DIY_EFI Digest Wednesday, 21 February 1996 Volume 01 : Number 049 In this issue: Re: 286 Vindication Re: Buick DIS coil drivers Re: 286 Vindication RS232 Data Aquisition Re: Buick DIS coil drivers Car Craft EFI Special Re: <911> Bosch Motronic -Forward -Reply Re: MPX2200 Altitude compensation (Re: 286 Vindication) Intake runner sizing.. Re: Altitude compensation Looking for DAC and w2w (for data acq project) Re: FW: Re: Radio Shack DMM with RS-232 interface and ProbeScope Re: <911> Bosch Motronic -Forward -Reply Real world TPI hp gains FW: Real world TPI hp gains Re: Intake runner sizing.. Re: Real world TPI hp gains Re: Real world TPI hp gains Re: Altitude compensation Re: Intake runner sizing.. Re: Ford 2.3 litre motor 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, 20 Feb 1996 10:24:25 EST Subject: Re: 286 Vindication ~ > ~ >BTW, my environmental correction WWW page shows the effects ~ >of altitude and barometer on engine HP/torque, and they can be dramatic. ~ ~ Yes, they sure can. ~ ~ My final point, if the pressure does not change then you don't have to ~ correct for it. ~ ie. there is nothing to correct. ~ ~ ~ This sounds good. However, what value would you choose for the absolute reference pressure, since this would have to be a hard-wired value. And what happens if you drive up to the mountains? Here is the equations which convert the barometric pressure read on a mountaintop to sea-level (the eqns are from 1978 CRC handbook): xk = 1.6e06*(1.+.0022222*(temp-32.)); bpc = -((30.48*elev-xk)/(30.48*elev+xk))*bpress; with: bpc = the corrected barometer reading to sea level. and inputs of temp in degrees F, elev in feet, bpress = actual barometer reading in in. Hg. I made a simple code which runs through the equation above for various elevations (the uncorrected barometer and temp is hardwire inputs): - -------------------------------------------------------------------------------------------- main() { float xk, bpc,temp, elev, bpress; temp = 70.; bpress = 30.00; elev = 0; printf("For temp of %2.1f degrees F and barometer of %2.2f inches Hg\n\n",temp,bpress); printf("Elevation(Feet) CorrectedBarometer\n---------------------\n"); while(elev <= 2000.) { xk = 1.6e06*(1.+.0022222*(temp-32.)); bpc = -((30.48*elev-xk)/(30.48*elev+xk))*bpress; printf(" %4.0f %f\n",elev,bpc); elev = elev + 100.; } } - --------------------------------------------------------------------------------------------- and here is a run of the above code: For temp of 70.0 degrees F and barometer of 30.00 inches Hg Elevation(Feet) CorrectedBarometer - --------------------- 0 30.000000 100 29.894785 200 29.789938 300 29.685459 400 29.581343 500 29.477591 600 29.374197 700 29.271164 800 29.168488 900 29.066166 1000 28.964199 1100 28.862583 1200 28.761314 1300 28.660397 1400 28.559824 1500 28.459595 1600 28.359709 1700 28.260162 1800 28.160955 1900 28.062088 2000 27.963554 Does this have an effect on a tuned engine? - - 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: John T Stein Date: Tue, 20 Feb 1996 12:09:45 ET Subject: Re: Buick DIS coil drivers > Date: Mon, 19 Feb 1996 17:00:19 -0800 > From: arthurok@xxx.com (ARTHUR OKUN ) > Subject: Re: Buick DIS coil drivers > To: diy_efi@xxx.edu > Reply-to: diy_efi@xxx.edu > their not that difficult to work with the crank shaft sensor hooks > directly to the module below 400 rpm the module directly controls the > spark for starting ; their are 8 cyl units availible > the module is expensive about $150 as a replacement part minus coils > ... and the coils will run you about $65.00 each at the dealer. (from recent experience!!) John ------------------------------ From: "Kenneth C. King" Date: Tue, 20 Feb 1996 12:05:47 -0600 (CST) Subject: Re: 286 Vindication On Mon, 19 Feb 1996, Bruce Bowling wrote: > I guess one can come up with an absolute pressure value and always > use this with the differential sensor. But this may work only if > you do not go up an mountain, and if the barometric pressure remains > the same forever. greetings: there are also problems for those who drive distances. driving out from under a dry high pressure to under a wet low pressure will likely cause some problems... even going from the alabama lowlands up thru the tennessee hills will cause my ears to pop, so there may be enough to make a difference for the engine. later, kc ------------------------------ From: dn Date: Tue, 20 Feb 96 11:57:24 MDT Subject: RS232 Data Aquisition GMD writes: > A/D converter, could an analog to RS232 module be built? Why build when you can buy? There are literally hundreds of this type of unit kicking around out there, you just have to look for them. Look in the back of Circuit Cellar Ink, Radio Electronics, PC magazine, Byte, etc. and you will find lots of small companies making a/d peripherals for PC's using both serial and parallel port connections. Looking in an old CCI magazine, I found 5 different companies selling such boards for under 150.00, with up to 16 channels of 12 bit a/d. Leave the hard stuff for somebody else, and spend more time doing your own thing rather than re-inventing the wheel! regards dn - -- - --------------------------------------------------------------------- Darrell A. Norquay Internet: dn@xxx.ca Datalog Technology Inc. Bang: calgary!debug!dlogtech!darrell Calgary, Alberta, Canada Voice: +1 (403) 243-2220 Fax: +1 (403) 243-2872 @ + < __/ "Absolutum Obsoletum" - If it works, it's obsolete -------------------------------------------------------------------- ------------------------------ From: Sandy Date: Tue, 20 Feb 1996 14:44:36 -0500 Subject: Re: Buick DIS coil drivers >> their not that difficult to work with the crank shaft sensor hooks >> directly to the module below 400 rpm the module directly controls the >> spark for starting ; their are 8 cyl units availible >> the module is expensive about $150 as a replacement part minus coils >> > >... and the coils will run you about $65.00 each at the dealer. (from recent >experience!!) > I think I paid $45 from electromotive for the same coil. Sandy ------------------------------ From: "James E. Brady III" Date: Tue, 20 Feb 1996 15:05:46 -0500 Subject: Car Craft EFI Special FYI, For those of you into EFI V-8's Car Craft has dedicated their latest issue to EFI. If this appeals to you please let the editors know so there can be more articles on Fuel Injection. I wrote a letter and mentioned this web site so that others may indulge. Jim Brady ------------------------------ From: BANESI@xxx.com (Brad Anesi) Date: Tue, 20 Feb 1996 12:44:04 -0800 Subject: Re: <911> Bosch Motronic -Forward -Reply In a recent post, I had gotten a response back about the temperature sensors NOT being linear. Listed below is the response I had to this post from my friendly (and quite knowledagble) Alfa mechanic. Serve ...volley ...volley ...??? >Brad, the temperature sensors Bosch uses are thermistors and in all >the testing I've done with them, it sure as hell looks like they're linear. >And even if they are not, adding a fixed resistor of whatever value >simply starts the base at a little higher value and goes on from there. >The object is to have the ECU understand that the engine temperature is >a little colder than the sensor says it is so it will be rich enough to start >easily and run smoothly if that proves to be the problem. The use of a >TrimPot tells the story. >I can be wrong, others can be wrong. Please let me know what you >find. Further opinions anyone? Brad '86 Porsche 911 Coupe '91 Alfa Romeo 164 ------------------------------ From: Tommy.Palm@xxx.se Date: Tue, 20 Feb 1996 16:38:25 -0500 Subject: Re: MPX2200 Item Subject: Meddelandetext Darrel wrote: >Looking through their catalog, I noticed that the MPX2200 is not available >in a differential configuration, and it is a 0-30PSI absolute sensor, >which would probably be used in a turbo application... The MPX2100A is >a 0-15 PSIA unit which is probably what you want. >MPX5100 series which have a built in amplifier/signal conditioner which > This one is available either absolute (MPX5100A) >or differential (MPX5100D), 0-15 PSI only, and would be a bit more expensive >than the 2100. In Sweden (ELFA) they only sell the differential MPX2200DP not the MPX2200AP that I rather would have. I had to buy the non temp compensated MPX200A therefore. The 2200 costs 231 SEK. The 5100 DP and AP cost 385 sek. Actally I got a sample for free when phoning to Motorola! Tommy ------------------------------ From: "Zublin, Bryan (SD-MS)" Date: Tue, 20 Feb 1996 13:48:00 -0800 (PST) Subject: Altitude compensation (Re: 286 Vindication) > That's what people do however you have to stop the engine and restart it > at the top of the mountain before it corrects! > Two sensors is the best method. Two absolute or one absolute and one > differential is does not matter. (If you want to change altitude). Isn't it true that for a speed density efi system with an _absolute_ MAP sensor, then altitude compensation is not needed? For example, if you changed altitude, the barometric pressure changes, which changes the pressure in the manifold, which the MAP sensor directly measures. Temperature (air density) compensation is still needed. Now for a efi system using the "trap door" air flow meter, I believe altitude compensation is needed. In addition to temperature compensation. Bryan Zublin bzublin@xxx.com ------------------------------ From: Craig Pugsley Date: Wed, 21 Feb 1996 10:02:59 +1100 (EST) Subject: Intake runner sizing.. Hi, A semi-efi qn on a forthcoming carb-efi conversion.. I have a Mazda 13B street port that I am planning to EFI, and am wondering about intake runner length/diameter characteristics for max torque/max power. For the un-initiated, mazda rotarys are a '2 cylinder' engine with a primary and a secondary intake port. These ports commonly have different opening & closing timing to spread the torque curve (to some extent). For example mine has almost stock primarys (for good low down torque) and large secondarys (for mid-high end power). Is it true that the longer a runner the lower in RPM the torque peak will be? If that's the case should the primarys be long and the secondarys short? Note that in the stock carburetted engines, the secondary runners are bigger and longer than the primarys (as the 'primarys' are in the 'middle' of the engine and the 'secondarys' are at the 'outside ends' of the engine). Any ideas or is experimentation the best teacher? (Hmm, go to the plumbing supplies place and get lots of angled bends and pipe with threaded ends for this one :-) Cheers, Craig. ------------------------------ From: robert dingli Date: Wed, 21 Feb 1996 10:41:25 +1100 (EST) Subject: Re: Altitude compensation Bryan wrote, > Isn't it true that for a speed density efi system with an _absolute_ MAP > sensor, then altitude compensation is not needed? For example, if you > changed altitude, the barometric pressure changes, which changes the > pressure in the manifold, which the MAP sensor directly measures. > Temperature (air density) compensation is still needed. This is correct to a certain extent. There is still the backpressure on the exhaust which makes a small difference. I have never come across an aftermarket efi which takes this into account. OEM speed-density controllers such as the Ford EECIV/V on the 6 cylinder Falcon do mesure barometric pressure (using the same sensor during prior to starting) and compensate. > Now for a efi system using the "trap door" air flow meter, I believe > altitude compensation is needed. In addition to temperature compensation. Indeed. Robert - -- Robert Dingli r.dingli@xxx.au Power and Control Systems (+613) 9344 7966 Thermodynamics Research Labs (+613) 9344 7712 University of Melbourne, AUSTRALIA ** he who dies with the most toys, wins ** ------------------------------ From: Grant Beattie Date: Tue, 20 Feb 1996 17:23:17 -0700 (MST) Subject: Looking for DAC and w2w (for data acq project) I'm trying to find people interested in building data logging equipment for racing (my application is karts). Perhaps something along the lines of diy_dac could be created (there was one once). I've found alot of interest from the karting community, but I'd like to contact the Wheel2Wheel racing list also, but I don't have the list address. So if you have that list address or would like to talk about data acquisition for racing let me know. Fow what it's worth, I've got mine working. Check http://ourworld.compuserve.com/homepages/grantb for more info on it. Thanks, GB ------------------------------ From: "George M. Dailey" Date: Tue, 20 Feb 1996 18:47:26 -0600 Subject: Re: FW: Re: Radio Shack DMM with RS-232 interface and ProbeScope At 06:25 PM 2/19/96 PST, john carroll wrote: .... What are you doing with all this fast data? Good question. Nothing! When Radio Shack premires its "PROBE SCOPE", I'll probably buy it. I was simply curious about how it worked, and was hoping to get that magical response from DIY members of "...built one last year for $2.17 and it took only 7 minutes to complete. You need ...." Thanks for your input folks. GMD ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Tue, 20 Feb 1996 17:13:37 -0800 Subject: Re: <911> Bosch Motronic -Forward -Reply the specs on the temp. sensor according to a troubleshooting reference are 175*f 270-290 ohms , 68*f 2100-2900 ohms , and 14*f 7000- 116,000 ohms the resistances are approxamate and the ranges include manufacturing tolerances those resistances are similar to gm's you see if you stuck anything over 50 ohms or so in series it would screw up the top end . with these numbers now you can check your sensor ------------------------------ From: "George M. Dailey" Date: Tue, 20 Feb 1996 19:19:06 -0600 Subject: Real world TPI hp gains Decreasing inlet air temp(and intake manifold temp) will increase horsepower with no other changes, assuming the ECM is allowed to adjust accordingly. Has any one dyno tested a '89 350 TPI engine and then changed only the thermostat (195 to 150) and removed the hot coolant going to the throttle body to see the net 'real world' torque increase? What do you guys think about an electronic controlled thermostat on FI cars? Dial it low for fun in the sun power. Dial it high when Jack frost is biting your head off. It's my understanding that, too low of an engine temp is bad for the engine (long term). Higher engine temps give better fuel economy and other desirable characteristics for every day driving. An electronic controlled thermostat could allow street roders to have the cake and eat it too... if the gain is substantial enough. GMD ------------------------------ From: jac@xxx.us (john carroll) Date: Tue, 20 Feb 96 20:19:34 PST Subject: FW: Real world TPI hp gains It is not clear to me that dropping the jacket temperature would significantly alter the induction air temperature. It is almost certain to increase the heat rejected to the cooling system. The more heat the system must handle, the less likely the system is to hold the engine temperature constant. The result is more wear. An increase of deposits from condensation of combustion products is almost certain. After the intake valve is closed the warmer engine is all for the better. I wonder what would be the effect of insulating the the induction air system, changing the coolant to a straight dry glycol and running engine at 240F? john carroll jac@xxx.us >Decreasing inlet air temp(and intake manifold temp) will increase horsepower >with no other changes, assuming the ECM is allowed to adjust accordingly. >Has any one dyno tested a '89 350 TPI engine and then changed only the >thermostat (195 to 150) and removed the hot coolant going to the throttle >body to see the net 'real world' torque increase? What do you guys think >about an electronic controlled thermostat on FI cars? Dial it low for fun >in the sun power. Dial it high when Jack frost is biting your head off. > >It's my understanding that, too low of an engine temp is bad for the engine >(long term). >Higher engine temps give better fuel economy and other desirable >characteristics for every day driving. An electronic controlled thermostat >could allow street roders to have the cake and eat it too... if the gain is >substantial enough. > >GMD > ------------------------------ From: "Graydon D. Stuckey" Date: Tue, 20 Feb 1996 22:46:58 -0500 (EST) Subject: Re: Intake runner sizing.. On Wed, 21 Feb 1996, Craig Pugsley wrote: > I have a Mazda 13B street port that I am planning to EFI, and am > wondering about intake runner length/diameter characteristics for max > torque/max power. ... > Is it true that the longer a runner the lower in RPM the torque peak > will be? If that's the case should the primarys be long and the > secondarys short? That is basically true. If you are using the secondary control valves, then, yes you could tune the secondaries for high rpm use (3500 and up) and tune the primaries for low rpm use (less than 3500 rpm). Personally, I think those 6-port valves are more restrictive than they are worth. I would take them out, and fab up variable length intake runners. Then you can tune all the runners for all rpm ranges. Later, Graydon D. Stuckey graydon@xxx.edu Flint, Michigan USA '86 Audi 5000 CS Turbo Quattro, GDS Racing Stage II '85 Mazda RX7 GS 12A-leaning-towards-a-13B-soon ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Tue, 20 Feb 1996 19:51:01 -0800 Subject: Re: Real world TPI hp gains an electric radiator fan can provide some of those benefits . "some of the new rwd cars and trucks have them ie ford v8 thunderbird. ------------------------------ From: Johnny Date: Tue, 20 Feb 1996 19:56:07 -0800 Subject: Re: Real world TPI hp gains George M. Dailey wrote: > > Decreasing inlet air temp(and intake manifold temp) will increase horsepower > with no other changes, assuming the ECM is allowed to adjust accordingly. > Has any one dyno tested a '89 350 TPI engine and then changed only the > thermostat (195 to 150) and removed the hot coolant going to the throttle > body to see the net 'real world' torque increase? What do you guys think > about an electronic controlled thermostat on FI cars? Dial it low for fun > in the sun power. Dial it high when Jack frost is biting your head off. > > It's my understanding that, too low of an engine temp is bad for the engine > (long term). > Higher engine temps give better fuel economy and other desirable > characteristics for every day driving. An electronic controlled thermostat > could allow street roders to have the cake and eat it too... if the gain is > substantial enough. It would seem that you wouldn't want to vary the engine operating temp though... would you? The key is to have the engine hot as hell, and the induction air cold as hell. Usually the power increases as the engine temp increases due to optimum clearances, lower oil viscosity, better combustion, etc. Likewise, the power increases with the reduction of intake charge temp due to an increases in density. So cutting any heating to the intake is great, but you don't need to lower the rest of the engine temp to do it. - -j- ------------------------------ From: Fred Miranda Date: Tue, 20 Feb 1996 23:03:57 GMT Subject: Re: Altitude compensation >> Isn't it true that for a speed density efi system with an _absolute_ MAP >> sensor, then altitude compensation is not needed? For example, if you >> changed altitude, the barometric pressure changes, which changes the >> pressure in the manifold, which the MAP sensor directly measures. >> Temperature (air density) compensation is still needed. > >This is correct to a certain extent. There is still the backpressure >on the exhaust which makes a small difference. I have never come across >an aftermarket efi which takes this into account. Autronic makes a box that has provisions for ex backpressure comp, they also seem to make barometric pressure estimations while running, off the same sensor measuring engine vacuum. As for the affect of altitude on a speed density system with no alt comp, take the case of an engine with little manifold vacuum, say it idles at 70-80kpa absolute at sea level. It's operating range of vacuum is so compressed that a change in elevation of 1000ft can through it's calibration all out of wack. It will go lean as you as you go up the mountain. Any system that only looks at barometric pressure at startup is useless in the real world. The motor could be gone well before you reach the top of the pass. Fred ------------------------------ From: Craig Pugsley Date: Wed, 21 Feb 1996 16:51:00 +1100 (EST) Subject: Re: Intake runner sizing.. > Personally, I think those 6-port valves are more restrictive than > they are worth. I would take them out, and fab up variable length intake > runners. Then you can tune all the runners for all rpm ranges. Not a 6 port, it's a 4 port (R5?? housings) - Japanese spec engine. Variable intake length would be fun - could you have the butterflys in a fixed position and use variable length trumpets, or do you mean variable length by changing it with several butterflys to turn on/off extra tubing. Hmm.. so if I had 4 feet of tube would the torque peak be at idle?? :-) (It's an automatic). Cheers, Craig. ------------------------------ From: masmith Date: Tue, 20 Feb 1996 23:27:00 -0800 Subject: Re: Ford 2.3 litre motor At 09:03 PM 2/19/96 -0800, you wrote: >Some time ago, I salvaged a 2.3 litre turbocharged motor from an '87 T-Bird. >Although I have everything (ECU, EGO, MAF, etc.), most of the wiring was cut >to facilitate removal of the equipment from the body. Does anyone have, or >know where to find a pin-for-pin wiring diagram for this equipment? Any >help would be greatly appreciated. > > > Thanks, > > > Bill Sarkozy > > Kalamazoo, MI > >try your local library - im serious! i got EVERY wire in my 85 ltd from the Mitchells manual at my local (Lancaster CA), generic public library. there is a Mitchells manual for each domestic model year) i saw similar wiring diags complete with numbers and color codes for the 4 in the ltd, which is the same motor - turbo of course. good luck and hopefully some illiterate asswipe hasn't ripped out your page. :-( Matt Smith masmith089@xxx.com Mailer Eudora 1.5.2 ------------------------------ End of DIY_EFI Digest V1 #49 **************************** 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".