DIY_EFI Digest Tuesday, January 11 2000 Volume 05 : Number 015 In this issue: Re: Knock sensor on dyno Re: Knock sensor on dyno Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno Re: DIY_EFI Digest V5 #14 Re: TWM & GMECM Re: LRP and O2 Pulse Width at -40 degrees Re: Pulse Width at -40 degrees Re: LRP and O2 Re: TWM & GMECM See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 10 Jan 2000 17:25:27 -0500 (EST) From: Andris Subject: Re: Knock sensor on dyno On Mon, 10 Jan 2000, DIY_EFI Digest wrote: > > DIY_EFI Digest Monday, January 10 2000 Volume 05 : Number 014 > > > > In this issue: > > Knock Sensor on Dyno > > See the end of the digest for information on subscribing to the > DIY_EFI or DIY_EFI-Digest mailing lists. > > I am currently building a eddy current dynamometer for testing small engines > up to 70 ft lbs of torque. I am working on the instrumentation now and I was > reading the archive and started thinking about knock sensing. > like to use a sensor out of the junkyard to keep costs down so any ideas of > which one would suit me the best (partial to GM parts)? The one problem that comes to mind if you were using the GM knock sensors is the sonic qualities of knocking in your small engine. From what I've read, the knock sensor is tuned to specifically hear+amplify the characteristic knock sound for that bore diameter, and block. GM has had several different knock sensors, and even had a different one for the LT1 and LT4, even though they have the same dimensions (LT4 was supposedly a little noisier). If you have the same bore, then I guess the knock would sound similar. > Can I put the sensor > in some type of holder then bolt it to the block for testing? I think as long as the sensor is in contact with the cooling jacket water, you should be OK. HTH! Andris/SPD Z28tt-89 IROC T56 DFi Twin Turbo ------------------------------ Date: Mon, 10 Jan 2000 17:58:44 -0500 From: "Bruce Plecan" Subject: Re: Knock sensor on dyno If, I were going to do something like this, I'd just grab a couple sensors from like a 4-6-8 Gm, then Chyrler, product line. Then just setup a little Op-Amp and wire that to a comparator to turn on a LED. Use an ajustable threshold on comparator to tune out back ground noise. If mounted in head parrarel with rod travel, if from side of cylinder right angle to rod travel seems to be about the logic in mounting from what I've seen. Securely mounted being the buzz word here. You might even try the stock ESC of the matching year application (there are several very different KS from gm), so they match the ESC module... If the EPA was breathing down my back, I would probably get real anal about being dead on for frequency. But for DIY_EFI, I think the above is close enough. Just remember free advise is just that..... No guarantees | > Knock Sensor on Dyno | > I am currently building a eddy current dynamometer for testing small engines | > up to 70 ft lbs of torque. I am working on the instrumentation now and I was | > reading the archive and started thinking about knock sensing. | > like to use a sensor out of the junkyard to keep costs down so any ideas of | > which one would suit me the best (partial to GM parts)? | The one problem that comes to mind if you were using the GM knock sensors | is the sonic qualities of knocking in your small engine. From what I've | read, the knock sensor is tuned to specifically hear+amplify the | characteristic knock sound for that bore diameter, and block. GM has had | several different knock sensors, and even had a different one for the LT1 | and LT4, even though they have the same dimensions (LT4 was supposedly a | little noisier). If you have the same bore, then I guess the knock would | sound similar. | > Can I put the sensor | > in some type of holder then bolt it to the block for testing? | I think as long as the sensor is in contact with the cooling jacket water, | you should be OK. HTH! | Andris/SPD ------------------------------ Date: Mon, 10 Jan 2000 15:00:32 -0800 (PST) From: Carter Shore Subject: Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno Bruce, I believe that the sensors are built to be sensitive to specific frequencies, to minimize false trigger, etc. In other words, they are specific to a given engine. I have been working with freeware audio spectrum analyzer program that uses the sound card on a PC. By connecting a wide band microphone to the motor, and then simulating knock (resembles pounding on the block with a hammer or broomstick), the characteristic frequencies of a given motor can be determined. The resonant frequencies show up as spikes. If you can safely induce actual knock in the running motor, even better results. Using that info, the PC software can be set up to look for knock signals for that specific motor. All freeware, just need to bolt on a microphone (guitar mic?) Save the results on a floppy. YMMV, I'm just playing with it right now. Carter Shore __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Mon, 10 Jan 2000 15:00:32 -0800 (PST) From: Carter Shore Subject: Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno Bruce, I believe that the sensors are built to be sensitive to specific frequencies, to minimize false trigger, etc. In other words, they are specific to a given engine. I have been working with freeware audio spectrum analyzer program that uses the sound card on a PC. By connecting a wide band microphone to the motor, and then simulating knock (resembles pounding on the block with a hammer or broomstick), the characteristic frequencies of a given motor can be determined. The resonant frequencies show up as spikes. If you can safely induce actual knock in the running motor, even better results. Using that info, the PC software can be set up to look for knock signals for that specific motor. All freeware, just need to bolt on a microphone (guitar mic?) Save the results on a floppy. YMMV, I'm just playing with it right now. Carter Shore __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Mon, 10 Jan 2000 18:18:49 -0500 From: "Bruce Plecan" Subject: Re: DIY_EFI Digest V5 #14:Knock sensor on Dyno I didn't say they were. That's why I said to get a few and try them... And BS to engine specific. The one I'm running in my F-Body (355 CID), is from a 3.8L 85MY, as I recall. See I went and got several ESC moddules, and sensors and actually tinkered with mix and matching them, so I do have some notion on how the things ACTUALLY work. Audio analyzer, gee great. I did my actual on car testing with a $20 old scanner, and will match my results to anyone's. Theory is fine, but execution is what matters!!.. Grumpy Hmm, wonder why?. | Bruce, | I believe that the sensors are built to be sensitive | to specific frequencies, to minimize false trigger, | etc. In other words, they are specific to a given | engine. | I have been working with freeware audio spectrum | analyzer program that uses the sound card on a PC. By | connecting a wide band microphone to the motor, and | then simulating knock (resembles pounding on the block | with a hammer or broomstick), the characteristic | frequencies of a given motor can be determined. The | resonant frequencies show up as spikes. If you can | safely induce actual knock in the running motor, even | better results. | Using that info, the PC software can be set up to look | for knock signals for that specific motor. | All freeware, just need to bolt on a microphone | (guitar mic?) Save the results on a floppy. | YMMV, I'm just playing with it right now. | Carter Shore ------------------------------ Date: Mon, 10 Jan 2000 18:26:21 -0500 From: "Gary Derian" Subject: Re: DIY_EFI Digest V5 #14 MAF or map will work fine on the dyno but you need a large damping volume between it and the engine. A knock sensor is just a piezoelectric microphone, you can mount it anywhere. You will have to do some trial and error to see what works. Gary Derian > I am currently building a eddy current dynamometer for testing small engines > up to 70 ft lbs of torque. I am working on the instrumentation now and I was > reading the archive and started thinking about knock sensing. I already have > a digital tach, torque and 10 channel thermocouple thermometer in the works. > I was wondering if I could add a knock sensor to my list also? What > specifically would I need to use a sensor ie power and how do I read it? I'd > like to use a sensor out of the junkyard to keep costs down so any ideas of > which one would suit me the best (partial to GM parts)? Can I put the sensor > in some type of holder then bolt it to the block for testing? Another idea I > have is to read intake air, not sure whether Mass air sensor will work due > to stand off fuel (might make a big flame), or a MAP sensor maybe inside > some type of velocity stack? Thanks in advance for any and all ideas! This > list is a wealth of knowledge, anyone wanting to see my ongoing dyno build > stop by my homepage at http://www.geocities.com/brucepts/pts.htm > > Bruce > > There are those that have, and those that will . . . ------------------------------ Date: Mon, 10 Jan 2000 19:17:19 -0500 From: "jtyler" Subject: Re: TWM & GMECM I like the "cut you own wheel" idea with the Crane, very clever. However, if I am going to go DIS, would it be that much harder to make a wheel for the crank pulley and use some kind of pickup down there? Is there one you especially like? Thanks in advance. Jim - ---------- Original Message ---------------------------------- >Date: Sun, 9 Jan 2000 19:51:37 -0500 >From: "Bruce Plecan" >Subject: Re: TWM & GMECM > >If your doing, or planning on possibly going DIS, then the Crane wins, and >get an uncut spare wheel or two. Alllison used to just about give em away >when you asked for em. > For the Dissy, it's just like a point signal. > For DIS, they most often use (4 cyl application), use 6 notches (equally >spaced), and one offset 10 degrees from one of them. I you get serious >about the DIS, I'll scan a diagram showing the notches/offset/which notch >fires which coil pack etc.. >Grumpy > ------------------------------ Date: Tue, 11 Jan 2000 09:00:42 +0800 From: dzorde@xxx.com Subject: Re: LRP and O2 OK, here's a true novice question then. Have never owned a car that runs unleaded, what colour should the plugs be when you are running unleaded, after all cars on unleaded always seem to have black tailpipes ? Dan dzorde@xxx.com Date: Sun, 9 Jan 2000 20:42:34 -0500 From: "Bruce Plecan" Subject: Re: LRP and O2 sensors All things being equal, I've never first hand had that problem. Now if they change the octane or Reed Vapor Levels while doing that then there will be problems, but with as many cos that have done that, there is no reason for it to be a problem. If in doubt just back to basics, reading plugs, and then reading them some more. The plugs will answer your questions. Grumpy ------------------------------ Date: Mon, 10 Jan 2000 18:18:23 -0800 From: "John Dammeyer" Subject: Pulse Width at -40 degrees Hi All, Other than the fact that the colder air is denser and drier how much longer should the pulse width be extended relative to a pulse width at say freezing temperatures? 5% 10% 100% 200% Is there anyone out there in a cold climate that can measure the pulse width of a cold engine at -20 to -40 compared to what it is when the engine has been parked in a garage at just above freezing? The problem is that where I live the Winter temperature is currently +2C and still fairly humid in this temperate rain forest. An engine we have installed out where it's -20C has a heck of a time starting unless they warm up the engine compartment with a space heater. I realize this is a problem that people in California do not have. Same with people who only race in the summer. Anyone done and DIY_EFI for an ice racer? Thanks, John ------------------------------ Date: Mon, 10 Jan 2000 21:47:02 -0500 From: "Bruce Plecan" Subject: Re: Pulse Width at -40 degrees Note a universal formula, depends on engine. If you were to look thru the hacs at www.tunercat.com there is lots of useful info about air temp., coolant temps for the gm ecms. Grumpy | Other than the fact that the colder air is denser and drier how much longer | should the pulse width be extended relative to a pulse width at say freezing | temperatures? 5% 10% 100% 200% | | Is there anyone out there in a cold climate that can measure the pulse width of | a cold engine at -20 to -40 compared to what it is when the engine has been | parked in a garage at just above freezing? | | The problem is that where I live the Winter temperature is currently +2C and | still fairly humid in this temperate rain forest. An engine we have installed | out where it's -20C has a heck of a time starting unless they warm up the engine | compartment with a space heater. I realize this is a problem that people in | California do not have. Same with people who only race in the summer. Anyone | done and DIY_EFI for an ice racer? | | Thanks, | | John | | | | ------------------------------ Date: Mon, 10 Jan 2000 21:49:52 -0500 From: "Bruce Plecan" Subject: Re: LRP and O2 Very light beige, to bone white (bleached off white color), watch for glue oozing out from the center electrode (heat range/timing). grumpy | OK, here's a true novice question then. Have never owned a car that runs | unleaded, what colour should the plugs be when you are running unleaded, after | all cars on unleaded always seem to have black tailpipes ? | | Dan dzorde@xxx.com | | | Date: Sun, 9 Jan 2000 20:42:34 -0500 | From: "Bruce Plecan" | Subject: Re: LRP and O2 sensors | | All things being equal, I've never first hand had that problem. | Now if they change the octane or Reed Vapor Levels while doing that then | there will be problems, but with as many cos that have done that, there is | no reason for it to be a problem. If in doubt just back to basics, reading | plugs, and then reading them some more. The plugs will answer your | questions. | Grumpy | | | ------------------------------ Date: Mon, 10 Jan 2000 21:54:10 -0500 From: "Bruce Plecan" Subject: Re: TWM & GMECM Geez, not even in the same league. Protractor and X-Acto knife vs AL, and measuring, and figuring out where the notches have to be and slotted for enough adjustment. If I owned a machine shop and had the engine on a stand, I'd still go the dissy route Grumpy | I like the "cut you own wheel" idea with the Crane, very clever. | However, if I am going to go DIS, would it be that much harder to | make a wheel for the crank pulley and use some kind of pickup down there? Is there one you especially like? Thanks in advance. | Jim | >From: "Bruce Plecan" | >Subject: Re: TWM & GMECM | >If your doing, or planning on possibly going DIS, then the Crane wins, and | >get an uncut spare wheel or two. Alllison used to just about give em away | >when you asked for em. | > For the Dissy, it's just like a point signal. | > For DIS, they most often use (4 cyl application), use 6 notches (equally | >spaced), and one offset 10 degrees from one of them. I you get serious | >about the DIS, I'll scan a diagram showing the notches/offset/which notch | >fires which coil pack etc.. | >Grumpy ------------------------------ End of DIY_EFI Digest V5 #15 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".