I'm reading up on knock detection and it's pretty complicated. The fact that the sensor is just a microphone leaves interpretation widely variable.

Very interesting stuff.

Based on the stock system and timing pulls, does one need an aftermarket monitor to make sure the stock system is functioning or is it lacking once you start pushing?

I am reading where some are just using the stock sensor and listening/recording/analyzing the noise for knock and wonder if it's just that the stock algorithm isn't good enough or if there is another reason.

Also trying to be more thrifty after finishing the turbo install.

 

Well, technically, the sensor is a microphone. However, it is not a microphone like we typically think of a microphone. That is, the sensor is not listening for the "sound" of knocking. In the previous sentence, I used the word "sound" like we normally mean the word- as vibrations traveling thru air.

The sensor is listening for the sound (scientific definition of sound) of detonation as it travels thru the engine block. That is, the sensor is detecting the vibration caused by detonation as it propagates thru the engine block.

So, it is not a microphone is the sense that we think of a microphone. No more so than a seismograph is a microphone. Because technically, in my opinion, a seismograph is a microphone too. The seismograph detects (aka, listens) for vibration (aka, sound) as it travels thru the earth. No one calls a seismograph as a microphone. Like wise, I wish people would not call a Knock Sensor as a microphone. Doing so causes a misunderstanding that the sensor is listening for knocking sounds that travel thru air. The sensor is detecting vibrations in the engine block.

Regarding your question of why do you need a knock monitor versus relying on the oem system -

The oem ecu uses a knock sensor to detect detonation. Knock must first occur, the oem sensor detects said knock, then the oem ecu *reacts* by retarding the timing. The main point here is that the oem ecu is reactive, not proactive.

When an engine is boosted to the limit (usually discovered in hindsight), all it takes is just one cylinder having a single power stroke with denotation to blow the whole motor. There is no margin (no luxury) to be *reactive* to any denotation.

If a motor is boosted to the limit, a person must be *proactive* to make sure that not even a single occurrence of detonation ever occurs. Not even for a fraction of a second.

This is why a Knock Monitor is important. A person needs to know if any denotation is occurring and retune the setup to prevent any detonation from ever occurring. That is, the denotation must be handled in a proactive manner and not in a reactive manner. To be proactive means preventing any denotation from ever occurring. Being proactive can only be done if a person is aware (via a Knock Monitor or other data logging) that denotation is occurring in the first place.

Just like your gauges, a knock monitor is commonly meant for daily monitoring. With a highly tuned engine, there are any number of things that could go wrong with the tune. The permanently mounted knock monitor is used to catch a failure that would cause the engine to begin to knock, even to the degree of engine damage.

One example of what could typically go wrong is purchasing some bad gasoline. Another example would be your water/meth tank ran dry or the injection pump failed. Or, the turbo was unable to control boost causing boost levels to soar.


Regarding "reading where some are just using the stock sensor" -

I am not going to say that this would not work, but I sure would not do it. I would only use the oem sensor *if* the oem sensor was the same exact sensor as used by the Knock Monitor manufacturer.

A knock sensor produces a very low voltage signal that is erratic and crude in nature. The most important component of any Knock Monitor is it's micro-processor. The crude output signal from the sensor is processed by the micro-processor based on that company's programming. Their programming is created to process signals from that exact sensor. And, different sensors produce different output characteristics.

It is a very difficult task, programming wise, to distinguish between background vibration and true detonation ringing. And, this is with the knock monitor using the sensor that it was programmed for. Now, imagine using a different sensor for that monitor. In my opinion, it would be unreliable and worthless.

If you get a aftermarket knock monitor, do not mount the aftermarket sensor where the oem sensor is mounted. Find some where else for the aftermarket sensor.

It is important for the oem sensor to stay in the oem location so that the ecu will not be giving you full timing mapping. I don't know if you are currently getting the full timing mapping or not. But to play it safe, we need to assume that the ecu is seeing some knocking periodically and is refusing to give you the full timing. If you moved the oem sensor, the ecu could falsely think that the engine is no longer knocking. The ecu could then give you too much timing than what the turbo kit was designed to handle.

 

Very good explanation and examples of what would cause detonation with an otherwise good timing map.

I would like to add that I always "over octane" my car. I'm pushing almost 700 crank hp on nearly stock internals. All it would take is one detonation event to destroy this engine. I run enough octane in the tank that if the methanol fails, hopefully I'll have time to lift when the knock detector warns me. My father has a blown headgasket wall of shame from his car. Luckily the headgaskets usually go first but unfortunately the TL is different.

You will run into weird things as you start pushing the envelope of the turbo engine. I've known cars to detonate when there's a lot of wheelspin even though load goes down with spin. Many times they knock on the shifts though that's not very likely with the manual trans. You'll start to see a pattern. One thing I always monitor is the 1-2 shift. If I see a little knock on the shift but it goes away quickly, I know I'm too close to the edge and it will likely ping in 3rd and especially in 4th. You'll get an idea of what the TL's characteristics are over time. Just pay close attention to the small details.

In the case of the turbo engine, I would never disable the factory knock system (fooling the ECU into thinking it's not knocking). It's a good strategy when NA but NA is not likely to blow things from a single event. Even though I've talked about how the TL's ECU can't properly control knock, it's much better than having nothing at all especially when boosted. The ECU can react much quicker than you can. I can't remember what's out there for the TL but in other cars I like monitoring what the car's ECU sees for knock. That way you know it's picking up knock as it should and there's very little guess work. I'm not sure if there's anything out there that does this.

Again, the best thing to do is prevent detonation in the first place and to do that you have to have constant monitoring.

 

Based on all this info, does it make sense to have a reactive system link J&S or just work with the timing maps in the F/IC based on the results of a knock monitor like the Phormula?

I'm thinking that I could get the KS-4 and feed the analog data to the F/IC and start logging from there. Then I can do something down the road that has multiple analog inputs to start looking at more things.

 

These questions are out of my area of knowledge.

I will share my thoughts with you. But please remember that I am not speaking with any authoritative knowledge.

Rodney developed and extensively tested this turbo kit. I am assuming that the turbo kit is sold with whatever engine management that Rodney was using on his test car. If so, I would run what Rodney has included in his turbo kit. His system worked for him with even higher boost than the kit being sold, and the system should work for your “detuned” kit.

If it was me (never can leave well enough alone), I would install a knock monitor just to double-check. Plus, the knock monitor is there to let you know that something is amiss and allow you to fix whatever is amiss before it kills your engine. Just don’t tamper with the oem knock sensor unless Rodney states otherwise.

Above everything else, I recommend following what Rodney says. He developed the kit and pushed the kit to ridiculously high power levels. He has proved that he knows what he is doing.

 

Porsche tuner using an Interceptor with a Vipec:

http://reutterwerk.com/forums/showthread.php?t=20754

 

I'll be installing my J&S here in the next month. I'll keep you guys posted on my findings.

 

This was my thinking exactly. I guess I will go ahead and just get the knock gauge to satisfy my curiosity and go from there.

Thanks

 

I would definately do both. Stuff happens so fast that you've had a few hundred detonation events before you can react and lift off the throttle. The computer responds nearly instantly. IMO, with boost, neither the stock knock system nor an aftermarket system is enough by itself. The stock system will reduce the severity of the knock and hopefully buy you a valuable second or so to react and lift off the throttle.

Be proactive and tune for 0 knock with the aftermarket system and leave the stock system in place for added security if it should knock.

 

Both meaning stock and monitor or stock and something like J&S to control timing on the fly?

I was thinking just doing the stock and monitoring.

The other thing I plan to add to help make sure I don't have any knock is to add some kind of injection to increase the octane. Unfortunately, I am going to have to go with a watered down kit. I tried contacting Julio again but I don't think he wants to do anything for me I guess because there isn't a kit available for a TL and not being close to his shop.

 

There are a few reasons I prefer the J&S setup over a combination of the stock + Phormula. First and foremost is the fact that you can more effectively tune per cylinder. The problem with running a stock setup is that you end up tuning for the noisiest cylinder and you end up losing valuable HP because of it. Second, the J&S has a headphone jack on the unit itself which your tuner can use to actually listen for the knock. Some places swear by being able to physically hear the engine noise versus read it off of a monitor. (With just a monitor, you must have the unit setup just right in order to alert you in time. When you can listen for it, you can tell how severe it is anytime.) The last is the cost. Yes it is more expensive than the KS-3 or the KS-4, but it is less than the KS-PRO TUNE. And that still won't net you any sort of knock management, only help you find the point at which all of your cylinders are free from knock.

Just my $.02

 

Agree. The J&S does seem to offer a much better solution.

How does the J&S unit acquire a true reference point for the timing? Ideally, the J&S unit would tap into the oem Crank Trigger. However from looking at the J&S schematic, the J&S unit does not reference the oem Crank Trigger.

This only leaves one other possibility. The unit intercepts the firing signal as the coil signal leaves the ecu, and alters the timing that the signal is sent to the coil. The problem with this is that the ecu is not consistent with the timing output. So, the J&S would not be consistently either if the J&S was based on the inconsistent output from the ecu. Bad data in equals bad data out.

I would be eager to buy the J&S if it was able to completely bypass the ecu's timing. Only way that I can think of to do that is if it had a crank trigger.

 

Inaccurate, you're completely correct on that. There is no hard wired reference coming from the crank angle sensor.

That's one item still left in the dark, but I'm hoping that with the stock bypass, that the data will clear up a bit allowing the J&S unit to work more effectively. It's not a perfect solution, but I feel like it's the best available for our cars at the moment. (Similar to the F/IC...)

 

Thank you for being able to clarify. I have been wondering about this for a while.

 

No problem. I'll be sure to get you guys some data logs once everything is in and working properly then hopefully we'll know for sure.

 

Just when I think I made a decision

I am beginning to read about these units. How do you typically tune with these, on a dyno?

Thinking that I'll get the J&S and get it up in detector mode first. I've got an appointment with a dyno on Friday and I'll find out if they know anything about these guys.

 

Just my 02 but if you have a way to tune it cylinder by cylinder, by all means do it. However, if you don't have the capacity to alter spark cylinder by cylinder, you have no choice but to go by the loudest cylinder which would make the more expensive system almost useless.

 

IMO, you should always do the initial tuning on a dyno. Especially when any components change that could affect your A/F or spark. After that, if you know what you're doing, you can make minor adjustments for street drivability.

That being said, typically you tune the car much the same except you just have an additional input. Tuners will wear a set of over the ear earphones while making incrementally higher runs though the RPMs. Once they hear the first signs of knock, they can make minor adjustments on the device itself or, depending on the current A/F trims or timing, attempt to add more fuel or pull some timing to try to correct it. They may also just decide that that point is your current limit.

The J&S unit does have a remote knock monitor (~$90) which you can still mount where it's visible. If in your face gauges aren't you're cup of tea, you can use the LEDs on the unit itself to monitor the knock periodically. The LEDs will not only alert you to the fact that there is knock, but also which cylinder is causing the knock at any given point. Great information to have.

 

a bit off topic but i found out that my surging is being caused my low oil levels. my engine is drinking oil but the leakdown test showed no leakage is present.

 

??? If it's low enough to cause any sort of surging AND the leakdown looks good, I would start looking at the PCV system for the oil loss. Do the plugs show any signs of oil burning?

If it was actually so low that it caused a power loss (loss of pressure), you've probably hurt the engine.

Of course, it can still show a good leakdown and get oil past the rings. If this turns out to be the case, it's one of the very rare times I would throw an ester based crankcase cleaner in there. Are you running Redline for the first time by any chance?

 

I received the above quoted question via a PM. I wanted to include it here to help others.

I do feel that the Phormula is the highest quality and best performing knock monitor. I do highly recommend the Phormula.

However, please be aware that you will need to do your own Research&Development to find a place to mount the sensor on the TL. And after your R&D, you might find that there is not an ideal location to mount the sensor that will allow it to perform the way it should. I am not saying that you can't get it to work. I am just preparing you for a worst case scenario.

No one on Acurazine has yet tried to mount an aftermarket knock monitor. Some one probably will soon. But no one has yet. I mounted mine in the oem location, and I do *not* recommend that you try it.

The Phormula comes in two flavors, the KS-3 and KS-4. If you plan to really get into data loggers and sophisticated tuning electronics, get the KS-4. The KS-4 has the ability to send the knock measurements to other electronic devices, such as data loggers and sophisticated tuning electronics. Otherwise, get the KS-3. I have the KS-3 in case you are wondering.

 

Inaccurate,

I just want to clarify that the reason you wouldn't recommend mounting the aftermarket knock sensor in the OEM location is because the Phormula is a knock monitor only and not a knock management unit. Moving the stock sensor out of the prime location and into a location where it is less sensitive to knock is a bad idea because it would allow the engine to produce knock, but the ECU would be unable to detect it in time in order to prevent engine damage. Is that correct?

 

Yes sir. Your explanation is exactly correct. Well worded.

I suppose I was being short-sighted. That is, if the oem sensor is being removed to install a complete Knock Management solution, this would be ok.

Thanks bmeyer

 

Where would it be placed then?

 

You'll want it as close to the OEM location as you can get. I believe that there are a couple of blanks on the top of the block that you can drill and tap to mount the additional sensor.

The reason that the stock placement is so good is because it's nearly on the same plane as the top of all of the cylinders - where the knock is going to happen. Not to mention that it's in the center of the block, between all of the cylinders. It's not perfect, but it's as good as you're going to get using only one sensor.

 

Where is the cheapest place to get the phormula ks-3?

 

The Phormula is made in Europe (click here). In the US, it can be purchased from Lindsey Racing (click here). To my knowledge, Lindsey Racing is the only US distributor. So, no price shopping.

 

On Page 1 and Post #30 (click here), I discussed how I was experimenting with different mounting locations for the piezo. I was looking for a mounting position that would give me the maximum timing map while still keeping the ecu happy.

In case someone finds this thread helpful in the future (as in "Back To The Future" ), I wanted to add this follow-up. Ever since I tried it five weeks ago, I have been happy with this Location #3. The data logging (click here) shows the timing looking good. And, the throttle response is phenomenal. The knock monitor shows light traces of knock along many places in the rpm range. Therefore, I feel that this Location 3 is giving me the full timing map like I had wanted. Plus, I have never had a CEL to appear. This Loacation #3 is the ideal spot I was seeking.

 

bmeyer, tried to PM you but you don't accept PM's.

I remembered you saying you were going to pick up a J&S Safeguard unit. I see it's in your list of mods so I'm wondering what model you bought and what your impressions are.

Thanks

 

@KN_TL

The unit that I picked up was the Interceptor. http://www.jandssafeguard.com/8ChInt...terceptor.html

The build quality is great and it's a very simple install (especially if you have an extension harness going to your ECU). The unit comes packaged with 2x 6-pin molex connectors for making the splice connections. If you take one connector pair and put it in between the 2 sides of the extension harness, you can bypass the unit at any time and revert it back to stock.

As Inaccurate pointed out though, there is one pitfall to the setup...

All in all, I feel good about the purchase and can't wait to get it in the car and tune with it. It's actually still sitting in the box waiting for the new engine to show up. :/ Paulter screwed up my rods and it's taking aeons to get it sorted out.

 

Thanks.

Anyone have an opinion on running a 2nd knock sensor if the unit has the option?

 

No problem. As far as the 2nd sensor is concerned, I'd be all for it if there was a proper spot on the block for it. The reason I'm only going to run the one is because the stock location is perfectly in the center of the block. There just aren't 2 other bosses to drill out that give you such an exact placement.

 

Are you going to remove the stock sensor? When I asked John for specific ordering info, he said that I couldn't use the stock sensor and I would need to purchase another.

 

Yes. The stock sensor will be removed and the Bosch-style sensor for the J&S will be installed in its place. I will then use the knock sensor emulator outlined in this thread and hook that up in place of the stock sensor. I plan on mounting that either near where the throttlebody used to be, or on the front valve cover.

The knock sensor emulator will keep the ECU happy and hopefully prevent it from retarding ANY timing which should leave 100% of the ignition timing control up to the J&S unit.

 

Ah, I see.....but that squashes my idea of using the J&S to monitor only at first and then implement the ability to pull timing at a later time

I'm just about ready to pull the trigger on the Interceptor. I've got the Innovate SSI-4 on the way so I can log my AEM A/F gauge and plan to log the data from the Interceptor as well.

 

For the time being, you can drill and tap another boss on the block and mount the Bosch sensor for the J&S there. Then just move it over once you're ready to eliminate the stock sensor.



I'd shoot for the one just to the left of where the sensor is located in this picture. (The one without a hole drilled in the center) That's as close as you're going to get without adversely affecting the ECU's ability to handle any knock.

 

I think I'll just go with replacing the stock sensor and doing as you describe. It removes the bad data in from the ECU and takes over the timing pull. Based on some of the reading I've been doing, there are a lot of people who praise these units.

Inacc, are you still running in location 3 and seeing no timing pulls from the ECU?

 

I *think* that Paul was saying to use the boss shown in the pic below.

 

^Yeah, that's the one bmeyer is suggesting as well.

 

Yep. That's the one. The only other thing I would consider is if there is another boss under the kink in the coolant tube in that picture. (between the 2nd and 3rd cylinders on the top of the picture) There likely isn't one there, which leaves this one as the next best thing.