DIY_EFI Digest Wednesday, March 8 2000 Volume 05 : Number 090 In this issue: Re: AFM measurement/backpressure (was Turbo speed sensor) DIY-EFI References FI question Re: DIY_EFI Digest V5 #89 Re: Crank angle sensor Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: Crank angle sensor Re: FI question Re: Subaru TBI Re: Subaru TBI Re: Turbo throttles (was Re: anti-lag) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 07 Mar 2000 21:34:56 -0800 From: clayb Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) nacelp wrote: > Compared to what Mechanical, FI, Carbbies?. Carbs. And I'm well aware of the fine points of carb and distributor tuning. > > Sweeping statements are often wrong. > AFM are probably the least accurate of the air flow sensors, or at least the > most restrictive. > In the archives at the GN Ttype there are statements from actual dyno > testing where even a MAF sensor cost 30HP. ??? I thought we all knew that throwing something in the airstream was restrictive. Speed density and turbos are like peanut butter and jelly. I did not mean to imply it was necessary to measure exhaust backpressure, just that the effects of good engine management are somewhat more noticeable on a turbo motor. > > An SU and electonic ignition control (far a small engine) would be hard to > beat when set up right. Webers come close to IR, and a blow thru IR vs > Weber would be within tenths of a percentage, I'd wager. > VE, and HP well there is alot for who's doing the tuning. Just really about > dry walls vs wet, and reelated issues. > Now drivibility, tunability, reliability, emissions are all other matters. > But, to claim EFI is that "secret to HP + VE" or especially good for turbos, > is kinda stretching a point, IMHO. > I notice noone has mentioned cross over so far. And that opens the doors > for all kinds of things. Compared to old technology, the wider and more varied timing and fuel curve requirements of a turbo motor are much more effectively addressed with EFI. Sure, this is true for NA, but not to the same extent. NA motors generally (here we go...) make similar horsepower carbed or EFI. Turbo motors can be run closer to that dangerous edge of mixture and timing. The shape of the timing and fuel curves (especially timing) don't match what old tech delivers. For NA motors, the approximation is much closer. I never claimed EFI is the "secret to HP + VE". It is, however, a bigger improvement to a turbo motor, than an NA motor. - - Clay - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Tue, 07 Mar 2000 22:29:39 -0600 From: Ken & Rae Bauman <303print@xxx.net> Subject: DIY-EFI References Hello, I came across your email on the DIY EFI list and wonder if you can point me in the right direction? I'm trying to find out more information on a GM Powertrain MPFI ECM. Unfortunately their website has no contact info. Specifically I wonder where to find information on its configurability for use on a 4 cyl DIS setup with preferably coil per cylinder. Anyway if you have some familiarity with this setup I would appreciate hearing about it. Thanks Ken Bauman - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 00:02:56 -0600 From: "John C." Subject: FI question This is a multi-part message in MIME format. - ------=_NextPart_000_0189_01BF8891.A88531C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi this isnt really diy efi but was wondering if anyone has ANY = experience or opinion about the speed pro/FP performance bank to bank FI = system with the wideband o2 option. I am thinking about using that on a = twin turbo V8 mopar I am build for the street and strip.... Thanks John C. - ------=_NextPart_000_0189_01BF8891.A88531C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi this isnt really diy efi but was = wondering if=20 anyone has ANY experience or opinion about the speed pro/FP = performance=20 bank to bank FI system with the wideband o2 option. I am thinking about = using=20 that on a twin turbo V8 mopar I am build for the street and=20 strip....
 
Thanks
John C.
- ------=_NextPart_000_0189_01BF8891.A88531C0-- - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 14:23:34 +0800 From: dzorde@xxx.com Subject: Re: DIY_EFI Digest V5 #89 Thanks all who replied, I suspected it was P/H style injector. I'll and have a look at the 332 driver board circuit. The use of the resistor still has me wondering though, Nissan (I think) used to have resistors in series with the injectors, were they low impedance injectors ? What value was the resistor (5R, 10R) ? Dan dzorde@xxx.com >Date: Tue, 7 Mar 2000 06:12:07 -0800 >From: "John Dammeyer" >Subject: Re: Subaru TBI > > >Yikes! or How to screw up an injector in one easy pulse. > >This is a PeakHold type injector. 13.8V / 1.6 Ohms is almost 9 Amps. Injectors normally >don't take more than about 1A. You have a choice on how to drive a PH injector. You can >place a Ballast resistor in series to limit the current to about 1A. This has the effect >of driving the injector hard until the current through the resistor is high enough to >reduce the voltage across the injector and therefore limit the current. You still end up >with a fast turn on time. Alternatively you can use a PH type injector driver or a >circuit with a comparator and a current sensing resistor (0.1 Ohm) that reduces the >current once it reaches 1A or a timer based driver that reduces the current after n >microseconds which is equivalent to the time it takes for the injector current to reach >1A. > >Only if the injector resistance is around 12 Ohms can you apply 12 volts directly to it. > >John Dammeyer - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 14:58:33 From: "Mike (Perth, WA)" Subject: Re: Crank angle sensor At 08:13 PM 7/03/2000 -0800, you wrote: >What do you mean by "four wire" ignition? A distributorless module (like >Ford EDIS, and other OEM units) that drives 2, 3 or 4 coils? You should >be ready to go. Generally, this module will directly accept cam pos to >sync the firing order to a crank trigger, which you already have. > >I don't believe the DFI does the "low voltage distributor" function, and >you've not described if you have this component already. For what its worth, over here in Perth, Western Australia there are many jap cars which have a 4 wire crank angle sensor made by Hitachi or Mitsubishi and for the most part (as far as I can see) are compatible. Wires are (not sure of actual order though) :- 1. Power (+12v) 2. 1 degree pulse (actually 1/2 degree ON, 1/2 degree OFF) 3. 120 degree pulse of same width as in 2 above but with an extra wide pulse at the TDC position - about 3 deg wide. (A small piece of hardware can generate a TDC reset as the 120deg pulse at this point only straddles the 1 degree pulse, whereas on other 120 degree points its the same width but coincident. 4. Ground My original unit (hitachi) output change of state regardless of rotation speed, the other from a jap import wrecker only supply output pulses at a minimum speed of around 100rpm - naturally both work in my car *but* the latest needs to be turned around by about 120 degrees as the ref mark on the teeth is in a different position - must suit a different model but works fine in my car with correct timing and block where one tightens it etc... Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 15:11:06 From: "Mike (Perth, WA)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 08:15 PM 7/03/2000 +0100, you wrote: >Hi ! >What I tryed to say was that the AFM cant give info for the retard of >ignition advance that the backpressure is indicating. OK - I understand now, the backpressure affects ignition timing but the AFM still manages to report actual air flow - over time as it were. I suppose in those conditions a simple pressure sensor off the exhaust before the turbo would be OK. ie Short (cooled) piece of pipe to carefully mounted sensor. The speed wouldn't be much of an issue for this reason. Once its installed and calibrated then the conditions which lead to a immediate ignition retard can be 'pre-emptive' ie. a differentiator off the pressure sensor could initiate an interrupt for immediate retard by a set number of degrees - or even better, the differentiator sets the interrupt pulse width depending on rate of 'upward' change of pressure in exh before turbo. Once this is done a few times the s/w can 'learn' the pre-emptive point combination of AFM, engine speed, turbo estimate speed (if no turbo speed sensor) and thereby not advance the timing by the same amount if such a pre-emptive condition was detected - naturally the pressure sensor provides the final OK such that when pressure drops (turbo spooled up) and combination of AFM, speed etc then the advance can go up again. Of course it would help heaps to have a turbo speed sensor as well which had a short gate time - like 10mS - it could report an output from 0 to 25 for range idle to 150,000 rpm at blade... I think 100 samples per second would be fine given the rate of change of turbine wheel (i think) might be a little less then that... Would this be a fair algorithisation of backpressure pressure sense for ignition retard on changing boost condition ? Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 15:13:49 From: "Mike (Perth, WA)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 11:53 PM 7/03/2000 -0500, you wrote: > >Compared to what Mechanical, FI, Carbbies?. >Sweeping statements are often wrong. >AFM are probably the least accurate of the air flow sensors, or at least the >most restrictive. Do I get the impresion that AFM's in the USA are mostly the flap type, because here in Australia - most if not all (by now) are platinum hot wire ? And on the latest V8's with 300 to 350Kw they are large 3" to 3.5" with modified platinum hot wire - not all all restrictive... Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Tue, 07 Mar 2000 23:04:23 -0800 From: clayb Subject: Re: Crank angle sensor > For what its worth, over here in Perth, Western Australia there are many > jap cars which have a 4 wire crank angle sensor made by Hitachi or Mitsubishi > and for the most part (as far as I can see) are compatible. > > Wires are (not sure of actual order though) :- > > 1. Power (+12v) > 2. 1 degree pulse (actually 1/2 degree ON, 1/2 degree OFF) > 3. 120 degree pulse of same width as in 2 above > but with an extra wide pulse at the TDC position - about 3 deg wide. > (A small piece of hardware can generate a TDC reset as the 120deg > pulse at this point only straddles the 1 degree pulse, whereas on > other 120 degree points its the same width but coincident. > 4. Ground Oh, you're referring to the crank sensor. And wondering about converting an Accel DFI/dizzy combo to DIS? (if I read you're post right). I think your Accel brain only wants the 120 degree signals. Sequential FI requires cam position, but DIS will be happy with the TDC signal from the wide pulse from the crank trigger. Waste spark coils firing on exhaust anyway. You'll still need to sort the ignition output from the Accel into a 3 channel signal, and drive coils. Many OEM "modules" do this, I mention the Ford EDIS because it is common here in the US, and easily adaptable. Not sure if I'm speaking to your question, or not. - - Clay - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Tue, 07 Mar 2000 23:12:34 -0800 From: clayb Subject: Re: FI question Speed Pro is an excellent system, at a fairly high price. Sequential wideband is $2600, bank to bank probably somewhat less. Second only to Motec in cost, and, I suppose, features. IMO, the Autronics unit offers more bang for the buck, is very flexible and adjustable, and utilizes the capable, (tho technically not *true* wideband O2) Bosch 258-104-002 4-wire sensor. Besides, they're releasing an upgraded unit that is "only a month away". Hah! - - Clay "John C." wrote: > Hi this isnt really diy efi but was wondering if anyone has ANY > experience or opinion about the speed pro/FP performance bank to bank > FI system with the wideband o2 option. I am thinking about using that > on a twin turbo V8 mopar I am build for the street and strip.... - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 00:25:00 -0800 From: "John Dammeyer" Subject: Re: Subaru TBI >Subject: Re: Subaru TBI > >At 06:12 AM 7/03/2000 -0800, you wrote: >>>No resistor required. Injectors are normally driven by sinking >>>current through them; no "ballast" required. The duty cycle of >>>pulsing determines the flow. No fancy timing requirements. It's >>>just a cheap way of implementing an electronically-controlled >>>carburettor. ;-) >> >>Yikes! or How to screw up an injector in one easy pulse. > >Yeah good point, when I first read the post I assumed he meant no fancy >gear off the end of the injector driver IC... > >>This is a PeakHold type injector. 13.8V / 1.6 Ohms is almost 9 Amps. > >Aren't all injectors in use in last 20 years or so equivalent, Nope! Both types are available. Drivers for saturated are less expensive. > >ie. Pullin current is far more then hold current. This is true but not imporatant for saturated. > >>Injectors normally >>don't take more than about 1A. You have a choice on how to drive a PH >injector. You can >>place a Ballast resistor in series to limit the current to about 1A. This >has the effect >>of driving the injector hard until the current through the resistor is >high enough to >>reduce the voltage across the injector and therefore limit the current. > >Sorry can't see that - surely the ballast resistor reduces 'sharpness' of >the initial pull in by limiting it to 1A hence also slower to pull in ? I know. It isn't intuitively obvious. Look at inductor theory. At time zero when a step waveform is applied to a coil the voltage across the coil is equal to the applied voltage and the current is 0 amps. At infinity, the voltage across the ideal coil is 0V and the current is infinity assuming the coil has no DC resistance component. So over time, the current increases until the voltage dropped across the coil is limited by the internal resistance. Now here is the key. The size of the voltage applied across this coil determines how fast the current reaches maximum. The faster the current reaches the maximum value, the faster the magnetic field increases and the sooner the injector opens. So the idea is to create a winding with a low inductance, low resistance and oodles of magnetism (oodles is a technical term). In reality what happens is that the coil has a low resistance and the current builds up very quickly opening the injector quickly but this happens at about 4V for a 4 Ohm coil. (1 Amp). However, there was 12 volts across this coil and so the resistor is chosen to limit the current to 1A by dropping the 8V across a power resistor. Now remember, the resistor drops 0 volts at 0 amps, and 8 volts at 1A so you can see as the current builds up in the inductor the voltage across the inductor also drops because the resistor starts resisting. Now this turn on time will not be as fast as an active circuit that Peaks the current at 4Amps for n microseconds and then Holds it down to a steady 1 amp for the rest of the injection time and the name of the game for accurate injection is to minimize the non-linear portion of the injector fuel flow during turn-on and turn-off. Got it? > Cheers, John Dammeyer - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 17:10:54 From: "Mike (Perth, Western Australia)" Subject: Re: Subaru TBI Of course v=Ldi/dt well I'll just put me right knee under left armpit and turn red with embarrasment - forgot about the damn formula drilled into me back during engineer :( Tah, Yes got it - assuming most are ideal, I'll still get me CRO out and check them current peaks on me FET :) Rgds Mike At 12:25 AM 8/03/2000 -0800, you wrote: >>Subject: Re: Subaru TBI >> >>At 06:12 AM 7/03/2000 -0800, you wrote: >>>>No resistor required. Injectors are normally driven by sinking >>>>current through them; no "ballast" required. The duty cycle of >>>>pulsing determines the flow. No fancy timing requirements. It's >>>>just a cheap way of implementing an electronically-controlled >>>>carburettor. ;-) >>> >>>Yikes! or How to screw up an injector in one easy pulse. >> >>Yeah good point, when I first read the post I assumed he meant no fancy >>gear off the end of the injector driver IC... >> >>>This is a PeakHold type injector. 13.8V / 1.6 Ohms is almost 9 Amps. >> >>Aren't all injectors in use in last 20 years or so equivalent, > >Nope! Both types are available. Drivers for saturated are less expensive. > >> >>ie. Pullin current is far more then hold current. > >This is true but not imporatant for saturated. >> >>>Injectors normally >>>don't take more than about 1A. You have a choice on how to drive a PH >>injector. You can >>>place a Ballast resistor in series to limit the current to about 1A. This >>has the effect >>>of driving the injector hard until the current through the resistor is >>high enough to >>>reduce the voltage across the injector and therefore limit the current. >> >>Sorry can't see that - surely the ballast resistor reduces 'sharpness' of >>the initial pull in by limiting it to 1A hence also slower to pull in ? > > >I know. It isn't intuitively obvious. Look at inductor theory. At time zero when a step >waveform is applied to a coil the voltage across the coil is equal to the applied voltage >and the current is 0 amps. At infinity, the voltage across the ideal coil is 0V and the >current is infinity assuming the coil has no DC resistance component. > >So over time, the current increases until the voltage dropped across the coil is limited >by the internal resistance. Now here is the key. The size of the voltage applied across >this coil determines how fast the current reaches maximum. The faster the current reaches >the maximum value, the faster the magnetic field increases and the sooner the injector >opens. > >So the idea is to create a winding with a low inductance, low resistance and oodles of >magnetism (oodles is a technical term). In reality what happens is that the coil has a >low resistance and the current builds up very quickly opening the injector quickly but >this happens at about 4V for a 4 Ohm coil. (1 Amp). However, there was 12 volts across >this coil and so the resistor is chosen to limit the current to 1A by dropping the 8V >across a power resistor. > >Now remember, the resistor drops 0 volts at 0 amps, and 8 volts at 1A so you can see as >the current builds up in the inductor the voltage across the inductor also drops because >the resistor starts resisting. Now this turn on time will not be as fast as an active >circuit that Peaks the current at 4Amps for n microseconds and then Holds it down to a >steady 1 amp for the rest of the injection time and the name of the game for accurate >injection is to minimize the non-linear portion of the injector fuel flow during turn-on >and turn-off. > >Got it? >> > > >Cheers, > >John Dammeyer > >---------------------------------------------------------------------------- >To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) >in the body of a message (not the subject) to majordomo@xxx.org > > Rgds Mike Massen Ancient Sufi saying: "Should your God save you from adversity, choose another God" Pictures of site installation at Mendulong near Sipitang, Sabah (Malaysia) for container based RAPS... http://www.wantree.com.au/~erazmus Vehicle modifications on GMH Turbo, twin tyres, possible 175Kw at wheels Preliminary pictures at http://www.wantree.com.au/~erazmus/Twin_tyre_vehicle/ My editorial on twin-tyre opinion and good reference about tyres:- http://www.geocities.com/MotorCity/2195/ttyreopinion.html - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 10:19:10 +0100 From: "Espen Hilde" Subject: Re: Turbo throttles (was Re: anti-lag) > What are the merits of post-turbo, and combination pre- and post-turbo > throttles? I dont know , but be aware of that the trottles must be syncrinised presisely.If you want to run the turbo in vac you need special seal in turbo charger or your oil consumtion will be going to the roof.I think this is mensioned in Mc Innes turbocharging book. Espen Hilde > > Espen Hilde wrote: > > > Hi! > > I have seen setups with 2 trottles ,one in front of turbo and one after. > > The compressor spinns much easier in lower pressure. > > This was on a dirttrack rally car. > > I have tryed carb in front of turbo and the adjustability of the output of > > the engine was much better. > > After the trottle is open I think the wastegate should be controlled by TPS > > possition.Adjusting the boost by increasing trottle. > > - ---------------------------------------------------------------------------- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 10:55:22 +0100 From: "Espen Hilde" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) Hi! Thanks Clay great sum up. Yes the turbo engine needs special care ,when using EFI, learned that the hard way....Have tryed blow trou with Webers and Dellortos and the drivability was wery good. I read a test of Lotus turbo car that where using dubble dellortos and the journalist stated it was the best turbo engine he had driven, offcurse we have to compare this with the crude ways of early oem turbo charging. One carb in each runner has an advantage over efi , it measures and delivers induvidual amount of fuel.Carbs has one problem the mixture leans out when the density of the air increases.This can be counteracted by fattening the fuel curve at the point where the boost sets in . Maybe the best of both worlds? Block the idle and low output channels in the carb and use efi for light cruising and closed loop with wery small injectors witch goes over to carb for high output , the carb can deliver as much fuel as the engine can use. Combined with a advanced ignition control. Remember how fun it was in the old days when you could just change a jet.......:-) But the mechanical ignition is for the past . Espen > Compared to what Mechanical, FI, Carbbies?. > Sweeping statements are often wrong. > AFM are probably the least accurate of the air flow sensors, or at least the > most restrictive. > In the archives at the GN Ttype there are statements from actual dyno > testing where even a MAF sensor cost 30HP. > An SU and electonic ignition control (far a small engine) would be hard to > beat when set up right. Webers come close to IR, and a blow thru IR vs > Weber would be within tenths of a percentage, I'd wager. > VE, and HP well there is alot for who's doing the tuning. Just really about > dry walls vs wet, and reelated issues. > Now drivibility, tunability, reliability, emissions are all other matters. > But, to claim EFI is that "secret to HP + VE" or especially good for turbos, > is kinda stretching a point, IMHO. > I notice noone has mentioned cross over so far. And that opens the doors > for all kinds of things. > Grumpy > > > > Espen Hilde wrote: > > > What I tryed to say was that the AFM cant give info for the retard of > > > ignition advance that the backpressure is indicating. > > > AFM is not fast enough for a high rpm engine with big turbo, the engine > can > > > dubble the hp in 250rpm change. > > > In a oem application ...no problem. > > > > Your points serve to illustrate a less-than-well-known (?) fact that > > sophisticated engine management contributes more efficiency and HP to a > turbo > > motor, than to a NA motor. > > - Clay (not that it isn't worthwhile on an NA motor...) > > - -------------------------------------------------------------------------- > -- > > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the > quotes) > > in the body of a message (not the subject) to majordomo@xxx.org > > > - ---------------------------------------------------------------------------- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 8 Mar 2000 11:12:01 +0100 From: "Espen Hilde" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) Once its installed > and calibrated then the conditions which lead to a immediate ignition > retard can be 'pre-emptive' ie. a differentiator off the pressure sensor > could initiate an interrupt for immediate retard by a set number of > degrees - or even better, the differentiator sets the interrupt pulse > width depending on rate of 'upward' change of pressure in exh before turbo. > > Once this is done a few times the s/w can 'learn' the pre-emptive point > combination of AFM, engine speed, turbo estimate speed (if no turbo > speed sensor) and thereby not advance the timing by the same amount if > such a pre-emptive condition was detected - naturally the pressure sensor > provides the final OK such that when pressure drops (turbo spooled up) > and combination of AFM, speed etc then the advance can go up again. > > Of course it would help heaps to have a turbo speed sensor as well which > had a short gate time - like 10mS - it could report an output from 0 > to 25 for range idle to 150,000 rpm at blade... I think 100 samples per > second would be fine given the rate of change of turbine wheel (i think) > might be a little less then that... > > Would this be a fair algorithisation of backpressure pressure sense for > ignition retard on changing boost condition ? Sounds good to me , but what do I know...... I think that what you can do with the trottle is making it difficult to predict when things happen , the turbo lives its own life outside the engine and thats making it difficult. I agree that measuring the turbo speed and backpressure is best ,if you know the speed and accleration of the turbo you know where its heading in advance. I would love to get these things implemented in the 332 efi prodject. please join and help getting the software suited for turbocharging. Thanks Espen - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 19:56:20 From: "Mike (Perth, Western Australia)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 11:12 AM 8/03/2000 +0100, you wrote: >I think that what you can do with the trottle is making it difficult to >predict >when things happen , the turbo lives its own life outside the engine >and thats making it difficult. mmm Fair enough in regard to TPS though this is easy to determine in a fast mode ie Through some dedicated h/w differentiator (as well) so the rate of change of TPS is handled as well as actual position - yet another input to a pre-emptive selector The poor 'limp home' mode is likely to be dumped at some point I think given all the potential smarts - so they don't play havoc if the cpu dies - though these days one would expect cpu's to be more reliable etc. A s/w limp mode could be implemented if a subsidiary task in the main o/s were to fail. Design of an o/s for such a device with multiple near real time events is interesting to say the least ! >I agree that measuring the turbo speed and backpressure is best ,if you >know the speed and accleration of the turbo you know where its heading >in advance. I really would like to do a turbo speed sensor - so far no reply from the emails I've sent out to distributors - not even a "we don't do it" :( I'm just not acquainted with the distance for beam, reflects, potential for multiple reflections etc etc. And I don't have a lot of time in next 4 weeks to experiment with that part - would feel I'd be more efficient do the signal conditioning electroncis etc >I would love to get these things implemented in the 332 efi prodject. mmm Yeah does sound interesting as a platform, though I'm also not acquainted with that processor and frankly I hate 'C' or 'C++' :( I'm far more comfortable with assembler and pascal. I think there's plenty expertise on the group already to look at those general algorithms - given my late entry I could shake things up too much;-) >please join and help getting the software suited for turbocharging. WOuld like to but my time is pretty limited, not acquainted with h/w or the task switcher in s/w so for time being I'd like to progress with some low end h/w for an 8051 derivative for my particular ECU replacement. Thanks for the offer, I'm subscribed to that list and will take a keen interest - perhaps I'll have time later on... Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #90 **************************** 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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