DIY_EFI Digest Friday, 12 September 1997 Volume 02 : Number 316 In this issue: Mis-Fire Dectection Re: O2 sensor readings Re: O2 sensor output Injector pintle end caps Re: Mis-Fire Dectection Re: Injector pintle end caps Re: Injector pintle end caps Re: Mis-Fire Dectection Re: Injector pintle end caps Re: Injector pintle end caps carb vs. efi Re: carb vs. efi Re: carb vs. efi RE: carb vs. efi Re: carb vs. efi RE: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re: carb vs. efi Re[2]: Injector pintle end caps See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Neall Booth Date: Fri, 12 Sep 1997 06:53:00 -0700 Subject: Mis-Fire Dectection Can anyone out there explain to me how Ford and Chrysler detect misfires on 96 and newer vehicles (OBD-II equiped). Of special instrest would be the Chrysler 5.2/5.9/8.0 engines, and the ford 4.6/5.4/6.8 engines. I know that Ford uses coil-on-plug on the 5.4/6.8 and that it plays some role in the detection system. How do they do it? With the Chrysler engines I have heard they look at torque pulses to determine misfires. Again, how do they do it? Thanks Neall ------------------------------ From: Frank F Parker Date: Fri, 12 Sep 1997 08:32:39 -0400 (EDT) Subject: Re: O2 sensor readings > Ok, all you O2 experts: > I nstalled my K&N A/F meter today on my MR2T and all seemed fine. > The little lights up&down,up&down, then I go out on the highway and > after 15 min of 70mph NO lights. "Oh damn, junk meter." BUT it starts > working during the cool down (~4min). So I drive it some more in town > and everythings fine. BUT when I take it out on the thru-way again the > read out is gone, returning only after during prolonged idle. > Take a dvm and read the sensor voltage directly. The K&N is just a 0-1.2 voltmeter. Suspect your O2 sensor is opening up. Regards, Frank Parker fparker@xxx.edu Motorsports Data Acquisition > > ------------------------------ From: Tom Cloud Date: Fri, 12 Sep 1997 07:57:01 -0500 Subject: Re: O2 sensor output Alex Nicu wrote: >> Ok , I'll use the average between high and low , but , I have to set the >> perfect ( stoich ) point . The EFI unit will have to take a decision >> according with this point . >> It's one page on web where I read that this point for normal sensor it's >> arround 0.45V . OK , but yesterday on the list (#313) I read >> that the stoich point it's arround 0.6V . What's the real one ? >> Alex and Seth replied: >Alex- the curve is so steep at lambda=~1 that any value from 0.35to 0.75v >might be considered stoich, depending on your definition. > >-------------\ 0.9v > | > | > | > \ > ------------- 0.1v > > ^ > | > the sacred lambda =1 > >appologies for the ascii art > >Seth Allen and then, I (oh sage one) 8^) interjected: below is graph for the EGO sensor (joltage on y-axis and A:F on x) as I copied it, as best as I could (note, need to use a Text editor or a non-proportional font to see this) 1000 ___|_______|_______|_______|_______|__ | | | | | * . | | | | | * | | | 800 ___|_______|___.___|_______|_______|__ | | | | | | | * | | | | | * | | 600 ___|_______|_______|_._____|_______|__ | | | | | | | | | | | | | | | 400 ___|_______|_______|____.__|_______|__ | | | | | | | | | | | | | | | 200 ___|_______|_______|______.|_______|__ | | | * | | | | | . | | | | | * . 0 ___|_______|_______|_______|_______|__ 14.4 14.5 14.7 14.8 15.0 (richer) (leaner) The X-axis nos aren't linear -- that's the way the graph was. I interspersed "*" and "." to try to get the slopes on the curve correct. The curve flattens out below 14.4 and above 15.0 A:F .... the max output being ~ 1 volt and the least theoretically being 0 (but not attainable in operation). Also note that the "flat" parts beyond 14.4 and 15.0 vary with temperature of the sensor -- and you're already working with millivolts difference for each A:F point -- any kind of accuracy is impossible in those regions !! This really substantiates Seth's statement (about anything between .35 and .7 jolts being "stoich" for all practical porpoises) ...... this is one reason the cute little LED meters from MSD and Edelbrock, et al are just that -- "cute" I use a $15 DPM from Hosfelt Electronics to read mine -- it gives an actual joltage reading -- I've never expected it to give me any qualitative data (i.e. no actual A:F values) but rather an indication of what's going on -- lean or rich .... REEEL lean or rich ;-) Also, Alex, I don't recall what you said your app was, but if your EGO isn't reading anything else, a simple lo-pass filter (capacitor across input to meter) should give you an average of the excursions Tom Cloud Just because you're paranoid doesn't mean they're NOT out to get you !! ------------------------------ From: James Thorne Date: Fri, 12 Sep 1997 08:23:31 -0500 Subject: Injector pintle end caps Does anyone know where to buy the plastic caps for the end of bosch type injectors? These are out of a Ford but should not matter. Most of the ones I have seen are about the same. Except MSD injectors which do not have plastic caps. I already talked to MSD, Kinsler and Cartech and Ford Parts. I also tried the obvious parts stores. Tried the junk yard too but old ones all seem to crack as you try to get them off. No luck. Any help will be appreciated. Thanks James Thorne jthorn@xxx.com ------------------------------ From: "Dave J. Andruczyk" Date: Fri, 12 Sep 1997 09:42:04 -0400 (EDT) Subject: Re: Mis-Fire Dectection > > With the Chrysler engines I have heard they look at torque pulses to > determine misfires. Again, how do they do it? > Well this isn't directly related to the chrysler system. But there is a feedback addon for carburted cars that uses a hall effect sensor that looks at the flywheel teeth, a misfire will cause a change in angular velocity of the teeth, ( and thus the pulses outputted by the hall sensor). A change in angular velocity (assuming no other inputs to the engine are changing) will show a misfire. If the computer had other position input info ( cam position/crank position) the computer would probably be able to figure out which cylider misfired. Dave ------------------------------ From: bwmsbldr@xxx.com (Bill Williams) Date: Fri, 12 Sep 1997 10:21:13 -0600 Subject: Re: Injector pintle end caps They were on the list a while back as being available from NAPA for $10/4. Sorry but I don't have the P/N at hand. - --- Bill in Boulder "Engineering as an Art Form" --- ------------------------------ From: michaels@xxx.com (Michael Skolones) Date: Fri, 12 Sep 1997 09:12:41 -0700 Subject: Re: Injector pintle end caps - --IMA.Boundary.286180478 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part I just bought some injector rebuild kits ($3.50 apiece) for my '84 Volvo LH-Jet; the kit included some O-rings, pintle caps and O-ring supports. I got them at RPR Volvo parts, in Albany CA (they're on the web). The kit instructions said not to replace the pintle caps if the originals on the FI were yellow (which mine were-I guess it's an older version of the injector). Mike Skolones ______________________________ Reply Separator _________________________________ Subject: Injector pintle end caps Author: diy_efi@xxx.edu at Internet Date: 9/12/97 8:23 AM Does anyone know where to buy the plastic caps for the end of bosch type injectors? These are out of a Ford but should not matter. Most of the ones I have seen are about the same. Except MSD injectors which do not have plastic caps. I already talked to MSD, Kinsler and Cartech and Ford Parts. I also tried the obvious parts stores. Tried the junk yard too but old ones all seem to crack as you try to get them off. No luck. Any help will be appreciated. Thanks James Thorne jthorn@xxx.com - --IMA.Boundary.286180478 Content-Type: text/plain; charset=US-ASCII; name="RFC822 message headers" Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Content-Disposition: inline; filename="RFC822 message headers" Received: from coulomb.eng.ohio-state.edu (128.146.90.150) by mailserver.mail1.com with SMTP (IMA Internet Exchange 2.1 Enterprise) id 00098BDA; Fri, 12 Sep 97 07:42:00 - -0700 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id NAA18900; Fri, 12 Sep 1997 13:24:05 GMT Received: from mail.mustangeng.com by coulomb.eng.ohio-state.edu via SMTP (940816.SGI.8.6.9/940406.SGI) for id JAA18891; Fri, 12 Sep 1997 09:24:02 - -0400 Received: from mustangeng.com. (mustangeng.com. [207.90.218.227]) by mail.mustangeng.com (NTMail 3.02.13) with ESMTP id ja114409 for ; Fri, 12 Sep 1997 08:24:59 -0500 Received: from MEI-Message_Server by mustangeng.com with Novell_GroupWise; Fri, 12 Sep 1997 09:23:37 -0500 Message-Id: X-Mailer: Novell GroupWise 4.1 Date: Fri, 12 Sep 1997 08:23:31 -0500 From: James Thorne To: diy_efi@xxx.edu Subject: Injector pintle end caps Mime-Version: 1.0 Content-Type: text/plain Content-Disposition: inline Sender: owner-diy_efi@xxx.edu Precedence: bulk Reply-To: diy_efi@xxx.edu - --IMA.Boundary.286180478-- ------------------------------ From: "Christopher G. Moog" Date: Fri, 12 Sep 1997 12:53:20 -0400 Subject: Re: Mis-Fire Dectection Dave J. Andruczyk wrote: > Well this isn't directly related to the chrysler system. But there is a > feedback addon for carburted cars that uses a hall effect sensor that > looks at the flywheel teeth, a misfire will cause a change in angular > velocity of the teeth, ( and thus the pulses outputted by the hall > sensor). A change in angular velocity (assuming no other inputs to the > engine are changing) will show a misfire. If the computer had other > position input info ( cam position/crank position) the computer would > probably be able to figure out which cylider misfired. > > Dave Since OBDII requires misfire detection numerious schemes have been developed. The ones measuring changes in engine speed (from crank sensor) incorporate signals from the ABS wheel sensors since rough roads can cause false readings. ------------------------------ From: djp@xxx.edu (Dick Protus) Date: Fri, 12 Sep 1997 13:17:31 -0400 (EDT) Subject: Re: Injector pintle end caps > > Does anyone know where to buy the plastic caps for the end of bosch type injectors? These Kinsler Fuel Injection should have these in stock. I don't have the number handy, but I think it has been posted recently anyways. dick protus ------------------------------ From: Chief Date: Fri, 12 Sep 1997 14:04:58 -0400 Subject: Re: Injector pintle end caps At 09:12 AM 9/12/97 -0700, you wrote: >Content-Type: text/plain; charset=US-ASCII >Content-Transfer-Encoding: 7bit >Content-Description: cc:Mail note part > > I just bought some injector rebuild kits ($3.50 apiece) for my '84 > Volvo LH-Jet; the kit included some O-rings, pintle caps and O-ring > supports. I got them at RPR Volvo parts, in Albany CA (they're on the > web). The kit instructions said not to replace the pintle caps if the > originals on the FI were yellow (which mine were-I guess it's an older > version of the injector). I have four on a Fiat L-Jet system that probably could use a rebuilding. Where did you purchase these kits? Is rebuilding a good alternative to new injectors? Will the rebuilt ones have comparable performance? Ed Hilker aka "Chief" '84 SS - 700R4 ------------------------------ From: Tom Cloud Date: Fri, 12 Sep 1997 13:33:26 -0500 Subject: carb vs. efi he'p me out here .... have a friend that's a died-in-the-wool Holley carb fan and thinks I've made a big mistake going to efi (I'm not racing) He's an engineer, has worked as a mechanic, owned a speed shop and raced for a number of years, so I regard his opinion. He argues that no top racer (NHRA is his game) runs efi. I admit that's probably right, but the reason isn't because it's not better, but rather that it's too danged difficult to change at the track .... what do the Formula 1 guys (and others) do ?? Like I say, he'p me here .... - he says he feels the carb gives better atomization -- and I can see that a constant fuel flow rather than pulsations might (though the pulsations are at high pressure) - the efi gives better fuel control, I'd think, though that may not be important for racing - clearly port injection gives better fuel distribution -- but, at 8 to 12 k does it matter ?? ???? anyone ?? Tom Cloud Just because you're paranoid doesn't mean they're NOT out to get you !! ------------------------------ From: "Dave Compton" Date: Fri, 12 Sep 1997 14:57:08 -0400 Subject: Re: carb vs. efi > he'p me out here .... have a friend that's a died-in-the-wool > Holley carb fan and thinks I've made a big mistake going to efi > (I'm not racing) > > He's an engineer, has worked as a mechanic, owned a speed shop > and raced for a number of years, so I regard his opinion. > > He argues that no top racer (NHRA is his game) runs efi. I admit My opinion is that he's a dinosaur..... Don't forget that alot of racing bodies don't ALLOW fuel injection. Don't forget where EEC-IV came from. Dave DCompton@xxx.com http://www.SmartWorx.com/DCompton ------------------------------ From: Tom Cloud Date: Fri, 12 Sep 1997 14:05:15 -0500 Subject: Re: carb vs. efi >he'p me out here .... have a friend that's a died-in-the-wool >Holley carb fan and thinks I've made a big mistake going to efi >(I'm not racing) > >He's an engineer, has worked as a mechanic, owned a speed shop >and raced for a number of years, so I regard his opinion. > >He argues that no top racer (NHRA is his game) runs efi. I admit >that's probably right, but the reason isn't because it's not better, >but rather that it's too danged difficult to change at the >track .... > >what do the Formula 1 guys (and others) do ?? I've thought about this summore ... I guess my question, really, is "why don't more top racers use efi (or do they ??)" ?? Tom Cloud Just because you're paranoid doesn't mean they're NOT out to get you !! ------------------------------ From: "Sam Weatherby (Volt Computer) (Exchange)" Date: Fri, 12 Sep 1997 12:07:16 -0700 Subject: RE: carb vs. efi I think that EFI is better for all around stuff. Look at those Cars, they operate in a narrow band of power. Those carbs have to be tuned for that range. In normal street duty you need good tuning from idle to the top end... -srw Sam Weatherby Mailto:A-SamWe@xxx.com http://insert.com/sammy '70 Mustang Grabber Sportsroof '93 F-150 XLT Lightning '78 Honda CX500 Reserved for '98 Harley FXD Super - Glide! "There are those that break and Bend, I'm the other kind..." > -----Original Message----- > From: Tom Cloud [SMTP:cloud@xxx.edu] > Sent: Friday, September 12, 1997 11:33 AM > To: EEC-EFI List; diy_efi@xxx.edu > Subject: carb vs. efi > > he'p me out here .... have a friend that's a died-in-the-wool > Holley carb fan and thinks I've made a big mistake going to efi > (I'm not racing) > > He's an engineer, has worked as a mechanic, owned a speed shop > and raced for a number of years, so I regard his opinion. > > He argues that no top racer (NHRA is his game) runs efi. I admit > that's probably right, but the reason isn't because it's not better, > but rather that it's too danged difficult to change at the > track .... > > what do the Formula 1 guys (and others) do ?? > > Like I say, he'p me here .... > > - he says he feels the carb gives better atomization -- and I > can see that a constant fuel flow rather than pulsations might > (though the pulsations are at high pressure) > > - the efi gives better fuel control, I'd think, though that may > not be important for racing > > - clearly port injection gives better fuel distribution -- but, > at 8 to 12 k does it matter ?? > > ???? anyone ?? > > Tom Cloud > > Just because you're paranoid doesn't mean they're NOT out to get > you !! ------------------------------ From: Zoltan Lajber Date: Fri, 12 Sep 1997 21:31:17 +0200 (MET DST) Subject: Re: carb vs. efi On Fri, 12 Sep 1997, Tom Cloud wrote: > what do the Formula 1 guys (and others) do ?? EFI, sure > Like I say, he'p me here .... > > - he says he feels the carb gives better atomization -- and I > can see that a constant fuel flow rather than pulsations might > (though the pulsations are at high pressure) He never see a an injection... Don't speek about compressed air injector. > - the efi gives better fuel control, I'd think, though that may > not be important for racing Not just fuel control, but a _good_ efi is big improovment in driveability. And some races jus forgot, the good driveability is more importatn like few percent more peek power. Ok for oval/drag ( a la USA) not a big issue, but for real tracks... > - clearly port injection gives better fuel distribution -- but, > at 8 to 12 k does it matter ?? For high power output, the injectors are half meter far from ports... for high rev engine the efi is better. You can set up carbs for igh speed, but your engine died at low. With efi, _should_ be both. Bye, - -=Lajbi=-------------------------------------------------------------------- LAJBER Zoltan lajber@xxx.hu/~lajbi E.S.E.M.,L.M.E. http://www.univ-orleans.fr/ESEM/LME/ A member of HuLUG http://www.cab.u-szeged.hu/local/linux/ ------------------------------ From: "Harms, Rick" Date: Fri, 12 Sep 1997 15:32:00 EDT Subject: RE: carb vs. efi My Holley Pro-jection died for the third time a couple of months ago. I am not going to purchase a fourth computer. So what? I replaced it with a Holley double-pumper. Now I am having to learn all about "holes", "transition slots", etc. I like computers better. The carb is fine in drag racing, a binary situation mostly, on or off. It is easy to get the correct mixture in a very narrow RPM range. For "real racing" :-), (sorry, I prefer road racing, but have nothing against drag racing) the mixture needs to be controlled over a much larger RPM range. The computer does that "good". You also avoid sloshing bowls and vent problems. The speed shop that does my engine's machine work is owned by a dyed-in-the-wool drag racer. He knows double-pumpers backwards and forwards. He does not understand computers, so, obviously they are not any good. The fact that my ECU keeps dying just reinforces his opinion, but we still have friendly "discussions" on the pros and cons of both. I am hoping to find a replacement ECU for my Holley throttle body that does not cost an arm or leg. These lists help me a lot to get ideas. Who knows, maybe I will decide to use the EEC-IV and intake; however, it is doubtful because I do not have a lot of hood clearance in my car (a 427 Cobra S/C replica using a 351W punched out to 408). That is my $.02 worth. From now on I will just keep "listening". ---------- From: Tom Cloud[SMTP:cloud@xxx.edu] Sent: Friday, September 12, 1997 1:33 PM To: EEC-EFI List; diy_efi Subject: carb vs. efi WWIS MIME Decoded (2.B) on , message parts: part1.txt (text/plain) ------------------------------ he'p me out here .... have a friend that's a died-in-the-wool Holley carb fan and thinks I've made a big mistake going to efi (I'm not racing) He's an engineer, has worked as a mechanic, owned a speed shop and raced for a number of years, so I regard his opinion. He argues that no top racer (NHRA is his game) runs efi. I admit that's probably right, but the reason isn't because it's not better, but rather that it's too danged difficult to change at the track .... what do the Formula 1 guys (and others) do ?? Like I say, he'p me here .... - he says he feels the carb gives better atomization -- and I can see that a constant fuel flow rather than pulsations might (though the pulsations are at high pressure) - the efi gives better fuel control, I'd think, though that may not be important for racing - clearly port injection gives better fuel distribution -- but, at 8 to 12 k does it matter ?? ???? anyone ?? Tom Cloud Just because you're paranoid doesn't mean they're NOT out to get you !! The following binary file has been uuencoded to ensure successful transmission. Use UUDECODE to extract. begin 600 WINMAIL.DAT M>)\^(B\3`0:0"``$```````!``$``0>0!@`(````Y`0```````#H``$(@`<` M&````$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V`!``"`````@`"``$$ M@xxx.B!C87)B('9S+B!E9FD`%`4!!8`#``X```#-!PD`#``/`"$` M)0`%`$,!`2"``P`.````S0<)``P`#P`.`"P`!0`W`0$)@`$`(0```$)#-S9! 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I admit > that's probably right, but the reason isn't because it's not better, > but rather that it's too danged difficult to change at the > track .... > > what do the Formula 1 guys (and others) do ?? > > Like I say, he'p me here .... > He's got a point. In any more-or-less steady state situation I think carbs can compete, and may be better in some ways. When speed/load vary as much as they do in road vehicles (or F1), well... For an exhaustive discussion on this subject, look at the 1935-45 era and the development of aircraft piston engines. One of Ricardo's editions had a good discussion on this subject, IIRC. Basically, though, it was the Brits vs the rest of the world, with the Brits defending carbs and everyone else going to injection (or injection carbs) Jim Davies ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Fri, 12 Sep 1997 20:08:59 GMT Subject: Re: carb vs. efi >he'p me out here .... have a friend that's a died-in-the-wool >Holley carb fan and thinks I've made a big mistake going to efi >(I'm not racing) > >He's an engineer, has worked as a mechanic, owned a speed shop >and raced for a number of years, so I regard his opinion. > >He argues that no top racer (NHRA is his game) runs efi. I admit >that's probably right, but the reason isn't because it's not better, >but rather that it's too danged difficult to change at the >track .... > >what do the Formula 1 guys (and others) do ?? > >Like I say, he'p me here .... > > - he says he feels the carb gives better atomization -- and I >can see that a constant fuel flow rather than pulsations might >(though the pulsations are at high pressure) > > - the efi gives better fuel control, I'd think, though that may >not be important for racing > > - clearly port injection gives better fuel distribution -- but, >at 8 to 12 k does it matter ?? > > ???? anyone ?? > >Tom Cloud > > Just because you're paranoid doesn't mean they're NOT out to get you !! > NHRA = Not Having Real Applications. Drag racing uses either carbs or mechanical injection because that's what the guys understand, and they can make balls of power - not having to worry about emissions, driveability, mileage, etc. Even reliability is not a big item - it ONLY has to go 1/4 mile at a time. For street use, EFI wins, hands down, for reliability, driveability, mileage - no matter how you slice it. As for better atomisation, I would tend to disagree, and port injection sure solves the fuel distribution balance gremlins. Whenfuel is sprayed, at high pressure, onto the back of an open, hot valve, there is no way for a carb to improve on the atonisation/vapourization. The valve port swirl and velocity, along with the heat, does a very good job. Now, if you are trying to overload the cyls, for max power, high rpm, hang the cost acceleration, that may be a different matter. ------------------------------ From: Michael J Weber Date: Fri, 12 Sep 1997 15:39:11 -0500 Subject: Re: carb vs. efi At 02:05 PM 9/12/97 -0500, you wrote: >>he'p me out here .... have a friend that's a died-in-the-wool >>Holley carb fan and thinks I've made a big mistake going to efi >>(I'm not racing) >> >>He's an engineer, has worked as a mechanic, owned a speed shop >>and raced for a number of years, so I regard his opinion. >> >>He argues that no top racer (NHRA is his game) runs efi. I admit >>that's probably right, but the reason isn't because it's not better, >>but rather that it's too danged difficult to change at the >>track .... >> >>what do the Formula 1 guys (and others) do ?? > >I've thought about this summore ... I guess my question, really, >is "why don't more top racers use efi (or do they ??)" ?? > >Tom Cloud > > Just because you're paranoid doesn't mean they're NOT out to get you !! > Top Fuel and Funny Car use fuel injection. If I remember correctly (most times I don't) Pro Stock rules don't allow the use of the fuel injection. Mike Weber mweber@xxx.com ------------------------------ From: bwmsbldr@xxx.com (Bill Williams) Date: Fri, 12 Sep 1997 14:38:23 -0600 Subject: Re: carb vs. efi There is a school of thought that the racers used to replace the Rochester QuadraJets with Holleys because they couldn't understand the QuadraJets! Given that they were in obvious but they were outstandingly effective over a wide range of requirements, lasting from 1965 to the end of GM carburettors. In the same way the EFI can be daunting at first. However all of the F1 and many other racers use FI. - --- Bill in Boulder "Engineering as an Art Form" --- ------------------------------ From: "Gregory R. Travis" Date: Fri, 12 Sep 1997 15:50:26 -0500 (EST) Subject: Re: carb vs. efi On Fri, 12 Sep 1997, Jim Davies wrote: > > He argues that no top racer (NHRA is his game) runs efi. I admit > > that's probably right, but the reason isn't because it's not better, > > but rather that it's too danged difficult to change at the > > track .... > > > > what do the Formula 1 guys (and others) do ?? > > > > Like I say, he'p me here .... > > > He's got a point. In any more-or-less steady state situation I think > carbs can compete, and may be better in some ways. When speed/load vary > as much as they do in road vehicles (or F1), well... > > For an exhaustive discussion on this subject, look at the 1935-45 era and > the development of aircraft piston engines. One of Ricardo's editions had > a good discussion on this subject, IIRC. Basically, though, it was the > Brits vs the rest of the world, with the Brits defending carbs and > everyone else going to injection (or injection carbs) Jim, and others, have hit the nail on the head. The performance differences between carbs and EFI vary as a function of two variables: Frequency of state change and percentage of total output. If the engine application is one that finds the engine in a roughly steady-state, high power, situation then EFI gives you nothing over continuous injection (CIS). CIS, in term gives very little over carburetors. What it does give there is much finer control of individual cylinder air mass/fuel control. On the other hand, if drivability (meaning response to widely and frequently varying throttle settings) is important then EFI wins hands down - especially closed-loop EFI. As for power output, virtually everything I've read on the subject says that there is virtually no difference on a four-stroke engine between sequential port injection EFT and continuous injection above about 2000 RPM. Sequential helps emissions and idle smoothness when the engine is loafing but as the pulse width or pulse frequency increase with increasing RPM the advantage over CIS starts to close until, at around 2000RPM, it's gone. Aircraft engines fitted with CIS injection typically outperform the same engine, fitted with a carb, by a BSFC of around 0.02-0.04 or so. The difference is entirely because the CIS injection allows the engine to be leaned more aggressively before roughness starts. There is no difference in power. gregory travis greg@xxx.org ------------------------------ From: Byron Clemens Date: Fri, 12 Sep 1997 17:00:08 -0400 Subject: Re: carb vs. efi At 01:33 PM 9/12/97 -0500, you wrote: >he'p me out here .... have a friend that's a died-in-the-wool >Holley carb fan and thinks I've made a big mistake going to efi >(I'm not racing) > >He's an engineer, has worked as a mechanic, owned a speed shop >and raced for a number of years, so I regard his opinion. > >He argues that no top racer (NHRA is his game) runs efi. I admit >that's probably right, but the reason isn't because it's not better, >but rather that it's too danged difficult to change at the >track .... > >Tom Cloud NHRA has not allowed injection in the Pro-stock ranks and this class sets the standard for the lower classes. In NMCA drag racing, however, fuel injection is allowed and Mike Moran's car, among others, runs EFI along with nitrous and has done very well. On a much lower scale, we will try to set the record in an obscure NHRA class (SS/EC) in mid October at Indy with an SDS EFI system on our 4 cyl.(2.2) front wheel drive, automatic, normally aspirated Sunfire. We currently run 13.70 @xxx. Byron ------------------------------ From: James Weiler Date: Fri, 12 Sep 1997 14:17:01 -0700 (PDT) Subject: Re: carb vs. efi My understanding is that NHRA has outlawed EFI because it would make the cars too fast AND you could program the computer to control launch so you always leave the line perfect every time. In drag racing EFI is the perfect application but the NHRA decided that it would detract from the sport and fans wouldn't come out. It has to do with the governing body and nothing to do with whether EFI is any good or not. Tell him to go back to the deep south with his sister (I mean wife) cheers to all members of the 20th century jw ------------------------------ From: Jim Davies Date: Fri, 12 Sep 1997 14:15:14 -0700 (PDT) Subject: Re: carb vs. efi On Fri, 12 Sep 1997, Bill Williams wrote: > There is a school of thought that the racers used to replace the > Rochester QuadraJets with Holleys because they couldn't understand the > QuadraJets! Given that they were in obvious but they were outstandingly > effective over a wide range of requirements, lasting from 1965 to the end > of GM carburettors. In the same way the EFI can be daunting at first. > However all of the F1 and many other racers use FI. The learning curve for anything reasonably complicated is always steep, and carbs are a good example. Brand preference is also a factor, just like it is with cars etc. The old UglyJet was a lot different than a 4150/60 Holley, but it was an exellent carb, both for emmissions and performance (IMO) Jim Davies ------------------------------ From: michaels@xxx.com (Michael Skolones) Date: Fri, 12 Sep 1997 13:58:32 -0700 Subject: Re[2]: Injector pintle end caps - --IMA.Boundary.026990478 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part "Rebuilt" is probably somewhat of a misnomer. Since I couldn't replace the pintle caps and o-ring supports, my "rebuild" consisted of replacing the o-rings at either end of the injectors, testing the valves by applying 12V to the connectors and compressed air to the fuel inlet, and repeatedly filling the injector with Gumout carb cleaner. At the same time I did this I cleaned the throttle body and replaced some throttle seals. After this my 250K+ mile engine runs like new (well, almost) with the original fuel injectors. I'd say test your injectors using the spray-in-the-jar method. If they squirt funny (stream rather than mist), clean them with carb cleaner and try again. If they spray nicely, clean them anyway. Switch 12V to them repeatedly on/off to see if they stick or leak at all. There's no way to tear them down, so if cleaning doesn't cure them they need to be replaced. Try www.rprusa.com or 1-800-81VOLVO for RPR in Albany. They are a Volvo-only outfit, but if you know the Bosch part number for your injectors they might be able to cross-reference a kit. Mike Skolones ______________________________ Reply Separator _________________________________ Subject: Re: Injector pintle end caps Author: diy_efi@xxx.edu at Internet Date: 9/12/97 2:04 PM At 09:12 AM 9/12/97 -0700, you wrote: >Content-Type: text/plain; charset=US-ASCII >Content-Transfer-Encoding: 7bit >Content-Description: cc:Mail note part > > I just bought some injector rebuild kits ($3.50 apiece) for my '84 > Volvo LH-Jet; the kit included some O-rings, pintle caps and O-ring > supports. I got them at RPR Volvo parts, in Albany CA (they're on the > web). The kit instructions said not to replace the pintle caps if the > originals on the FI were yellow (which mine were-I guess it's an older > version of the injector). I have four on a Fiat L-Jet system that probably could use a rebuilding. Where did you purchase these kits? Is rebuilding a good alternative to new injectors? Will the rebuilt ones have comparable performance? Ed Hilker aka "Chief" '84 SS - 700R4 - --IMA.Boundary.026990478 Content-Type: text/plain; charset=US-ASCII; name="RFC822 message headers" Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Content-Disposition: inline; filename="RFC822 message headers" Received: from coulomb.eng.ohio-state.edu (128.146.90.150) by mailserver.mail1.com with SMTP (IMA Internet Exchange 2.1 Enterprise) id 0009911A; Fri, 12 Sep 97 12:21:13 - -0700 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id SAA26062; Fri, 12 Sep 1997 18:07:09 GMT Received: from freenet5.afn.org by coulomb.eng.ohio-state.edu via ESMTP (940816.SGI.8.6.9/940406.SGI) for id OAA26057; Fri, 12 Sep 1997 14:07:06 - -0400 Received: from special-proj1 (ppp-07-nerdc-ts14.nerdc.ufl.edu [128.227.206.75]) by freenet5.afn.org (8.8.5/AFN-1.0) with SMTP id OAA25310 for ; Fri, 12 Sep 1997 14:07:00 -0400 (EDT) Message-Id: <1.5.4.32.19970912180458.00683fcc@xxx.org> X-Sender: afn14222@xxx.org X-Mailer: Windows Eudora Light Version 1.5.4 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Sep 1997 14:04:58 -0400 To: diy_efi@xxx.edu From: Chief Subject: Re: Injector pintle end caps Sender: owner-diy_efi@xxx.edu Precedence: bulk Reply-To: diy_efi@xxx.edu - --IMA.Boundary.026990478-- ------------------------------ End of DIY_EFI Digest V2 #316 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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