DIY_EFI Digest Thursday, January 13 2000 Volume 05 : Number 019 In this issue: Re: DIY_EFI Digest V5 #17:Knock sensor, etc. Re: Knock sensor on dyno Injector Sizes for CrossFire Re: Injector Sizes for CrossFire Re: TWM & GMECM injector questions - sleepless in Seattle knock sensor/dyno Turbo motor See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 12 Jan 2000 18:17:44 -0500 From: "Bruce Plecan" Subject: Re: DIY_EFI Digest V5 #17:Knock sensor, etc. | Thanks Bruce, | I had not thought about noise contribution from mech | valvetrain. And of course, IGOR will allow some very | accurate knock detection, but I didn't think it was | available yet. IGOR, no, but SAAB's been using it for years. | Here's a Q, do you know how/if GM systems handle false | KS trigger, vs RPM? Nope they don't handle vs rpm, 800 rpm, 2000, 4000, 8000, if it's set for 4,000Hz, and hears the right sound off goes the timing. I've seen cars set 12d retard wile cranking. That's also why I consider acoustic sensors as a joke, and not to be trused. | For example, say an ECU has a KS sensitive to say, | 4,000 Hz. Frequency of bormal internal noise from the | motor varies with RPM, so at some RPM, it will also | create 4,000 Hz noise that would trigger the KS. Does | the code ignore KS at certain RPM? See above. Grumpy ------------------------------ Date: Wed, 12 Jan 2000 18:31:08 -0500 From: "Bruce Plecan" Subject: Re: Knock sensor on dyno What you call AE Enrichment noise might be trace detonation (gm uses a "burst knock table to cover this situation in some applications) Grumpy | Take a look at | http://home.netcom.com/~bsundahl/knock/sound/KnockSounds.htm | | This shows some of the work that I have done on recording and analyzing | the signal off of an Eagle Talon knock sensor. The sensor does not | seem to be "tuned" that I can tell, it's just a wide band microphone. | I am assuming that the GM sensors are very similar. | | The Talon uses a fancy filter circuit inside the ECU to detect knock, | but I have never been able to figure out exactly what it looks for | in the signal. | | -Bill | ------------------------------ Date: Wed, 12 Jan 2000 17:32:52 -0600 From: "Ken Kelly" Subject: Injector Sizes for CrossFire Does anyone know what the difference between the two actually is? Or the reasoning why they had two different sized injectors? Ken Kelly (#2) ------------------------------ Date: Wed, 12 Jan 2000 18:45:22 -0500 From: "Bruce Plecan" Subject: Re: Injector Sizes for CrossFire As I recall 4-5 lbs/hr.. The diference in size was due to the fact one ran with the fuel pressure regulator, andf the other with the accumulator. Grumpy | Does anyone know what the difference between the two actually is? Or the | reasoning why they had two different sized injectors? | Ken Kelly (#2) ------------------------------ Date: Wed, 12 Jan 2000 18:56:10 -0500 From: "Bruce Plecan" 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? Crank, and cam sensor wire into the DIS module. On some PCMs the sensor goes directly to the pcm. So an ecm doesn't look for a signal from the sensor Now the input to the DIS varies, by type some are Hall effect sensors, and some are reluctor. So you gotta figure out what ya got, and work from there. Grumpy | 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? Your going to need to go from the coil trigger output of the crank to the sensor input to the DIS, and again it varies. | 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: Wed, 12 Jan 2000 20:26:20 -0800 From: "Stowe, Ted-SEA" Subject: injector questions - sleepless in Seattle ok, got some injector questions. I have an 1800 cc, (1798) motor, (77 mgb) 90 hp, saimsed intake ports, I think the stromberg cd was something like 200 cfm but I might be wrong. I am going to put 2 injectors in it. and an air mass sensor. the donor efi car used 4 bosch injectors for 2300 cc according to the data I could find on the web, the motor (b230f), used a 0 280 150 762 bosch injector. these had fuel rails, and are listed as 214 cc per minute, or 21 lbs per hour. and a chart at www.wolfems.com.au/injector_flow_rates.htm tells me that these injectors were good for 42.8 hp each. I can't remember the actual rail pressure in their natural environment, (86 240dl). standard bosch jet-jh so if I scale it up a bit , and for argument's sake use the volume of the injectors that I have. (they were all batch fired btw). I would then need to get 2 injectors that were low impedance, to make them look like bosch injectors to the ecm, and they would have to have a flow rate of 428 cc per minute or 42 lbs per hour. question 1 : does this math sound correct ? I wonder about this because they were batch fired. this means that they were fired when there was no benefit to do so, the expended fuel must of gone somewhere. I can't work out the math in my head to take into account the batch-fired effect. ok well, I am going to use the msd epoxy injector mounts, I think that these are made for GM mounting specs. or am I misreading their fuel injection catalog incorrectly ? it seems that you can use their injectors to replace gm injectors, if that's the case I'm assuming a gm injector will fit in their mount. no one that I can tell, makes mounts like this for bosch injectors, besides the bosch injectors used a fuel rail anyway, I really liked the flexible fuel hose hardware from msd. the angles of the injectors would preclude a normal fuel rail. I can't find an msd injector that does 42 lbs per hour. they jump from 34 to 50 lb/hr. where would I find a gm parts list that rates stock gm injectors by flow volume/impedance ? question 2: or am I digging a hole for myself ? the ecm I have is going to think it's talking to a specific environment, i.e. stock rail pressure, combined flow volume etc. as usual thanks for your expert advice. Ted NOTICE: This communication may contain privileged or other confidential information. If you are not the intended recipient, or believe that you have received this communication in error, please do not print, copy, retransmit, disseminate, or otherwise use the information. Also, please indicate to the sender that you have received this email in error, and delete the copy you received. Thank you. ------------------------------ Date: Thu, 13 Jan 2000 00:02:35 -0500 From: brucep@xxx.net Subject: knock sensor/dyno Thanks for all the great things to think about! I like the microphone/software idea, this would allow me to analyze a dyno run. Not just for knock but what ever else I could see or figureout. More data to look at. Unfortunatly, I can't at this time put data acquisition on the dyno due to lack of $$$'s so I am looking for "cheap" ways of doing things. Sorry for the lack of Fuel injection content but it did spark some thoughts. "the other Bruce" ------------------------------ Date: Wed, 12 Jan 2000 22:49:16 -0800 From: Greg Tully Subject: Turbo motor Hi I am running the efi332 two layer cpu board and the i/o board in my car. Just doing spark, boost control for the moment. I am picking the signal off of the distributor with the TPU PPWA, and setting advance, retard, and turbo boost. No problems with cpu board yet but still looking.. I am using a map sensor from a mid 80's (chrysler,dodge,plymouth) turbo K car. There are a lot of these cars in the wrecking yards. This is a one atmosphere boost unit. It has a ground wire, 5 volt supply wire and a sense wire. Measured data: Pressure output volts 30" hg .56 15" hg 1.30 0 2.47 5psi 3.25 10psi 4.13 15psi 5.00 Under boost I have noticed that my car has a tendency to ping more at 3000 rpm , which I would guess is the tuned configuration of the motor. So boost and/or timing can be reduced. If the timing is reduced to prevent any detonation, and the boost is left alone. It will generate spectacular boost numbers and it runs strong. But it runs about the same when I reduce the timing a little bit and limit the boost. So it looks like there are two different ways to get to the same point. So what is the best way to tune a turbocharger motor? I would guess reducing the timing a little, and then limit boost to prevent detonation... Also I have noticed that GM spark rpm/load tables arrays seem to be 16 bytes wide, even when its a Grand National turbo motor. It seems like that if its a one atmosphere map unit the table should be 32 bytes wide for the same resolution. Any comments on this one? My car is a 4 cyl turbocharger Saab, dual overhead cams, four valves per cylinder, with intercooler.. not bad for a stock 1989 car. Its not a performance car, its heavy and the transmission is weak, but it is an interesting platform to fool around with. Aloha Greg ------------------------------ End of DIY_EFI Digest V5 #19 **************************** 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".