DIY_EFI Digest Friday, 29 January 1999 Volume 04 : Number 073 In this issue: Re: Love This Re: Anyone trigger a electronic IG module with points? Re: Anyone trigger a electronic IG module with points? Re: New Turbo from Garrett Re: home dyno kit?? Re: Love This replace an EPROM with an EEPROM? Oh Class, tap, tap, tap ECM'sa smokin Memcal's Re: replace an EPROM with an EEPROM? Re: Anyone trigger a electronic IG module with points? Re: Cubic Dollars Re: Love This Re: Love This Different Strokes Re: home dyno kit?? RE: Love This RE: Different Strokes Re: Different Strokes Re: Love This Re: RE: Different Strokes Re: Anyone trigger a electronic IG module with points? Re: Different Strokes Re: Oh Class, tap, tap, tap ECM'sa smokin Re: Cubic Dollars Re: Oh Class, tap, tap, tap ECM'sa smokin Re: Cubic Dollars Re: Different Strokes Re: home dyno kit?? Re: Oh Class, tap, tap, tap ECM'sa smokin Re: Love This See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 29 Jan 1999 14:01:24 -0700 Subject: Re: Love This >-----Original Message----- >From: James Weiler >To: diy_efi@xxx.edu> >Date: Friday, January 29, 1999 1:07 AM >Subject: RE: Love This > >For me it's not the plumbing that is the "news". It's being able to >manipulate >fuel line pressure without needing a mechanical device. As things sit now >for TPI the fuel pressure is referenced to engine vac/boost. With this >device >a closed loop electrically controlled Fuel pressure trimmer is possible, >meaning >big injectors, lower pressure at idle, to help get reasonable pulse widths. >Bruce Hey--if you wanna do it right--use a rising rate regulator IN COMBINATION with a pwm voltage control to the fuel pump AND a calculated fuel pressure correction to the injector pw calc. It would hafta be a primary--secondary fuel pressure control loop to be stable--program what the fuel pump is supposed to do according to load/rpm ()with a look-up table), let the rising rate regulator fine tune the rail pressure (it would be A LOT more accurate cuzza bypass flow rate being nearly constant), AND also use your rail pressure input to apply a calculated correction to the injector pw on the fly. Doing these things in combo would prolly improve the accuracy of the fuel quantity delivered to the engine by at least 2 or 3%, particularly under transient conditions!! Also, you will NOT lose the DISTINCT ADVANTAGE of having some fuel recirculating through the rails--to keep them cooler--this way. Methinks that the GM comments about less emissions have only to do with keeping the fuel TANK cooler and keeping the evaporative problem smaller by doing so. If you get vapor in the rails--it has to either go through the injectors or back to the tank--no where else it COULD go. And--IMHO--if it goes thru the injectors, it will give you a lean episode, and a stumble at best, or, more likely, a detonation episode. Fact is--I believe in putting a float vent at the high point of the fuel rail plumbing, so as to be SURE that all vapor goes back to the tank, and NOT into the injectors. Regards, Greg > > >>Sorry to get in this late but so what? I mean whats the advantage of >a >one line EFI vs. 2 fuel line set-up? Besides less plumbing. >>thanks >>jw >> ------------------------------ From: "Bruce Plecan" Date: Fri, 29 Jan 1999 16:37:05 -0500 Subject: Re: Anyone trigger a electronic IG module with points? - -----Original Message----- From: AL8001@xxx.com> To: diy_efi@xxx.edu> Date: Friday, January 29, 1999 3:00 PM Subject: Anyone trigger a electronic IG module with points? Points need enough current thru them to "burn" the oxidation off. Hence, better off to use hall effect or optical replacements for the points. IMHO Bruce >Hi all, I have some old tractors/trucks and such that I would like to convert >to electronic IG. Mostly because since they are limited use, the plugs tend >to carbon foul. > >I would like to keep the points intact and just wire up the module and >realated parts. I could convert the dist to a pick up coil and such but would >rather not. > >I'm thinking of a high ohm resistor from 12 V to the points. Then tap the + >pickup coil input on the IG module to the points. I would rather use somthing >common like a GM 4 pin/ Chrysler 5 pin/ or a Ford Duraspark. The Ford 3 pin >dist mounted TFI looks good as well. > > >Thanks for the help. > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 29 Jan 1999 14:35:05 -0700 Subject: Re: Anyone trigger a electronic IG module with points? >Hi all, I have some old tractors/trucks and such that I would like to convert >to electronic IG. Mostly because since they are limited use, the plugs tend >to carbon foul. > >I would like to keep the points intact and just wire up the module and >realated parts. I could convert the dist to a pick up coil and such but would >rather not. > >I'm thinking of a high ohm resistor from 12 V to the points. Then tap the + >pickup coil input on the IG module to the points. I would rather use somthing >common like a GM 4 pin/ Chrysler 5 pin/ or a Ford Duraspark. The Ford 3 pin >dist mounted TFI looks good as well. > > >Thanks for the help. Years ago, Delta Products, from Grand Junction, CO , used to make a CD ignition box--available either assembled or in kit form--- that used the points for a trigger. One of the tricks was that you had to keep the current thru the points high enough to keep them clean. With you resistor approach, that would not be the case. Dunno whatever happened to Delta, or if there is anything like their system around now. It was a fine ignition. It even had a switch so you could go back to standard points ignition if the electronics screwed up somewhere "inconvenient". Regards, Greg ------------------------------ From: Jim Davies Date: Fri, 29 Jan 1999 13:36:27 -0800 (PST) Subject: Re: New Turbo from Garrett On Fri, 29 Jan 1999, Clarence Wood wrote: > adaptable to anything. It offers 'supercharger-like low end response and > excellent packaging'. The drive motor is about half the size of the > exhaust-driven turbine and is direct-coupled to the impeller. They also > are working on a 'dry' tirbo using air bearings." > Sounds a bit like the Merceded Benz 600 series V-12 blower drive from WW2 ------------------------------ From: Roger Heflin Date: Fri, 29 Jan 1999 09:47:53 -0600 (CST) Subject: Re: home dyno kit?? On Fri, 29 Jan 1999, Mike wrote: > > > >That is mostly what the home dyno kit does. You collect the > >information off of a spark plug, and then use that to calculate > >acceleartion based on the rpm changes. The program is setup to record > >the data as a audio signal and then later process that audio signal on > >a computer to get the info out. > > > > That'll teach me to read (more accurately "peruse") only a few posts on a > thread then post a follow-up... > > Still, I'd have thought that doing this measurement in the "digital" domain > with a timer resolution of 500nS or better would produce better results than > in the audio domain with the associated noise and distortion etc. > > After looking at the web page though I see the results look pretty good > though so things can't be that bad in audio-land. Neat. > > I would guess that the trigger point or the center of a given spark (measured in the audio-domain) is probably centered pretty consistantly at the same point, and since you don't have to do things real time you can take some time to analyze and determine exactly were each pulse was centered. And even if they varied a bit, the average should be pretty good. I did some quick calcs, and 3000 rpm the pulse spacing is 20 ms, and 3025 rpm is 19.83 ms (DIS), so if you have .1 ms resolution you would be able to get better than 25 rpm accuracy at this point. And ao long as you have enough bandwidth to be able to determine each pulse you should be able to do it. My guess is that a basic cheap take recorder should give you enough data to do the job. A 6000 rpm pulse is 100 pps (DIS) or 50 pps (fire every other rpm), so to get accurate and distinct centers you would not require that much bandwidth (ie 1-2khz looks to be adequate) Roger ------------------------------ From: "Walter Sherwin" Date: Fri, 29 Jan 1999 17:01:54 -0800 Subject: Re: Love This Hey Greg, don't burst a bubble......... :) ! Missouri-Rola came through, a copy is in the mail. Walt. - -----Original Message----- From: Greg Hermann To: diy_efi@xxx.edu> Date: Friday, January 29, 1999 1:40 PM Subject: Re: Love This >>Does anybody use a PWM fuel pressure regulator? Or know more about the >>part referenced here? >>http://efi332.eng.ohio-state.edu/diy_efi/archive/archive_num_88;lines=6114 - -6151 >> >> How about the aftermarket systems that come with tc/sc? It just >>seems funny to me to use mechanical regulators and vary pump speed, >>instead of maintaining constant pump speed/volume and adjusting >>regulated pressure. It seems so simple, and no one does it, that >>there must be a "catch". >> >>Shannen > >By now you prolly read my post on the subject. If you're doing nothing >else, put a #$%ing float vent on the high point of the rails. This will >cure vapor in the rails INSTANTLY!! And pump control in combo with a good >PR WILL give more accurate control. Variable pumping WILL work alone, but >not as well as in combo with a regulator (set up with pri/sec control). But >if you are doing variable pumping alone, for $#% sakes, use a float vent on >the rails, so as to get the #$#% bubbles back to the tank!!! > >Regards, Greg > > >>Bruce Plecan wrote: >>> >>> -----Original Message----- >>> From: James Weiler >>> To: diy_efi@xxx.edu >>> Date: Friday, January 29, 1999 1:07 AM >>> Subject: RE: Love This >>> >>> For me it's not the plumbing that is the "news". It's being able to >>> manipulate >>> fuel line pressure without needing a mechanical device. As things sit now >>> for TPI the fuel pressure is referenced to engine vac/boost. With this >>> device >>> a closed loop electrically controlled Fuel pressure trimmer is possible, >>> meaning >>> big injectors, lower pressure at idle, to help get reasonable pulse widths. >>> Bruce >>> >>> >Sorry to get in this late but so what? I mean whats the advantage of >a >>> one line EFI vs. 2 fuel line set-up? Besides less plumbing. >>> >thanks >>> >jw >>> > > > ------------------------------ From: Tedscj@xxx.com Date: Fri, 29 Jan 1999 17:06:50 EST Subject: replace an EPROM with an EEPROM? Has anyone tried to replace an Eprom with and EEprom? Specifically, Replace the 27c256 in a Memcal with a 28256? Does anyone know if it would work? or is the pinout somehow different? The reason I'm interested in doing this is because it would be more economical and efficient. Also, what do people do about removing and replacing their Eproms from the Memcals when reprogramming them? Do you solder in ZIF sockets? I want to start lookin at and modifying my Memcal, but have never done any of this stuff before. Thanks, Ted ------------------------------ From: "Bruce Plecan" Date: Fri, 29 Jan 1999 17:19:19 -0500 Subject: Oh Class, tap, tap, tap ECM'sa smokin Todays' lesson so far is series/parrarel injectors don't work, ie 2 groups (of 8 injectors) in series, and the slow injector openings don't happen. Where a stock setup will fire injectors to less than 1 msec. the series/ par, sign off at about 2.1 The intake air temp., correction makes little difference at idle, but at higher rpm makes a huge difference. The above information is specific to a gm 1227730 using a AUJP calibration. More to follow Cheers Bruce ------------------------------ From: EFISYSTEMS@xxx.com Date: Fri, 29 Jan 1999 17:20:51 EST Subject: Memcal's Hi People, While we're on the memcal subject....I am in need of approx 30 blue memcal covers....(I had some meet an unfortunate death) Does anyone know where to buy these or does anyone have some to sell??????Thanks, - -Carl Summers ------------------------------ From: Roger Heflin Date: Fri, 29 Jan 1999 10:26:14 -0600 (CST) Subject: Re: replace an EPROM with an EEPROM? On Fri, 29 Jan 1999 Tedscj@xxx.com wrote: > Has anyone tried to replace an Eprom with and EEprom? > Specifically, Replace the 27c256 in a Memcal with a 28256? > Does anyone know if it would work? or is the pinout somehow different? > The reason I'm interested in doing this is because it would be more economical > and efficient. > I would be interested in this answer. That would accelerate the erasing and reprogramming cycle quite a bit. > Also, what do people do about removing and replacing their Eproms from the > Memcals when reprogramming them? Do you solder in ZIF sockets? > Get a IDC wire wrap socket, and modify it with a dremel type tool, (it is already the correct width and spacing to plug a memcal into, the slots are wrong though, and it won't be long enough) and modify it to allow you to plug the memcal in. Bend the wire wrap socket's legs enough to plug it into the programmer, and then just leave it there and plug the memcal into it. You will only have about 1/2 of the memcal plugged into the IDC socket and the rest will be unconnected, but nothing left is part of the prom. YOu will need to figure the correct way to plug it in (both the socket into the programmer and the memcal into the socket) I have done then and used it to read out my memcals, to do the erasing you would have to take off the top of the memcal, and the window cover and put the whole thing in the eraser. > I want to start lookin at and modifying my Memcal, but have never done any of > this stuff before. > > Thanks, > Ted > ------------------------------ From: "Clarence L.Snyder" Date: Fri, 29 Jan 1999 17:34:21 -0500 Subject: Re: Anyone trigger a electronic IG module with points? Bruce Plecan wrote: > > -----Original Message----- > From: AL8001@xxx.com> > To: diy_efi@xxx.edu> > Date: Friday, January 29, 1999 3:00 PM > Subject: Anyone trigger a electronic IG module with points? > > Points need enough current thru them to "burn" the oxidation off. > Hence, better off to use hall effect or optical replacements for the > points. IMHO > Bruce > > >Hi all, I have some old tractors/trucks and such that I would like to > convert > >to electronic IG. Mostly because since they are limited use, the plugs > tend > >to carbon foul. > > > >I would like to keep the points intact and just wire up the module and > >realated parts. I could convert the dist to a pick up coil and such but > would > >rather not. > > > >I'm thinking of a high ohm resistor from 12 V to the points. Then tap the > + > >pickup coil input on the IG module to the points. I would rather use > somthing > >common like a GM 4 pin/ Chrysler 5 pin/ or a Ford Duraspark. The Ford 3 > pin > >dist mounted TFI looks good as well. > > > > > >Thanks for the help. > > Point triggered electronic ignition has been around for a dog's age. Mid - - late seventies Toyota did it for several years. Worked great. Use a hall effect module and the points will do the job just fine. ------------------------------ From: Mitch Date: Fri, 29 Jan 1999 14:42:20 -0800 Subject: Re: Cubic Dollars At 12:59 PM 1/28/99 -0700, Greg Hermann wrote: > >OK --this is what I was talking about--does anybody know what you gotta do >to "register" a copyright?? > >I freely admit to being WAY out of date on this, but it would seem that >they cannot sue you over it if they have not registered it. Nonsense. If they can prove they originated it, and that you stole it (for that is what is being advocated here), your ass is grass. Assuming they care. Mitch - -------------------------------------------------------------------- Mitch Barrie's Chevelles: http://www.employees.org/~ozyman/carstuff Southern California Chevelle Caminos: http://www.chevelles.net/scccc ------------------------------ From: Shannen Durphey Date: Fri, 29 Jan 1999 18:04:03 -0500 Subject: Re: Love This Greg Hermann wrote: > > >Does anybody use a PWM fuel pressure regulator? Or know more about the > >part referenced here? > >http://efi332.eng.ohio-state.edu/diy_efi/archive/archive_num_88;lines=6114-6151 > > > > How about the aftermarket systems that come with tc/sc? It just > >seems funny to me to use mechanical regulators and vary pump speed, > >instead of maintaining constant pump speed/volume and adjusting > >regulated pressure. It seems so simple, and no one does it, that > >there must be a "catch". > > > >Shannen > > By now you prolly read my post on the subject. If you're doing nothing > else, put a #$%ing float vent on the high point of the rails. This will > cure vapor in the rails INSTANTLY!! And pump control in combo with a good > PR WILL give more accurate control. Variable pumping WILL work alone, but > not as well as in combo with a regulator (set up with pri/sec control). But > if you are doing variable pumping alone, for $#% sakes, use a float vent on > the rails, so as to get the #$#% bubbles back to the tank!!! > > Regards, Greg I don't disagree. Besides, doing so might bring about another symbolic reply. ; ) I just wondered why I haven't seen any electronic pressure regulators under PW control. Automotive fuel pumps seem like a great place for variables to accumulate, machined solenoids seem more accurate. If fuel injectors can be made, something similar should be possible as an inline valve. So why make circuits to control high current pump rather than inline valve? shannen ------------------------------ From: Clarence Wood Date: Fri, 29 Jan 1999 17:17:17 -0600 Subject: Re: Love This Thanks Greg! I think you have put your finger on a problem that I have been having. Please elaborate on the float vent; on what junk cars can I remove one and where do I look for it on the car? At 02:01 PM 1/29/99 -0700, Greg wrote: (snip) >But >if you are doing variable pumping alone, for $#% sakes, use a float vent on >the rails, so as to get the #$#% bubbles back to the tank!!! > >Regards, Greg > > >>Bruce Plecan wrote: >>> >>> -----Original Message----- >>> From: James Weiler >>> To: diy_efi@xxx.edu> >>> Date: Friday, January 29, 1999 1:07 AM >>> Subject: RE: Love This >>> >>> For me it's not the plumbing that is the "news". It's being able to >>> manipulate >>> fuel line pressure without needing a mechanical device. As things sit now >>> for TPI the fuel pressure is referenced to engine vac/boost. With this >>> device >>> a closed loop electrically controlled Fuel pressure trimmer is possible, >>> meaning >>> big injectors, lower pressure at idle, to help get reasonable pulse widths. >>> Bruce >>> >>> >Sorry to get in this late but so what? I mean whats the advantage of >a >>> one line EFI vs. 2 fuel line set-up? Besides less plumbing. >>> >thanks >>> >jw >>> > > > > ------------------------------ From: "David Sagers" Date: Fri, 29 Jan 1999 16:34:36 -0700 Subject: Different Strokes I'm building a twin turbo small block chevy for a 1981 Corvette, auto trans and all the power accessories. It'll be used for a hotrod street car, primarily on weekends and sunny days. In a conversation with the machine shop this afternoon the engine builder said I should consider going with a shorter stroke. I can build a 4" stroke 434 ci, a 3.75" 406 ci, or a 3.48" stroke 355 ci engine. The block I have is already clearanced for the 4" stroke so the additional cost of preparing the block isn't a factor. I already own the 4" crank and rods, and the crank can be traded out for a shorter stroke without any additional cost. The builder said that a short stroke engine will respond better to a turbo as it'll rev faster. So I'm looking for someone with knowledge and experience with turbo engines. Do I go with the shorter stoke that'll rev faster, or go with the 4" stroke that makes a lot of torque, especially in the low RPM ranges. Low RPM torque seems to be important as this is going to be a street engine generally run in the lower RPM ranges. Some of the things I want from the engine are throttle response and low rpm power. I was hoping that by going with the big 434 ci engine I could over come some of the slow acceleration associated with turbo lag in small engines. ------------------------------ From: Jay Wallace Date: Fri, 29 Jan 1999 19:04:23 -0500 Subject: Re: home dyno kit?? At 07:06 PM 1/28/99 -0500, you wrote: >> >>> At 08:24 AM 1/28/99 -0500, Dan Llewellyn2 wrote: >> >>> >level ground. At least were I live, level stretches of road where >>> >you can get up to speed are rare. If they incorporated the data >>> >from a G-field measuring device, like an Analog Digital ADXL05, >>> >you could calculate horsepower even if the road was not level. >> About 6 - 8 years ago (?) in Road & Track there was a Tech Tidbit (or some such) article about accelerometers / stopwatch / coastdown to determine rolling and wind resistance and horsepower. Does anybody have the reference? TIA, Jay ------------------------------ From: "James Montebello" Date: Fri, 29 Jan 1999 16:21:05 -0800 Subject: RE: Love This > I just wondered why I haven't seen any electronic pressure regulators > under PW control. Automotive fuel pumps seem like a great place for > variables to accumulate, machined solenoids seem more accurate. If > fuel injectors can be made, something similar should be possible as an > inline valve. So why make circuits to control high current pump > rather than inline valve? They have been. The Bosch CIS with Lambda system used a plain-jane injector has an electronically controllable inline pressure regulator. Used in several European cars in the 80s (VW, Porsche, and Volvo, to name three). On the subject of dynamic fuel pressure regulators, the Digifant system used by VW in the late 80s had a vacuum-controlled pressure regulator that was simply plumbed directly to the intake manifold. I suppose it would be possible to have this do most load compensation, and only vary PW by temperature and switches for fully-closed and fully-open throttle. Dunno if Digifant did this or not, but it sounds like just the kind of thing the Germans would do. james montebello ------------------------------ From: Mike Pitts Date: Fri, 29 Jan 1999 19:32:51 -0500 Subject: RE: Different Strokes <> Maybe he's not familiar with turbocharged street cars? In my experience, turbocharged engines do not require alot of RPM to build exceptional power. I never take my V6 past 5500 RPM, yet I've run 11.38 @xxx. And that's just a measly little ole 3.8L engine in a full weight Buick with t-tops. You might want to chat with Harry Hruska at Precision Turbo and Engine in Indiana (219) 996-7832. They have already built at least one twin turbo V8 vette which runs VERY fast! What are you planning to use for fuel? EFI I hope. :) - -Mike ------------------------------ From: James Ballenger Date: Fri, 29 Jan 1999 19:51:26 -0500 Subject: Re: Different Strokes David Sagers wrote: > The builder said that a short stroke engine will respond better to a turbo as it'll rev faster. So I'm looking for someone with knowledge and experience with turbo engines. Do I go with the shorter stoke that'll rev faster, or go with the 4" stroke that makes a lot of torque, especially in the low RPM ranges. Low RPM torque seems to be important as this is going to be a street engine generally run in the lower RPM ranges. I've thought about a twin turbo Poncho 400 ;^) How high do you need to rev to get full boost? The smaller stroke responding better would make sense. With enough boost, you could get plenty of torque and good hp. How high are you going to rev this engine? James Ballenger ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 29 Jan 1999 18:07:25 -0700 Subject: Re: Love This >Hey Greg, don't burst a bubble......... :) ! > >Missouri-Rola came through, a copy is in the mail. > >Walt. > Well--I prolly oughtta quit using the top row characters so much, or I might pop something!! And Thanks!! Regards, Greg ------------------------------ From: "David Sagers" Date: Fri, 29 Jan 1999 18:13:55 -0700 Subject: Re: RE: Different Strokes Thanks for the lead on Precision Turbo. As for fuel, yes it'll be EFI. >>> Mike Pitts 01/29 5:32 PM >>> <> Maybe he's not familiar with turbocharged street cars? In my experience, turbocharged engines do not require alot of RPM to build exceptional power. I never take my V6 past 5500 RPM, yet I've run 11.38 @xxx. And that's just a measly little ole 3.8L engine in a full weight Buick with t-tops. You might want to chat with Harry Hruska at Precision Turbo and Engine in Indiana (219) 996-7832. They have already built at least one twin turbo V8 vette which runs VERY fast! What are you planning to use for fuel? EFI I hope. :) - -Mike ------------------------------ From: Mike Morrin Date: Sat, 30 Jan 1999 14:38:18 +1300 Subject: Re: Anyone trigger a electronic IG module with points? At 02:46 pm 29/01/99 EST, AL8001@xxx.com wrote: >I would like to keep the points intact and just wire up the module and >realated parts. I could convert the dist to a pick up coil and such but would >rather not. > >I'm thinking of a high ohm resistor from 12 V to the points. Then tap the + >pickup coil input on the IG module to the points. I would rather use somthing >common like a GM 4 pin/ Chrysler 5 pin/ or a Ford Duraspark. The Ford 3 pin >dist mounted TFI looks good as well. If the ignition module uses the MC3334 chip, then it wont work properly with a digital (points) input, as the dwell compensation relies on a floating DC path through the pick-up coil. If you are using a standard coil and ballast resistor, it should be OK, but you wont get HEI. regards, Mike ------------------------------ From: EFISYSTEMS@xxx.com Date: Fri, 29 Jan 1999 20:43:39 EST Subject: Re: Different Strokes Hi David, It has been my experience that it does take less time for the engine to accelerate with a shorter stroke,,,but like you said the larger cu in will give more streetable torque and that would probably be the trade off I would take if I already had the parts as you do.....The biggest downfall of the 4" arm is the fact that you have very little(if any...was this 350 mains or 400?) journal overlap and if you are planning to make alot of hp(1000+) and/or rpm,,expect this crank to crack probably after 30 1/4 mile blasts.....just some experience....hth's - -Carl Summers In a message dated 1/29/99 3:34:37 PM Pacific Standard Time, dsagers@xxx.west- valley.ut.us writes: << Subj: Different Strokes Date: 1/29/99 3:34:37 PM Pacific Standard Time From: dsagers@xxx.us (David Sagers) Sender: owner-diy_efi@xxx.edu Reply-to: diy_efi@xxx.edu To: diy_efi@xxx.edu I'm building a twin turbo small block chevy for a 1981 Corvette, auto trans and all the power accessories. It'll be used for a hotrod street car, primarily on weekends and sunny days. In a conversation with the machine shop this afternoon the engine builder said I should consider going with a shorter stroke. I can build a 4" stroke 434 ci, a 3.75" 406 ci, or a 3.48" stroke 355 ci engine. The block I have is already clearanced for the 4" stroke so the additional cost of preparing the block isn't a factor. I already own the 4" crank and rods, and the crank can be traded out for a shorter stroke without any additional cost. The builder said that a short stroke engine will respond better to a turbo as it'll rev faster. So I'm looking for someone with knowledge and experience with turbo engines. Do I go with the shorter stoke that'll rev faster, or go with the 4" stroke that makes a lot of torque, especially in the low RPM ranges. Low RPM torque seems to be important as this is going to be a street engine generally run in the lower RPM ranges. Some of the things I want from the engine are throttle response and low rpm power. I was hoping that by going with the big 434 ci engine I could over come some of the slow acceleration associated with turbo lag in small engines. >> ------------------------------ From: thergen@xxx.net Date: Fri, 29 Jan 1999 17:45:18 -0800 (PST) Subject: Re: Oh Class, tap, tap, tap ECM'sa smokin Bruce, How are you measuring injector opening time? Change in current? Thanks for the info. Tom On Fri, 29 Jan 1999, Bruce Plecan wrote: > Todays' lesson so far is > series/parrarel injectors don't work, ie 2 groups (of 8 injectors) in > series, and the slow injector openings don't happen. Where a > stock setup will fire injectors to less than 1 msec. the series/ > par, sign off at about 2.1 > The intake air temp., correction makes little difference at idle, > but at higher rpm makes a huge difference. > The above information is specific to a gm 1227730 using a AUJP > calibration. > More to follow > Cheers > Bruce > ------------------------------ From: xxalexx@xxx.com Date: Fri, 29 Jan 1999 20:53:37 +0000 Subject: Re: Cubic Dollars >> (snip) > >Do any of the software oriented folks out there know what material you have > >to submit to complete a copyright on software???? Or does anybody even > >bother cuz of the development cycle being so short???? > > > > When writing windows programs, in the 'Help' menu box, the copyright and 'c' in a circle is present with date and author. I have not really dug into this in depth but I believe that this procedure> Clarence > Borland Inprise, does this, undocumented key combinations have been known to bring up a picture of one of the orginal developers of Delphi. alex ------------------------------ From: "Bruce Plecan" Date: Fri, 29 Jan 1999 21:07:30 -0500 Subject: Re: Oh Class, tap, tap, tap ECM'sa smokin - -----Original Message----- From: thergen@xxx.net> To: DIY_EFI Date: Friday, January 29, 1999 8:56 PM Subject: Re: Oh Class, tap, tap, tap ECM'sa smokin Diacom Bruce >How are you measuring injector opening time? Change in current? >Thanks for the info. >Tom > Todays' lesson so far is >> series/parrarel injectors don't work, ie 2 groups (of 8 injectors) in >> series, and the slow injector openings don't happen. Where a >> stock setup will fire injectors to less than 1 msec. the series/ >> par, sign off at about 2.1 >> The intake air temp., correction makes little difference at idle, >> but at higher rpm makes a huge difference. >> The above information is specific to a gm 1227730 using a AUJP >> calibration. >> More to follow >> Cheers >> Bruce >> > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 29 Jan 1999 19:04:30 -0700 Subject: Re: Cubic Dollars >At 12:59 PM 1/28/99 -0700, Greg Hermann wrote: >> >>OK --this is what I was talking about--does anybody know what you gotta do >>to "register" a copyright?? >> >>I freely admit to being WAY out of date on this, but it would seem that >>they cannot sue you over it if they have not registered it. > >Nonsense. If they can prove they originated it, and that you stole it (for >that is what is being advocated here), your ass is grass. Assuming they care. Nope--read the book---Clarence posted the relevant language----in order to initiate a legal action for copyright infringement, they HAVE to have registered the copyright. They will NOT register it, because then all (or more than they want) of their source code would have to put into the public record, for all (Go BRUCE) to see and study. They want not to do that badly enough that they will not be suing anybody over using/selling/playing with the stuff anytime soon. Their lawyers are not stupid--if they sued you without having registered the copyright on it, and you had anything approaching a decent lawyer, their action would be dimissed for something along the lines of "failure to state a claim for which relief can be granted" before the fool thing ever got started. And, by statute, in most places, they can be held liable to pay YOUR legal fees when something is dismissed that way--so don't be shy about hiring a GOOD lawyer if it ever happens! To make a long story short---- I'm not too worried!! Regards, Greg > >Mitch > >-------------------------------------------------------------------- >Mitch Barrie's Chevelles: http://www.employees.org/~ozyman/carstuff >Southern California Chevelle Caminos: http://www.chevelles.net/scccc ------------------------------ From: Chill4@xxx.com Date: Fri, 29 Jan 1999 20:10:56 -0600 (CST) Subject: Re: Different Strokes On 01/29/99 16:34:36 you wrote: > >I'm building a twin turbo small block chevy for a 1981 Corvette, auto trans >and all the power accessories..... >In a conversation with the machine shop this afternoon the engine builder >said I should consider going with a shorter stroke. I can build a 4" >stroke 434 ci, a 3.75" 406 ci, or a 3.48" stroke 355 ci engine..... >The builder said that a short stroke engine will respond better to a turbo >as it'll rev faster..... >Low RPM torque seems to be important as this is going to be a street engine >generally run in the lower RPM ranges. To keep this as short as possible I'll start by saying that for the reasons you were given (quicker revving, will work better with a turbo?) I completely disagree with your builder. Torque is king on the street and there will be a huge difference between a big engine and a smaller one in the lower rpm's. Now, I personally don't recommend the 41/8" bore engine for other reasons, and since you said you can build either a 434(4.155x4.00), 406(4.155x3.750), or a 355(4.030x3.480), if that is the case you should have two blocks a 4" & a 4&1/8", I personally would consider an engine based on the 4" block. Anyway given the same size turbocharger, a larger engine will see much less turbo lag, and provide more bottom end torque, and once the boost comes in you'll be amazed at how fast the engine revs. However if you size the hot sides correctly even the smaller engine can get similar boost response (you can virtually have boost start when you want it to), but since you said you already have the crank and rods build the big engine and I think you'll be very happy with the performance. By the way I have a TT 355 SBC and have no problem with boost response or turbo lag at all. I will be switching over to a single turbo (class rules) and I will size my torque converter and the turbine side to make sure I have proper spool up and response. I can help with turbo sizing for virtually any vehicle as I have experience in this area and I am also a distributor for turbochargers and other performance items for a few major manufacturers, if you or anyone else is looking for a good deal on some turbochargers or need more assistance on sizing or anything else email me directly. Chris Advanced Performance Chill4@xxx.com ------------------------------ From: Roger Heflin Date: Fri, 29 Jan 1999 20:27:16 -0600 (CST) Subject: Re: home dyno kit?? On Fri, 29 Jan 1999, Jay Wallace wrote: > At 07:06 PM 1/28/99 -0500, you wrote: > >> > >>> At 08:24 AM 1/28/99 -0500, Dan Llewellyn2 wrote: > >> > >>> >level ground. At least were I live, level stretches of road where > >>> >you can get up to speed are rare. If they incorporated the data > >>> >from a G-field measuring device, like an Analog Digital ADXL05, > >>> >you could calculate horsepower even if the road was not level. > >> > > > About 6 - 8 years ago (?) in Road & Track there was a Tech Tidbit > (or some such) article about accelerometers / stopwatch / coastdown > to determine rolling and wind resistance and horsepower. Does > anybody have the reference? > No, but it is pretty easy to do. Get the car to 65, and time how long it takes to get down to 55 in neutral. Given the car weight, you know how much energy was in the car a 65, and you know how much energy is in the car at 55. Subtract those, and divide by the number of seconds. here is the equations: energy = 1/2 * (( mph / 3600) *1609 ) ^ 2 * ( mass / 2.2 ) So with a 3000 lb vehicle that takes 10 seconds in neutral we have: energy@65 = 575 * ( 10 ^ 3) energy@55 = 412 * ( 10 ^ 3) change in energy is: 163 (KW) change in energy per second: 16.3 KW 1hp = 746 watts, so hp is 16.3 / 746 = 21.84 hp. So, 21.84 hp is required to overcome wind/friction at about 60mph. Roger ------------------------------ From: Roger Heflin Date: Fri, 29 Jan 1999 20:35:42 -0600 (CST) Subject: Re: Oh Class, tap, tap, tap ECM'sa smokin On Fri, 29 Jan 1999, Bruce Plecan wrote: > > -----Original Message----- > From: thergen@xxx.net> > To: DIY_EFI > Date: Friday, January 29, 1999 8:56 PM > Subject: Re: Oh Class, tap, tap, tap ECM'sa smokin > > Diacom > Bruce > > > >How are you measuring injector opening time? Change in current? > >Thanks for the info. > >Tom > How are you measuring it with diacom? Are you lowering the opening time until they don't open anymore? Roger ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 29 Jan 1999 19:39:27 -0700 Subject: Re: Love This >Thanks Greg! I think you have put your finger on a problem that I have >been having. Please elaborate on the float vent; on what junk cars can I >remove one and where do I look for it on the car? I dunno of any cars that have used one!!! :-) Basically all it is is like the float bowl of a carb working in reverse--the float chamber would be connected to the high point of the fuel rails--when the float chamber is full of liquid fuel, the float rises, and closes a needle valve. The outlet side of the needle valve is connected to your vent line back to the tank. If enough vapor collects for the float to drop, the needle valve opens, and the vapor goes bye bye into the vent system. There are lots of float vents out there for various industrial piping systems, but most weigh about 20 pounds, min. There are tiny little ones out there, made out of sheet metal, for domestic hot water heating systems, which would not take the fuel pressure--general environmental/vibration conditions under the hood at all. I have found one, made by Honeywell, which is rated 150psi, 250 degrees F, which is OK as to bulk/weight, and they rate it as OK for water/glycol/petroleum based heat transfer fluids, so I think it MIGHT be OK for use in an automotive fuel system. Have not tried it out yet--and I would be pretty sure that Honeywell would have a whole litter of kittens if they found out their product was being used that way, so I am a little reluctant to state the part # of it. But that should not stop anybody from getting hold of a Honeywell "Tradeline" catalogue at a local HVAC /controls wholesaler and figuring out which part it is!! Been thinking about asking somebody that makes quality fuel system stuff--mebbe Barry Grant-- if they would be interested in making them specifically for our intended use. Prolly would have to go through a bunch of BS to show them why it's a needed part--and that would be a real PITA. Regards, Greg > >At 02:01 PM 1/29/99 -0700, Greg wrote: >(snip) >>But >>if you are doing variable pumping alone, for $#% sakes, use a float vent on >>the rails, so as to get the #$#% bubbles back to the tank!!! >> >>Regards, Greg ------------------------------ End of DIY_EFI Digest V4 #73 **************************** 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".