DIY_EFI Digest Wednesday, 13 August 1997 Volume 02 : Number 272 In this issue: Rover V8 Efi Re: Eprom switcher Re: TPI Questions Re: Reality of Fuel Consumption Re: Reality of Fuel Consumption Re: Adjusting Boost Re: Controller Questions Re: Adjusting Boost Re: Reality of Fuel Consumption Treatise on intake systems Re: Reality of Fuel Consumption Please disregard Re: Reality of Fuel Consumption Re: Anti-turbo lag systems Re: Rover V8 Efi RE: Treatise on intake systems RE: Treatise on intake systems Re: Adjusting Boost RE: Treatise on intake systems Re: Not strickly efi........more turbo stuff Turbo boost RE: TPI Questions Re: Anti-turbo lag systems Re: fuel filter location See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Andrew McKenzie Date: Wed, 13 Aug 1997 19:06:18 +1000 (EST) Subject: Rover V8 Efi Hello, I'm new to the list and have a few queries on EFI. Firstly, I want to convert my 1980 Rover V8 to EFI for extra performance and slightly greater economy. I have an 1988 Range Rover EFI factory manifold and harness, but lack an airflow meter and the dreaded Lucas ECU. What are my options, i'd like to stick with factory parts if possible. I've heard about some people using an XJ12 Jaguar HE Airflow meter and a Jag ECU but have never seen both in action. I have also seen some people running an AC Delco MAP MPFI setup adapted from a GM Holden Australian 5.Ol V8, which is essentially a GM Buick MPFI setup adapted from a 3800 V6 Series one engine. Any advice would be welcomed. Cheers. Andrew McKenzie Sydney, Australia 1980(?) Rover 3500 S V8 Series 1 5 Speed Hybrid ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Wed, 13 Aug 1997 12:29:34 GMT Subject: Re: Eprom switcher I missed the start of this thread. What are you trying to accomplish? I have two eproms in the disk controller of my old COCO. They are connected in parallel, pin for pin, except for the enable pin, which has a simple spdt switch to select which prom is being accessed. This allowed use of two different operating systems, RSDOS and ADOS. I likely still have the diagram in an old Rainbow magazine somewhere. >Hi, >I promised to make some suggestions to improve the eprom switcher. Here >they are. >The main problem is to make shure that the adress data does not become >instabil while there is an access to the eprom. The result may be only a >hickup or even worse. My idea now is to allow changings to the two relevant >adress lines only when there is no access. >The parts are a 7474 (double flipflop) and a bunch of or-gatters. Connect >each two normal adress line to a or-gatter and connect all gatter outputs >together to the Clock line of the 7474. On the input sides of the 7474 are >the two switches with their 4.7k pulldown resistors. The outputs of the >7474 go to the relevant adress lines of the eprom. The preset and reset >lines are always high. >My thought is, that when the adress status changes from low to high there >will soon be an access. At that moment the status of the switches is added >to the other lines and does what it shall do. I also thought of connecting >Clock with inverter direct to the active low OE of the eprom, because the >7474 has a very short delay of around 15ns, but maybe that is a bit to >late. (Maybe someone wants to test it with a fast osci; i have none) It is >still important to use bounceless switches (scsi id-selector) and program >codes that are only different in the table section. If you use totally >different eprom contents even that wont work. >Just some thoughts, every improvement welcome. Maybe there is another way >to get rid of the or-gatters. >Peter Rueb >s68558@xxx.de > > ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Wed, 13 Aug 1997 12:47:10 GMT Subject: Re: TPI Questions >When nitrogen and oxygen (air) are combined at high temperatures nitrigen >oxides are formed. Nitrogen oxides are an ingredient which leads to the >formation of ground level ozone. EGR adds exhaust, an inert gas, to the >intake. This dilutes the air/fuel mixture and lowers the combustion >temperature which reduces the formation of NOx. Lower combustion >temperature also makes an engine less prone to detonation. The less NOx >created in the engine, the less is emitted out the exhaust, even with 3-way >catalysts. Most but not all engines have EGR. > >In the bad old days of the 70's, engines ran with EGR and retarded spark. >This led to a great loss of economy. Modern engine controls can advance the >spark during heavy EGR use. The EGR permits lots of advance without >detonation. This gets back most all of the economy. When EGR is removed, >the part throttle advance must be cut back to "normal" levels otherwise >detonation will occur. > >At full throttle, EGR is not used so spark advance and power are already at >proper levels. > >Gary Derian > >-----Original Message----- >From: Clare Snyder >To: diy_efi@xxx.edu> >Date: Tuesday, August 12, 1997 2:58 PM >Subject: Re: TPI Questions > > > >>> >>>I was under the impression that EGR was to clean up emissions by >>>recirculating exhaust gas. I read that a performance mod was to >>>disable the EGR valve with big cams. >>> >>>gchan@xxx.ca >>>> >> >>Big cams blead off effective compression at low speeds, where the ping is >>usually the problem. A big cam can negate the requirement for EGR . Ping at >>full throttle is not affected by EGR as it is shut down in that mode >> >>My opinion, only, for what it is worth >> > > > I fully understand the emmission implications. I was responding to the "fact" that non egr equipped vehicles with big cams do not suffer as much from detonation as stock engines when EGR is disabled. Another part of the reason is that, at low RPM, scavenging is incomplete, and a degree of EGR is inherent in the operation and design. Only at higher RPMs the cyls are effectively purged and filled. This is why 12.X :1 compression ratios are possible on some of the lumpy hot-rod engines, while being totally impractical on mildly tuned engines. ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Wed, 13 Aug 1997 13:05:18 GMT Subject: Re: Reality of Fuel Consumption >At 02:16 AM 8/12/97 -0400, you wrote: > >>1. Until Columbus, the world was flat, not round. > >Actually, there where a whole lot of people who thought the world was >round way before Columbus! Heck, in the bible Christ says "In the day >in which I come........ In the night in which I come....." That was >just a bit before Columbus, don't you think? > >>4. Certain purpose-built automobiles have broken the 300MPH bracket. > >Actually, certain purpose-built automobiles have gotten right up to the >speed of sound! > >>5. Stealth fighers exist. (we think). > >They are not fighters, but light bombers. Unless you count the F-22. > >>6. Helicopters can fly straight up, with the rotor assembly held on by a >>single grade 5 aircraft nut. (okay, a big one) > > >>And while we don't have 100MPG cars, the technology is right around the >>corner. Advanced materials are constantly being developed, new ideas form, >>people think. The Wankel engine was a fantastic example of a new idea. No >>pistons. Piston engines have been around since 1903. Its 1997. Its time >>for a new idea folks. > >Uh, the Wankel DOES have pistons. They just aren't round! But they are >pistons >by any measure. As for 100MPG cars, they are going to be itty bitty tiny >things >unless someone figures out a good way around the laws of thermodynamics. I'm >definitely not going to hold my breath waiting on that on! Now me, I >personally >would like to see a vehicle that ran on the background cosmic energy! That >would >be interesting! > >Clint > >PS: Sorry folks, just couldn't help but add my $0.01 worth. > IF you could capture ALL of the heat energy known to exist in a gallon of gasoline, and get it ALL to the wheels, 100MPG would not be such a stretch. A low-tech Austin Mini 850 from the very early 60's was capable of in excess of 50 MPG. That engine is only about 30% efficient, by common knowlege. With heat rejection coatings, fuel injection, full engine management, and turbocharging, possibly a bit of ceramic componentry to allow higher temperatures, it should be do-able. 100 MPG from a behemoth like a 61 Cadilac IS a stretch.> ------------------------------ From: "Rob Lloyd" Date: Wed, 13 Aug 1997 08:09:39 -0500 Subject: Re: Reality of Fuel Consumption > by any measure. As for 100MPG cars, they are going to be itty bitty tiny > things > unless someone figures out a good way around the laws of thermodynamics. I'm > definitely not going to hold my breath waiting on that on! Now me, I > personally > would like to see a vehicle that ran on the background cosmic energy! That > would > be interesting! > > Clint > > PS: Sorry folks, just couldn't help but add my $0.01 worth. Actually, aren't there cars which get more 1000mpg? I think they're called supermileage(a university competition...). These "cars" resemble a bicycle with bodywork more than cars. They average about 12 mph, and take _hours_ to acceleate to top speed.The one that I read about had a 50cc 6-stroke engine built specially by Honda. That's right 6-stroke. Don't ask me I have no idea... Rob Lloyd ------------------------------ From: senator@xxx.edu (Bill Bradley) Date: Wed, 13 Aug 1997 07:22:05 -0700 (PDT) Subject: Re: Adjusting Boost > One variable boost controller (HKS - Norgen made) > Some silicon tubes and T-joints plus clips > Is an after market boost meter necessary? The boost guage is a bit plus for adjusting your new boost. > I will be hooking them as follows: > > Turbo housing -----| > | > | > | | > |V| > boost meter------= B =----------PCV > |C| > | | > | > | > Actuator-----------| You want to hook the boost meter to the intake manifold since the setup you show would only show the boost the wastegate "sees" not what the engine gets, which is what you want to know. Bill ------------------------------ From: Tom Cloud Date: Wed, 13 Aug 1997 09:36:19 -0500 Subject: Re: Controller Questions >Questions for this list: > >I'm sorta new to electronics. I'm in it partially out of interest, and >partly out of necessity. (I have a gizmo that I want to build, but it is >UNWIELDY, and I need a computer to keep it in check.) Because the >project I'm working on borrows heavily from the technologies discussed >in this group, I learn a lot by hanging out. My only problem is that >I''m not exactly a microcontroller whiz. I tried to ease into the area [ snip ] >1. If you had to pick a controller to learn on, which one would it be? [ snip s'more ] >2. (After I have learned a bit more) If you had to pick a controller >to monitor temperature and pressure, and vary an ignition and a fuel >injection firing pattern at the same time, which controller would you >use? Do you use multiple controllers for all these tasks, or is your >code multi-threaded? Or, are these microcontrollers so fast that the >interference with the firing sequences is negligible? I've not done any micro-controller coding or process control coding (same enchilada with efi) in over 20 years (though I do teach it) .... but I'll throw out a few thoughts - BASIC (not VB) is not a bad language to learn on (but it's politically incorrect in many circles) ... problem here is that I don't know if anyone currently puts out a version that's as simple as GW-BASIC or the earlier versions and with primitive I/O like PEEK, POKE, IN and OUT to access memory and I/O directly but that's not necessarily bad. The advantage of BASIC, IMHO, is it lets you develop a high-level algorithm in a fairly readable format (the complaint about BASIC's lack of structure is totally up to the programmer -- and I think there's more power in having the choice of being structured or not rather than being fenced into a structure {forgive the temporary tirade} ). After the basic (pun) algorithm is completed, then coding in assembler or C is simpler (IMO) -- in fact, the earlier BASIC compilers would print out the corresponding assembly code ..... one could take that skeletal structure and flesh it out in a shorter time than starting with assembler initially. When I want to do a quick check of something I still fire up GW-BASIC. - regarding your multiple controller question, I'd say there's two schools 1 - let the (main) controller do everything 2 - have high-level hardware ("controllers") take over the repetitive or easily defined tasks (like a controller for disk I/O or for keyboard, etc) WRT (1) above, the disadvantage to that is what you've already said -- you can get into tight timing constraints and develop severe indigestion and/or migraines trying to manage all the interrupt processing you'll be doing. The processor can be used to scan a keyboard, light pixels on a screen, act as a timer, run the A-D convertor (control the integrator switches, count the discharge time, etc), but I doubt very many still do that, so the question is how far to take the external control concept. WRT (2), it costs a little more to buy the extra chips to control the various functions -- it also locks you into doing the control a certain way -- can't rewrite code to change it, have to redesign a PCB. The obvious advantages are that the coding becomes easier with less concern for timing (note that I said that I've not done any coding for efi, so someone else will have to tell you just how much of a problem the timing is -- my last *real* programming was on the 8085 and Z80). It would seem to me that the injector pulse width would be determined by a counter/timer chip (or on-chip to the processor) with the trigger coming either from the processor or, mo-bettah IMO, from the ignition pulse. Then all the processor would have to do would be to load the counter -- and then reload it only when the value changed more than a certain amount. Same thing for the ignition timing -- load a counter with a value that relates to the advance and let the counter be triggered from the ignition TDC pulse. >3. Are there any other mailing-lists you monitor besides this list that >deal specifically with microcontroller topics? Are there any mailing >lists that deal with metal working / machining / CNC stuff? there's newsgroups (I don't participate in those so can't help there) >Jason Walters Tom Cloud ------------------------------ From: bibie@xxx.com (Bibiana Lim) Date: Wed, 13 Aug 1997 23:55:31 +0800 Subject: Re: Adjusting Boost Good point Bill....Yes I'll connect the boost meter to the intake manifold. BTW I was told that I should insert an orifice before the T-joint at the VBC. Why? What does this orifice do? Is venting the pressure to the PCV ok? Updated setup: Boost meter===========>Intake manifold Turbo housing ------| | |V| |B========>PCV |C| | Actuator--------------| > > You want to hook the boost meter to the intake manifold since the >setup you show would only show the boost the wastegate "sees" not what the >engine gets, which is what you want to know. ..ere catchhhhh it....a Budweiser for you Bill ! Bibie ------------------------------ From: Tom Cloud Date: Wed, 13 Aug 1997 11:30:40 -0500 Subject: Re: Reality of Fuel Consumption >Frederic Breitwieser wrote: >> >> >> Thank you for that, Terry. Now go away. And start practicing what you >> >> preach from now on. Pedal your blinkety-blink bicycle to work. > >Insert retraction wait .... I don't think Fred wrote the first part ... >> >> Up until now, I was going to stay out of the slander . >> >> While that particular website and owner of said site (100MPG Carbeurators) >> might be full of horse-bunk, just keep in mind several things... > >Exactly my point, for anybody that didn't just dump on me without >reading what I actually wrote. Fuel >injection is the most probable means to breach the hurdle of >hydro-carbon fueled piston engine machines. Carburetors have out lived >their usefulness, and EFI provides the technology necessary to bring in >a replacement without disrupting the capitalist structure within which >all of this has to work. I, by the way, am an unabashed self-employed >capitalist. let me try to get this back onto efi .... I doubt there's anyone this list that would disagree with your point. Unfortunately, the carb is still the easiest, cheapest and quickest to make go-power. There is no reason I can see that an efi system cannot be made to be MUCH more generic than a carb -- and even as inexpensive -- except for the lack of volume to bring down the costs. I think it was George on this list (mebbe I'm wrong) that seemed to share my feelings on this .... I'd think a TBI (or CPI, as Ford calls it) with MAF would be the "end-all to be-all". I know of no one who's done this, but it would allow the use of current carb intake manifolds, and would be self-adjusting. I know that the window for this is small, only encompassing pre-efi cars, but there's still lots of them out there that probably would convert if the price were right -- esp if they could have the economy and reliability of efi with the big PLUS of better emissions control. Tom Cloud ------------------------------ From: wstrass@xxx.com Date: Wed, 13 Aug 1997 12:55:37 -0400 Subject: Treatise on intake systems To: DIY --INTERNET DIY From: Wayne Strasser (CED Polymer Development) *** Resending note of 08/12/97 11:24 _______________________________________________________________________ Subject: Treatise on intake systems ========================================================================= Now to calculate intake velocity the volume displaced during the intake stroke is taken as flowing during the time of the intake stroke. This gives a volume flow rate (length cubed per time). If you divide this quantity by the intake area (length squared) you end up with a (pseudo) velocity (length per time). The volume is the cylinder volume - 500cc in your case. Note that this displacement takes place during half of a revolution. If one revolution takes 1/rpm minutes then 1/(2*rpm) minutes is the length of time for a half of a revolution. Since we are going to divide the volume by the time we end up with V*rpm*2 as the volume flow rate. Then you simply divide by the area and the appropriate conversion factors to get to feet per second or m/s whichever is preferred. JIM: YOU PROBABLY SHOULD HAVE MENTIONED THAT THIS IS ONLY A CRUDE APPROXIMATION OF INTAKE MEAN VELOCITY. YOUR CALCULATION DOES NOT TAKE INTO ACCOUNT TWO MAIN THINGS: FORM FRICTION AND SKIN FRICTION THAT BOTH LEAD TO V.E. < 100%. AS THE INTAKE VALVE OPENS AND A PRESSURE DIFF. IS CREATED ACROSS YOUR INTAKE AND THE GAS BEGINS TO FLOW, A LAMINAR HYDRODYNAMIC BOUNDARY LAYER DEVELOPES IN THE RUNNER(S) AND THEN SEPARATES ACROSS THE VALVE. THE LAYER IN THE RUNNER CREATES SKIN FRICTION (TO THE TUNE OF 4*FANNING FRICTION FACTOR*L/D*VELOCITY HEAD SQUARED). THE LAYER SEPARATING ACROSS THE VALVE CREATES FORM FRICTION (RELATED TO SOME EMPERICAL FUNCTION OF VALVE GEOMETRY). BASED ON BERNOULLI (EXTREMELY SIMPLIFIED VERSION OF NAVIER-STOKES EQUATION), ANY GIVEN PRESSURE DIFFERENTIAL IS BALANCED BY FLOW AND FRICTION. THEREFORE, THE MEAN VELOCITY WILL BE REDUCED BY THESE FRICTION EFFECTS....BUT CAN EASILY BE COMPENSATED FOR BY MULTIPLYING YOUR VOLUME BY SOME V.E. (INSTEAD OF 500CC, USE 400CC AT 80% V.E.) ------------------------------ From: wstrass@xxx.com Date: Wed, 13 Aug 1997 13:00:43 -0400 Subject: Re: Reality of Fuel Consumption To: DIY --INTERNET DIY From: Wayne Strasser (CED Polymer Development) *** Resending note of 08/13/97 10:45 _______________________________________________________________________ Subject: Re: Reality of Fuel Consumption ========================================================================= Received: from eastman.com by GWVM1F.emn.com (IBM VM SMTP V2R4) with TCP; Wed, 13 Aug 97 10:45:14 TOD Received: by eastman.com id AA26388 (5.67b/IDA-1.5 for wstrass@xxx.com); Wed, 13 Aug 1997 10:44:26 -0400 Received: from gatekeeper.eastman.com by eastman.com with SMTP id AA26129 (5.67b/SMI-4.1 for ); Wed, 13 Aug 1997 10:44:26 -0400 Received: by gatekeeper.eastman.com; id LAA17670; Wed, 13 Aug 1997 11:15:53 - -0400 (EDT) Received: from coulomb.eng.ohio-state.edu(128.146.90.150) by gatekeeper.eastman.com via smap (3.2) id xma017632; Wed, 13 Aug 97 11:15:51 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id NAA15860; Wed, 13 Aug 1997 13:05:26 GMT Received: from out1.ibm.net by coulomb.eng.ohio-state.edu via ESMTP (940816.SGI.8.6.9/940406.SGI) for id JAA15855; Wed, 13 Aug 1997 09:05:20 -0400 Received: from 486desktop (slip129-37-161-240.on.ca.ibm.net [129.37.161.240]) by out1.ibm.net (8.8.5/8.6.9) with SMTP id NAA94834 for ; Wed, 13 Aug 1997 13:05:18 GMT Date: Wed, 13 Aug 1997 13:05:18 GMT Message-Id: <199708131305.NAA94834@xxx.net> X-Sender: clsnyde@xxx.net X-Mailer: Windows Eudora Version 1.4.4 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: diy_efi@xxx.edu From: clsnyde@xxx.net (Clare Snyder) Subject: Re: Reality of Fuel Consumption Sender: owner-diy_efi@xxx.edu Precedence: bulk Reply-To: diy_efi@xxx.edu >At 02:16 AM 8/12/97 -0400, you wrote: > >>1. Until Columbus, the world was flat, not round. > >Actually, there where a whole lot of people who thought the world was >round way before Columbus! Heck, in the bible Christ says "In the day >in which I come........ In the night in which I come....." That was >just a bit before Columbus, don't you think? > >>4. Certain purpose-built automobiles have broken the 300MPH bracket. > >Actually, certain purpose-built automobiles have gotten right up to the >speed of sound! > >>5. Stealth fighers exist. (we think). > >They are not fighters, but light bombers. Unless you count the F-22. > >>6. Helicopters can fly straight up, with the rotor assembly held on by a >>single grade 5 aircraft nut. (okay, a big one) > > >>And while we don't have 100MPG cars, the technology is right around the >>corner. Advanced materials are constantly being developed, new ideas form, >>people think. The Wankel engine was a fantastic example of a new idea. No >>pistons. Piston engines have been around since 1903. Its 1997. Its time >>for a new idea folks. > >Uh, the Wankel DOES have pistons. They just aren't round! But they are >pistons >by any measure. As for 100MPG cars, they are going to be itty bitty tiny >things >unless someone figures out a good way around the laws of thermodynamics. I'm >definitely not going to hold my breath waiting on that on! Now me, I >personally >would like to see a vehicle that ran on the background cosmic energy! That >would >be interesting! > >Clint > >PS: Sorry folks, just couldn't help but add my $0.01 worth. > IF you could capture ALL of the heat energy known to exist in a gallon of gasoline, and get it ALL to the wheels, 100MPG would not be such a stretch. A low-tech Austin Mini 850 from the very early 60's was capable of in excess of 50 MPG. That engine is only about 30% efficient, by common knowlege. With heat rejection coatings, fuel injection, full engine management, and turbocharging, possibly a bit of ceramic componentry to allow higher temperatures, it should be do-able. 100 MPG from a behemoth like a 61 Cadilac IS a stretch.> ------------------------------ From: wstrass@xxx.com Date: Wed, 13 Aug 1997 13:02:50 -0400 Subject: Please disregard To: DIY --INTERNET DIY From: Wayne Strasser (CED Polymer Development) _______________________________________________________________________ Subject: Please disregard Please disregard the most recent note I sent that was just a duplication of a Clyde's note. _______________________________________________________________________ Wayne Strasser wstrass@xxx.com ------------------------------ From: wstrass@xxx.com Date: Wed, 13 Aug 1997 13:07:08 -0400 Subject: Re: Reality of Fuel Consumption To: DIY --INTERNET DIY From: Wayne Strasser (CED Polymer Development) *** Resending note of 08/13/97 10:45 _______________________________________________________________________ Subject: Re: Reality of Fuel Consumption ========================================================================= IF you could capture ALL of the heat energy known to exist in a gallon of gasoline, and get it ALL to the wheels, 100MPG would not be such a stretch. A low-tech Austin Mini 850 from the very early 60's was capable of in excess of 50 MPG. That engine is only about 30% efficient, by common knowlege. With heat rejection coatings, fuel injection, full engine management, and turbocharging, possibly a bit of ceramic componentry to allow higher temperatures, it should be do-able. 100 MPG from a behemoth like a 61 Cadilac IS a stretch.> YOU CAN NEVER CAPTURE ALL OF THE ENERGY IN THE COVALENT PI AND SIGMA BONDS IN GASOLINE...EVER HEARD OF A"CARNOT"ENGINE (ISENTROPIC, REVERSIBLE PROCESS)? ------------------------------ From: muwtj1@xxx.edu (Bill Jenkins) Date: Wed, 13 Aug 1997 13:18:16 -0400 Subject: Re: Anti-turbo lag systems >Not strictly DIY_EFI but sorta related. This thread on the Saab APC system >has got me thinking. I have seen several references in Racecar Engineering >to anti-lag systems used on current FIA rally cars like the ford, subaru and >mitsubishi. In particular I was wondering how the system worked? > >I know that early eighties ferrari F1 cars used a system that bypassed air >from the turbo compressor straight into the exhaust system when the throttle >was closed and ran a rich mixture to create combustion in the exhaust. I >also read somewhere that peugeot used to inject propane into the exhaust to >acheive the same effect before it was banned in the group B rally cars. > >Depending on how these current systems work, I would like to adapt it to my >current project. > >Any info would be appreciated. > >Max I will say that I saw quite an interesting thing of the sort one time. A Mitsubishi Eclipse Turbo came in with a fried plug wire; therefore it was firing on three cylinders, running rather roughly. However, all of that fuel was dumping into the exhaust manifold. Therefore, you could rev the thing in neutral, and the turbo would start whining (we had the intake hose off) and the boost would come up. It was the only car I have ever seen that could get full boost without moving. Really neat. The extra fuel and air in the exhaust manifold was burning, and propelling the turbo. ------------------------------ From: Webb Date: Wed, 13 Aug 1997 09:36:59 -0800 Subject: Re: Rover V8 Efi Andrew McKenzie wrote: > Hello, > I'm new to the list and have a few queries on EFI. > Firstly, I want > to convert my 1980 Rover V8 to EFI for extra performance and > slightly > greater economy. I have an 1988 Range Rover EFI factory > manifold and > harness, but lack an airflow meter and the dreaded Lucas ECU. > > Say - is it true that the reason the british like warm beer is that Lucas builds refrigerators??? ;-} ------------------------------ From: James Boughton Date: Wed, 13 Aug 1997 14:03:12 -0400 Subject: RE: Treatise on intake systems I think I covered myself on this with the reply to Wayne Strasser's comments, but to make sure g is actually gamma, the ratio of specific heats. It is listed in numerous tables on properties of air. If it is not listed the specific heats (constant pressure and constant volume) should be listed thus gamma can be calculated by the ratio of specific heat at constant pressure to specific heat at constant volume. Jim Boughton boughton@xxx.net - ---------- From: James Weiler[SMTP:james@xxx.ca] Sent: Tuesday, August 12, 1997 7:54 PM To: diy_efi@xxx.edu Subject: Re: Treatise on intake systems On Tue, 12 Aug 1997 wstrass@xxx.com wrote: > (The speed of sound is simply (gRT)^0.5 where g and R are considered > constant. If you wanted to be rigorous you could actually vary g and R > for temperature, but probably not worth it.) > > Jim: I have a question....how can g (is this gravitational constant?) and > R (the universal gas constant) vary with temperature? n is the number of moles of gas. Part of this formula comes from the ideal gas law PV=nRT except he's using g instead of n. R is a constant and so there is no variation. later jw ------------------------------ From: James Boughton Date: Wed, 13 Aug 1997 14:20:59 -0400 Subject: RE: Treatise on intake systems If you make a proper individual runner (IR) system and tune intake, exhaust, and cams properly you can see well in excess of 100% volumetric efficiency due to the standing pressure waves in the intake and exhaust systems. So indeed you are correct that this is an approximation, but the whole concept is based on empirical rules of thumb. I am curious about something you mentioned, though. Do you think that parts of the intake system have laminar flow and the flow separates somewhere in the intake runner? I had never put much thought to this. Jim Boughton boughton@xxx.net - ---------- From: wstrass@xxx.com] Sent: Wednesday, August 13, 1997 12:55 PM To: diy_efi@xxx.edu Subject: Treatise on intake systems To: DIY --INTERNET DIY From: Wayne Strasser (CED Polymer Development) *** Resending note of 08/12/97 11:24 _______________________________________________________________________ Subject: Treatise on intake systems ========================================================================= Now to calculate intake velocity the volume displaced during the intake stroke is taken as flowing during the time of the intake stroke. This gives a volume flow rate (length cubed per time). If you divide this quantity by the intake area (length squared) you end up with a (pseudo) velocity (length per time). The volume is the cylinder volume - 500cc in your case. Note that this displacement takes place during half of a revolution. If one revolution takes 1/rpm minutes then 1/(2*rpm) minutes is the length of time for a half of a revolution. Since we are going to divide the volume by the time we end up with V*rpm*2 as the volume flow rate. Then you simply divide by the area and the appropriate conversion factors to get to feet per second or m/s whichever is preferred. JIM: YOU PROBABLY SHOULD HAVE MENTIONED THAT THIS IS ONLY A CRUDE APPROXIMATION OF INTAKE MEAN VELOCITY. YOUR CALCULATION DOES NOT TAKE INTO ACCOUNT TWO MAIN THINGS: FORM FRICTION AND SKIN FRICTION THAT BOTH LEAD TO V.E. < 100%. AS THE INTAKE VALVE OPENS AND A PRESSURE DIFF. IS CREATED ACROSS YOUR INTAKE AND THE GAS BEGINS TO FLOW, A LAMINAR HYDRODYNAMIC BOUNDARY LAYER DEVELOPES IN THE RUNNER(S) AND THEN SEPARATES ACROSS THE VALVE. THE LAYER IN THE RUNNER CREATES SKIN FRICTION (TO THE TUNE OF 4*FANNING FRICTION FACTOR*L/D*VELOCITY HEAD SQUARED). THE LAYER SEPARATING ACROSS THE VALVE CREATES FORM FRICTION (RELATED TO SOME EMPERICAL FUNCTION OF VALVE GEOMETRY). BASED ON BERNOULLI (EXTREMELY SIMPLIFIED VERSION OF NAVIER-STOKES EQUATION), ANY GIVEN PRESSURE DIFFERENTIAL IS BALANCED BY FLOW AND FRICTION. THEREFORE, THE MEAN VELOCITY WILL BE REDUCED BY THESE FRICTION EFFECTS....BUT CAN EASILY BE COMPENSATED FOR BY MULTIPLYING YOUR VOLUME BY SOME V.E. (INSTEAD OF 500CC, USE 400CC AT 80% V.E.) ------------------------------ From: senator@xxx.edu (Bill Bradley) Date: Wed, 13 Aug 1997 11:05:47 -0700 (PDT) Subject: Re: Adjusting Boost > Good point Bill....Yes I'll connect the boost meter to the intake manifold. BTW > I was told that I should insert an orifice before the T-joint at the VBC. Why? > What does this orifice do? Is venting the pressure to the PCV ok? I don't know about the set up on your car, but on mine (Volvo 245Turbo) , the PCV is connected to the intake before the Turbo. I wouldn't hook up the bleed to the PCV on mine since the hose is always at less than atmospheric pressure, and the higher the air flow, the LOWER the pressure, so the amount of pressure bled would depend on the engine RPM and boost level, not a great situation to set a stable boost level(although it would let you have a load dependant boost control, higher boost at higher flow rates, but I'd be more worried about overboosting) Don't worry about venting to the atmosphere, the hose to the wastegate is never under vacuum (It's ahead of the throttle body), and at low boost the oxygen sensor will correct for the (ever so slight) extra richness in the mixture, and at WOT, who cares? Bill ------------------------------ From: James Weiler Date: Wed, 13 Aug 1997 11:53:07 -0700 (PDT) Subject: RE: Treatise on intake systems Oops my fault, I'm way out in left field. Think I'll just shut up now. jw On Wed, 13 Aug 1997, James Boughton wrote: > I think I covered myself on this with the reply to Wayne Strasser's > comments, but to make sure g is actually gamma, the ratio of specific > heats. It is listed in numerous tables on properties of air. If it is not > listed the specific heats (constant pressure and constant volume) should > be listed thus gamma can be calculated by the ratio of specific heat at > constant pressure to specific heat at constant volume. > > Jim Boughton > boughton@xxx.net > > ---------- > From: James Weiler[SMTP:james@xxx.ca] > Sent: Tuesday, August 12, 1997 7:54 PM > To: diy_efi@xxx.edu > Subject: Re: Treatise on intake systems > > > > On Tue, 12 Aug 1997 wstrass@xxx.com wrote: > > > (The speed of sound is simply (gRT)^0.5 where g and R are considered > > constant. If you wanted to be rigorous you could actually vary g and R > > for temperature, but probably not worth it.) > > > > Jim: I have a question....how can g (is this gravitational constant?) and > > R (the universal gas constant) vary with temperature? > > n is the number of moles of gas. Part of this formula comes from the > ideal gas law PV=nRT except he's using g instead of n. R is a constant > and so there is no variation. > > later > jw > > > ------------------------------ From: "Joni Mikkola" Date: Wed, 13 Aug 1997 21:45:21 +0300 Subject: Re: Not strickly efi........more turbo stuff I agree with you, good idea !!!!! - ---------- > > >It has some good turbo info and some handy java scripts for > >calulatiing turbos size C/R's etc.... > > >Does anyone know if there is a turbo mailing list??? > >I have looked for one but no joy :-( > > We need to get one started. I think that there are probably enough people > interested, unfortuneatly I know nothing about starting something like this. > Just would want to participate. > > Max ------------------------------ From: dusher@xxx.com Date: Wed, 13 Aug 1997 20:56:21 BST Subject: Turbo boost Hi all , Can anyone expalin to me turbo boost on a diesel engine ie same engine speed, foot to the floor and boost rises. Guess it must be more fuel= more boost, ie faster exhaust gases mmmmm. All this is on a Cummins C8.3 CTA , BTW. Dave Usher. - -- ------------------------------ From: Tom Cloud Date: Wed, 13 Aug 1997 14:51:47 -0500 Subject: RE: TPI Questions James Boughton wrote: >EGR is used to decrease NOx emissions, as well as to dilute the >incoming mixture to improve fuel economy. Because EGR causes >the burn rate of the mixture to decrease the spark advance must be >increased. So for an engine calibrated with EGR there is a spark >advance increase any time the engine controller thinks the engine >is breathing in EGR. The problem with removing the EGR valve >is that some people don't let the engine controller know that EGR is >not functional (to keep the check engine light from coming on). This >means that the engine controller thinks you have EGR when you really >don't and therefore the spark advance is far more than what it should >be. This can cause very high peak pressures and possibly knock. >I know when I did this I holed a piston:-P I wish somebody had told me >what I am telling you. so, James, on a non-ecu engine (distributor with centrifugal & vac advance controlling timing) how would you recommend compensating for the "loss" of the EGR function ? I had my distributor "re-curved" (actually think he just set the vac advance spring a little stiffer -- talking Ford vac advance canister) Tom Cloud ------------------------------ From: bwmsbldr@xxx.com (William A Williams) Date: Wed, 13 Aug 1997 14:09:51 -0600 Subject: Re: Anti-turbo lag systems This whole line of GT development dates back to the 50's when there were some gas turbine starters developed for ground use in very cold climates. They were simply small gas turbines that burned enough fuel to put out a hot, pressurized exhaust that was ducted to the engine that you wanted to start. The hot gasses flowed through the engine, spooling it up, warming it up, and leaving sufficient oxygen in the exhaust to support combustion in the engine being started. They were really small and light units and when they came on the surplus market there was a flurry of interest in them as potential conversions for homebuilt aircraft. Sadly it was found that they didn't have good enough metallurgy in the turbine wheel to make a decent power. This concept of a bypass of air/fuel for turbo spinup was discussed in the 60's with respect to the Corvair turbo setup as a cure for a high rotational inertia in it's turbo. Of course with the carburetted mixture it was rather simpler, requiring only a pressure driven shutoff and some pneumatic control logic. Bill in Boulder ---- "Engineering as an Art Form" ---- ------------------------------ From: Simon Quested Date: Thu, 14 Aug 1997 09:00:13 +1200 Subject: Re: fuel filter location Hi Stuart > Got to give ourselves something to measure... A good point ;-) > Hopefully what will happen will be the same as what happens when the > float bowl is full on a carbed vehicle, You may want to put a needle valve and float in too.... Once you get it running I'd like to hear how it goes. Cheers Simon +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Simon Quested (E-mail questeds@xxx.nz) Computer Technician, Silicon Graphics & Windows NT Support Centre for Computing and Biometrics LINCOLN UNIVERSITY OF NEW ZEALAND Phone (64)(03) 3252811 Ext. 8087 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ http://www.lincoln.ac.nz/ccb/techs/simon/default.htm +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ f u cn rd ths, u cn gt a gd jb n cmptr prgmmng +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------ End of DIY_EFI Digest V2 #272 ***************************** 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".