DIY_EFI Digest Wednesday, 20 November 1996 Volume 01 : Number 351 In this issue: Re: O2 Sensor Open/Close Loop Re: MACHINE DESIGN magazine? Air Flow Measurement Re: ALDL info Re: Air Flow Measurement Re: O2 Sensor Open/Close Loop Re: Air Flow Measurement Re: Air Flow Measurement RE: Air Flow Measurement RE: Air Flow Measurement Re: Air Flow Measurement Re: Air Flow Measurement RE: Air Flow Measurement Re: Air Flow Measurement RE: Air Flow Measurement Re: Air Flow Measurement Lambda Readings Re: Air Flow Measurement Re: Air Flow Measurement Re: Lambda Readings Re: Air Flow Measurement Re: Lambda Readings Re: Lambda Readings Re: Lambda Readings Digital D-Jetronic Replacement Air Flow Measurement - Formula 1 Re: Lambda Readings See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: tiw3edan@xxx.de (Eduard Anna) Date: Tue, 19 Nov 1996 13:05:11 +0100 (MET) Subject: Re: O2 Sensor Open/Close Loop > Care to share any of that hard earnd protocol you worked out? I still got > dreams of using a PC, windows operating env., and ALDL data to create > virtual instrument display. > > GMD > > At 07:54 PM 11/12/96 -0800, you wrote: > > > I have been meaning to make a decent scan tool to watch the O2 controller > > at work in the ECM under actual driving conditions. I have completely > > worked out GM ALDL protocol, but am not really a programmer. :-( This > > makes it hard to build a scan tool. > > > > > > Scot Sealander Sealand@xxx.com > > I am also interested in the GM ALDL protocol. I want to build a scan tool, but i have not been able to get any Information about the ALDL protocol, or the specs here in europe (Germany). If I manage to build a scan tool I will share it with you. Eduard Anna tiw3edan@xxx.de ------------------------------ From: "Michael D. Porter" Date: Tue, 19 Nov 1996 08:56:51 -0800 Subject: Re: MACHINE DESIGN magazine? Walter Kaufmann wrote: > > Does anyone know where in Europe I can get the MACHINE DESIGN magazine? Walter, "Machine Design" is a trade publication, and is generally only sent to people with a business address. And, I suspect, its circulation is probably limited to free mailings in the US. They probably have paid subscriptions for outside the US, but likely still to a business address. If you are just looking for an occasional read, why not try calling your area libraries to see if they include it in their periodicals? - -- My other Triumph doesn't run, either.... ------------------------------ From: Robert McElroy Date: Tue, 19 Nov 1996 09:33:06 -0600 Subject: Air Flow Measurement What methods have been used to measure intake air flow other than the = heated-wire sensor and the Bosch air-flap (that silly door thingy just = ahead of the throttle plates.) Specifically, I am wondering if anyone has looked into using a = differential-pressure manometer to calculate air flow. This manometer = could be located in the same location as GM puts its heated-wire = mass-air-flow sensor. Any thoughts/comments? (FYI - Air flow could be calculated from a differential pressure = manometer by measuring air pressure in an appropriately sized (perhaps 4 = inch dia.) venturi located before the throttle plates. Air velocity = through the venturi throat is related to the difference in pressure = between the venturi throat and the pressure before the venturi. Air = velocity is thus used (along with air temperature) to determine total = air mass flowing into the intake system.) Bob McElroy ------------------------------ From: Jody Shapiro Date: Tue, 19 Nov 1996 11:00:47 -0500 (EST) Subject: Re: ALDL info > > Care to share any of that hard earnd protocol you worked out? I still got > > dreams of using a PC, windows operating env., and ALDL data to create > > virtual instrument display. > > > > GMD > > > > At 07:54 PM 11/12/96 -0800, you wrote: > > > > > I have been meaning to make a decent scan tool to watch the O2 controller > > > at work in the ECM under actual driving conditions. I have completely > > > worked out GM ALDL protocol, but am not really a programmer. :-( This > > > makes it hard to build a scan tool. > > > > > > > > > Scot Sealander Sealand@xxx.com > > I am also interested in the GM ALDL protocol. > I want to build a scan tool, but i have not been able to get any Information > about the ALDL protocol, or the specs here in europe (Germany). > If I manage to build a scan tool I will share it with you. > > Eduard Anna tiw3edan@xxx.de Check out: http://www.dcc.edu/vettenet/aldl.txt ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Tue, 19 Nov 1996 11:12:21 -0600 Subject: Re: Air Flow Measurement > What methods have been used to measure intake air flow other than the heated-wire sensor and the Bosch air-flap (that silly door thingy just ahead of the throttle plates.) > > Specifically, I am wondering if anyone has looked into using a differential-pressure manometer to calculate air flow. This manometer could be located in the same location as GM puts its heated-wire mass-air-flow sensor. Any thoughts/comments? > >(FYI - Air flow could be calculated from a differential pressure manometer by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) venturi located before the throttle plates. Air velocity through the venturi throat is related to the difference in pressure between the venturi throat and the pressure before the venturi. Air velocity is thus used (along with air temperature) to determine total air mass flowing into the intake system.) > >Bob McElroy My long-standing question -- precisely ...... 'cept I think I've one-upped you (?? tell me what's wrong with this concept ??). If you know BAP and MAP, you know delta-P across opening -- granted, the opening size varies with throttle position, but you've got TPS for that -- seems that air flow could be rather accurately determined without much hassle????? Tom Cloud ------------------------------ From: MikeTurner@xxx.com (Mike Turner) Date: Tue, 19 Nov 1996 12:49:15 -0500 Subject: Re: O2 Sensor Open/Close Loop From: Eduard Anna @ INTERNET Date: 96/11/19 08:47:08 Subject: Re: O2 Sensor Open/Close Loop > Care to share any of that hard earnd protocol you worked out? I still got > dreams of using a PC, windows operating env., and ALDL data to create > virtual instrument display. > > GMD > > At 07:54 PM 11/12/96 -0800, you wrote: > > > I have been meaning to make a decent scan tool to watch the O2 controller > > at work in the ECM under actual driving conditions. I have completely > > worked out GM ALDL protocol, but am not really a programmer. :-( This > > makes it hard to build a scan tool. > > > > > > Scot Sealander Sealand@xxx.com > > I am also interested in the GM ALDL protocol. I want to build a scan tool, but i have not been able to get any Information about the ALDL protocol, or the specs here in europe (Germany). If I manage to build a scan tool I will share it with you. Eduard Anna tiw3edan@xxx.de I believe Gordon Killibrew (sp?) has a manual that sheds a lot of light on ALDL. Gordon specializes in late model Corvette stuff. ------------------------------ From: kleenair@xxx.com Date: Tue, 19 Nov 1996 13:00:12 -0800 Subject: Re: Air Flow Measurement Robert McElroy wrote: > > What methods have been used to measure intake air flow other than the heated-wire sensor and the Bosch air-flap (that silly door thingy just ahead of t > > Specifically, I am wondering if anyone has looked into using a differential-pressure manometer to calculate air flow. This manometer could be located > > (FYI - Air flow could be calculated from a differential pressure manometer by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) venturi lo > > Bob McElroyThis is achievable, the only problem is any restriction in the air intake reduces peak air flow to the engine, so its not the best method for power. I have some experience with venture based gasous fuel systems which work on a pressure differential principle. I don't know what size engine you have in mind, but for anything smaller than a small block V8, a four inch venture may be too big to register any meaningful data at idle and light load. M. Ebrahimi ------------------------------ From: kleenair@xxx.com Date: Tue, 19 Nov 1996 13:11:28 -0800 Subject: Re: Air Flow Measurement > > My long-standing question -- precisely ...... 'cept I think I've > one-upped you (?? tell me what's wrong with this concept ??). > > If you know BAP and MAP, you know delta-P across opening -- granted, > the opening size varies with throttle position, but you've got TPS > for that -- seems that air flow could be rather accurately determined > without much hassle????? > > Tom Cloud This method actually works pretty good. In fact, for throttle body injected applications, it is theoredically better than a MAP sensor measurement for transient fueling reasons. But neither the MAP / RPM / IAT (speed density) nor TPS / RPM / IAT method are as accurate in measuring air flow as a mass air flow system. I have read an SAE paper on using TPS for air flow, although the purpose of the paper was to improve on transient fueling calculations currently used. The only problem with applying this to a stock fuel injected car is of course the IAC motor which bypasses the throttle blades (in most cases). By the way, don't ask me what the SAE paper number was, cause I don't have it and I can't remember. Mmmmm I'm starting to sound like a politician! ------------------------------ From: Anthony Tsakiris Date: Tue, 19 Nov 1996 13:46:02 -0500 Subject: RE: Air Flow Measurement > Specifically, I am wondering if anyone has looked into using a differential-pressure manometer to calculate air flow. This manometer could be located in the same location as GM puts its heated-wire mass-air-flow sensor. Any thoughts/comments? >(FYI - Air flow could be calculated from a differential pressure manometer by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) venturi located before the throttle plates. Air velocity through the venturi throat is related to the difference in pressure between the venturi throat and the pressure before the venturi. Air velocity is thus used (along with air temperature) to determine total air mass flowing into the intake system.) You still need a measure of density to determine mass flow rate, even if you know the begin 600 WINMAIL.DAT M>)\^(@,2`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <` M& ```$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V ! `"`````@`"``$$ MD 8`9 $```$````,`````P``, (````+``\.``````(!_P\!````8P`````` M``"!*Q^DOJ,0&9UN`-T!#U0"`````&1I>5]E9FE 8V]U;&]M8BYE;F``(P`0````4```!33510`````!X``S !````(P```&1I>5]E M9FE 8V]U;&]M8BYE;F``$P`0```"4````G9&EY7V5F:4!C;W5L;VUB+F5N9RYO:&EO+7-T871E M+F5D=2<``````@$+, $````H````4TU44#I$25E?149)0$-/54Q/34(N14Y' M+D](24\M4U1!5$4N1415``,``#D`````"P! .@$````"`?8/`0````0````` M```"VDT!!( !`!D```!213H@06ER($9L;W<@365A`' ``0```!D```!213H@06ER($9L;W<@ M365AG&SO-P*D(3$="=:P`@ MK],$! ``'@`># $````%````4TU44 `````>`!\,`0```!P```!A='-A:VER M:4!P;V)O>"YSL"@P!0$P-4`@!C: K RW0*#,P/&!Q,"@xxx.!N M9S$P,Q60"PH6P>!S,3@@/@M&%9(,`7D3H&]T!9 %00&1!@!P$P60!I!I8P= M;'DL@"!)(&%M('<"(#,$@0N 9R &D!^ ;GDY`B!E(!' !" 9`&]KQPF (% " M,&\@=0"0(#%H82!D!I!F!) )\'3M!S$M$Z 'D',(<"#@`X&?`W 2`!3A(=$? M`6-U"V ;'? ?@&D%P!KP;W!*@`LD@-@ M+.$H(SIV/"+_)1 @4 0@&7 S!"'1*#(BALYC-U,TIR=0='<)X3Z/_S^1`'! M42A!0 Date: Tue, 19 Nov 1996 14:20:52 -0500 Subject: RE: Air Flow Measurement >>(FYI - Air flow could be calculated from a differential pressure manometer by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) venturi located before the throttle plates. Air velocity through the venturi throat is related to the difference in pressure between the venturi throat and the pressure before the venturi. Air velocity is thus used (along with air temperature) to determine total air mass flowing into the intake system.) If you knew velocity and area, you could calculate volumetric flow rate. This assumes that average velocity measure you have adequate represents the real velocity profile over the area. You still to know density to determine mass flow rate. >If you know BAP and MAP, you know delta-P across opening -- granted, the opening size varies with throttle position, but you've got TPS for that -- seems that air flow could be rather accurately determined without much hassle????? OK, now you've added barometric pressure (and you had temperature above), so you can figure out ambient air density. And you're transforming throttle angle to area, so presumably you can get mass flow rate. (Assumption: flow coefficient of throttle (or orifice for that matter) is known.) But is it any less of a hassle than using a MAF sensor? I don't see a huge advantage of one system over the other. Anthony Tsakiris begin 600 WINMAIL.DAT M>)\^(C83`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <` M& ```$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V ! `"`````@`"``$$ MD 8`9 $```$````,`````P``, (````+``\.``````(!_P\!````8P`````` M``"!*Q^DOJ,0&9UN`-T!#U0"`````&1I>5]E9FE 8V]U;&]M8BYE;F``(P`0````4```!33510`````!X``S !````(P```&1I>5]E M9FE 8V]U;&]M8BYE;F``$P`0```"4````G9&EY7V5F:4!C;W5L;VUB+F5N9RYO:&EO+7-T871E M+F5D=2<``````@$+, $````H````4TU44#I$25E?149)0$-/54Q/34(N14Y' M+D](24\M4U1!5$4N1415``,``#D`````"P! .@$````"`?8/`0````0````` M```"VDT!!( !`!D```!213H@06ER($9L;W<@365A`' ``0```!D```!213H@06ER($9L;W<@ M365AE0-9A,4(]$="=:P`@ MK],$! ``'@`># $````%````4TU44 `````>`!\,`0```!P```!A='-A:VER M:4!P;V)O>"YSL"@P!0$P-4`@!C: K T2'7]PN (- E$7 = MP130!S =\)9L(W `D'H@82AP!)!U$""& %0+QM=2=Q$< $$"IP/V(2\U",&]U/2T&03@):U4AP_PVP'Y$*P"*2 M0\(AUS<0,L&_1^0VEC@9(- &X"A@*4&0WG,NT$&S`Y%+8&`#T``0````4```!213H@``````,`#33]-P```];6 ` end ------------------------------ From: kleenair@xxx.com Date: Tue, 19 Nov 1996 14:11:50 -0800 Subject: Re: Air Flow Measurement Anthony Tsakiris wrote: > > > Specifically, I am wondering if anyone has looked into using a > differential-pressure manometer to calculate air flow. This manometer > could be located in the same location as GM puts its heated-wire > mass-air-flow sensor. Any thoughts/comments? > > >(FYI - Air flow could be calculated from a differential pressure manometer > by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) > venturi located before the throttle plates. Air velocity through the > venturi throat is related to the difference in pressure between the venturi > throat and the pressure before the venturi. Air velocity is thus used > (along with air temperature) to determine total air mass flowing into the > intake system.) > > You still need a measure of density to determine mass flow rate, even > if you know the > > begin 600 WINMAIL.DAT > M>)\^(@,2`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <` > M& ```$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V ! `"`````@`"``$$ > MD 8`9 $```$````,`````P``, (````+``\.``````(!_P\!````8P`````` > M``"!*Q^DOJ,0&9UN`-T!#U0"`````&1I>5]E9FE 8V]U;&]M8BYE;F M;RUS=&%T92YE9'4`4TU44 !D:7E?969I0&-O=6QO;6(N96YG+F]H:6\M M=&4N961U```>``(P`0````4```!33510`````!X``S !````(P```&1I>5]E > M9FE 8V]U;&]M8BYE;F M```>``$P`0```"4````G9&EY7V5F:4!C;W5L;VUB+F5N9RYO:&EO+7-T871E > M+F5D=2<``````@$+, $````H````4TU44#I$25E?149)0$-/54Q/34(N14Y' > M+D](24\M4U1!5$4N1415``,``#D`````"P! .@$````"`?8/`0````0````` > M```"VDT!!( !`!D```!213H@06ER($9L;W<@365A M``X```#,!PL`$P`-`"X``@xxx.````S <+`!,`#0`L`"X``@!: > M`0$)@xxx.X& > M`0.0!@!L! ``% ````L`(P```````P`F```````+`"D```````,`+@`````` > M`P`V``````! `#D`X$C)Z4G6NP$>`' ``0```!D```!213H@06ER($9L;W<@ > M365AG&SO-P*D(3$="=:P`@ > MK],$! ``'@`># $````%````4TU44 `````>`!\,`0```!P```!A='-A:VER > M:4!P;V)O>"YS M90```%-014-)1DE#04Q,62Q)04U73TY$15))3D=)1D%.64].14A!4TQ/3TM% > M1$E.5$]54TE.1T%$249&15)%3E1)04PM4%)%4U-54D5-04Y/345415)43T-! > M3$-53$%414%)4D9,3U<``````@$)$ $```#5`@``T0(``*D$``!,6D9U&O'F > M??\`"@$/`A4"I /D!>L"@P!0$P-4`@!C: K MRW0*#,P/&!Q,"@xxx.!N > M9S$P,Q60"PH6P>!S,3@@/@M&%9(,`7D3H&]T!9 %00&1!@!P$P60!I!I8P= > M;'DL@"!)(&%M('<"(#,$@0N 9R &D!^ ;GDY`B!E(!' !" 9`&]KQPF (% " > M,&\@=0"0(#%H82!D!I!F!) )\'3M!S$M$Z 'D',(<"#@`X&?`W 2`!3A(=$? > M`6-U"V ;'? ?@&D%P!KP;W M)'#::"#@ M42TEDBA@"?!S!;"=)=%!(* H(0A@9V@IT)HO!:!M!X ",',_"H6/"H<;_QT/ > M'A$H1ED? M* $#D6%P'<$3H$\',!WP'S H8&EZ(8$HU1Z@ M=B+A"'%_)W!*@`LD@-@ > M+.$H(SIV/"+_)1 @4 0@&7 S!"'1*#(BALYC-U,TIR=0='<)X3Z/_S^1`'! > M42A!0 M.E AT0VP)$%M"X [P1W@xxx.D M > MWM\+&1U4+CX2\2]B60A@*&#[(P`?(" @T"&!(F V!"#@_F\@< VP`($]XDGJ > M2T<_X/LE$1]093IQ3@4@82"P43"^:R0`!^ H,DX%&)$`5X ````#`! 0`0`` > M``,`$1 `````0 `',%!$N+Q)UKL!0 `(,%!$N+Q)UKL!'@`]``$````%```` > 24D4Z( `````#``TT_3<``&@[ > ` > end Can someone guide me to descramble this? ------------------------------ From: Thor Johnson Date: Tue, 19 Nov 1996 15:24:22 -0500 (EST) Subject: Re: Air Flow Measurement On Tue, 19 Nov 1996 kleenair@xxx.com wrote: > > > > My long-standing question -- precisely ...... 'cept I think I've > > one-upped you (?? tell me what's wrong with this concept ??). > > > > If you know BAP and MAP, you know delta-P across opening -- granted, > > the opening size varies with throttle position, but you've got TPS > > for that -- seems that air flow could be rather accurately determined > > without much hassle????? > > This method actually works pretty good. In fact, for throttle body injected applications, it is theoredically > better than a MAP sensor measurement for transient fueling reasons. But neither the MAP / RPM / IAT (speed > density) nor TPS / RPM / IAT method are as accurate in measuring air flow as a mass air flow system. I have > read an SAE paper on using TPS for air flow, although the purpose of the paper was to improve on transient > fueling calculations currently used. The only problem with applying this to a stock fuel injected car is of > course the IAC motor which bypasses the throttle blades (in most cases). What's wrong with speed-density? And what exactly do you do to it? I thought it was just found by Air=K*MAP*RPM (where K is a magic constant), but I'm naive. Am I going to get into trouble using this? Thor Johnson johnsont@xxx.edu http://falcon.mercer.peachnet.edu/~johnsont Have you seen the WarpMap lately? http://falcon.mercer.peachnet.edu/~johnsont/warpmap ------------------------------ From: Anthony Tsakiris Date: Tue, 19 Nov 1996 15:38:35 -0500 Subject: RE: Air Flow Measurement >You still need a measure of density to determine mass flow rate, even >if you know the Sorry about the incomplete message. Let me try once more. Knowing velocity and area allows the determination of volumetric flow rate. (This assumes the velocity measurement adequately represents the real velocity profile over the entire flow area.) Density must still be known to determine mass flow rate. Density can be determined if barometric pressure and temperature are know. At this point though, is it any less of a hassle than a MAF sensor? (Again, sorry for the lack of context. I'm completely underwhelmed by Microsoft Exchanges abilities.) Anthony Tsakiris ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Tue, 19 Nov 1996 14:42:19 -0600 Subject: Re: Air Flow Measurement the MAP / RPM / IAT (speed >density) nor TPS / RPM / IAT method are as accurate in measuring air flow as a mass air flow system. I have [ snip ] what's IAT ? Tom Cloud ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Tue, 19 Nov 1996 14:46:56 -0600 Subject: RE: Air Flow Measurement >> Specifically, I am wondering if anyone has looked into using a >differential-pressure manometer to calculate air flow. This manometer >could be located in the same location as GM puts its heated-wire >mass-air-flow sensor. Any thoughts/comments? > >>(FYI - Air flow could be calculated from a differential pressure manometer >by measuring air pressure in an appropriately sized (perhaps 4 inch dia.) >venturi located before the throttle plates. Air velocity through the >venturi throat is related to the difference in pressure between the venturi >throat and the pressure before the venturi. Air velocity is thus used >(along with air temperature) to determine total air mass flowing into the >intake system.) > > >You still need a measure of density to determine mass flow rate, even >if you know the > >begin 600 WINMAIL.DAT >M>)\^(@,2`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <` >M& ```$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V ! `"`````@`"``$$ >MD 8`9 $```$````,`````P``, (````+``\.``````(!_P\!````8P`````` Anthony, can't you speak English ? I'd like to read this ... it's like watching 'X' files and having it TO BE CONTINUED !! Tom Cloud ------------------------------ From: kleenair@xxx.com Date: Tue, 19 Nov 1996 15:50:43 -0800 Subject: Re: Air Flow Measurement Thor Johnson wrote: > What's wrong with speed-density? And what exactly do you do to it? I > thought it was just found by Air=K*MAP*RPM (where K is a magic constant), > but I'm naive. Am I going to get into trouble using this? There is nothing wrong with speed-density, especially if you are not worried about emissions certification. But I don't know if K can be a magic CONSTANT. Generally there is a volumetric efficiency table that is a function of MAP and RPM, which gives you the percentage of maximum static air flow calculation, which is Displacement * RPM /2 * units correction factor. The throttle position input, along with MAP and BAP can be used for air flow measurement also, and its also a good way to verify if either TPS or MAP sensor readings as a diagnostics method. ------------------------------ From: Doug Robson Date: Wed, 20 Nov 1996 08:51:32 +1100 Subject: Lambda Readings Hi All is the relationship between lambda and A/F always 14.7 or is there some sort of relationship, because on the weekend i adjusted the fuel table in my race car down fro L.95 to L.9 and it felt like a 10% power drop ?? also does the 4 wire Heated ($350) sensor do the temp correction or does the ecu do it - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson (H) mailto:doug@xxx.au | | (W) mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ From: Carl Haas Date: Tue, 19 Nov 1996 18:09:04 -0500 (EST) Subject: Re: Air Flow Measurement On Tue, 19 Nov 1996, tom cloud wrote: > > If you know BAP and MAP, you know delta-P across opening -- granted, > the opening size varies with throttle position, but you've got TPS > for that -- seems that air flow could be rather accurately determined > without much hassle????? > > > Tom Cloud > I like how you think... Would any corrction be needed for density? If so, is there such a thing as an electronic air-density sensor to use as a running correction factor? Carl Haas ------------------------------ From: Mazda Ebrahimi Date: Tue, 19 Nov 1996 18:05:17 -0500 Subject: Re: Air Flow Measurement tom cloud wrote: > > the MAP / RPM / IAT (speed > >density) nor TPS / RPM / IAT method are as accurate in measuring air flow > as a mass air flow system. I have > > [ snip ] > > what's IAT ? > > Tom Cloud Date: Tue, 19 Nov 1996 18:17:44 -0500 Subject: Re: Lambda Readings Doug Robson wrote: > > Hi All > is the relationship between lambda and A/F always 14.7 or is there some > sort of relationship, because on the weekend i adjusted the fuel table > in my race car down fro L.95 to L.9 and it felt like a 10% power drop > > ?? > > also does the 4 wire Heated ($350) sensor do the temp correction or does > the ecu do it > 14.7 only produces good power if you have excellent air / fuel mixing. As others have commented, theoredically you should get more power going slightly rich, because the vaporization of the extra gasoline should cool the charge down. Here are a couple of questions that come to mind: Does the system currently run open loop? If so, when you have A/F set to 14.7, have you verified stoichiometric operation by monitoring an O2 sensor or CO reading? Maybe the problem is that in case of the open loop system there is an inherent error in the air mass calculation. How sure are you about your A/F cylinder to cylinder? ------------------------------ From: Mazda Ebrahimi Date: Tue, 19 Nov 1996 18:21:07 -0500 Subject: Re: Air Flow Measurement Carl Haas wrote: > > > > On Tue, 19 Nov 1996, tom cloud wrote: > > > > > If you know BAP and MAP, you know delta-P across opening -- granted, > > the opening size varies with throttle position, but you've got TPS > > for that -- seems that air flow could be rather accurately determined > > without much hassle????? > > > > > > Tom Cloud > > > > I like how you think... > > Would any corrction be needed for density? If so, is there such a thing > as an electronic air-density sensor to use as a running correction > factor? > > Carl HaasThat is what intake air temperature is used for. Also, if you are going to use this approach, you may want to be careful about the location of the MAP sensor take-off. It is important (especially with large intake plenums) to have the take-off near the throttle body not in the back of the manifold. This makes a difference in transient response of the system because of the intake manifold filling time during a snap throttle condition. ------------------------------ From: Doug Robson Date: Wed, 20 Nov 1996 11:47:59 +1100 Subject: Re: Lambda Readings Mazda Ebrahimi wrote: > > Doug Robson wrote: > > > > Hi All > > is the relationship between lambda and A/F always 14.7 or is there some > > sort of relationship, because on the weekend i adjusted the fuel table > > in my race car down fro L.95 to L.9 and it felt like a 10% power drop > > > > ?? > > > > also does the 4 wire Heated ($350) sensor do the temp correction or does > > the ecu do it > > > > 14.7 only produces good power if you have excellent air / fuel mixing. As others have > commented, theoredically you should get more power going slightly rich, because the > vaporization of the extra gasoline should cool the charge down. Here are a couple of > questions that come to mind: > Does the system currently run open loop? If so, when you have A/F set to 14.7, > have you verified stoichiometric operation by monitoring an O2 sensor or CO reading? > Maybe the problem is that in case of the open loop system there is an inherent error in > the air mass calculation. > > How sure are you about your A/F cylinder to cylinder? Now im really confused My lambda number comes from Autronic SMC ecu the program allows users to choose A/F type input or O2 exhaust input. the out put is always a number like A/F 12-15 ish. and i divide mine by 14.7 I cant gaurantee the individual a/f except to say that the plugs all look very similiar The same sensor ( literally) is used by a friend in a mote m4pro system and works fine it sits 1 foot after 4 -2 1 collector how do i verify the a/f on the way in?? is that what you mean regards - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson (H) mailto:doug@xxx.au | | (W) mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ From: Frank F Parker Date: Tue, 19 Nov 1996 20:34:56 -0500 (EST) Subject: Re: Lambda Readings > Hi All > is the relationship between lambda and A/F always 14.7 or is there some > sort of relationship, because on the weekend i adjusted the fuel table > in my race car down fro L.95 to L.9 and it felt like a 10% power drop I believe it normally 14.7 but Ford controls at 14.62 and others could be different.> > > also does the 4 wire Heated ($350) sensor do the temp correction or does > the ecu do it > Depends on what sensor you are talking about. The Bosch LSM-11 when used with a Motec cpu can control wot rich a/f ratios. The temp correction is in the Motec cal when you get that option. No other fi cpu I know of can do this. Frank Parker ------------------------------ From: Mazda Ebrahimi Date: Tue, 19 Nov 1996 20:49:14 -0500 Subject: Re: Lambda Readings Doug Robson wrote: > > Mazda Ebrahimi wrote: > > > > Doug Robson wrote: > > > > > > Hi All > > > is the relationship between lambda and A/F always 14.7 or is there some > > > sort of relationship, because on the weekend i adjusted the fuel table > > > in my race car down fro L.95 to L.9 and it felt like a 10% power drop > > > > > > ?? > > > > > > also does the 4 wire Heated ($350) sensor do the temp correction or does > > > the ecu do it > > > > > > > 14.7 only produces good power if you have excellent air / fuel mixing. As others have > > commented, theoredically you should get more power going slightly rich, because the > > vaporization of the extra gasoline should cool the charge down. Here are a couple of > > questions that come to mind: > > Does the system currently run open loop? If so, when you have A/F set to 14.7, > > have you verified stoichiometric operation by monitoring an O2 sensor or CO reading? > > Maybe the problem is that in case of the open loop system there is an inherent error in > > the air mass calculation. > > > > How sure are you about your A/F cylinder to cylinder? > > Now im really confused > My lambda number comes from Autronic SMC ecu > the program allows users to choose A/F type input or O2 exhaust input. > the out put is always a number like A/F 12-15 ish. and i divide mine by > 14.7 > > I cant gaurantee the individual a/f except to say that the plugs all > look very similiar > The same sensor ( literally) is used by a friend in a mote m4pro system > and works fine > > it sits 1 foot after 4 -2 1 collector > > how do i verify the a/f on the way in?? is that what you mean > > regards > That is what I mean. I wasn't sure if you had an O2 sensor on the engine or not. If you can monitor the O2 sensor, and it reads between .4 to .5 volts while your indicated A/F is 14.7, then the indicated A/F is correct (as verified by the O2 sensor), so that is not your problem. Since your spark plugs are good, then you shouldn't have a MAJOR distribution problem. If nothing else has changed, you should have made slightly more power at A/F = .9*14.7 = 13.2, although I don't know how much "slightly" is. I think that depends on your specific fuel system (i.e. type and location of your injectors) and how well fuel is atomized. I know others reading this disagree. Anyway, if you have good distribution (probably the best way to check is to measure exhaust temps or exhaust CO cylinder to cylinder), you should experiment with A/F to get max power. I don't think the numbers people generally throw around (like 12:1 for peak power) are set in stone. But before you take my advise too seriously, I should caution you that I have little experience with gasoline (most of my work is involved in natural gas and propane engines). It'll be interesting to see what other explanations there are for a power loss at Lambda =.9 compared to Lambda = 1! Best Regards M. Ebrahimi ------------------------------ From: "David C. Carlson" Date: Tue, 19 Nov 1996 19:54:27 -0600 Subject: Digital D-Jetronic Replacement I am considering designing a system for upgrading D-Jetronic systems. The original manifolds, injectors, temperature sensors, and throttle body will be maintained. The throttle switch, presssure sensor, and the ECM will be replaced. Electronic ignition will also be part of the package. This upgrade is intended for Porsche 914's and type 3 VW's. It will be able to accomodate engine modifications and be PC configurable. If anyone has an interest in this upgrade please e-mail. ------------------------------ From: "Jeff Bailey (Exchange)" Date: Tue, 19 Nov 1996 18:01:45 -0800 Subject: Air Flow Measurement - Formula 1 On a related note, how do the Formula 1 guys measure air flow? From pictures of their engines they don't seem to have any hot wires or anything. I would guess that they are just using Throttle position, RPM, and air temp. jeff ------------------------------ From: Doug Robson Date: Wed, 20 Nov 1996 14:21:39 +1100 Subject: Re: Lambda Readings Frank F Parker wrote: > > > Hi All > > is the relationship between lambda and A/F always 14.7 or is there some > > sort of relationship, because on the weekend i adjusted the fuel table > > in my race car down fro L.95 to L.9 and it felt like a 10% power drop > > I believe it normally 14.7 but Ford controls at 14.62 and others could > be different.> > > > > > also does the 4 wire Heated ($350) sensor do the temp correction or does > > the ecu do it > > > Depends on what sensor you are talking about. The Bosch LSM-11 when used > with a Motec cpu can control wot rich a/f ratios. The temp correction > is in the Motec cal when you get that option. No other fi cpu I know of > can do this. > > Frank Parker thanks frank but how does the motec cpu know the exhaust temp to make the alteration - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson (H) mailto:doug@xxx.au | | (W) mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ End of DIY_EFI Digest V1 #351 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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