every-last-horsepower in this car, perhaps this is something for you. However it's far safer to take a slightly more conservative route and keep it from knocking, rather than respond to a knock and keep pushing to reach that point again. Having tuned cars on a dyno, a couple degrees on a dyno is likely not going to make your car a winner, not for the risk I consider it to be. If you are competitive racing, for money, go for it. If not, I vote to stay conservative and keep the motor together with a well dialed distributor, it can be made to work fine.

You can also lock-out the factory distributor and use an ignition box to control timing via a table/computer, this is what FiTech [and others] do to take control over the ignition timing. That may be what you want it to do...

« Last Edit: March 16, 2017 - 09:56:40 PM by GoodysGotaCuda »
Build Page: Goody's 'Cuda Build Page
1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

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Offline jordan

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Re: knock sensor?
« Reply #5 on: March 16, 2017 - 11:54:51 PM »
I see what you are saying.  My goal is to get the distributor set up better.  My plan was to go with a Holley EFI set up, but I blew my budget on other go fast toys.  Megasquirt is way over my head to tune.  I really want the EFI to control timing more than fuel.  My carbs work fine, but work still needs to be done on the distributor.  I was hoping the Safeguard would help with the differences with gas, temperature, or xtra weight in the car.
"Don't brake until you see God!"