DIY_EFI Digest Tuesday, January 11 2000 Volume 05 : Number 016 In this issue: Re: DIY_EFI Digest V5 #15:Knock Sensors Re: DIY_EFI Digest V5 #15:Knock Sensors Re: TWM & GMECM Re: GMECM and Crank Sensors Re: Knock sensor on Dyno See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 11 Jan 2000 04:52:37 -0800 (PST) From: Carter Shore Subject: Re: DIY_EFI Digest V5 #15:Knock Sensors Ouch! Geez Grumpy, gimme a break. I was replying to the original post by brucep@xxx.net, not to your reply, (got my Bruce's mixed up). You've probably forgotten more than I'll ever learn on this subject, and I appreciate the fact that you are willing to share it with us. But bear with me a second. I'm facing a similar problem to the dyno-building Bruce (he is testing tractor motors). The problem is that no one has applied knock sensors to my engine (at least not the manufacturer). Maybe there's a KS that will work, maybe not. I've seen a spec sheet for Ford KS that specifies the resonant frequencies for some, but not for any other manufacturers. Since I have worked professionally with noise and signal analysis, I looked to the tools that I used every day for years. Spectrum analysis is one of them. It's just a measurement tool, not abstract theory. When I was in the biz, the instruments cost thousands of dollars. Now it's free for the downloading. I believe that a lot of list members would find a simple cheap system for detecting knock very accurately on any motor a useful tool. Maybe you too. I'll share whatever I find with the list, if there's any interest. Even if turns out to be BS, at least we will have found out what does not work, and move on. Thanks, Carter __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Tue, 11 Jan 2000 04:52:37 -0800 (PST) From: Carter Shore Subject: Re: DIY_EFI Digest V5 #15:Knock Sensors Ouch! Geez Grumpy, gimme a break. I was replying to the original post by brucep@xxx.net, not to your reply, (got my Bruce's mixed up). You've probably forgotten more than I'll ever learn on this subject, and I appreciate the fact that you are willing to share it with us. But bear with me a second. I'm facing a similar problem to the dyno-building Bruce (he is testing tractor motors). The problem is that no one has applied knock sensors to my engine (at least not the manufacturer). Maybe there's a KS that will work, maybe not. I've seen a spec sheet for Ford KS that specifies the resonant frequencies for some, but not for any other manufacturers. Since I have worked professionally with noise and signal analysis, I looked to the tools that I used every day for years. Spectrum analysis is one of them. It's just a measurement tool, not abstract theory. When I was in the biz, the instruments cost thousands of dollars. Now it's free for the downloading. I believe that a lot of list members would find a simple cheap system for detecting knock very accurately on any motor a useful tool. Maybe you too. I'll share whatever I find with the list, if there's any interest. Even if turns out to be BS, at least we will have found out what does not work, and move on. Thanks, Carter __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Tue, 11 Jan 2000 08:32:54 -0500 From: "jtyler" Subject: Re: TWM & GMECM Well it certainly pays to ask first. Thanks a bunch. I could always go to a crank wheel later after all the otherstuff is sorted out, but for street use I certainly don't need to. I just wanted to eliminate the dist if possible. So back to the Crane. What electrical input is the ecm looking for from the trigger wheel? Do I build a circuit to condition the Crane box output to the GM ecm, or do you need to make a new driver for the optical sensor itself and have it trigger the ecm directly? Has someone been down this path...sounds like? If you can send me the wheel drawing that would be great. If a fax is less effort let me know. BTW there is absolutely no rush on this. I am one of those "Blessed" with too many projects. Dopey >------------------------------ > >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 ------------------------------ Date: Tue, 11 Jan 2000 09:24:50 -0500 From: "jtyler" Subject: Re: GMECM and Crank Sensors For yet another project, is there a nice reliable, relatively easy to mount crank sensor that interfaces easily to the GM ECM's you favor? In this case a dist is not an option. I have provisions to build a mount, make/adapt a crank wheel of some type or precisely install magnets in a pulley or even a flywheel. Does the GM DIS have 5 or 6k rpm limits, something I read somewhere indicated that, but they may have been talking about HEI coils? All this stuff I am playing with needs to make it to 6.5K, the race app at least 8500. Dopey >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 12:11:58 -0600 From: steve ravet Subject: Re: Knock sensor on Dyno > 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 -- what is this software called and where is it available from? This is very interesting. - --steve - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ End of DIY_EFI Digest V5 #16 **************************** 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".