DIY_EFI Digest Tuesday, 25 June 1996 Volume 01 : Number 178 In this issue: RE: H*LP needed understanding fuel\ignition curve dynamics Re: 1/4 Wave Tuning Re: H*LP needed understanding fuel\ignition curve dynamics fuel/torque/hp Looking for Cadillac Error Codes O2 Re: O2 Re[2]: O2 Re: Honda engine info Re: H*LP needed understanding fuel\ignition curve dynamics Re: -No Subject- See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Orin Harding" Date: Mon, 24 Jun 96 08:41:37 UT Subject: RE: H*LP needed understanding fuel\ignition curve dynamics Jim, This reply is from a real novice but here goes...As I understand it, max torque and fuel required occur at peak engine volumetric efficiency and volumetric efficiency and fuel requirements fall off after that point. That's why you have the "hump" in your fuel curve at max torque. Orin@xxx.com NAMGBR@xxx.net WEB: www.deltacp.com Phone/Fax: (910) 854-3232 Mobil Phone: (910) 601-8418 ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 24 Jun 1996 10:53:14 +0500 Subject: Re: 1/4 Wave Tuning The 1/4 wave 'modules' that someone described are indeed there for noise reduction. Well designed ones have no effect on power. Volume is THE primary variable in tuning a 1/4 resonator, not length. The conventional Helmholtz methods aren't perfect since they are one dimensional, but they ususally get you close. I would not worry about duplicating this resonator if you are tranplanting the engine unless the noise really get to you. Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 24 Jun 1996 11:05:43 +0500 Subject: Re: H*LP needed understanding fuel\ignition curve dynamics "What I'd like to better understand is how torque and fuel relate along with ignition." Max fuel occurs at max airflow, which is usually not at peak torque. Peak torque corresponds with peak volumetric efficiency unless you are severely retarding spark due to detonation. Max spark advance occurs under light loads(i.e.cruise) since burn duration is longer and it's tougher to light the charge under those conditions. Spark advance is a rough measure of combustion chamber efficiency, not necessarily overall engine efficiency: the better(read, *faster burning*) chambers need less spark advance. Under WOT conditions, max spark typically occurs around the middle of the rpm range and increase slightly, if at all, up through redline. Stock Mustang spark curves are conservative, so they're not a bad place to start. That engine is knock limited to begin with, and it will get worse since you've blown it, so you will be setting your spark advance by hearing knock. Still, you will be faster than you were unblown! What fuel do you intend to use? Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: Brian Neill Tiedemann Date: Tue, 25 Jun 1996 01:52:26 +1000 (EST) Subject: fuel/torque/hp WRT the question of fuel mapping curves and how they relate to torque/hp curves, I believe the key is that torque is RPM specific, as is fuel pulse width required, whereas hp is dependant on both torque and RPM....clear as mud? What I am saying is that though the engine torque output changes with RPM, the hp changes with torque AND rpm, so mapping fuel pulse width directly to hp may not be correct, but mapping it to torque kinda makes sense. (Fuel pulse repetition rate varies with RPM too-obviously) hope my logic makes some backward sense to others... Brian. P.S. something inside me wonders about specific energy*mass of fuel and whether that should not map directly to work output of engine. mmmmm that means torque doesn't it? I guess this would be true in an IDEAL (read not real) engine, but mechanical and volumetric efficiency probably change things..... ------------------------------ From: ferguson@xxx.ca (Lloyd Ferguson) Date: Mon, 24 Jun 96 11:44:07 EDT Subject: Looking for Cadillac Error Codes A couple of weeks ago the "Check Engine" light in my father-in-law's 1990 Cadillac Fleetwood 4.5 litre has come on. Accessing the error codes on its built-in system displayed: E49 E98 EE 70 I cleared the codes and the light did not come on again for 2 weeks, this time the codes are: E31 E34 E49 EE E49 70 None of the books I can find explain what these codes mean (I guess the Caddy is different from other GMs). Can anyone translate these for me? Lloyd Ferguson ferguson@xxx.ca ------------------------------ From: m.cortecchia@xxx.it (Marco Cortecchia) Date: Mon, 24 Jun 1996 19:45:21 +0200 (METDST) Subject: O2 I am called Mark Cortecchia and I am a student of engineering to Bologna (Italy). I'm me enrolled from little to this ListServ and I would need that anybody helps me. I want to build the Led meter for the probe 02, but I don't know that type of probe use (Brand and Model). Thank you for the collaboration. I MARK CORTECCHIA m.cortecchia@xxx.it ------------------------------ From: Frank Parker Date: Mon, 24 Jun 1996 15:28:19 -0600 (EDT) Subject: Re: O2 > Date: Mon, 24 Jun 1996 19:45:21 +0200 (METDST) > From: Marco Cortecchia > To: DIY_EFI@xxx.edu > Cc: m.cortecchia@xxx.it > Subject: O2 > > I am called Mark Cortecchia and I am a student of engineering to Bologna > (Italy). I'm me enrolled from little to this ListServ and I would need that > anybody helps me. I want to build the Led meter for the probe 02, but I > don't know that type of probe use (Brand and Model). Thank you for the > collaboration. I MARK CORTECCHIA m.cortecchia@xxx.it > All O2 sensors that are normal production sensors have the same voltage curve so you can use most any production car sensor. Be aware that the output voltage in the rich range ( around 0.7 to 0.9 volts) changes a lot with temperature, the voltage dropping as temp rises: Eg from 650 deg C to 900 deg C. frank parker > ------------------------------ From: Gary W Harris Date: Mon, 24 Jun 96 16:34:00 PDT Subject: Re[2]: O2 Text item: > Date: Mon, 24 Jun 1996 19:45:21 +0200 (METDST) > From: Marco Cortecchia > To: DIY_EFI@xxx.edu > Cc: m.cortecchia@xxx.it > Subject: O2 > > I am called Mark Cortecchia and I am a student of engineering to Bologna > (Italy). I'm me enrolled from little to this ListServ and I would need that > anybody helps me. I want to build the Led meter for the probe 02, but I > don't know that type of probe use (Brand and Model). Thank you for the > collaboration. I MARK CORTECCHIA m.cortecchia@xxx.it > All O2 sensors that are normal production sensors have the same voltage curve so you can use most any production car sensor. Be aware that the output voltage in the rich range ( around 0.7 to 0.9 volts) changes a lot with temperature, the voltage dropping as temp rises: Eg from 650 deg C to 900 deg C. frank parker I also beleive that there are fast and slow response O2 sensors--The switchover from slow to fast occurred around 1993 in GM vehicles. If someone could elighten me(us), I would like to know how one identifies which are the fast response O2 sensors! Gary Harris Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Reply-To: diy_efi@xxx.edu Precedence: bulk Sender: owner-diy_efi@xxx.edu Content-Type: TEXT/PLAIN; charset=US-ASCII MIME-Version: 1.0 Message-ID: In-Reply-To: <199606241745.TAA00287@xxx.it> X-Sender: fparker@xxx.edu Subject: Re: O2 cc: DIY_EFI@xxx.it To: diy_efi@xxx.edu From: Frank Parker Date: Mon, 24 Jun 1996 15:28:19 -0600 (EDT) Received: from frankparker.chem.lsa.umich.edu by runningman.rs.itd.umich.edu (8. 7.5/2.3) with SMTP id PAA07742; Mon, 24 Jun 1996 15:25:52 -0400 (EDT) Received: from runningman.rs.itd.umich.edu by coulomb.eng.ohio-state.edu via ESM TP (940816.SGI.8.6.9/940406.SGI) id PAA13258; Mon, 24 Jun 1996 15:25:54 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) id TAA13263; Mon, 24 Jun 1996 19:26:02 GMT Received: from coulomb.eng.ohio-state.edu (coulomb.eng.ohio-state.edu [128.146.9 0.150]) by ormail.intel.com (8.7.4/8.7.3) with SMTP id OAA09898 for ; Mon, 24 Jun 1996 14:12:00 -0700 (PDT) Received: from ormail.intel.com (ormail.intel.com [134.134.248.3]) by relay.jf.i ntel.com (8.7.4/8.7.3) with ESMTP id PAA19062 for ; Mon, 24 Jun 1996 15:04:09 -0700 (PDT) Return-Path: owner-diy_efi-outgoing@xxx.edu ------------------------------ From: CHarris233@xxx.com Date: Mon, 24 Jun 1996 20:19:25 -0400 Subject: Re: Honda engine info >From dzorde@xxx.au- > Does anyone know which model CRX engine runs anti-clockwise ? To the best of my knowledge, all Honda 4-cylinders run clockwise when viewed from the flywheel. This means that the crank turns the same direction as the front wheels when going forward. This is backwards from most engines, which turn Counter-Clockwise when viewed from the flywheel. I'd also be interested in knowing about exceptions to this. later- Charlie ------------------------------ From: Todd Knighton Date: Mon, 24 Jun 1996 18:35:52 -0700 Subject: Re: H*LP needed understanding fuel\ignition curve dynamics Jim, In response to your torque vs. fuel question, yes I hope when you bump up the torque, that the fuel also jumps up. When the engine is properly mapped out, the fuel curve at full throttle (at a given boost or normally aspirated) should match the volumetric efficiency curve almost to a tee. The horsepower end of it is accounted for in the rpm part of the equation, so if you have the same injector pulse at 2000 rpms and 4000 rpms you're producing double the horsepower at 4000 vs 2000 rpm's and also using twice the fuel because you should be injecting every rpm or at least every other rpm. But regardless, the time of injection should stay relative to the rpm's. If you multiplied out the fuel duration times the tpm's to get a specific quantity used per unit time, and plotted it, that plot would look just like your power curve (less friction and some small efficiency factors). Make sure the unit is decreasing the air fuel ratio according to boost as well. Light cruise should be about stoichiometric (14.7/1), 100kpa or 0 boost should be about 10% rich (13.3/1), and around a bar of boost you should be getting to the real low 12's, unless you want to burn up a few set of pistons. As far as spark goes, it varies with rpm and torque. At low rpm you don't need as much advance due to the time it takes to burn the mixture. At higher rpm the time is about the same to ignite the mixture, but the motor is spinning faster, so you must ignite it a bit earlier. At any given rpm, you can almost map advance to the load, at light load you can use a lot of advance, where at heavy load you must decrease the advance. How much depends on your combustion chamber design, compression ratio as well as fuel. Try this. Boost: 250kpa 15deg 18deg 17deg 19deg 100kpa 18deg 30deg 28deg 32deg 000kpa 10deg 40deg 45deg 50deg 1000 3000 5000 7000 RPM Outside of missing about 132 points, this is a close semblance to what I run on my Twin-Turbo 911. Bear in mind that V.E. affects the amount of ignition timing as well, as shown by the dip at 5000 rpm's at n.a. and high boost. The only reason that 1000 rpm and high vacuum is low is for driveability, idle, and starting conditions. Hope this helps. Todd Knighton Protomotive Engineering Jim Pearl wrote: > > I've got some tough (IMO) questions! > > Recently I've gotten the new version of DFI's software and it generates fuel curves for you based upon max HP, torque, and the RPMs where they occur. > > What I'd like to better understand is how torque and fuel relate along with ignition. I've noticed that when I input a greater torque figure that the "hump" in > > Should max fuel occur at max torque? What about ignition? should max spark occur at light cruise? Peak torque? Currently my spark curve is a mess with spark pe > > I know this really isn't enough data for specific tips but what I really want to understand better is when I should max spark and fuel. I may be able to get ho > > Last but not least (sigh) anyone know which pin on the EEC-IV harness is for the driver's side O2 signal? I currently can't run closed loop as my signal is rea ------------------------------ From: "James V. Pearl/QSI" Date: Tue, 25 Jun 1996 01:13:27 -0400 Subject: Re: -No Subject- "What I'd like to better understand is how torque and fuel relate along with ignition." Max fuel occurs at max airflow, which is usually not at peak torque. Peak torque corresponds with peak volumetric efficiency unless you are severely retarding spark due to detonation. Max spark advance occurs under light loads(i.e.cruise) since burn duration is longer and it's tougher to light the charge under those conditions. Spark advance is a rough measure of combustion chamber efficiency, not necessarily overall engine efficiency: the better(read, *faster burning*) chambers need less spark advance. Under WOT conditions, max spark typically occurs around the middle of the rpm range and increase slightly, if at all, up through redline. Stock Mustang spark curves are conservative, so they're not a bad place to start. That engine is knock limited to begin with, and it will get worse since you've blown it, so you will be setting your spark advance by hearing knock. Still, you will be faster than you were unblown! What fuel do you intend to use ? Ed Hernandez Ford Motor Company ehernan3@xxx.com Thanks Ed - I'm using premium pump gas and currently m running GT-40 heads (ported) with stock pistons. The motor's been gone through and freshened but compression was left alone. When I place my TFS (old style) onto a new shortblock I'll be shooting for between * and 8.1 to 1 compression and lot's more boost. Currently I'm limiting it to 8lbs of boost but have seen it a bit higher. With two smallish turbos I'm seeing about 5lbs of boost at 2K - it's a torquey puppy! Best times to date are 12.15 at 118mph with 3.08 gears (5 speed). 3.27's were installed after 3.73s turned out to be too much for the track and road - I seldom take it over 6K.. Any hints as to what the stock Mustang curve looks like at WOT? (smile). I know someone that's cracked it but his software doesn't display it real well for someone simple like me.... P.S. The list will most likely reject this posting due to my SMTP gateway (had to use another package for my previous posting) feel free to forward this if you think it would be of value (sigh). ------------------------------ End of DIY_EFI Digest V1 #178 ***************************** 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".