DIY_EFI Digest Wednesday, 24 July 1996 Volume 01 : Number 207 In this issue: Re: G-Tech Hp Meter Update Re: Re[2]: G-Tech Hp Meter Update Re: water injection questions Re: water injection Re: water injection questions??? MAF Reading at cold temp? Re: Bosch Motronic AFM Spring Tension - Further Comments Re: MAF Reading at cold temp? Throttle Pos sensor vs. MAP/MAF Spark Advance Engine POWER! re: Re: water injection questions Re: water injection questions Re: Spark Advance Engine POWER! Re: Spark Advance Engine POWER! Re: water injection questions Re: Spark Advance Engine POWER! Re: water injection questions Re: water injection questions Re: water injection questions spark advance curve modification Re: Filtering supply lines Windsor EFI manifold Re: water injection questions EFI control units Re: water injection questions??? Re: water injection questions Re: water injection questions Water injection questions See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Bruce Bowling Date: Tue, 23 Jul 1996 10:21:25 EDT Subject: Re: G-Tech Hp Meter Update > > You are correct that it is horsepower delivered at the wheels > minus rolling and aero losses. There is no correction figure > available for frontal area and coeficient of drag or friction. > > Because of all these things I think is is a OK as a qualitative > tool, but lacks as an absolute quantitative tool. You can > still see instantaneous HP versus speed or RPM. However, that > means keeping one eye on the meter, which is not ideal. It will work as a qualitative tool only if comparisons are done at the same environment, or one corrects for the environment. In other words, one can perform *relative* comparisons only if performs all of the testing at the same temperature, barometer, or humidity, or compensates. To see the effects, here are some numbers: Assume I measure 250 horsepower at 6000 RPM,by some method (G-meter, dyno,etc). This measurement was taken at some test temperature, humidity, altitude, and barometer. It is desirable to correct to some "common" temperature,barometer, and humidity that everyone agrees to. The two common ones are Standard and SAE corrections. Standard Correction is at 29.92 Inches Hg Barometric pressure at sea-level, 0% relative humidity, and 60 degrees F. The numbers below were are all corrected to this "standard" environment: Data taken from http://devserve.cebaf.gov/~bowling/stdcorr.html TEMPERATURE TEST - Baro-29.92, Rel humidity=0% Engine: Small Block Chevy 350 Temperature Corrected HP (Farenheight) - ------------------------------- 20 236 40 243 60 250 80 257 100 264 Remember: Engines produce more power when the temps are colder, and the correction compensates, so cold temps correct the 250 HP to a lower number (what the engine would produce at 60 degrees F) BAROMETER TEST - Temp-60, Rel humidity=0% Engine: Small Block Chevy 350 Barometer Corrected HP (Inches Mercury) - ------------------------------- 29.00 261 29.50 255 29.92 250 30.20 247 HUMIDITY TEST - Temp-60, Barometer=29.92 Engine: Small Block Chevy 350 Relative Corrected HP Humidity (%) - ------------------------------- 0 250 50 253 100 256 > > It still may be the best thing available today, and easier to > use than a stopwatch. I suspect the braking and cornering > functions are less problematic. > > paul timmerman > And the price is good, too! - - Bruce - -- - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- Bruce A. Bowling Staff Scientist - Instrumentation and Controls The Continuous Electron Beam Accelerator Facility 12000 Jefferson Ave - Newport News, VA 23602 (804) 249-7240 bowling@xxx.gov http://devserve.cebaf.gov/~bowling - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- ------------------------------ From: Chuck Tomlinson Date: Tue, 23 Jul 1996 11:00:54 -0400 Subject: Re: Re[2]: G-Tech Hp Meter Update At 07:51 AM 7/19/96 cdt, John Faubion wrote: > >I read your response and am curious about parts of it. For example the >following equation for air density: > > AirDensity=0.0228645 * barometer(In Hg)/(0.5555* (temp - 32) + 273.15) > >I understand the barometer and the ((temp - 32) + 273.15) to get degrees Kelvin >I'm sure the constants 0.0228645 and the 0.5555 are for unit conversion but how >are they derived? Sorry it took me awhile to respond to this (the question may be answered already) but the above equation works iff AirDensity is in slugs/ft3 and temp is in degrees Fahrenheit. The 0.5555 (i.e. 5/9) is part of the conversion from deg F to deg C or Kelvin. The general form of the (ideal gas) equation is: GasDensity = AbsPressure * GasMolWt / (UnivGasConst * AbsTemp) The molecular weight of air is about 28.96. The Universal Gas Constant is the same for all ideal gases, and pressure and temperature are absolute (i.e. referred to hard vacuum and absolute zero, respectively). The 0.0228645 term comes out in the wash if you choose slugs/ft3 and deg F (and inHg for pressure). >Also concerning the next equation: > > AeroDragFactor = 1.07556 * AirDensity * Coeff_Drag * Frontal Area > >Again the 1.07556 is probably for unit conversion, how is it derived. This is an >area that always intrigued me. Thanks for bringing up the topic. I missed the first part of this thread, but I presume that the AeroDragFactor is used in: AeroDragForce = AeroDragFactor * AeroSpeed^2. Then 1.07556 is correct iff AeroDragForce is in lbf, AirDensity is in slugs/ft3, FrontalArea is in ft2, *and* AeroSpeed is in mph. What a mess! The general (independent of units) form of the equation is: AeroDragFactor = 1/2 * AirDensity * Coeff_Drag * Frontal Area IMHO, units-dependent equations are evil incarnate, especially when combined with the hodge-podge of units typical of non-SI units systems. The AeroDragForce equation is a prime example. SI rules!! ~8-) Later. Chuck Tomlinson ------------------------------ From: Martin Scarr Date: Tue, 23 Jul 1996 08:17:48 -0700 (PDT) Subject: Re: water injection questions On Mon, 22 Jul 1996, Darrell Norquay wrote: > > Reminds me of the old Corvair Turbo Spyder's. (Original application of the > "turbo" muffler). They came from the factory with water injection, trouble > was everybody forgot to fill the reservoir. That's one reason why they are > almost impossible to find anymore... I think Darrell is thinking of the Turbocharged Olds 215 that came out in '62 or '63. The turbo Olds used water injection. Corvair turbos never came with water injection from the factory; they used a pressure retard unit on the distributor to combat detonation. Martin Scarr ------------------------------ From: ptimmerm@xxx.GOV Date: Tue, 23 Jul 1996 09:33:31 -0700 Subject: Re: water injection Someone asked about peroxide, thinking more O2 was a good think. It is not. Raising the percentage of oxygen in the combustion chamber will cause detonation. Increasing the air volume may not. Remember what happened to those astronauts in the Apollo days that insisted on sucking pure O2? They burned up, good, real good! Back to water injection, a second point (beyond cooling the air charge) is the reduced need for WOT enrichment. This means you can theoretically run more boost, more horsepower, and not worry so much about leaning out and holing a piston. Unless, as everyone keeps saying (and rightfully so) you run dry. paul timmerman ------------------------------ From: tom sparks Date: Tue, 23 Jul 1996 11:47:43 -0500 Subject: Re: water injection questions??? If all a person wants to do is lower the heat of combustion and hence the speed of the flame front, then why not just fatten up the fuel curve at the point where detonation is expected? Why add all the extra hardware and expense (and risk) of a water injection system? ------------------------------ From: Markus Strobl Date: Tue, 23 Jul 1996 12:49:01 -0500 Subject: MAF Reading at cold temp? I'm new to the list so forgive me if this is old stuff... I have a '96 Z28 that has the OBD-II compliant PCM. One of the new diagnostics on the 96 is a MAF diagnostics. If the MAF reads higher than 293 G/S for more than 1 second it will set off a trouble code and switch to speed density. I had some mishaps with my car. First the heads fell off and then some material mysteriously vanished from the intake and exhaust ports... When I got it all back together it was faster... And gulps alot more air. I measured it in the Texas heat (MAT of 109F!!) and I have a peak of 283 G/S, with more than 262 G/S the last 300rpm before the revlimiter. My question is: Can someone tell me how much these readings will increase when temps drop? Say to 50F? Will the MAF diagnostics fail? Thanks Markus Strobl 96 Z28 6M Black. Borla, !CAGS, 1LE shaft, B&M Shifter Dallas, Texas 1.6 rockers, ported heads, Swaybars, SFC, Crane Springs F-member 9/93 No times since latest mods 27.5mpg @85mph ------------------------------ From: Todd Knighton Date: Tue, 23 Jul 1996 10:55:32 -0700 Subject: Re: Bosch Motronic AFM Spring Tension - Further Comments Matthew, What exactly do you want to know? We turbocharge late model Porsche's as a business and utilize the Motronics Fuel management modified in many different ways for the appropriate system. Do you have a Carrera? Or are you just interested in the EFI mods? Todd Knighton Protomotive Engineering Email: knighton@xxx.com Matthew Wallis wrote: > > > > > > 12. Our experiences with DIY modified EFI systems do not yield > > > measurable differences. > Todd, > > Can you give some more details on this change. > > > > > We've taken 911 Carrera's from 214 hp Normally aspirated to > > 250+hp normally aspirated and all the way to 765 Hp turbocharged, I tend > > to think that's measureable!! > > > > > > Conclusion: for DIY, it seems more cost effective to use carburetors and > > > a modern ignition system, leaving original EFI system intact for use later > > > at resale. ------------------------------ From: atsakiri@xxx.com Date: Tue, 23 Jul 96 14:41:20 -0400 Subject: Re: MAF Reading at cold temp? > I measured it in the Texas heat (MAT of 109F!!) and I have a peak > of 283 G/S, with more than 262 G/S the last 300rpm before the revlimiter. > > My question is: Can someone tell me how much these readings will increase > when temps drop? Say to 50F? Will the MAF diagnostics fail? A rough estimate can be obtained by calculating the increase in density of the ambient air. rho1 = p/(R*T1) = density at 109 F rho2 = p/(R*T2) = density at T2 where rho = density p = pressure (assumed the same at both temperatures) R = gas constant T = absolute temperature (R) So, rho2/rho1 = T1/T2 = (109 + 460)/T2 At a temperature of 50 F, T2 = 50 + 460 R, and the density is about 12% greater. rho2/rho1 = 1.12. Anthony Tsakiris - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: "Lamari, Matthew" Date: Tue, 23 Jul 96 13:52:00 PDT Subject: Throttle Pos sensor vs. MAP/MAF In looking at the engine as an air flow circuit, I look at the throttle as an impedance, a fairly constant pressure outside, MAP pressure inside, another impedance (valves etc.), and a vacuum caused by engine at a certain speed. The thing is, temperature/external pressures aside (which have to be catered for anyway even when measuring air pressure/flow), For a given engine at a given speed, doesn't one throttle position map to one pressure? I understand there can be some lag; but MAP sensors aren't instantaneous in reading anyway. I understand that pressure readings may harken back to the days of vacuum advance in old distributors; but, temperatures aside, would a throttle to RPM lookup be any different to a Pressure to RPM lookup in any situation? (I understand existing systems use Throttle pos as a signal of intent, e.g. full throttle tells the system to throw extra fuel on top of what it would normally in a situation, and low throttle means try to idle; but is the lag that significant that, for a given physical setup, one throttle setting for one RPM the pressure/airflow changes? Granted, without this, ducting changes and even a filter change would screw things up; but not in a fully calibrating system. . . . Matthew. ------------------------------ From: brewer@xxx.com (John Brewer) Date: Tue, 23 Jul 1996 15:01:01 -0500 Subject: Spark Advance Engine POWER! Given the close relationship between ignition timing and fuel metering, I decided to post this to this list as well as the OffRoad Mailing List, hope you all don't mind. Comments would be appreciated. I've been doing a little light reading (always dangerous) on Internal Combustion, Spark Ignition Engines. I have discovered that, theoretically, for peak power and fuel economy, the spark should be advanced (degrees BTDC) as far as possible until the engine begins to knock, then of course backed off a little- you don't want it knocking. Also, for peak power and performance, the vacuum and centrifugal advances should be in good working order and should advance the spark under load or RPMs. However, in American cars, the vacuum advance is (and has been since about 1972) a vacuum *retard*. This does reduce NOX emissions but it is detrimental to power and mpg. Now, I noticed on my '78 Toyota FJ40, that the spark 'advance' assembly has two ports. Typically a spark advance unit looks kind of like this: /---\ / : \ / : \ vacuum connection---| : o |---mechanical link to dist. \ : / \ : / \---/ The dotted lines in the middle are where the rubber diaphragm is inside. My FJ40, and I'm guessing everyone elses as well, has a second port pointing straight up where the 'o' is in the figure above. This port is plugged with some kind of rubber sealer. I'm guessing that this port leads to the plenum on the other side of the vacuum advance unit and I'm guessing that if you removed the plug, plugged the other side, and hooked manifold vacuum up, voi'la, you'd have yourself a real spark advance in addition to being in violation of federal emissions laws! *Neat* I suppose Toyota, since they sell TLC's all over the world, and only the US requires a retarded vacuum advance, manufactured only one unit with two ports. They plugged one of the ports depending on to what country they were shipping the vehicle. Of course, I'd never monkey with the assembly as being in violation of a Federal law is unthinkable to me but I was simply wondering if anyone else has tried this. Of course you would never keep it that way, it would be purely for experimental purposes and switched back to SOP as soon as you were convinced that there was a difference :) John Brewer "Any man who would trade liberty for security deserves neither." - Ben Franklin ------------------------------ From: SRavet@xxx.com Date: Tue, 23 Jul 96 10:31:41 CDT Subject: re: Re: water injection questions atsakiri@xxx.com Wrote: | | | > How about running a hydrogen peroxide injection system? | | Just a cautious thought out of the blue (i.e. I don't know the | answer) ... it might be a good idea to check on the corrosiveness | first, especially if you have aluminum heads. Any chemists out | there? | | | Anthony Tsakiris | This topic came up on the hotrod list some time ago. the peroxide you buy in the store is too dilute to do any good. Anything stronger is very corrosive. Aparently peroxide was used as rocket fuel a long time ago. - --steve Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: "Josh Karnes" Date: Tue, 23 Jul 1996 15:16:15 +0000 Subject: Re: water injection questions > How about running a hydrogen peroxide injection system? Well, Hydrogen Peroxide is some really mean stuff. My bet is that it is extremely corrosive. Take a look on the bottle of Hydrogen Peroxide you get at the drugstore, and you'll notice that it is typically 99% water, give or take, and 1% H2O2. H2O2 is going to wanna oxidize anything that gets near it. Terrific for the gas in the combustion chamber, but terrible for all those metals that compose the car engine. _____________________________________________________________________________ Josh Karnes joshk@xxx.com Renaissance Man http://www.tanisys.com/~joshk/home.htm Tanisys Technology http://www.tanisys.com Austin, Texas '78 BMW 530i | '72 Datsun 240Z | IZCC #308 _____________________________________________________________________________ *** opinions expressed herein are MINE, ALL MINE!! *** ------------------------------ From: "Tony Bryant" Date: Wed, 24 Jul 1996 09:57:03 +1200 Subject: Re: Spark Advance Engine POWER! > > I've been doing a little light reading (always dangerous) on Internal > Combustion, Spark Ignition Engines. I have discovered that, theoretically, > for peak power and fuel economy, the spark should be advanced (degrees > BTDC) as far as possible until the engine begins to knock, then of course > backed off a little- you don't want it knocking. Also, for peak power and This is not necessarily true. It is possible to over advance without causing knock (on low compression engines on high octane). What happens then is that the rapidly expanding gases are doing more work against the rising piston BTDC than ATDC (when the work does something useful). *********************************************************** * "Insanity is the only sane response to an insane world" * * >> bryantt@xxx.nz << * *********************************************************** ------------------------------ From: Markus Strobl Date: Tue, 23 Jul 1996 17:08:35 -0500 Subject: Re: Spark Advance Engine POWER! > Also, for peak power and > performance, the vacuum and centrifugal advances should be in good working > order and should advance the spark under load or RPMs. However, in > American cars, the vacuum advance is (and has been since about 1972) a > vacuum *retard*. This does reduce NOX emissions but it is detrimental to > power and mpg. Now, I noticed on my '78 Toyota FJ40, that the spark > 'advance' assembly has two ports. [big snip] > John Brewer I wouldn't dream of understanding a Toyota (they are weird), but I DO understand the workings of the GM HEI distributor (all GMs 75-80 something) and they have vacuum advance, not retard. Markus Strobl 96 Z28 6M Black. Borla, !CAGS, 1LE shaft, B&M Shifter Dallas, Texas 1.6 rockers, ported heads, Swaybars, SFC, Crane Springs F-member 9/93 No times since latest mods 27.5mpg @85mph ------------------------------ From: "George M. Dailey" Date: Tue, 23 Jul 1996 17:24:48 -0500 Subject: Re: water injection questions At 08:38 PM 7/21/96 -0700, you wrote: ...this unit is controlled by an adjustable "O.E" quality pressure switch, for >turbo engine use, so some other means of turning it on would have to be used >on non-turbo cars. A 4-gallon aluminum reservoir is shown on the catalog page. > >A lot of people mix Methanol (50/50) with the water. Water alone will act >to slow the combustion process; equivalent to raising the Octane rating (All >Octane rating is, is a gauge of how fast a particular gasoline fuel burns in >a combustion chamber). The ignition timing can then be CAREFULLY advanced >to take advantage of this. With Methanol, you have a more pronounced effect >(The equivalent Octane rating for Methanol is 105). > >If anybody tries this, be extremely careful. If you forget to keep the tank >filled and you don't have sophisticated controls to either tell you of this >or to shut the advance curve down to stock when there is no injection taking >place, you will cause yourself a problem.... > How would GM EST react to this situation? On my 89 TPI set up, I noticed that after running high octane fuel for a week and then switching to the cheap stuff, if I floored the throttle I would hear a few detonations and the check engine light would come on. Code 43 EST. After two or three times of this, it would start working normally. Does it take the ECM this long to adjust. GMD ------------------------------ From: scicior@xxx.com (Steve Ciciora) Date: Tue, 23 Jul 1996 16:40:31 -0600 Subject: Re: Spark Advance Engine POWER! On my '72 Ford 302, the dist. also had two ports: the vaccum advance that went to the manifold, and a vaccum retard, that went to the carb that retarded the dist. under deccel (high vaccum, no throttle, etc). Well, this is how I rember it, reality might resemble the above... - -Steven Ciciora > > > Also, for peak power and > > performance, the vacuum and centrifugal advances should be in good working > > order and should advance the spark under load or RPMs. However, in > > American cars, the vacuum advance is (and has been since about 1972) a > > vacuum *retard*. This does reduce NOX emissions but it is detrimental to > > power and mpg. Now, I noticed on my '78 Toyota FJ40, that the spark > > 'advance' assembly has two ports. > > [big snip] > > > John Brewer > > I wouldn't dream of understanding a Toyota (they are weird), but I DO > understand the workings of the GM HEI distributor (all GMs 75-80 something) > and they have vacuum advance, not retard. > > Markus Strobl 96 Z28 6M Black. Borla, !CAGS, 1LE shaft, B&M Shifter > Dallas, Texas 1.6 rockers, ported heads, Swaybars, SFC, Crane Springs > F-member 9/93 No times since latest mods 27.5mpg @85mph > ------------------------------ From: "Robert E. Yorke" Date: Tue, 23 Jul 1996 16:14:40 -0700 (PDT) Subject: Re: water injection questions Donald: You are correct; I was referring to the end consequence of octane rating procedure and rationale. The resistance to pre-ignition/detonation (They're NOT the same) is closely associated with burn rate, which in turn is associated with combustion (Test) chamber configuration, which affects flame front propagation as well as a host of other factors (ad nauseum). The real world use of octane rating for fuels is as a gauge for determining burn time to allow for successful advance curve determinations. Cutting through all this crap I've tried to throw up, I'm trying to say that even though octane is a measure of "knock" resistance, it as a consequence, is a measure of burn rate! At 09:38 AM 7/22/96 -0400, you wrote: >> From: Robert Yorke >> Date: Sun, 21 Jul 1996 20:38:47 -0700 (PDT) >> Subject: Re: water injection questions >> >> >> >> A lot of people mix Methanol (50/50) with the water. Water alone will act >> to slow the combustion process; equivalent to raising the Octane rating (All >> Octane rating is, is a gauge of how fast a particular gasoline fuel burns in >> a combustion chamber). The ignition timing can then be CAREFULLY advanced >> to take advantage of this. With Methanol, you have a more pronounced effect >> (The equivalent Octane rating for Methanol is 105). >> >> > > >I have a question about octanes (and this may show my ignorance regarding >octane ratings, but) -- I've always been told and under the impression >that the octane ratings on gasoline (not sure how it compares with >Methanol) were not ratings as to how slow the fuel burned, but a rating of >its resistance to pre-mature burn -- i.e. ignition from combustion chamber >heat while being compressed... But here, you are saying the octane >determines the rate it burns ... If that were the case, wouldn't increasing >the octane w/ignition advance give exactly the same results as lowering >the octane w/ignition retard? -- I guess the point is to have a repeatible >mixture that is consistant (i.e. not having pre-mature ignition on some >cycles and delayed ignition on others)... > >Donald Whisnant >dewhisna@xxx.com > > Riverside, CA 2 '88 GTs! ------------------------------ From: "Robert E. Yorke" Date: Tue, 23 Jul 1996 16:38:34 -0700 (PDT) Subject: Re: water injection questions Dave: From the photograph on the sheet I have, it looks like several nozzle heads are provided; just to make sure I'd recommend giving Spearco a phone call. Wish I could help more! At 08:13 AM 7/22/96 -0700, you wrote: >Do you have any information on how the water is supplied to the engine? >(Fogger nozzle or spray bar?) How decent is the pump with this system? >Thanks. >Dave > >At 08:38 PM 7/21/96 -0700, you wrote: >>Water Injection Systems are still available from Spearco Performance >>Products, Inc., 14664 Titus Street, Panorama City, CA 91402. Their Phone >>number is: >> >> (818)901-7851 >> FAX: (818)785-4362 >> >>The part number for their complete system is P.N 980 Turbo Water Injection >>System; Price listed is $146.00 (This may have changed by now) >> > > > > Riverside, CA 2 '88 GTs! ------------------------------ From: "Tony Bryant" Date: Wed, 24 Jul 1996 13:29:30 +1200 Subject: Re: water injection questions > Donald: You are correct; I was referring to the end consequence of octane > rating procedure and rationale. The resistance to pre-ignition/detonation > (They're NOT the same) is closely associated with burn rate, which in turn > is associated with combustion (Test) chamber configuration, which affects > flame front propagation as well as a host of other factors (ad nauseum). The > real world use of octane rating for fuels is as a gauge for determining > burn time to allow for successful advance curve determinations. Cutting > through all this crap I've tried to throw up, I'm trying to say that even > though octane is a measure of "knock" resistance, it as a consequence, is a > measure of burn rate! > To my knowledge, knocking is not a fast burn. The burning process takes some time (for the flame front to travel accross the cylinder). As this burning is happening the pressure in the cylinder rises dramatically. The pressure is also rising (BTDC) due to the piston compressing the mixture. If these two pressure rises combine (due to over-advancing the timing), the resulting pressure = internal energy of the gases may exceeded the activation energy of the combustion reaction. This energy will be present at all points in the unburnt gas, so all molecules of unburnt gas are likely to react, and when the do the pressure rises very suddenly (around TDC) with shock damage resulting to your precious lump o' steel. Knock resistance is a measure of the activation energy required to combust (react) the mixture. Slowing the burn rate can be achieved a number of ways, but its net effect is that the peak unburnt gas energy density is lower because the actual peak will occur when the piston is somewhat past TDC. Knocking is not burning, so knock resistance cannot be a measure of burn rate. *********************************************************** * "Insanity is the only sane response to an insane world" * * >> bryantt@xxx.nz << * *********************************************************** ------------------------------ From: Dave Zug Date: Tue, 23 Jul 1996 21:57:31 -0400 Subject: spark advance curve modification I have a turbo car (8.7:1 compression, 91 octane required) with a GMP4 ECM. I KNOW where the spark curves are on the eeprom, my question is: can someone give a description of a baseline tequnique i can use to modify the spark table for "mild/medium" performance increase? example: increase advance for the lower load lines 1-2 defress, and the upper load lines 3-4 deg, or increase beginning of all lines 1 degree, middle of lines 2-3 degrees and ends of lines 1-2 degrees.. engine is MAP controlled, not MAF and HAS ELECTRONIC SPARK CONTROL with knock sensor.. can i rely in knock sensor to protect against possible over-advance on eeprom if i accidently use a "FA" insted of "2A" ? sorry if i left out vital info for an answer, i'll revise it with any requested info and re-mail if so. thanks. dave ~~~~~~~~~~~~~~~~ "still waiting for a DIY issue i can contribute to, though it looks unlikely, I wont give up." ~~~~~~~~~~~~~~~~ ------------------------------ From: "Stuart Woolford" Date: Wed, 24 Jul 1996 14:14:31 +1100 Subject: Re: Filtering supply lines > The only way to guarantee you are at a true 0v ground is to run > a wire back to the battery terminal. and what defines the battery terminal as 0v ground? really - the battery terminal can be a particularly noise prone ground point depending on the charging system design.. (from too much car sterio install experience..) looking for a 'true' ground is usually not the solution, finding a non-noisy one is quite a different job - I have usually found a good solid frame ground to be good - you pick up so much noise on you earth line to the battery that it gets real bad real fast. You just need to find a frame ground with good conduction paths to the other ground references you are linked to. - ---------------------------------------------------------------------- Stuart Woolford, stuart@xxx.nz >>>>In VI Where Available<<<< - ---------------------------------------------------------------------- ------------------------------ From: David Channon Date: Wed, 24 Jul 1996 15:08:31 +1000 (EST) Subject: Windsor EFI manifold I am playing with the efi332 project and want to start setting up the EFI hardware for a 289/302 Windsor V8 (late 60s). I was thinking along several lines 1) Make a manifold, 2) Modify a Manifold eg Add (tig weld) efi bosses into a alloy single plain manifold 3) Import a factory EFI manifold (New or Second hand). Questions: 1) Suggested solutions - opinions please. 2) Can someone offer to get the EFI manifold from a wrecker with some of the sundary bits - and I send some money to cover the costs (I would like an idea of cost before I agree). 3) What is the cost of a second hand single plane manifold (I will play for the costs). Since this is a project I am trying to save some money while trying to learn something and experiment with the car. Any and all suggestions appreciated - Thanks in advance. Cheers David. - -- - ----------------------------------------------------------------- David Channon .-_|\ Department of Computer Science / \ The University of Newcastle \.--._/ NSW, 2308, AUSTRALIA v Email : mailto://dchannon@xxx.au URL : http://wwwcs.newcastle.edu.au/Research/VMRG/dchannon.html - ----------------------------------------------------------------- "Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald E. Knuth ------------------------------ From: "Michael D. Porter" Date: Tue, 23 Jul 1996 22:18:28 -0700 Subject: Re: water injection questions > | Just a cautious thought out of the blue (i.e. I don't know the > | answer) ... it might be a good idea to check on the corrosiveness > | first, especially if you have aluminum heads. Any chemists out > | there? > | Anthony Tsakiris > | > > This topic came up on the hotrod list some time ago. the peroxide you buy > in the store is too dilute to do any good. Anything stronger is very > corrosive. Aparently peroxide was used as rocket fuel a long time ago. > > --steve Quite correct, Steve. The use I remember is in the Messerschmidt ME-163 rocket plane. As I recall, pure H2O2 is a sufficiently strong oxidizer that it can burn skin on contact. There were problems with tank integrity in the planes, and they occasionally leaked. Made for an unpleasant flight, from the pilot interviews I've seen. Cheers. ------------------------------ From: "Michael D. Porter" Date: Tue, 23 Jul 1996 22:04:21 -0700 Subject: EFI control units I'm very new here--just been reading this group for a couple of weeks--and have a question or two on available control units. I've been sorting out what I think I need to convert Triumph six-cylinder to digital FI, but have not yet found a control unit which seems to meet the requirements I've set. I'd like to find a controller with sequential injection and is also programmable via laptop and can accept input from a domestic MAF sensor. I realize many of the folks here are concerned with building their own control units and doing much or all of their own programming, but I simply don't have the time or test equipment for that sort of undertaking. Any suggestions? Thanks. ------------------------------ From: "Michael D. Porter" Date: Tue, 23 Jul 1996 23:05:30 -0700 Subject: Re: water injection questions??? tom sparks wrote: > > If all a person wants to do is lower the heat of combustion and hence the > speed of the flame front, then why not just fatten up the fuel curve at the > point where detonation is expected? Why add all the extra hardware and > expense (and risk) of a water injection system? It may be that enrichment might work for a very short while, but then, the mixture would have to go below that for maximum power, and there's fuel wasted, besides. The other consideration (just speculating, here) is that richer mixtures may not prevent detonation--if the chamber is warm enough, and there are hot spots hot enough, the mixture may not be _homogenously_ rich enough, and detonation may begin anyway, unless the mixture is downright lumpy, sooty rich. The other thing I've not seen mentioned yet is that water, in a Brayton-cycle turbine, serves to add mass to the burning mixture, which translates to higher forces impinging on the turbine section. Water injection may serve the same purpose in an IC engine, to some small degree, by applying slightly greater force to the pistons. Cheers. ------------------------------ From: Robert Yorke Date: Tue, 23 Jul 1996 22:54:07 -0700 (PDT) Subject: Re: water injection questions Tony: As I read this, I believe you are correct. I've been trying to refer to my little "Bible" regarding automotive gasoline (The FAQ "Automotive Gasoline" by Bruce Hamilton; posted to several usenet groups on a monthly basis) in an effort to either refute you or agree with you, and I can't find his definition of knock! However, I believe you're right... WAIT, I just found it: "The octane rating of the fuel reflects the ability of the unburnt end gases to resist spontaneous autoignition under the engine test conditions used. If autoignition occurs, it results in an extremely rapid pressure rise, as both the desired spark-initiated flame front, and the undesired autoignited end gas flames are expanding. The combined pressure peak arrives slightly ahead of the normal operating pressure peak, leading to a loss of power and eventual overheating. The end gas pressure waves are superimposed on the main pressure wave, leading to a sawtooth pattern of pressure oscillations that create the knocking sound" You are correct; I was wrong... At 01:29 PM 7/24/96 +1200, you wrote: > >> Donald: You are correct; I was referring to the end consequence of octane >> rating procedure and rationale. The resistance to pre-ignition/detonation >> (They're NOT the same) is closely associated with burn rate, which in turn >> is associated with combustion (Test) chamber configuration, which affects >> flame front propagation as well as a host of other factors (ad nauseum). The >> real world use of octane rating for fuels is as a gauge for determining >> burn time to allow for successful advance curve determinations. Cutting >> through all this crap I've tried to throw up, I'm trying to say that even >> though octane is a measure of "knock" resistance, it as a consequence, is a >> measure of burn rate! >> > > >To my knowledge, knocking is not a fast burn. The burning >process takes some time (for the flame front to travel accross the >cylinder). As this burning is happening the pressure in the cylinder >rises dramatically. The pressure is also rising (BTDC) due to the >piston compressing the mixture. If these two pressure rises combine >(due to over-advancing the timing), the resulting pressure = internal >energy of the gases may exceeded the activation energy of the >combustion reaction. This energy will be present at all points in the >unburnt gas, so all molecules of unburnt gas are likely to react, and >when the do the pressure rises very suddenly (around TDC) with shock >damage resulting to your precious lump o' steel. > >Knock resistance is a measure of the activation >energy required to combust (react) the mixture. Slowing the >burn rate can be achieved a number of ways, but its net effect is >that the peak unburnt gas energy density is lower because the >actual peak will occur when the piston is somewhat past TDC. > >Knocking is not burning, so knock resistance cannot be a measure of >burn rate. >*********************************************************** >* "Insanity is the only sane response to an insane world" * >* >> bryantt@xxx.nz << * >*********************************************************** > > 2 "88 GTs, both autos! ------------------------------ From: Robert Yorke Date: Tue, 23 Jul 1996 23:20:00 -0700 (PDT) Subject: Re: water injection questions George: I haven't the slightest idea why this would occur in your car; apparently the ECM in some way adjusted the advance to take advantage of the higher octane gas being used, then required a re-adjustment period to compensate for a return to 87 octane gas... Does your shop manual describe in any way this kind of ECM operating characteristic? If this is indeed what happens with your ECM, it's a hell of a lot more sophisticated than the C3 ECMs in V-6 Fieros! At 05:24 PM 7/23/96 -0500, you wrote: Snipped > >How would GM EST react to this situation? On my 89 TPI set up, I noticed >that after running high octane fuel for a week and then switching to the >cheap stuff, if I floored the throttle I would hear a few detonations and >the check engine light would come on. Code 43 EST. After two or three times >of this, it would start working normally. Does it take the ECM this long to >adjust. > >GMD > > > 2 "88 GTs, both autos! ------------------------------ From: David.Haynes@xxx.uk Date: Wed, 24 Jul 96 08:20:40 GMT Subject: Water injection questions I remember a discussion of this subject about a year ago on this group. Someone posted an example of the dangers of running the tank dry, mentioning (I think) a 240Z Datsun with turbo and water injection. Running out of water on the strip resulted in the 'usual' meltdown, but also a crankcase oil fire ! How much benefit might be produced in a non-turbo, stock motor. I'm think purely of the charge cooling and increased charge mass. Could this produce significant gains used with enrichment at WOT? Roughly how much water would be required per volume of air? How much ignition advance would be required ? I have the idea of messing about with a DIY system, since without a turbo or serious engine mods, there should be no danger of serious damage if the flow stops. I dont know about filling the engine with water as was mentioned the other day, but I have had the cylinders filled with petrol, due to water in the flywheel sensor. It oscillated when wet, and the ECU believed that 8000rpm was dialled in, while the engine was lumping along at 750rpm. At the inevitable stall, so much fuel was injected that hydraulic lock resulted and the engine could not be cranked. The solution was to take the plugs out and walk home, to wait for the fuel and water to evaporate! Dave Haynes ------------------------------ End of DIY_EFI Digest V1 #207 ***************************** 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".