DIY_EFI Digest Saturday, January 22 2000 Volume 05 : Number 035 In this issue: Re: DIY_EFI Digest V5 #32 Re: [ADMIN] The Move Re: DIY_EFI Digest V5 #32 EGR stuff RE: DIY_EFI Digest V5 #34 Re: Digest V5 #34 Min GM ECM Knock S., VE, CR Re: believe iot or not Re: believe iot or not ftp site [ADMIN] Non-digest Re: believe iot or not See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 21 Jan 2000 05:40:05 -0800 (PST) From: Roy Subject: Re: DIY_EFI Digest V5 #32 >From Roy Spectrics Ltd The sole purpose of EGR is to reduce exhaust emisions, it has a detrimental effect on both engine efficiency and power output. To reduce the heating effect EGR has on the incomming air in the inlet manifold, EGR coolers are being introduced, so basic EGR does not reduce the incomming air temperature !. What it does do is to reduce the rate at which the flame front travels through the mixture during combustion. Hope this helps Roy - --- DIY_EFI Digest wrote: > > DIY_EFI Digest Thursday, January 20 2000 > Volume 05 : Number 032 > > > > In this issue: > > re:Minimum to run GMECM? > Re: re:Minimum to run GMECM? > Re: Knock > Re: DIY_EFI Digest V5 #29 > > See the end of the digest for information on > subscribing to the > DIY_EFI or DIY_EFI-Digest mailing lists. > > - ---------------------------------------------------------------------- > > Date: Thu, 20 Jan 2000 08:53:19 -0500 > From: "jtyler" > Subject: re:Minimum to run GMECM? > > Bruce wrote: > > >So you with this limited > >background want to jump in and redesign what gm has > spent millions of >dollars on.. > > Not at all. The point is NOT to design a ground up > system! > In fact you are whom suggested I check into the GM's > for a BASIC > FI conversion application. > > >2nd, leaving all/most/some of the sensors > disconnected negates any > >benefits to running efi, might as install a carb.. > > > You misunderstood the purpose of the question. I > plan on running > several sensors (except VSS)for the reason you > mentioned, but I would like to start with just the > ignition, map,temp and TPS if that would work. > > So, other than setting service codes, will the ECM > run like this, > or will it likely go into a limp home mode of some > type? > > Jim > Dopey > > ------------------------------ > > Date: Thu, 20 Jan 2000 10:07:27 -0500 > From: "Bruce Plecan" > Subject: Re: re:Minimum to run GMECM? > > You want to run the system, in your own > configuration, for what ever reason. > Your not going to like it when your done. > Look in the archives, for the dozen of so threads > about deleting the VSS. > The other inputs are all necessary, also. > It is far easier to plan things out once, install it > all, and then fine tune > something then cob bit by bit together. > I'm just trying to save you time/money, I been thru > this dozens of times, > on+off list. > You want to ignore this, fine, least I tried > Grumpy > > | You misunderstood the purpose of the question. I > plan on running > | several sensors (except VSS)for the reason you > mentioned, but I would like > to start with just the ignition, map,temp and TPS if > that would work. > | So, other than setting service codes, will the ECM > run like this, > | or will it likely go into a limp home mode of some > type? > | Jim > | Dopey > > ------------------------------ > > Date: Thu, 20 Jan 2000 09:13:51 -0600 > From: "Robert W. Hughes" > Subject: Re: Knock > > > > Actually, the exhaust gases dilute the mixture > and make the combustion > > > temperatures lower. > > > > How do you add hot and get cold? > > I'm confused.... > > > > > From: "Scott Croughwell" > > > > > > How does the hot exhaust gas cool the fresh > charge.... Or have I got this > > > > wrong and you mean that the exhaust gas isn't > heating the cool intake charge > > > > and the cold intake charge is causing the > detonation???? > > > > > > Believe it or not... the gasses coming from the > EGR have had enough time to cool > > > enough so that the portion of exhaust temp > re-entering the intake port is cooler > > > than the intake manifold. > > and from another note > > > With EGR operational, as > > soon as the valve opened under the same conditions > the intake manifold temp > > jumped to 210F on a 75F day. I think that it is > less a temperature issue > > than a charge dilution issue. But with some fine > tuning of the spark map, > > you can easily eliminate any detonation you may > experience. > > This is what I was saying. The exhaust gases dilute > the mixture and and > result in cooler combustion chamber temperatures > which reduces nitrogen > oxide formation. The mixture also burns slower and > so requires more > ignition advance. The exhaust gases are not cooler > than the intake, on > my car they are hot enough to melt and burn out > 60-40 solder in copper > piping. > > > > > Wow so the exhaust gas is cooler than the intake I > never would have thought > > so.... hell I'm not even running emmissions gear, > don't have to here in NZ. It > > is even legal to remove cats.... > How about dogs? sorry > - -- > Robert W. Hughes (Bob) > BackYard Engineering > 29:40.237N, 95:28.726W > Houston, Texas > rwhughe@xxx.net > > ------------------------------ > > Date: Wed, 19 Jan 2000 19:15:30 +0000 > From: Ade + Lamb Chop > Subject: Re: DIY_EFI Digest V5 #29 > > >Hi Ade, > > > >I had a mini catalogue a while ago which listed an > LCB Y peice with a boss > >for mounting a lambda sensor. Unfortunately I can't > find the catalogue > >anymore, but I would suggest you try the usual big > suppliers MiniSpares, > >MiniSport, MiniSpeed, etc. I bet you non mini > owners just can't believe the > >cunning originality in these names ;-) Or maybe > even try going directly to > >somebody like Maniflow. Either way it would be > cheaper than wrecking a whole > >LCB. > > > >Gareth Jones > > I have just bought a nice maniflow LCB... I am not > going to buy another > other one! > > Ade > > ------------------------------ > > End of DIY_EFI Digest V5 #32 > **************************** > > 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". > === message truncated === __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 07:45:12 -0600 From: steve ravet Subject: Re: [ADMIN] The Move A big round of applause for Orin and John on this apparently seamless transition. You may have noticed that the WWW pages are on the new server, www.diy-efi.org. There are lots of broken links right now, I'm getting them fixed as I can. Should look lots better after this weekend. - --steve Orin wrote: > > This lists are currently running off the new server. > > You might have noticed your filters not working anymore. > You will have to change references to esl.eng.ohio-state.edu > or efi332.eng.ohio-state.edu to diy-efi.org in your filters, aliases > and address books. > > The new address for subscribe/unsubscribe requests is: > > majordomo@xxx.org > > We even have an annoying reminder at the bottom of each message > at the moment :). > > If you are on diy_efi-digest, please refrain from switching > to diy_efi for a day or two while we make sure everything > is running smoothly. > > Thanks, > > Your list admins. > ---------------------------------------------------------------------------- > To unsubscribe from efi332, send "unsubscribe efi332" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 09:30:26 -0500 From: "Bruce Plecan" Subject: Re: DIY_EFI Digest V5 #32 No, cause, it's nonsense (the ** part).. EGR reducing the IAT, look at the bottom of an intake with working egr (SBC), note all the coke deposited where the egr runner is. It takes temps of like 350+dF to do that. If your IAT is over 350dF, I hope it's due to alot of boost, other wise ya got problems. Grumpy Please note, this was edited to a resonable lenght. | >From Roy Spectrics Ltd | The sole purpose of EGR is to reduce exhaust emisions, | it has a detrimental effect on both engine efficiency | and power output. | To reduce the heating effect EGR has on the incomming | air in the inlet manifold, EGR coolers are being | introduced, ***so basic EGR does not reduce the incomming | air temperature !***. What it does do is to reduce the | rate at which the flame front travels through the | mixture during combustion. Hope this helps Roy - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 10:23:19 EST From: A70Duster@xxx.com Subject: EGR stuff << Ok.... so the inlet manifold temp goes up but the mixture is diluted by the exhaust gas from the erg. I would have thought that this would have leaned the AFR if anything causing detonation or isn't there enough O2 left in the exhaust? >> Leaning the mixture (via the EGR) would mean adding more O2, but the EGR does not do this. It adds N2, C02 and H20 (vapor) to the airstream of N2 and O2 and HxCx. The correct A/F ratio has been determined (carb or ECU), the EGR just "thins" the mixture. I left the small amout of Argon out as not to confuse the issue. Hope this helps... Mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 13:20:15 -0500 From: Hunt David Subject: RE: DIY_EFI Digest V5 #34 >Ok.... so the inlet manifold temp goes up but the mixture is diluted by the >exhaust gas from the erg. I would have thought that this would have leaned >the AFR if anything causing detonation or isn't there enough O2 left in the >exhaust? Having worked with oxygen sensors in other applications, it is the excess oxygen that is measured, so lean is less oxygen not excess fuel. The exhaust is just an inert that has little to do with the combustion process except that it has to be heated by the oxidation process. The result is less fuel, less oxygen and cooler PEAK temperatures, thus improved emissions. I believe, but ain't sure, that the exhaust temperature is reduced with an increase in the engine's efficiency. The free oxygen remaining (and sensed) is relatively unchanged. Now I have a question, when a piston is burned, is the excess oxygen reacting with the Aluminum? Or is it something else? >How does the hot exhaust gas cool the fresh charge.... is a good >question. Unfortunately it's not the right one. >If you want to get/or seemingly pissy, fine, I'll withdraw my efforts to >answer your questions. > Grumpy Grumpy, I find your answers quite enlightening and enjoyable, but you too can come off as pissy. Don't take this to heart, but in this format anyone can be misunderstood. Review your first response. In my opinion, we should be expecially accomodating and understanding in a forum such as this. Or are you just upholding your good name, Grumpy. Don't get upset, we all love you. >This doesn't make sense to me. Static CR would remain the same. >The dynamic/effective CR should still be the same since nothing none >compressable was added to the mix. The VE should drop (less O2 to react), >hence lower fuel amount needed, leaner mixture takes longer to burn hence >more timing needed. >Grumpy Since the spend gas is added after the throttle plate the total gas in the combustion chamber is increased as compared to no recirculation. Thus the "dynamic" pressure (effective compression ratio) is increased. At part throttle the chamber certainly doesn't fill due to the restriction of the throttle and the dynamic compression ratio is quite small, so even a small amount of recirculated gas increases the dynamic compression ratio. It also increases the preignition temperature (promoting better vaporization (mixing)), and provides a (relatively) cooling effect for pockets of "leanness" reducing the possiblity of detonation. REDUCING. That "leanness" might be caused by fuel dropout which means that the oxygen rich, low fuel (lean) areas will also have a lot of recirculation gasses. Win - Win - Win - Win situation, quite ingenous actually. Bama - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 16:51:39 -0500 From: Todd Israels Subject: Re: Digest V5 #34 Min GM ECM >------------------------------ > >Date: Thu, 20 Jan 2000 21:35:48 -0500 >From: "jtyler" >Subject: re:Minimum to run GMECM? > >No I wasn't getting pissy. Thank you for all your help already. > >I really meant it just seems for the relatively simple >app I described, trying to disable/fool/recode 80% of the ECM >provisions may not be the way to go. SDS or similar may be smarter >if it is going to take 2 years to figure out how too undo all that >GM spent millions doing. > >With all the provisions in the GM code (and I realize why they have to do that stuff), it seems like trying to use a sledgehammer to drive a nail. All the complexity GM had to do for a production vehicle simply isn't neccesary for my application. > >I was trying to find more info on the 168/808 applications you >mentioned. I haven't found if any of those where DIS. > >I could use a speedo cable VSS if the ECM is going to get dumb without it. > >So: > >VSS,MAP,Temp,TPS,Ignition maybe that would be enough. > >I looked at the 165 app on TC, it was a MAF. The 227 app there >had a 4 cyl switch and was MAP, but was auto, so I'll look for the manual version. > > >>Perhaps this application is just too basic for all that GM wizardry... >>sorry I bothered you with it. > >>Jim > >- ------------------------------ > All that GM complexity could come in handy. I dont recall your aplication but it is my recolection that as sensors error it dissabels that part of the code and runs on a simpler map not affected by the erroring sensor. You dont have to hook all the sensors up but they are there fro a reason. I got a 4cl Fiero to start and run with RPM Vss(needed for start but will keep running if unpluged) and MAP. This was on a scraped car with the clutch out so driveability was not checked. Hopefully someone can help with the details I know are missing, have just started looking at the code in GM ECMs Good Luck Todd Israels - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 16:36:36 -0500 From: Jim Fitzgerald Subject: Knock S., VE, CR I found some more Knock S. Info in "Automotive Elect Handbook" by Ronald K. Jurgen (McGraw Hill). Author says that knock frequency ranges from 2 to 15 kHz and is given by: "Drapers Equation" Fr = Pmn(C)/pi(B) Pmn = vibration mode constant C = velocity of sound in Cyl. gas B = radius of cylinder He gives an example, that with gas temp of 2000K, velocity C = 900 m/s, and for a 100 mm Dia cylinder the 1st knock harmonic would be 5.75 kHz. So looking at the equation you can see that freq. is proportional to cylinder dia. Using the same constants and Fr = .0575 B you can estimate other size cylinders. He also says that any cyl knock travels through the engine block to the sensor in less than 1 ms. And that the successive cylinders are consecutive in time and are not overlapped. At 6000 RPM they would be 2.5 ms apart. He says Manuf. originally tried to tune the sensor to a particular freq. and that they had a Q factor of about 2. He thinks that they now use a filter in the ECM. This was all referenced to SAE papers 920702, 920808, and 910858 Actually I think that most common KS are similar and if someone wanted to tune the KS response for a particular app, that a simple RLC band pass filter would be sufficient. On another note, I think that an engines compression ratio, both static and effective, and the VE are strictly determined by the mechanical design of the engine. It would be the same if the engine were driven as an air compressor. Its the cylinder pressure curve that changes depending on the characteristics of the intake charge gas mixture, Temp, Ing. Timming and all the other combustion variables. Its also commonly known that lean mixtures can lead to burt pistons and valves. Is that because the excess O2 is burning the metal (cutting torch) while the overall combustion temp. is cooler?? Jim F. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 21:07:59 -0500 From: "Clare Snyder" Subject: Re: believe iot or not > > Date: Thu, 20 Jan 2000 23:55:06 -0500 > From: "Bruce Plecan" > Subject: Re: Believe it or not... NOT > > This doesn't make sense to me. Static CR would remain the same. > The dynamic/effective CR should still be the same since nothing none > compressable was added to the mix. The VE should drop (less O2 to react), > hence lower fuel amount needed, leaner mixture takes longer to burn hence > more timing needed. > Grumpy > He's got it down pretty close. Addition of an inert gas allows more complete filling of the cyl with less fuel, yet no leaning of the mixture. Lets say for argument's sake a full charge is one litre. At low load, partial throttle, VE may be throttle limitted to 20or 30%. The A/F mixture is 14:1. CR is 8:1. With a 30% VE effective CR is reduced somewhat - possibly as low as about 3:1. Now, lets add 200cc of inert gas to the cyl. We now have an effective VE of 40 or 50%, raising the effective compression ratio at the same throttle opening, with the same A/F ratio, to closer to 5:1. We get the same power out of the burning fuel - likely even a bit more due to more squeeze. We also expand the inert gas charge due to heating, and a portion of the heat that would normally go out the pipe is absorbed here. This absorption of cyl heat by the inert charge also reduces the cyl temperature to a point where less nitrogen is oxidized, thus reducing NOX emissions. A Miller Cycle engine takes this to extremes, with the engine running for all practicle purposes at close to 100% VE for the majority of it's operating regimen. > > | As the exhaust is 70% nitrogen and nearly 30% CO2 it is very nearly > | inert gas. Adding this gas without any change in throttle position > | increases the relative compression ratio. > | The raised compression allows the engine mapper to > | lower the amount of fuel i.e. increase the A/F ratio to a greater > | number prior to the onset of unstable combustion. > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 21:07:59 -0500 From: "Clare Snyder" Subject: Re: believe iot or not > > Date: Thu, 20 Jan 2000 23:55:06 -0500 > From: "Bruce Plecan" > Subject: Re: Believe it or not... NOT > > This doesn't make sense to me. Static CR would remain the same. > The dynamic/effective CR should still be the same since nothing none > compressable was added to the mix. The VE should drop (less O2 to react), > hence lower fuel amount needed, leaner mixture takes longer to burn hence > more timing needed. > Grumpy > He's got it down pretty close. Addition of an inert gas allows more complete filling of the cyl with less fuel, yet no leaning of the mixture. Lets say for argument's sake a full charge is one litre. At low load, partial throttle, VE may be throttle limitted to 20or 30%. The A/F mixture is 14:1. CR is 8:1. With a 30% VE effective CR is reduced somewhat - possibly as low as about 3:1. Now, lets add 200cc of inert gas to the cyl. We now have an effective VE of 40 or 50%, raising the effective compression ratio at the same throttle opening, with the same A/F ratio, to closer to 5:1. We get the same power out of the burning fuel - likely even a bit more due to more squeeze. We also expand the inert gas charge due to heating, and a portion of the heat that would normally go out the pipe is absorbed here. This absorption of cyl heat by the inert charge also reduces the cyl temperature to a point where less nitrogen is oxidized, thus reducing NOX emissions. A Miller Cycle engine takes this to extremes, with the engine running for all practicle purposes at close to 100% VE for the majority of it's operating regimen. > > | As the exhaust is 70% nitrogen and nearly 30% CO2 it is very nearly > | inert gas. Adding this gas without any change in throttle position > | increases the relative compression ratio. > | The raised compression allows the engine mapper to > | lower the amount of fuel i.e. increase the A/F ratio to a greater > | number prior to the onset of unstable combustion. > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 20:44:42 -0600 From: steve ravet Subject: ftp site All -- The OLD FTP site is no longer accepting uploads. The new one is, or at least it should be. Make sure that all new uploads go to the new ftp site. The layout is the same, only the address has changed. It's now: ftp.diy-efi.org or ftp://ftp.diy-efi.org - --steve - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 21 Jan 2000 21:23:14 -0800 (PST) From: Orin Subject: [ADMIN] Non-digest Go ahead and switch if you are desperate :) You'll have to go through the authorization process to get on diy_efi, so don't unsubscribe from the digest until you get the welcome message. Orin. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 22 Jan 2000 06:16:31 -0500 From: "Bruce Plecan" Subject: Re: believe iot or not | Addition of an inert gas allows more complete filling of the cyl with less | fuel, yet no leaning of the mixture. Lets say for argument's sake a full | charge is one litre. At low load, partial throttle, VE may be throttle | limitted to 20or 30%. The A/F mixture is 14:1. CR is 8:1. | With a 30% VE effective CR is reduced somewhat - possibly as low as about | 3:1. We agree line for line up until the last sentence. Now even with it drop the mention of the CR, and I agree with you. But, I don't see how you can tie CR to VE. The VE is a funstion of tuning, not calculation. You can guess at a VE, but it ain't so, till the tuner says "Done".. | Now, lets add 200cc of inert gas to the cyl. | We now have an effective VE of 40 or 50%, raising the effective compression | ratio at the same throttle opening, with the same A/F ratio, to closer to | 5:1. Did you remove a 200cc amount of air?. What you say here, is just the opposite of what I see happening, again ignoring the mention of CR. | We get the same power out of the burning fuel - likely even a bit more due | to more squeeze. We also expand the inert gas charge due to heating, and a | portion of the heat that would normally go out the pipe is absorbed here. | This absorption of cyl heat by the inert charge also reduces the cyl | temperature to a point where less nitrogen is oxidized, thus reducing NOX | emissions. I've always seen an increase in TPS, when adding EGR. While I haven't done alot of adding of EGR, I've never seen a lowering of TPS, or increase in MPG. Yes, what I generally tinker with is cammed alot more then oem, so self egr'ing is alot more at low speed, and maybe that's a bigger issue then I'd thought. Grumpy - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #35 **************************** 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".