Knock controller?

[ycode90]

^^Thats what I did....doing. Untill j/y 3.2L cost more than 500$ no need for purty forged pistons.

 

[John at JandS]

Gary:

Ford has been using knock control on their naturally aspirated engines for a long time, but decided not to use it on most of their forced induction engines.

They went to the expense of installing a sensor on the Lightning, but didn't enable it in software. The '03-'04 Cobras have no knock sensor, and the GT500's didn't get one until 2010.

Forum speculation is they couldn't get it to work because of "blower whine", but I haven't seen any.

Do you have any insight as to the real reason? It would seem the forced induction engines need it more than the others.

Refer to the scope photo here:
http://picasaweb.google.com/JohnPiz...id=QCNuclpdhkzXf4jh86UX5A#5270635998783238690

This was taken at freeway cruise on a Lightning. The bottom trace is the knock signal. It's basically a flat line, but the first hint of inaudible knock (as detected in headphones), the signal is so large it goes off the scope.

 

[gmorrell]

John,

I've run into this before, and unless you can talk to the Principal Calibration Engineer on that particular vehicle, it's damn near impossible to answer this question. A friend of mine used to be a PCE for Roush, and he calibrated quite a few of the Roush and SVT specialty vehicles. He mentioned that they often software-disabled knock systems. When I probed further, I always got the same answer "We couldn't make it work..."

What that often means in Ford corporate parlance is "We didn't have enough time/money/resources/engine dyno time/my boss was breathing down my back/my wife-girlfriend-mistress was pregnant, etc."

Most of Ford's PCE's will admit (if tortured...) that Ford's knock sensors weren't always properly selected for the engine knock signature, or were poorly placed on the block, and by the time the calibrators got the vehicle, Job 1 was imminent, and changing the sensor or it's location was by Papal Directive only. At this point, they will admit that they throw up their hands, shut off knock processing, and slap the "Premium Fuel Required" sticker on the dash.

Off topic, anyone here shoot pool?
gmorrell: You might get a smile out of my pool gizmo:
http://jandssafeguard.com/PoolGizmo/Stroke-Alyzer.html

Slick. I'm curious, who's accelerometer did you use? My company has, at one time or another evaluated or characterized many of the single and multiple-axis accelerometers on the market. We typically only see them in wafer form, not the finished, packaged product. We're starting to look at MEMS gyros now, stuff with mechanical resonant Q's at 50,000 to 100,000, it's a real challenge to measure this stuff.

I shot, and won enough pool in college to keep me in beer money. I always knew it would be an easy win when my opponent had one shot strength: "SMACK THE **** OUT OF THE CUE BALL!" My Dad taught me to shoot pool when I was a young lad, and he showed me how to use only as much energy as was necessary to do the job.

 

[SHOZ123]

I know the KS on the V8 works great and is quite programmable. There also is a spark advance modifier for each cylinder.

 

[John at JandS]

Gary:

You know someone that used to work at Roush? I called Roush about two years ago, telling them about the system. The guy said "let me have your number, and we'll get back to you." I gave him my number then asked him to read it back to me. He couldn't come up with the last four numbers. Oh well (cold calling sucks).

*******

I made the pool gizmo in '03 before three axis devices were available, so I used two ADXL 311's. I want to make it wireless but that will have to wait.

Made a vid of my stroke last week, front and side views:
http://www.youtube.com/watch?v=wgQcSmr9l6Q

 

[sho_sc]

I think I can add a little to this discussion. I’ve had a MSD Knock Alert installed on my race SHO for years. I installed it many years before the TwEECer and kept it installed just as a failsafe measure. I’ve ran a lot of experiments trying to determine what is knock and what isn’t by referencing the gauge against what the TwEECer reports. What I can tell you is the following: The blower adds lots of noise that can be picked up by the MSD Knock Alert and not show as knock by the OEM sensor/EEC. Aggressive cams can add noise that is picked up by both the MSD unit and the OEM sensor as knock; however, more times than not if the OEM sensor shows knock then it is detonation. Rod bearings going out will be picked up as knock by both the MSD unit and the OEM sensor as knock: this happens 100% of the time. Loose items (bolts/screws/etc) that rattle against the block/head/intake will show up as knock by the MSD unit and “sometimes” by the OEM sensor. The OEM sensor/EEC in a high boost situation sometimes is too slow to respond causing catastrophic results.

What I’ve concluded is that without a tunable sensor that mimics the OEM sensor, a lot of noise can give you a false positive. However, since I have learned my engine so well, I can pretty much determine what is knock and what is false knock by watching the MSD unit.

Now my views on the Vampire Ignition: (on a FI vehicle) If you need to pull timing on a signal cylinder then I believe 1) you are running on the “razors” edge of the timing (knock limit) and 2) you have a problem with that 1 cylinder. Next my experience tuning NA vehicles has shown that most have a “plateau” of most power vs. timing. Once you reach that “plateau” adding timing does very little for power but adds more risk for knock. As timing is increased, then at the moment of detonation, there will be a slight bump in HP, but at what risk? Then I get back to the question of why do I need to pull timing in just 1 or 2 cyl? Am I running on the “razors” edge of timing or do I have a problem with those cylinders?

 

[SHOZ123]

I've seen timing way high with no knock but little performance gain. I'm talking about +40 degrees at high rpm (on the V8).

It is suggested to use the Mean Brake Torque table and apply that to the actual timing tables. The MBT table is what the car was found to produce the most power when dynoed by the manufacturer. It usually is higher in the upper rpm/load area of the usable timing tables.

 

[rubydist]

.... The OEM sensor/EEC in a high boost situation sometimes is too slow to respond causing catastrophic results.

If the SHO pcm is programmed like the other Ford pcm's that I have studied and boosted, then part of the challenge is that the oem knock sensor is limited to pulling out 10* of timing when it detects knock. In potentially catastrophic situations, 10* of timing retard may not be enough, allowing the engine to melt down even though the knock sensor is 'hearing' knock.

Part of the tuner's challenge is that the engines typically produce maximum torque when there is slight detonation. Controlling that in the real world is very difficult, hence vehicles are typically tuned to stay away from any detonation.

For those of you who are doing tuning, and who are interested in fuel economy, if you tune the low-load part-throttle portion of the engine map for slight detonation, you will increase torque and reduce fuel consumption with no risk to the engine since a little knock at low-load doesn't produce high enough bearing loads to cause damage. Just be sure that by the time you get to 50-60% load you have the timing pulled back enough to eliminate the detonation.

 

[sho_sc]

If the SHO pcm is programmed like the other Ford pcm's that I have studied and boosted, then part of the challenge is that the oem knock sensor is limited to pulling out 10* of timing when it detects knock. In potentially catastrophic situations, 10* of timing retard may not be enough, allowing the engine to melt down even though the knock sensor is 'hearing' knock.

Part of the tuner's challenge is that the engines typically produce maximum torque when there is slight detonation. Controlling that in the real world is very difficult, hence vehicles are typically tuned to stay away from any detonation.

For those of you who are doing tuning, and who are interested in fuel economy, if you tune the low-load part-throttle portion of the engine map for slight detonation, you will increase torque and reduce fuel consumption with no risk to the engine since a little knock at low-load doesn't produce high enough bearing loads to cause damage. Just be sure that by the time you get to 50-60% load you have the timing pulled back enough to eliminate the detonation.

Agree'd!

 

[John at JandS]

Louis Ott "Louie928" has one on an 11.4:1 NA 928.

He posted a dyno experiment on the EFI University forum (efi101). google "louie928 vampire".

See his long post on page three of that thread. Nothing earth shattering, but it allows him to run low octane fuel if he has to, without retuning or sacrificing much power.

Concerning a "bad cylinder". Have any of you installed a colder plug in just one cylinder? I know a tuner that says he installs a three heat range colder plug in #5 on a 5.4L Ford. He said my Lightning video was confirmation.

 

[ycode90]

This is the best thread on this forum in a while.

That is all. Back to my corner.

 

[gmail]

Louis Ott "Louie928" has one on an 11.4:1 NA 928.

He posted a dyno experiment on the EFI University forum (efi101). google "louie928 vampire".

See his long post on page three of that thread. Nothing earth shattering, but it allows him to run low octane fuel if he has to, without retuning or sacrificing much power.

Concerning a "bad cylinder". Have any of you installed a colder plug in just one cylinder? I know a tuner that says he installs a three heat range colder plug in #5 on a 5.4L Ford. He said my Lightning video was confirmation.

ive read this whole thread twice now, not sure why....

ok let me make it easy for you so we dont have to go threw this again.....


no one showed interest in your crap...
you have to pay to advertise here so just stop it please i dont wanna read this again....

 

[John at JandS]

Your rudeness is impressive.

In case you didn't notice, I raised the white flag when I posted my pool stuff.

I understand every one here is happy with the stock system. I'm just trying to demonstrate my design is not crap, as you call it. Plus, isn't it fun reading about other ways to do things?

I'm very proud of what I have accomplished on my own, with limited resources, perseverance, and God given talent. Yes, I said it.

I started working with knock sensors in 1983 while a tech at Hughes Aircraft, then introduced individual cylinder knock control to the after market in 1991.

To date, there are no other after market ignition boxes that have it. Even MoTeC and Autronic didn't have it until last year. MoTeC USA offered to buy my code after we demonstrated the system to them in '92.

I recently pm'd a GM knock sensor engineer on the C4 Corvette forum, and he wrote back "I enjoyed your letter, and I'm very impressed with your work."

His profile page:
http://forums.corvetteforum.com/members/64456-69427.html

 

[frosho]

Don't mind the troll, he just likes to come out of his hole every once in a while.

 

[sho_sc]

Your rudeness is impressive.

In case you didn't notice, I raised the white flag when I posted my pool stuff.

I understand every one here is happy with the stock system. I'm just trying to demonstrate my design is not crap, as you call it. Plus, isn't it fun reading about other ways to do things?

I'm very proud of what I have accomplished on my own, with limited resources, perseverance, and God given talent. Yes, I said it.

I started working with knock sensors in 1983 while a tech at Hughes Aircraft, then introduced individual cylinder knock control to the after market in 1991.

To date, there are no other after market ignition boxes that have it. Even MoTeC and Autronic didn't have it until last year. MoTeC USA offered to buy my code after we demonstrated the system to them in '92.

I recently pm'd a GM knock sensor engineer on the C4 Corvette forum, and he wrote back "I enjoyed your letter, and I'm very impressed with your work."

His profile page:
http://forums.corvetteforum.com/members/64456-69427.html

I'm in curiosity/learning mode: From your experience, have you seen a substantial amount of vehicles that need to have individual cylinders timing trimmed by a considerable amount and if you have what is your option on why?

 

[John at JandS]

I think the primary cause is a coolant issue.

Here's a discussion on a 280z forum, where #5 is a problem:
http://forums.hybridz.org/showpost.php?p=800559&postcount=17

Don't expand the thread unless you want your head to explode from talk about "the thing".