DIY_EFI Digest Tuesday, 12 March 1996 Volume 01 : Number 074 In this issue: Re: volumetric efficiency equations Re: volumetric efficiency Re: EGT for mixture setting? Re: Al u-bends Re: EFI without a lookup table Re: EGT for mixture setting? Re: EGT for mixture setting? Re: EFI without a lookup table Re: volumetric efficiency Re: volumetric efficiency Re: volumetric efficiency Re: EGT for mixture setting? Re: volumetric efficiency equations Re: volumetric efficiency Re: EGT for mixture setting? RE: EFI without a lookup table DIY FI facts Re: Al u-bends RE: EFI without a lookup table Help on 2.3 litre turbo motor Long returns!!! Re: EGT for mixture setting Suzuki Swift GTi Twincam 1.3 (87) Re: volumetric efficiency See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 11 Mar 1996 06:44:36 +0500 Subject: Re: volumetric efficiency equations "...must use a sophisticated program such as Ford's MANDY (can you send me a copy of that? :-))...." Ah, no :( but I was impressed with someone's listing of inputs into the Engine Analyzer and that's only $80. MANDY would cost you some number with lots of zeros behind it plus a workstation to run it on. Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 11 Mar 1996 06:37:56 +0500 Subject: Re: volumetric efficiency "We concluded this when we got an volumetric efficiency of 1.1 !" What makes you think having a volumetric efficiency of 1.1 makes your meter incorrect? It is entirely possible to get volumetric efficiencies greater than one. What engine? What rpm? What was it designed to do? ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 11 Mar 1996 06:51:23 +0500 Subject: Re: EGT for mixture setting? - ----- Begin Included Message ----- >From owner-diy_efi-outgoing@xxx.edu Sun Mar 10 18:32 EST 1996 X-Sender: jsturs@xxx.nl > Could somebody please explain the relationship between EGT and mixture in a practical sense for tuning purposes, i.e. how would you actually go about setting fuel curves based on EGT readings? > A very conservative method would be to tune A/F for the same EGT at WOT across the rpm range. A more aggressive approach would be to tune A/F for a shallow but constant rising slope vs rpm. There are lots of ideas as to a maximum EGT which you shouldn't exceed. Some like to use about 1800 F on dyno, but that's pretty short term. I love it when the exhaust glows red! Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: matthew@xxx.com (Matthew Wallis) Date: Mon, 11 Mar 96 09:20:50 EST Subject: Re: Al u-bends > X-Sender: dhe1@xxx.edu > Mime-Version: 1.0 > Content-Type: text/plain; charset="us-ascii" > Date: Sun, 10 Mar 1996 19:38:00 -0700 > From: dhe1@xxx.edu (Dan Elsberg) > Sender: owner-diy_efi@xxx.edu > Precedence: bulk > Reply-To: diy_efi@xxx.edu > Content-Length: 759 > > We got tired of the high prices and low availability of Aluminum u-bends so > we made a mandril bender. It was a _lot_ of work. (about a week of > machining and then another couple of days playing around with the > technique.) Anyway if anyone needs 1-3/8"x0.058 we may be able to work > something out that would be a lot cheaper than the estimates we got from > various other sources (one wanted $275 to bend 6 semi-circles (180 degrees) > including the labor and material). E-mail me directly if you want to talk > about it. > > If anyone wants a description of the tool we made e-mail me about that too. I would like to get a description of the tool. Any plans available? I need to do some bending of some 0.75", 0.035" Wall 5052 Al tubing. - Matthew > > --dan > > -- > Dan Elsberg (607) 272-1574 > Cornell University, Engineering Physics dhe1@xxx.edu ------------------------------ From: "Paul E. Campbell" Date: Mon, 11 Mar 1996 10:43:00 -0500 (EST) Subject: Re: EFI without a lookup table Bruno writes: > Is it possible to have an efi computer control the engine entirely in > closed loop? I'd like to design a ecu which does not rely on having to be > dyno-tuned, or other ways where the engine has to run at different loads, > speeds, etc. Yes. It's called an "adaptive algorithm" but it requires more CPU power than simple table lookups. BUT you will have to at least temporarily run open loop during warmup until your O2 sensor is functioning (unless you want to buy a sensor with a 4 digit price tag). > The rationale behind this is I want to be able to design the computer, > plug it in, and control the engine from day one. I understand that there > are more things to consider, what they are exactly are slowly coming to me. What you might also consider is if you came up with a generic map that would at least get the vehicle started, it could then do map updates and slowly tune itself. This is along the lines I've been thinking of. > When using a hall effect sensor, what is the material that the metal vane > that passes through the gap made of? Iron or aluminium? Has to be ferrous. So aluminum is out. ------------------------------ From: MSargent@xxx. Sargent) Date: Mon, 11 Mar 1996 11:18:38 -0500 Subject: Re: EGT for mixture setting? > I love it when the exhaust glows red! Are Titanium valves geting cheaper? :-) +--------------------------------------------------------------------------+ | Michael F. Sargent | Net: msargent@xxx.com | Phone: 1(613)721-0902 | | Gallium Software Inc.| | FAX: 1(613)721-1278 | +--------------------------------------------------------------------------+ ------------------------------ From: Frank Parker Date: Mon, 11 Mar 1996 11:52:52 -0500 (EST) Subject: Re: EGT for mixture setting? > > A very conservative method would be to tune A/F for the same EGT at > WOT across the rpm range. A more aggressive approach would be to tune > A/F for a shallow but constant rising slope vs rpm. There are lots of > ideas as to a maximum EGT which you shouldn't exceed. Some like to > use about 1800 F on dyno, but that's pretty short term. I love it when > the exhaust glows red! > > Ed Hernandez > Ford Motor Company > ehernan3@xxx.com > I have had a hard time getting a good relationship between absolute exhaust temp and a/f ratio and temp limits. I have taken data on my datalogger @ 100 times/sec monitoring fuel pressure, turbo boost, o2 sensor voltage and egt. The type k t/c was located about 3" from head exhaust outlet flange. I saw about 1650 deg F max at wot, with about 10sec @ max 8psi boost. I could adjust nonlinear fuel press regulator to add more fuel and see 50 deg temp drop. O2 sensor voltage went from about .82 to about .84, but std o2 sensors are very nonlinear here. Does anyone have comments on how egt temps change with thermocouple placement and what max limits may be????. The turbo mfr suggests 1750 max inlet temp. As a secondary question, are there any sources from the wide range o2 sensors other than the overpriced unit from Horriba ($2500-actually made by NGK)??? ------------------------------ From: atsakiri@xxx.com Date: Mon, 11 Mar 96 11:57:49 -0500 Subject: Re: EFI without a lookup table > Is it possible to have an efi computer control the engine entirely in > closed loop? I'd like to design a ecu which does not rely on having to be > dyno-tuned, or other ways where the engine has to run at different loads, > speeds, etc. That would depend on what the variable(s) you're trying to control are. Current table-based routines are attempts at achieving desired torque, power, emissions, and fuel consumption, plus many more less quantifiable parameters like drivability, noise, shift quality, etc. There is also, at least for mass-produced vehicles, to minimize cost. That affects sensors, actuators, and computing power. (Where is that darn low-cost in-line torque sensor anyway? :) ) Add to this that engines behave very nonlinearly (just look at emissions versus fuel/air ratio) and you have a very challenging problem. > The rationale behind this is I want to be able to design the computer, > plug it in, and control the engine from day one. Wow. If you ever get to this point with a cost-effective design, companies will line up to buy it. Anthony Tsakiris - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: matny@xxx.se (Mattias Nyberg) Date: Mon, 11 Mar 1996 17:58:44 +0100 Subject: Re: volumetric efficiency > > "We concluded this when we got an volumetric efficiency of 1.1 !" > > What makes you think having a volumetric efficiency of 1.1 makes your > meter incorrect? It is entirely possible to get volumetric efficiencies > greater than one. What engine? What rpm? What was it designed to do? The engine is a SAAB 2.3L standard production engine (fuel injection, no turbo, no EGR). The volumetric efficiencies close to 1.1 was obtained around 4000 rpm. Normally the vol. eff. should be 0.85 (see any engine book) which makes an error of (1.1-.85)/.85=29%. How can vol. eff. be greater than 1? Mattias Nyberg ------------------------------ From: atsakiri@xxx.com Date: Mon, 11 Mar 96 12:31:42 -0500 Subject: Re: volumetric efficiency > How can vol. eff. be greater than 1? A non-boosted engine can still have a volumetric efficiency greater than one. A highly tuned induction system can produce manifold pressure pulsations (at some engine speeds) which are higher than ambient pressure and which occur when the intake valve is open. Since volumetric efficiency is usually calculated using ambient pressure as the reference, the result ends up being greater than one. It's possible, but I don't think common. Anthony Tsakiris - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: Bruce Bowling Date: Mon, 11 Mar 1996 13:30:05 EST Subject: Re: volumetric efficiency ~ How can vol. eff. be greater than 1? ~ ~ Mattias Nyberg ~ Quoting from the superflow flow bench manual: "Inertial Supercharging Effect: When the intake valve starts to close, the fast moving air column tries to keep ramming itself into the cylinder. If the inlet valve is closed at just the right instant, the extra charge will be trapped in the cylinder (called inertial supercharging). Volumetric efficiencies up to 130 percent can be obtained......." They then go on to define the inertia-supercharge index Z, which is an empirical value which is a measure of the strength of the inertia supercharge. To compute this: 1) Find Cv = (valve flow (total) for one cylinder filling event at given test pressure) --------------------------------------------------- (Maximum flow possible at given test pressure) Cv is intake system flow rating (normalized) 2) Find average inlet valve area: A = Cv * (valve area in sq. inches) 3) Compute Z: Z=((RPM/126000)) * sqrt((CID * Inlet Length)/(A)) Z will usually be between 0.9 and 1.2 - - Bruce - -- - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- Bruce A. Bowling Staff Scientist - Instrumentation and Controls The Continuous Electron Beam Accelerator Facility 12000 Jefferson Ave - Newport News, VA 23602 (804) 249-7240 bowling@xxx.gov http://devserve.cebaf.gov/~bowling - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- ------------------------------ From: orlin steven jared Date: Mon, 11 Mar 1996 14:33:00 -0500 (EST) Subject: Re: EGT for mixture setting? > I have had a hard time getting a good relationship between absolute exhaust > temp and a/f ratio and temp limits. I have taken data on my datalogger @ > 100 times/sec monitoring fuel pressure, turbo boost, o2 sensor voltage > and egt. The type k t/c was located about 3" from head exhaust outlet > flange. I saw about 1650 deg F max at wot, with about 10sec @ max 8psi > boost. I could adjust nonlinear fuel press regulator to add more fuel and > see 50 deg temp drop. O2 sensor voltage went from about .82 to about .84, > but std o2 sensors are very nonlinear here. > Does anyone have comments on how egt temps change with thermocouple > placement and what max limits may be????. The turbo mfr suggests 1750 max > inlet temp. In my opinion, EGT's aren't really very useful in tuning AFR. You will spend more time and money doing this, and have more failures (most likely) than if you just plunked down the initial investment in the Horiba UEGO unit. The main advantage of EGT's is checking fuel distribution. > As a secondary question, are there any sources from the wide range o2 > sensors other than the overpriced unit from Horriba ($2500-actually made > by NGK)??? You may want to look into Bosch. Last I heard they were coming out with some type of a comparable unit, with UEGO sensors for $250 ea., instead of the $900 Horiba sensors. STeve ------------------------------ From: orlin steven jared Date: Mon, 11 Mar 1996 14:29:45 -0500 (EST) Subject: Re: volumetric efficiency equations > >However the book by Taylor & > >Taylor from MIT Press does have some equations that indicate how various > >changes effect volumetric efficiency. An example is the equation that shows > >how volumetric efficiency is affected by the ratio of Intake to Exhaust > >manifold pressure. For some applications that level of sophistication is > >sufficient. > > Could you give me a cite for said book, and also whoudl you be kind enough > to summarize (or just dump) that formula ... I'm VERY curious as to the > effect of Exhaust backpressure on Ve ... > The book is called _The internal combustion engine in theory and practice_ It's by Charles Fayette Taylor, and the one you want for these formulas is Volume 1. There are several formulas for volumetric efficiency he gives. The one that includes the pressure ratio is the following: Ev = 0.285 + (r - Pe/Pi)/(1.4*(r - 1)) Don't expect super accurate answers from this formula, because he 'derived' it from experimental results for engines with small valve overlap and pressure ratios greater than 0.5 I would suggest reading the book. And if your engine is similar to what he tested, then your results will be better. He also includes graphs of Ev and every possible engine parameter. Volumetric efficiency defined, for an ideal fuel-air cycle is: Ev = Mi/(V1 - V2)pi where: Mi is the mass of fresh mixture supplied and pi is the density of this mixture at the pressure and temp. V1-V2 is the total displacement of the engine. Evolved into formulas you can use directly for engines: Ev = 2*mass flow rate of fresh mixture / (rpm * total displacement * inlet dens) You can also express this formula on the basis of dry air, and make it even more user friendly: Ev = 4*mass fl rate of dry air/(dens air * total piston area * mean piston spd) Where mean piston speed = 2 * stroke * rpm This is easier to use because you can calculate the density of dry air with good accuracy for your given temp/press. And the only thing you need is the mass flow rate of the dry air. To the guy who doesn't understand how you can get an Ev over 1, consider a forced induction situation, or a tuned supercharge effect from the intake design. Also consider that the strict definition of Ev only accounts for the mass of the mixture in the displacement volume -NOT including the combution chamber volume. Even so, unless you have an extremely large combustion chamber, or a forced induction, you should not rule out numerical inaccuracy in your calculations. But for the record books, you can have volumetric efficiencies over 1. Steve ------------------------------ From: orlin steven jared Date: Mon, 11 Mar 1996 18:07:24 -0500 (EST) Subject: Re: volumetric efficiency > "Inertial Supercharging Effect: > > When the intake valve starts to close, the fast moving air column > tries to keep ramming itself into the cylinder. If the inlet > valve is closed at just the right instant, the extra charge will be trapped > in the cylinder (called inertial supercharging). Volumetric efficiencies > up to 130 percent can be obtained......." I think this is mentioned in the ASME paper "design of a tuned intake", probably where superflow got it from ;-) > They then go on to define the inertia-supercharge index Z, which > is an empirical value which is a measure of the strength of the > inertia supercharge. To compute this: > 3) Compute Z: > > Z=((RPM/126000)) * sqrt((CID * Inlet Length)/(A)) > > Z will usually be between 0.9 and 1.2 > This looks like a 'makeshift' Inlet Mach Index formula. (I could be wrong). The Inlet mach index is the ratio of the typical inlet velocity to the inlet sonic velocity. Z = ((b/D)^2 )* s /(Ci*a) pg 173 of Taylor's book. Where b = cylinder bore D = inlet valve diameter s = mean piston speed = 2 X rpm X stroke Ci = mean inlet flow coefficient a = local velocity of sound a can be calculated by multiplying a constant by the square root of the temperature (absolute). Ci is the hanger here. It correlates to the ratio of the lift/inlet valve diameter. But my guess is that for whatever you need to come up with a mach index for, an approximation is good enough ;) There are graphs for Ci in the book too. The reason why I have doubts that maybe this isn't the same "Z" factor as Bruce posted is because you don't want a value of over .6 for the inlet mach index. volumetric efficiency starts to drop off fast after that. I didn't hack through the math/units to compare the two, but they look similar. Steve ------------------------------ From: Michael Fawke Date: Tue, 12 Mar 1996 10:20:43 +1000 Subject: Re: EGT for mixture setting? At 11:52 AM 11/3/1996 -0500, you wrote: >As a secondary question, are there any sources from the wide range o2 >sensors other than the overpriced unit from Horriba ($2500-actually made >by NGK)??? > Bosch makes a 'motorsport' wide range lambda probe. About $350 Australian. But they only have a life of about 500 hours for unleaded and 50 hours for leaded. Michael Fawke fawkacs@xxx.au ------------------------------ From: Andrew Dalgleish Date: Mon, 11 Mar 1996 20:19:13 -0500 Subject: RE: EFI without a lookup table On Monday, 11 March 1996 11:57, owner-diy_efi-outgoing wrote: > > > Is it possible to have an efi computer control the engine entirely in > > closed loop? I'd like to design a ecu which does not rely on having to be > > dyno-tuned, or other ways where the engine has to run at different loads, > > speeds, etc. > > That would depend on what the variable(s) you're trying to control are. > Current table-based routines are attempts at achieving desired torque, > power, emissions, and fuel consumption, plus many more less quantifiable > parameters like drivability, noise, shift quality, etc. > > There is also, at least for mass-produced vehicles, to minimize cost. > That affects sensors, actuators, and computing power. (Where is that > darn low-cost in-line torque sensor anyway? :) ) How about a strain gauge on the tail-shaft? Calibrating it might be a bear... > > Add to this that engines behave very nonlinearly (just look at emissions > versus fuel/air ratio) and you have a very challenging problem. > > > > The rationale behind this is I want to be able to design the computer, > > plug it in, and control the engine from day one. > > Wow. If you ever get to this point with a cost-effective design, > companies will line up to buy it. > > > > > Anthony Tsakiris > > -------------------------------------------------------------------------- - > The opinions expressed are my own and not necessarily those of my employer. > Regards, Andrew Dalgleish Senior Software Engineer Axon Research, Pty Ltd 6 Wallace Ave, Toorak, VIC 3142 AUSTRALIA Tel +61-3-9826-5538 Fax +61-3-9824-0083 ------------------------------ From: "George M. Dailey" Date: Mon, 11 Mar 1996 19:19:58 -0600 Subject: DIY FI facts At 02:01 PM 3/8/96 -0800, Jerry Wills wrote: >If you believe that did-it-yourself EFI and daily driver go together without needing >TLC before your oil changes, I believe your dreaming. The factories go way beyond the >reasonable testing to get the bugs out of production cars. We have the advantage that >many parts we will use to build 'our' systems, are already factory qualified, but the >Auto enviroment/specs are worse than the mil specs ,in many cases. I would be proud >if the system I put together, could just meet mil spec. > >I have tried to turn projects (like mech T.J. FI on a lotus)into daily drivers, and >found that I was always looking over my shoulder. > Jerry Wills ============================================================================ ========== I almost agree with you 100% on this one Jerry. But... I've been driving an up-graded '58 Chevy truck for ten years. I depend on it for everyday transportation (170 +miles/week) and she seldom lets me down (can't say that about some of the women in my life :). The only thing that's original is a few body parts. The main thing that I've learned about modifying auto machinery (FI, brakes, body, chassis, or what ever), is to know at what level to start D_I_Y_ing at. Have you ever herd of a "do it your self" person try to cast their own engine block or smelt their own alloys? My philosophy is, "when in question, see what the OEM uses and adapt it to your application". In most cases, not all, the OEM knows best. They've got better toys and have been playing with them much longer than most of us have. Occasionally, we (D_Y_I_ers) can slip up on something original. I don't know about you guys, but I do it strictly for fun. Keep the D_I_Y mentality alive! BTW, this is comming from a guy who is building a car... from scratch :-() GMD ------------------------------ From: William Sarkozy Date: Mon, 11 Mar 1996 20:26:59 -0800 Subject: Re: Al u-bends At 07:38 PM 3/10/96 -0700, you wrote: >We got tired of the high prices and low availability of Aluminum u-bends so >we made a mandril bender. It was a _lot_ of work. (about a week of >machining and then another couple of days playing around with the >technique.) Anyway if anyone needs 1-3/8"x0.058 we may be able to work >something out that would be a lot cheaper than the estimates we got from >various other sources (one wanted $275 to bend 6 semi-circles (180 degrees) >including the labor and material). E-mail me directly if you want to talk >about it. > >If anyone wants a description of the tool we made e-mail me about that too. > >--dan > >-- >Dan Elsberg (607) 272-1574 >Cornell University, Engineering Physics dhe1@xxx.edu > > > I'm very interested. Is the 1-3/8" diameter the only size you do? Bill ------------------------------ From: Jody Shapiro Date: Mon, 11 Mar 1996 22:29:46 -0500 Subject: RE: EFI without a lookup table I'm cross-posting this to both the DIY_EFI list and the F-Body list because this topic has come up and I haven't seen anyone mention the item belower which looks interesting. >---------- >From: Andrew Dalgleish[SMTP:andrewd@xxx.au] >Sent: Monday, March 11, 1996 8:19 PM >To: diy_efi@xxx.edu >Subject: RE: EFI without a lookup table > > >On Monday, 11 March 1996 11:57, owner-diy_efi-outgoing wrote: >> There is also, at least for mass-produced vehicles, to minimize cost. >> That affects sensors, actuators, and computing power. (Where is that >> darn low-cost in-line torque sensor anyway? :) ) >> Anthony Tsakiris > >How about a strain gauge on the tail-shaft? >Calibrating it might be a bear... > >Andrew Dalgleish On page 54 of the Feb 96 issue of Chevy High Performance under the article "50 Hot New Parts" which talks about items from the SEMA show (Specialty Equipment Manufacturers Assocation): "Ever wondered what your engine's horsepower is at operating conditions? DYNOmite ((603)329-5645) has an onboard dyno that allows monitoring and recording of the horsepower at the driveshaft while the car is on the road. The key is an output-shaft-mounted strain gauge." - -Jody - --- http://www.cs.cornell.edu/Info/People/jshapiro/jshapiro.htm begin 600 WINMAIL.DAT M>)\^(CL#`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$-@ 0` M`@````(``@`!!) &`) "```"````# ````,``# $````"P`/#@`````"`?\/ M`0```&,`````````@2L?I+ZC$!F=;@#=`0]4`@````!D:7E?969I0&-O=6QO M;6(N96YG+F]H:6\M``,P`0`` M`",```!D:7E?969I0&-O=6QO;6(N96YG+F]H:6\M5]E9FE 8V]U;&]M8BYE;F4!C:7-C;RYC;VT````>``(P`0````4```!33510`````!X``S !````$0`` M`&8M8F]D>4!C:7-C;RYC;VT``````P`5# (````#`/X/!@```!X``3 !```` M#@xxx.D8M0D]$64!# M25-#3RY#3TT````#```Y``````L`0#H``````@'V#P$````$````````!7&# M`0B !P`8````25!-+DUI8W)OV 1SYO91$535 `````>`!X,`0`` M``4```!33510`````!X`'PP!````& ```&IS:&%P:7)O0&-S+F-O``@0`0```&4```!)34-23U-3+5!/4U1) M3D=42$E35$]"3U1(5$A%1$E9149)3$E35$%.1%1(148M0D]$64Q)4U1"14-! 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I presume its a problem with the pressure regulator mounted on the fuel rail, but could it be (I don't know how) a clogged return line to the tank? Any suggestions or insights would be greatly appreciated. Thanks...... Bill ------------------------------ From: MTaylorfi@xxx.com Date: Tue, 12 Mar 1996 00:53:57 -0500 Subject: Long returns!!! To those people that cut and paste two paragraphs from a previous listing, just to add one or two sentences, please quit. Thanks in advance!! ------------------------------ From: Darrell Norquay Date: Mon, 11 Mar 96 22:03:54 MDT Subject: Re: EGT for mixture setting Ed Hernandez wrote: > A very conservative method would be to tune A/F for the same EGT at > WOT across the rpm range. A more aggressive approach would be to tune > A/F for a shallow but constant rising slope vs rpm. There are lots of > ideas as to a maximum EGT which you shouldn't exceed. Some like to > use about 1800 F on dyno, but that's pretty short term. I love it when > the exhaust glows red! Does the EGT sensor have to be close to the head? The reason I ask is that I have headers, and the only practical place to mount EGT's would be in the collectors. I assume that the temperatures would be somewhat reduced, but still proportional(?) How does the mixture affect EGT? Do lean mixtures produce lower or higher temps than rich ones? Can you determine if you are at stoich with this method (with any accuracy)? Is there a linear relationship between EGT and AFR or is it a complex function? Is this a practical/effective/reliable way to adjust mixture? Is it only useful at WOT, or does it maintain some validity at all throttle settings? What other factors affect EGT? regards dn - -- - --------------------------------------------------------------------- Darrell A. Norquay Internet: dn@xxx.ca Datalog Technology Inc. Bang: calgary!debug!dlogtech!darrell Calgary, Alberta, Canada Voice: +1 (403) 243-2220 Fax: +1 (403) 243-2872 @ + < __/ "Absolutum Obsoletum" - If it works, it's obsolete -------------------------------------------------------------------- ------------------------------ From: "Th.M.Boehm" Date: Tue, 12 Mar 1996 08:28:40 MET-1 Subject: Suzuki Swift GTi Twincam 1.3 (87) I'm not into engine modification at all ,and I know this mail-list is a lot more hitech than I am. When that's said, I was just wondering if anybody has got some tips of parts (I've read about chiptuning!) I can easily modify or replace (Also the shops who supply them (I live in Europe)). If it demands special knowledge please tell me, or I'll probably ruin my engine. Thomas. ------------------------------ From: Mark Boxsell Date: Tue, 12 Mar 96 17:42:54 +1000 (EST) Subject: Re: volumetric efficiency At 05:58 PM 11/03/96 +0100, you wrote: > >How can vol. eff. be greater than 1? > >Mattias Nyberg > Mattias, most good racing engines would typically see 120% over a limited RPM range. regards, Mark Boxsell MRB Design. ------------------------------ End of DIY_EFI Digest V1 #74 **************************** 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".