DIY_EFI Digest Tuesday, 26 August 1997 Volume 02 : Number 290 In this issue: RE: For REALLY good injection, check this out Re: DIY_EFI Digest V2 #289 Re: P4ECM-SWITCHING RE: Header parts... Ignition timing set-up Re: For REALLY good injection, check this out Re: Ignition timing set-up Interface specs for an Audi 80 Re: Ignition timing set-up Re: Ignition timing set-up Re: : Re: Anti-turbo lag systems Re: O2 sensor buffering/interfacing 1003HP on 93 octane pump gas Re: : Re: Anti-turbo lag systems Re: Ignition timing set-up Re: Ignition timing set-up See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: James Boughton Date: Tue, 26 Aug 1997 08:54:25 -0400 Subject: RE: For REALLY good injection, check this out If the energy available in fuel is related mostly to the carbon content does that hydrogen about worthless? Sorry, just had to say it:-) Jim Boughton boughton@xxx.net - ---------- From: Robert Harris[SMTP:bob@xxx.com] Sent: Sunday, August 24, 1997 11:02 AM To: diy_efi@xxx.edu Subject: Re: For REALLY good injection, check this out Dah - dere is a more saturated fuel available - its called M85 or Methanol. Now time for basic chemistry. The more oxygen a fuel contains - the lower the power density of the fuel, and the more of the fuel you have to burn to make the same level of power. Your flipping magnets electromagnetic spectrum analopticytous whacko fantasy's aside, thats reality. And since the oxygenation of fuel is NOT for POWER nor for MILEAGE nor to make CARBS work better, but is for a cheap ass way of reducing certain emissions in ALL engines and causes an INCREASE in other type emissions, more is not BETTER! By the way, NOX is related to combustion TEMP, of which ethers and alcohol's tend to lower because they have LESS energy, but the prime purpose is they raise the OCTANE CHEAPER than most other additives with two nice side effects - the HC's do get lowered and the ENERGY NAZIS love it. Side effects include increased formaldehyde outputs and radically increased evaporation HC's - dats why it can only be used during winter. And Terry and others - might I suggest reading the "Exhaustive Gasoline FAQ" parts 1 to 4 posted and made available numerous places on the net. This will explain many of your fuel questions with enough provable theory so that you don't get snake oiled or side tracked into fantasy land. Final note. Diesel fuel contains ZERO oxygenates, ZERO alcohol's or ethers and is as close to liquid COAL (straight carbon) as can be made and meet other requirements. The ENERGY in a fuel is very closely related to the amount of carbon available to combine with oxygen, and pre-combining oxygen in effect pre-burns that portion of the fuel. Sorry - no plasmaizing puke yellow page magic today boys. Further, comparing gasoline to diesel requiring special fuels ain't in the realm of reality. It took Fuel Injection about 70 plus years to equal a properly tuned high performance carb such as a Weber. Further, after the fuel and air are mixed, there is NO Difference in combustion - so mixing a special fuel for one or the other is right up there with SLICK 50 and the POGUE carburetor and the fuel line magnet. Regional differences in temp, altitude, humidity etc swamp any difference blending special fuels would make with todays STREET state of the art and would be POLITICAL suicide. Just my not so humble opinion which is probably wrong anyway. Read the FAQ please before fueling my asbestos panty liners. "When some one gets something for nothing - some one else gets nothing for something " If the first ingredient ain't Habanero, then the rest don't matter. Robert Harris - ---------- > From: Don Bowen > To: diy_efi@xxx.edu > Subject: Re: For REALLY good injection, check this out > Date: Saturday, August 23, 1997 4:55 PM > > Seems like it would also do to reduce NOX even further than the current > oxygenated stuff. > > At 12:44 PM 8/23/97 -0700, you wrote: > I suppose the so called "oxygenation" of fuel has some merit, > >but it's still a concept trying to formulate fuel to fit both carbed, > >and injected engines. That's just plain stupid. If the gas companies > >want to get on the boat, why not formulate a fuel specifically for > >injected engines, (like diesel is), and make a serious attempt to > >saturate the fuel with oxygen, so that the intake air stream is reduced. > >Hell, they could even get into agriculture, and use the oxygen given off > >by plants as the source by tapping the enriched air of the massive acres > >of greenhouses popping up everywhere. I have no idea what sort of oxygen > >absorption a particular liquid hydro-carbon has, (pressure dependant, > >among other things), but getting even a small amount of the nitrogen out > >of the process in favour of oxygen has big leverage on combustion and > >power efficiency, as does recovering lost heat, and moving heat out of > >the intake charge. > > > >Terry > > > > > > > Robert Bowen > California, via Thailand, Czech Republic > > Linguistics Student; mechanic; Vespa collector > *1967 Toyota Corona, 1976 Vespa Rally 200* > Ska is the ONLY Jamaican music that counts ------------------------------ From: txhartma@xxx.com (Terry Hartman) Date: Tue, 26 Aug 1997 08:05:22 -0500 (CDT) Subject: Re: DIY_EFI Digest V2 #289 > From: Johnny > Subject: Re: Coil-on-Plug Systems > > > Get up to date by checking out the new LS1 in the '97+ Corvette and the '98 > > F-body (Firebird & Camaro) cars.... > > Speaking of '98 F-body, do you know if they are offering a 90 degree V6 > with aluminum heads? I mean the Vortec, or 4.3L or whatever you want to > call it, but with a new set of heads and sequential injection like it's > big brother? > > - -j- AFAIK - GM will use the highly successful 3800 Series II V6 as the base engine. It holds its own quite well against the 'stang GT. The 3800 puts out 200hp vs the single cam 4.6s 215(?)hp. I don't know of a source for aluminum 4.3 heads other than GMPP... good luck, T. ------------------------------ From: wrm@xxx.za (Wouter de Waal) Date: Tue, 26 Aug 1997 15:25:58 +0200 Subject: Re: P4ECM-SWITCHING >From: Jennifer Rose >Date: Mon, 25 Aug 1997 18:52:35 -0700 >Subject: Re: P4ECM-SWITCHING *snip* >>As an aside, theres an interesting series of articles in recent Silicon >>Chip issues giving some details about the DELCO ECM's used in locally made >>Commodes. Thanks for the warning... :-) W ------------------------------ From: James Boughton Date: Tue, 26 Aug 1997 09:41:22 -0400 Subject: RE: Header parts... Try around the local airport. Aircraft exhausts seem to be mostly fabricated tubing. There is Woolfe (sp?) Aircraft near the Detroit Metro Airport, if you are in that area. Another source is Burns Stainless in California. I have worked with some of their stuff and it is mighty nice. All of this is for stainless steel. Jim Boughton boughton@xxx.net - ---------- From: John C. Lagerquist[SMTP:vision_a@xxx.net] Sent: Monday, August 25, 1997 6:26 AM To: diy_efi@xxx.edu Subject: Header parts... I am looking for some sources for header parts i.e. U-bends, J-bends and particularly 2 into 1 collectors. Any suggestions? John C. Lagerquist (vision_a@xxx.net) Staff Engineer Control Vision, Inc. #include ------------------------------ From: Tom Cloud Date: Tue, 26 Aug 1997 09:29:52 -0500 Subject: Ignition timing set-up Help ... I've done a lot of work rebuilding a Ford 351W for a Bronco and am experiencing similar problems to what I had when I first pitched the old variable venturi carb and EGR for efi and a regular distributor and DuraSpark ignition off a different vehicle. Here's the problem -- timing! (at least that's what I *think* is the problem) If I set the timing to give good low end response (requires 20 to 25 degrees advanced at 600 rpm, no vacuum), I get clatter under load at high rpm's. If I back the timing off to 10 degrees at idle (closer to a stock engine setting, it runs okay at high rpm's but is disappointing at the low end. I've set the timing to a compromise position of 18 degrees and now I hear something that "could" be something loose rattling (that's really what it sounds like) at exactly "neutral" throttle (i.e. no accel/decel) above about 1800 rpm. This bothers me, as I'm afraid it's pre-ignition (or whatever it's called 8^) so I'm going to set the timing back some more before I drive it home this afternoon. Here's the questions - does anyone know which way to turn the adjustment screw inside the Ford vac advance cannister (well, obviously you can turn it *either* way ;-) .... but which does what ?? - How should timing **really** be set up ?? I know people who rebuild engines and race and they set their base timing at least as far advanced as I if not farther (they set it up until it kicks back starting and then back it off a tad). I had this problem with the stock engine (well, it had a Performer intake and had the EGR removed). Now I've got a "Lightning" short block (supposed to be 8.8:1 CR) and an E-303 roller cam with headers (still have the 2" dual pipes -- but not for long, going to 2.5" duals) and GT-40 cast iron heads, C-6, stock stall convertor and 3.50:1 diff. I keep hearing that the lack of exhaust back pressure might be the cause of my lack of low-end torque (which I can get back by advancing the timing, BTW) but then I've read that relieving exhaust back pressure **never** hurts low-end torque -- only that the engine needs to be set up for it .... that removing exhaust back pressure **always** increases torque and hp at **all** rpm's -- and I've seen dyno curves to support that claim. It seems to me that I need a distributor curved to start at 15 to 18 degrees advance and go to a maximum of 30 degrees or so at 2500 rpm ???? And then, how should the vacuum canister be connected (manifold or ported/"spark") -- and how much advance/retard should it introduce ?? If you can help me with this, I'll be eternally grateful and will tell all my friends (oops, friend ;-) how wonderful you are ;-) Tom Cloud He laughs last thinks slowest ------------------------------ From: "Robert Harris" Date: Tue, 26 Aug 1997 07:39:05 -0700 Subject: Re: For REALLY good injection, check this out Nope. Hydrogen has high energy, but the amount of hydrogen in a hydro-carbon is closely related to the number of carbon atoms. Example H H H | | | H - C ... C .... C -H | | | H H H for paraffin's like methane, ethane, propane, butane etc and then it gets complex. Generally speaking the amount of H is aprox 2x the amount of carbon atoms - but this still is a very low mass compared to the carbon mass. Since the hydrogen is bonded to the carbon ( coal and H2 if it were not), it is very convenient to only look at the carbon content for most purposes. For a discussion about fuels, in particular with regard to your need for speed, check out Jeff Hartmans book "High Performance fuels and lubricants" EFI content - Jeff is a strong advocate of a SECOND EFI system that piggybacks onto a tweaked stock system and injects a second separate fuel that could be as radical as Nitromethane on demand. Check out chapter 14 "When some one gets something for nothing - some one else gets nothing for something " If the first ingredient ain't Habanero, then the rest don't matter. Robert Harris - ---------- > From: James Boughton > To: 'diy_efi@xxx.edu' > Subject: RE: For REALLY good injection, check this out > Date: Tuesday, August 26, 1997 5:54 AM > > If the energy available in fuel is related mostly to the carbon > content does that hydrogen about worthless? > > Sorry, just had to say it:-) > > Jim Boughton > boughton@xxx.net > > ---------- > From: Robert Harris[SMTP:bob@xxx.com] > Sent: Sunday, August 24, 1997 11:02 AM > To: diy_efi@xxx.edu > Subject: Re: For REALLY good injection, check this out > > Dah - dere is a more saturated fuel available - its > called M85 or Methanol. Now time for basic chemistry. > > The more oxygen a fuel contains - the lower the power > density of the fuel, and the more of the fuel you have to > burn to make the same level of power. Your flipping magnets > electromagnetic spectrum analopticytous whacko fantasy's > aside, thats reality. > > And since the oxygenation of fuel is NOT for POWER nor for > MILEAGE nor to make CARBS work better, but is for a cheap ass > way of reducing certain emissions in ALL engines and causes > an INCREASE in other type emissions, more is not BETTER! > > By the way, NOX is related to combustion TEMP, of which ethers > and alcohol's tend to lower because they have LESS energy, but the > prime purpose is they raise the OCTANE CHEAPER than most > other additives with two nice side effects - the HC's do get lowered > and the ENERGY NAZIS love it. Side effects include increased > formaldehyde outputs and radically increased evaporation HC's - > dats why it can only be used during winter. > > And Terry and others - might I suggest reading the "Exhaustive Gasoline > FAQ" parts 1 to 4 posted and made available numerous places on the net. > This will explain many of your fuel questions with enough provable theory > so that you don't get snake oiled or side tracked into fantasy land. > > Final note. Diesel fuel contains ZERO oxygenates, ZERO alcohol's or ethers > and is as close to liquid COAL (straight carbon) as can be made and meet > other requirements. The ENERGY in a fuel is very closely related to the > amount of carbon available to combine with oxygen, and pre-combining > oxygen in effect pre-burns that portion of the fuel. Sorry - no plasmaizing > puke yellow page magic today boys. Further, comparing gasoline to diesel > requiring special fuels ain't in the realm of reality. It took Fuel Injection > about > 70 plus years to equal a properly tuned high performance carb such as a > Weber. Further, after the fuel and air are mixed, there is NO Difference in > combustion - so mixing a special fuel for one or the other is right up there > with SLICK 50 and the POGUE carburetor and the fuel line magnet. Regional > differences in temp, altitude, humidity etc swamp any difference blending > special fuels would make with todays STREET state of the art and would > be POLITICAL suicide. > > Just my not so humble opinion which is probably wrong anyway. Read > the FAQ please before fueling my asbestos panty liners. > > "When some one gets something for nothing - > some one else gets nothing for something " > > If the first ingredient ain't Habanero, then the rest don't matter. > Robert Harris > > > ---------- > > From: Don Bowen > > To: diy_efi@xxx.edu > > Subject: Re: For REALLY good injection, check this out > > Date: Saturday, August 23, 1997 4:55 PM > > > > Seems like it would also do to reduce NOX even further than the current > > oxygenated stuff. > > > > At 12:44 PM 8/23/97 -0700, you wrote: > > I suppose the so called "oxygenation" of fuel has some merit, > > >but it's still a concept trying to formulate fuel to fit both carbed, > > >and injected engines. That's just plain stupid. If the gas companies > > >want to get on the boat, why not formulate a fuel specifically for > > >injected engines, (like diesel is), and make a serious attempt to > > >saturate the fuel with oxygen, so that the intake air stream is reduced. > > >Hell, they could even get into agriculture, and use the oxygen given off > > >by plants as the source by tapping the enriched air of the massive acres > > >of greenhouses popping up everywhere. I have no idea what sort of oxygen > > >absorption a particular liquid hydro-carbon has, (pressure dependant, > > >among other things), but getting even a small amount of the nitrogen out > > >of the process in favour of oxygen has big leverage on combustion and > > >power efficiency, as does recovering lost heat, and moving heat out of > > >the intake charge. > > > > > >Terry > > > > > > > > > > > Robert Bowen > > California, via Thailand, Czech Republic > > > > Linguistics Student; mechanic; Vespa collector > > *1967 Toyota Corona, 1976 Vespa Rally 200* > > Ska is the ONLY Jamaican music that counts > ------------------------------ From: "Dave Compton" Date: Tue, 26 Aug 1997 11:03:46 -0400 Subject: Re: Ignition timing set-up You basically need to recurve the distributor. There is too much centrifugal advance being added to the curve by the distributor. Stiffer springs, limiting plates, lighter weights, however you want to do it. If you can take advance out of the dist and then add it abkc in with the static timing (at the crank) then you'll be way ahead. Ford Motorsport used to sell a little pack of 8 springs for like 5 bucks but I haven't seen one in ages. I don't know how different your engine is from stock, but EGR actually helps to reduce detonation. I can't remember which way does what on the vac can. I suggest you pull the distributor, and "play" with it to see what happens, when it's spinning. Then remove some of that advance. You can also watch the plate move when you apply vacuum with a hand pump, and determine which way to turn it. In general, the whole timing curve, should be set for no knocking acceleration from 1000 on up to max revs, in top gear. Then, you add vac advance til just before it pings. This will give max power and economy. Oh, I always liked ported spark best. Hey TOM! BUY AND READ DR.JACOBS GUIDE TO AUTOMOTIVE IGNITION!!!!!!!!!!!! CU Dave DCompton@xxx.com www.SmartWorx.com/DCompton - ---------- > From: Tom Cloud > To: EEC-EFI List ; diy_efi@xxx.com> > Cc: Todd Knighton > Subject: Ignition timing set-up > Date: Tuesday, August 26, 1997 10:29 AM > > Help ... I've done a lot of work rebuilding a Ford 351W for > a Bronco and am experiencing similar problems to what I had > when I first pitched the old variable venturi carb and EGR > for efi and a regular distributor and DuraSpark ignition > off a different vehicle. > > Here's the problem -- timing! (at least that's what I *think* > is the problem) > > If I set the timing to give good low end response (requires > 20 to 25 degrees advanced at 600 rpm, no vacuum), I get > clatter under load at high rpm's. > > If I back the timing off to 10 degrees at idle (closer to a stock > engine setting, it runs okay at high rpm's but is disappointing > at the low end. > > I've set the timing to a compromise position of 18 degrees > and now I hear something that "could" be something loose > rattling (that's really what it sounds like) at exactly > "neutral" throttle (i.e. no accel/decel) above about 1800 > rpm. This bothers me, as I'm afraid it's pre-ignition (or > whatever it's called 8^) so I'm going to set the timing > back some more before I drive it home this afternoon. > > Here's the questions > > - does anyone know which way to turn the adjustment screw > inside the Ford vac advance cannister (well, obviously you > can turn it *either* way ;-) .... but which does what ?? > > - How should timing **really** be set up ?? I know people > who rebuild engines and race and they set their base timing > at least as far advanced as I if not farther (they set it > up until it kicks back starting and then back it off a tad). > > I had this problem with the stock engine (well, it had a > Performer intake and had the EGR removed). Now I've got > a "Lightning" short block (supposed to be 8.8:1 CR) and > an E-303 roller cam with headers (still have the 2" dual pipes -- > but not for long, going to 2.5" duals) and GT-40 cast iron > heads, C-6, stock stall convertor and 3.50:1 diff. > > I keep hearing that the lack of exhaust back pressure > might be the cause of my lack of low-end torque (which > I can get back by advancing the timing, BTW) but then > I've read that relieving exhaust back pressure **never** > hurts low-end torque -- only that the engine needs to be > set up for it .... that removing exhaust back pressure > **always** increases torque and hp at **all** rpm's -- > and I've seen dyno curves to support that claim. > > It seems to me that I need a distributor curved to start > at 15 to 18 degrees advance and go to a maximum of 30 degrees > or so at 2500 rpm ???? And then, how should the vacuum > canister be connected (manifold or ported/"spark") -- and how > much advance/retard should it introduce ?? > > If you can help me with this, I'll be eternally grateful and > will tell all my friends (oops, friend ;-) how wonderful > you are ;-) > > Tom Cloud > > He laughs last thinks slowest ------------------------------ From: Weynand Kuijpers Date: Tue, 26 Aug 1997 19:08:20 +0200 (CEST) Subject: Interface specs for an Audi 80 Hay People, First of all thank you all for the responses on my previous question. (It was about a not so good running engine in my Audi 80, the problem is not completely fixed, but the mechanics are going to work on it next monday). The next questions triggered by other questions on this list, is like: has anyone any idea how to interface with the BOSCH mono jetronic EFI system in a Audi 80, build in '90? It there a factory installed plug that is usable to extract data from the engine, or must I make my own interface (i'm not so familiar with mechanical/car engineering, but electronincs and programming are no problem). Thanx in advance, Groets, Weynand "Akta Gamat!" Leeloo, "5th element" -------------------------oOOO------OOOo---------------------------------- | Weynand Kuijpers | | Unix Support Nederland Unix admin Fokker Space B.V. | | Tel. :070-3630462 Tel 071-5245262 | | Fax :070-3630470 Email : unix.admin@xxx.nl| | Email :weynand@xxx.nl| | .oooO | | ( ) Oooo. | ------------------------- \ (-----( )---------------------------------- \_) ) / (_/ ------------------------------ From: Matt Sale Date: Tue, 26 Aug 1997 10:48:31 -0500 (EST) Subject: Re: Ignition timing set-up > > Help ... I've done a lot of work rebuilding a Ford 351W for > a Bronco and am experiencing similar problems to what I had > when I first pitched the old variable venturi carb and EGR > for efi and a regular distributor and DuraSpark ignition > off a different vehicle. > > Here's the problem -- timing! (at least that's what I *think* > is the problem) > > If I set the timing to give good low end response (requires > 20 to 25 degrees advanced at 600 rpm, no vacuum), I get > clatter under load at high rpm's. > I've been battling much the same problem with my 351W DuraSpark/MSD-6A combo. I run a fairly warm cam (Comp-cams dual-pattern hydraulic), & recently switched from a Holley 650 to an Edelbrock 750. I've tried both ported & direct vacuum advance. I've turned the vacuum advance adjustment screw to its limit for least advance, and run direct vacuum presently, with about 10 degrees idle advance (mech). I ended up setting the carb fairly rich to reduce pre-ignition(?) at part throttle accel (like trying to maintain speed on an uphill grade in 5th). Then my O2 sensor says I'm a bit rich on level ground. Playing with the timing light in the garage, I see way beyond 30 degrees advance at 3000 RPM with the vacuum hooked up, causing pre-ignition. Like you, best idle is obtained with about 20 degrees advance (vacuum + mechanical). I wouldn't recommend setting idle mechanical advance beyond 12 degrees, or your total advance at 3000 will be over 30 (no vacuum), and thats not good. Although idle and startup suffer, I've had my best high-rpm operation with the idle advance (mechanical only) set around 6 degrees. Again, this keeps the ignition from being over advanced at high RPM. I have a terrible time with idle at 6 degrees though. Realistically, most of my problems are due to attempting to operate the engine outside its optimum point. I have a cam, carb, intake (Torker-II), and heads (Dart-II) that are intended for 3000-6000 RPM, yet I want to cruise at 2000 RPM in 5th. If the Vettes and Camarobirds can run so well and cruise at 1500, why can't I, right? The reason I can't is that I don't have EFI and EST, and to obtain my HP, I've compromised the low end. With megabucks of engineers, computers, labs, etc GM can analyze everything to the last nano-whatever, and balance the whole system. You and I are just hacking around the edges, experimenting by trial-and-error, with a very limited number of trials. Supposedly you can take the distributor apart and bend some tabs to limit total mechanical advance. I've tried, and found the tabs very hard to bend. I haven't tried hotter plugs, but maybe I should. So whats this have to do with EFI? Only an understanding of what works and what doesn't, and why I need an ECM! Oh, and another reason not to set your idle advance so high is wear and tear on your starter. I've burned up a few starters trying to start a warm engine with too much advance. - -- Matthew D. Sale, IC Development Engineer, Delco Electronics Corp. msale@xxx.net/~msale '69 Mustang 351W 5-spd (13.464@xxx. All responses are my own and should not be mistaken for those of Delco Electronics or General Motors. ------------------------------ From: "Gary Derian" Date: Tue, 26 Aug 1997 12:33:34 -0400 Subject: Re: Ignition timing set-up I think you're on the right track with your last statement. You need a "short "distributor curve that begins at 20 to 25=B0 and ends at 30 or s= o. I don't know all about Fords but Chevys like 36 to 38=B0 max. High performance cams lose cylinder pressure at low rpm and can therefore tolerate more low speed spark advance than a stock setup. Usually, the onset of detonation is the limit for spark advance but it is possible to have optimum timing less advanced than the detonaton limit. = I you had 8:1 compression and used 108 octane fuel, the optimum advance cou= ld not be determined by listening for detonation. When I set up my engines, I use low octane fuel and listen for detonation. Make sure your mufflers are quiet enough to hear the engine noises. Mayb= e a knock sensor could be used with a scope to see detonation. Anyway, wigh = the engine warmed up, make an acceleration run from idle to redline in 2nd or 3rd gear. The goal is to have a consistent amount of detonation the whol= e way up. This will determine the optimum advance curve for full throttle. Experiment with advance weights and springs to achieve this. Mark your damper and measure your advance curve with a timing light for each test. This will keep you on track. Once the optimum curve is achieved, retard slightly so there is no or almost no detonation. Then add vacuum advance= , as much as possible to improve part throttle economy. This is much easier to do with an engine dyno and lots of computerized st= uff but it can be done with an ear and a timing light. I have heard many times that lack of backpressure causes a loss of torque. I don't believe it for a second. Backpressure can be tolerated but has n= o benefits other than a cheaper and lighter exhaust system. Anyway, at low rpm, even a restricted exhaust offers little backpressure because the exhaust flow is low. Exhaust pulse timing can be changed by changing exhaust systems which can affect carburetor calibration. Make sure you install a balance pipe in your new exhaust about 36 inches from the engin= e. This will smooth out the exhaust sound so you need less muffler for the c= ame noise level and provides a spot for pressure waves to reflect back to the engine to help tuning. Gary Derian - -----Original Message----- From: Tom Cloud To: EEC-EFI List ; diy_efi@xxx.edu>; Bronco Group Cc: Todd Knighton Date: Tuesday, August 26, 1997 11:59 AM Subject: Ignition timing set-up >Help ... I've done a lot of work rebuilding a Ford 351W for >a Bronco and am experiencing similar problems to what I had >when I first pitched the old variable venturi carb and EGR >for efi and a regular distributor and DuraSpark ignition >off a different vehicle. > >Here's the problem -- timing! (at least that's what I *think* >is the problem) > >If I set the timing to give good low end response (requires >20 to 25 degrees advanced at 600 rpm, no vacuum), I get >clatter under load at high rpm's. > >If I back the timing off to 10 degrees at idle (closer to a stock >engine setting, it runs okay at high rpm's but is disappointing >at the low end. > >I've set the timing to a compromise position of 18 degrees >and now I hear something that "could" be something loose >rattling (that's really what it sounds like) at exactly >"neutral" throttle (i.e. no accel/decel) above about 1800 >rpm. This bothers me, as I'm afraid it's pre-ignition (or >whatever it's called 8^) so I'm going to set the timing >back some more before I drive it home this afternoon. > >Here's the questions > > - does anyone know which way to turn the adjustment screw >inside the Ford vac advance cannister (well, obviously you >can turn it *either* way ;-) .... but which does what ?? > > - How should timing **really** be set up ?? I know people >who rebuild engines and race and they set their base timing >at least as far advanced as I if not farther (they set it >up until it kicks back starting and then back it off a tad). > >I had this problem with the stock engine (well, it had a >Performer intake and had the EGR removed). Now I've got >a "Lightning" short block (supposed to be 8.8:1 CR) and >an E-303 roller cam with headers (still have the 2" dual pipes -- >but not for long, going to 2.5" duals) and GT-40 cast iron >heads, C-6, stock stall convertor and 3.50:1 diff. > >I keep hearing that the lack of exhaust back pressure >might be the cause of my lack of low-end torque (which >I can get back by advancing the timing, BTW) but then >I've read that relieving exhaust back pressure **never** >hurts low-end torque -- only that the engine needs to be >set up for it .... that removing exhaust back pressure >**always** increases torque and hp at **all** rpm's -- >and I've seen dyno curves to support that claim. > >It seems to me that I need a distributor curved to start >at 15 to 18 degrees advance and go to a maximum of 30 degrees >or so at 2500 rpm ???? And then, how should the vacuum >canister be connected (manifold or ported/"spark") -- and how >much advance/retard should it introduce ?? > >If you can help me with this, I'll be eternally grateful and >will tell all my friends (oops, friend ;-) how wonderful >you are ;-) > >Tom Cloud > > He laughs last thinks slowest > ------------------------------ From: Ed or Jose Date: Tue, 26 Aug 1997 12:41:29 -0700 Subject: Re: : Re: Anti-turbo lag systems Anyone remember a device from a company called Turbodyne? It's basically a one-way motor that spins the compressor wheel. Once the exhaust gasses spin the turbo, the unit would freewheel. - -Ed ------------------------------ From: Tom Cloud Date: Tue, 26 Aug 1997 13:20:27 -0500 Subject: Re: O2 sensor buffering/interfacing >I am looking for a circuit example to buffer an O2 sensor. I am unable to obtain the LM9904, and >would like an equivalent circuit. > > > >John C. Lagerquist (vision_a@xxx.net) >Staff Engineer >Control Vision, Inc. > >#include > John, what is an LM9904 ?? I've come up with a circuit I can share -- and it should answer another question that's been circulating also -- about how to force a richer mixture. The circuit I've seen that was posted a few weeks back only reduces the amplitude of the signal. If you were to change the offset reference (is now ground), you'd be able to keep the amplitude of the EGO swing around "stoich" while adjusting for richer or leaner. If anyone is interested, I have the circuit in a GIF format Tom Cloud He laughs last thinks slowest ------------------------------ From: Jody Shapiro Date: Tue, 26 Aug 1997 16:22:39 -0400 (EDT) Subject: 1003HP on 93 octane pump gas Interesting article in the latest issue of Street Power magazine by Jeff Hartman on the Ferrari monsters Bob Norwood has built for John Carmack (of DOOM fame). With twin turbo's and a shot of nitrous to assist in low rpm along with some modifications to the Testarossa motor, they're cranking out some crazy numbers. If I remember right they're running a Haltech PCM.. - -Jody - -- 97 Blue Vortech Z28 - 13.100 @xxx.98 http://www.bit-net.com/~jshapiro/z28/ ------------------------------ From: jb24@xxx.com Date: Tue, 26 Aug 1997 16:20:48 -0400 Subject: Re: : Re: Anti-turbo lag systems >>Anyone remember a device from a company called Turbodyne? It's basically a one-way motor that spins the compressor wheel. Once the exhaust gasses spin the turbo, the unit would freewheel.<< I actually have a flyer from Turbodyne. It is a high-speed DC motor with an over-running clutch (always on, current draw low when not accelerating turbo). No idea on cost, but seems to work, their durability vehicle was turbo-diesel semi rig. Vector cars spec'd the unit for their twin-turbo V8 couple of years ago. Some (including me) have looked at it for externally scavenged two-strokes so you don't need a drive belt on the compressor - once started the exhaust drives the turbine. The demo units slipped over the clamp face of the compressor with a high-misalignment bearing/clutch. I'll try to look up their address. John Bucknell ------------------------------ From: Tom Cloud Date: Tue, 26 Aug 1997 15:14:59 -0500 Subject: Re: Ignition timing set-up >> >> Help ... I've done a lot of work rebuilding a Ford 351W for >> a Bronco and am experiencing similar problems to what I had >> when I first pitched the old variable venturi carb and EGR >> for efi and a regular distributor and DuraSpark ignition >> off a different vehicle. >> >> Here's the problem -- timing! (at least that's what I *think* >> is the problem) >> >> If I set the timing to give good low end response (requires >> 20 to 25 degrees advanced at 600 rpm, no vacuum), I get >> clatter under load at high rpm's. >> >I've been battling much the same problem with my 351W >DuraSpark/MSD-6A combo. I run a fairly warm cam (Comp-cams >dual-pattern hydraulic), & recently switched from a Holley >650 to an Edelbrock 750. I've tried both ported & direct >vacuum advance. I've turned the vacuum advance adjustment >screw to its limit for least advance, and run direct >vacuum presently, with about 10 degrees idle advance (mech). I >ended up setting the carb fairly rich to reduce pre-ignition(?) >at part throttle accel (like trying to maintain speed on >an uphill grade in 5th). Then my O2 sensor says I'm a bit >rich on level ground. Playing with the timing light in >the garage, I see way beyond 30 degrees advance at 3000 RPM >with the vacuum hooked up, causing pre-ignition. personally, I'd not worry too much about the EGO reading, except to be sure you're not running too lean >Like you, best idle is obtained with about 20 degrees >advance (vacuum + mechanical). I wouldn't recommend >setting idle mechanical advance beyond 12 degrees, or >your total advance at 3000 will be over 30 (no vacuum), >and thats not good. Although idle and startup suffer, >I've had my best high-rpm operation with the idle >advance (mechanical only) set around 6 degrees. Again, >this keeps the ignition from being over advanced at >high RPM. I have a terrible time with idle at 6 >degrees though. I've taken my distributor and silver-soldered part of the slot the mech advance tab moves in to limit the max centrifugal advance and then turned back the vacuum advance .... and that seemed to work (I broke that distributor putting the steel cam gear on it so I'm back to square one). Problem with that method is there's this guy with torch in hand blobbing silver solder on until he says "yep, looks about right". Then he files off the excess. Problem with this problem is this guy likes to be a little more precise than that. >From my observations, I "think" that I want about 18 - 20 degrees initial advance (you're right about the starter, though) with mechanical advance limited to 10 degrees max and maybe another 5 degrees of vacuum advance But .... is that right ?? I'll tell you it *feels* good !! And then, where to hook the vac advance ?? With ported vac, the extra 5 degrees would come in as the throttle is tipped in (is it in at part throttle cruise ???? if so, that would answer my question -- that'd be the place to pick off the vac). If the ported vac doesn't affect part-throttle cruise, then seems manifold vac would be the best ???? oh, myyyy .... and the efi content here is that I've converted to efi (though it's not diy) Tom Cloud He laughs last thinks slowest ------------------------------ From: JRECPA@xxx.com Date: Tue, 26 Aug 1997 16:22:55 -0400 (EDT) Subject: Re: Ignition timing set-up In a message dated 97-08-26 12:41:49 EDT, you write: << Help ... I've done a lot of work rebuilding a Ford 351W for a Bronco and am experiencing similar problems to what I had when I first pitched the old variable venturi carb and EGR for efi and a regular distributor and DuraSpark ignition off a different vehicle. =20 Here's the problem -- timing! (at least that's what I *think* is the problem) =20 If I set the timing to give good low end response (requires 20 to 25 degrees advanced at 600 rpm, no vacuum), I get clatter under load at high rpm's. =20 If I back the timing off to 10 degrees at idle (closer to a stock engine setting, it runs okay at high rpm's but is disappointing at the low end. =20 I've set the timing to a compromise position of 18 degrees and now I hear something that "could" be something loose rattling (that's really what it sounds like) at exactly "neutral" throttle (i.e. no accel/decel) above about 1800 rpm. This bothers me, as I'm afraid it's pre-ignition (or whatever it's called 8^) so I'm going to set the timing back some more before I drive it home this afternoon. >> Some of the older ford distributors have 2 settings for the mechanical advance. Just take the distributor apart and you may see that the machanical advance inside can be taken apart and turned 180 degrees, and have only 11=B0 distributor advance instead of 16=B0 of distributor advance. That equates to 22=B0 engine advance instead of 32=B0 engine advance. Try it to see if this applies to your distributor. This will giv= e you 10=B0 more engine advance at idle and still set the advance of the engine to the same total advance. James ------------------------------ End of DIY_EFI Digest V2 #290 ***************************** 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".