DIY_EFI Digest Friday, May 21 1999 Volume 04 : Number 299 In this issue: Re: Mr Helmholz - simple model Re: Simple Injection Questions more O2 sensor BS Re: Mr Helmholz - simple model Re: alternative engines, now Hemi RE: Simple Injection Questions Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: More Lists Re: Opel Omega Diagnostic Conector Re: Simple Injection Questions Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: Simple Injection Questions Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: Mr Helmholz - simple model RE: Simple Injection Questions Re: alternative engines, now Hemi Re: Mr Helmholz - simple model, top fuel Re: Simple Injection Questions Re: Mr Helmholz - simple model, top fuel Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: Mr Helmholz - simple model, top fuel Re: Simple Injection Questions See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 21 May 1999 12:45:18 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model Squash, Ya just HAD to make me go and look at a bunch of different tq/hp graphs, didn't ya! Will research a bit and let ya know, someone in here probably already knows... LATER! Todd....!! Squash wrote: > > --- "Todd....!!" wrote: > > Hey Gary, > > > > More actual TOTAL POWER is produced under the power > > curve, I believe, > > where the Torque curve meets the HP curve... Ya > > think? > > I don't know, but don't hp and torque curves always > cross at 5252 RPM? How would that work on any engine > that has a peak HP over 5252 RPM? > > _____________________________________________________________ > Do You Yahoo!? > Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Fri, 21 May 1999 14:11:39 -0400 From: "Bruce Plecan" Subject: Re: Simple Injection Questions Alpha-N means the EFI just uses Throttle Posistion, and rpm to figure fuel and/or timing. PE is Power enrichment. Self tuning is a dream for really high performance. There is no way to optimize tuning other than by testing. Self compensating for slight changes, maybe.. If you change the volumetic effeciency, the you'll have to test to find best Air Fuel Ratio, and to be best, would also, be optimizing timing. "Self-Tunig", is a buzz word. Compensating does exist in the world as we know it. Self Tuning was done by the Cutler EFI Co., in FL. But, they are out of business as far as I know. The problem was loading the engine down long enough at one time for the computer to learn things. Talked with a guy who had done several of the installations, and after 4, he was finished trying. Took many hours on dyno, and 2 applications were boats. Not enough waterway for unlimited WOT testing. Single cylinder closed loop might be a real challenge. The time from cycle to cycle is so long.. To get any averages you'd be using waiting days for when to apply the correction, unless you go event by event and at low rpm you might wind up with stalling before an odd event is averaged out. Singles can be very erratic at idle, from what Cub work i did years ago. A basic Alpha-N, with barometric, and Intake air Temp compensation would be about as sweet and complex as I'd think would be practicle. Probably best to use a "fixed" pullse at idle (other than for the above corrections), and some pots for accleration, transistion (accleration, and decleration), and WOT tuning. Might use a WB O2 for just seeing where you are, rather than close looping it. Just my 02 cents Grumpy | > I think a single cylinder engine will have a very discontinuous air flow | > which effectively eliminates MAP and MAF. The simplest system I can think | > of is alpha-n, rpm and throttle position. It can be mapped to a lookup | Ok, MAP/MAF = manifold air pressure/flow right?What's alpha-n? | > table and then corrected for temperature and exhaust O2. But why do you | > insist on closed loop? As far as I know, that is most useful for making a 3 | > way cat work. Without a cat, you actually want a lean cruise and rich PE. | > Neither of which are well indicated with a normal O2 sensor. | What's PE? The reason I want some sort of closed loop is that in bike | applications, people are always changing things like different exhaust, air | filters, modified airbox, etc. I want the injection system to compensate and | I've been instructed that MAF with O2 will compensate for modifications like | this. | > To answer your second question, no, you don't need to include ignition | > timing although there are advantages associated with electronic spark | > timing. | Well, most bikes already have CDI now so it might be pretty easy to take over | triggering. What are the advantages/disadvantages? | Thanks! | Beez ------------------------------ Date: Fri, 21 May 1999 14:13:10 -0400 From: Chris Conlon Subject: more O2 sensor BS Because I can't resist putting my $0.05 worth of confounding info into the fray, here it is. Yes most of this is just me BSing so the rigorous in the audience might feel free to delete already. >Nominal volts: ~-40mv in free air, returned to this >after each test by fanning above can with piece of paper. This is probably just the thermocouple voltage from the cell being heated. It's in the right range anyway for ~800+C and some rough average thermocouple outputs. The first thing is that the cell probably develops a voltage due to more than one reaction, or could do so. If it does have a platinum/platinized electrode, why couldn't it act as a fuel cell and oxidize stuff (HC included) to produce some voltage? This would give a voltage dependent on redox potential, sort of, and might explain some of the confusing results. Note that I'm not saying "it senses HC", I'm saying it might sense an oxidation potential gradient acoss the sensor membrane. HC on one side and O2 on the other could cause this, but other things could too. Has anyone flooded both sides of a warm sensor with a small HC (methane or acetylene)? I bet you get ~40mv, i.e. no output. Also the size of the HC most likely makes a big difference. In the exhaust stream you're looking at lots of small HC and alcohols, ketones, etc which might be more likely to participate in a membrane-located oxidation process. In my mind a good first test would be to use nitrogen (air minus all oxygen) on one side or the other of the cell. I think this will tell you if the sensor responds to an oxygen gradient, without any other confouding HC, CFCs, etc. The argon test is close to this but not quite there. Also Bruce's test with pure O2 vs. air (if I understood how he ran the test) suggests that the sensor might not respond much to just an O2 gradient. (A partial response, yielding a different voltage or lower current output at the same voltage, is a possibility, I think.) Ok my producer is signalling me to wrap, so here goes: >Thinking about this, it makes sense. Once you reach stoich (450mv), >how can you go higher? Only if the excess hc takes it there... First do we at least agree that the O2 sensor does basically *work*? That it does sense something, and lets you measure rich vs. lean, if not very precisely? Given that... My guess is the sensor responds to O2 partial pressure gradients (as claimed), with a medium to low sensitivity. I don't know if it also responds (with a higher sensitivity) to O2/HC redox directly (a la fuel cells), or if the presence of small HC on a hot (possibly platinized) surface is just very good at creating a bigger O2 gradient by consuming O2. This would allow response on both sides of stoich; on the lean side there is excess O2, up to the amount found in air, which lowers the O2 gradient and the output voltage. (Also in the case of rich misfire, where the HC is mostly uncracked larger HC stuff, which I'm guessing is too large and slow burning in this situation to consume as much O2. Remember where I said size might matter? ;) On the rich side there is spare HC (small HC residues) to sop up extra O2, and create more of an O2 gradient than just N2 + H2O + CO2 (which is what you would get at stoich, in theoory) would. So there you go, fwiw. ---Chris C. ------------------------------ Date: Fri, 21 May 1999 15:03:31 -0400 From: Frederic Breitwieser Subject: Re: Mr Helmholz - simple model > Gary what's a CVT...? Constantly Variable Transmission, whereas the engine maintains an RPM in its optimal torque curve, and the transmission, via a belt of some sort, adjusts the axle speed. This is typically done with two interlaced pulley halves that mate together. The closer the pulley halves are together, the larger diameter the pulley is. The reverse would also be true, whereas the pulley halves pulling apart would yield a smaller pulley diameter. Works great in go-karts, and been used for years. Some of the carm manufacturers have been making units for electric powered cars, and nowadays even small gas engine powered cars. Problem has been (to date) belt tearing under high power applications. > ALSO a TOP FUEL dragster is still traction limited, doesn't have more > than one gear, and the clutch slides the entire run... Our funny car has *no* gears. Engine, flywheel, clutch, giant lubricated spherical bearing, driveshaft. We worship our SFI rated bellhousing :) - -- Frederic Breitwieser Bridgeport CT 06606 1993 Supercharged Lincoln Continental 1989 HWMMV w/turbocharged 500cid Caddy 1975 Dodge D200 Club Cab soon to have 431 stroker + turbos 2000 (I hope) Buick GTP (Mid-Engined Sports Car) ------------------------------ Date: Fri, 21 May 1999 15:05:18 -0400 (EDT) From: Pat Ford Subject: Re: alternative engines, now Hemi Previously, you (Todd....!!) wrote: > C'mon David...., > > They used to think it was impossible to travel to the moon, much less > mars.... we've done it... > > They used to think a 4 minute mile was impossible... Done > > As well as a sub 4 second 1/4 run outof a piston engined dragster... > Done > snip > > As for the bolts, use isolated anchors within the block or merely secure > the heads onto the block via some sortof external mechanism...(like a > vice) > > Most obstacles are easily overcome, if ya think the 'right' way.... why not have a spark plug with a very long nose and no side electrode ie the nose clears the threaded part by .5" to .75" and sparks to the piston due to proximity a problem I could see is the oil insulating the return path > > Anything else? > > LATER! > > Todd....!! > > David A. Cooley wrote: > > > > > Makes ya wonder why they don't just use the piston as the electrode and > > > the head as the ground or vice versus and omit the spark plug all > > > together due to not having a need for em anymore! > > > > > > The block and/or pistons can be electrically isolated from the heads > > > fairly wasily with nonconductive head gaskets, etc... > > > > Actually, they can't. Head bolts are metal, water in the cooling jacket is > > conductive etc... > > It's basically an impossibility. > > - -- Pat Ford email: pford@xxx.com QNX Software Systems, Ltd. WWW: http://www.qnx.com (613) 591-0931 (voice) mail: 175 Terrence Matthews (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Fri, 21 May 1999 15:32:28 -0400 From: "Chew, Aaron" Subject: RE: Simple Injection Questions Alpha-n is a throttle-position and rpm fuel map control strategy. - -----Original Message----- From: Christopher J Beasley [mailto:chris_beasley@xxx.com] Sent: Friday, May 21, 1999 1:43 PM To: diy_efi@xxx.edu Subject: Re: Simple Injection Questions Gary Derian wrote: > I think a single cylinder engine will have a very discontinuous air flow > which effectively eliminates MAP and MAF. The simplest system I can think > of is alpha-n, rpm and throttle position. It can be mapped to a lookup Ok, MAP/MAF = manifold air pressure/flow right?What's alpha-n? > table and then corrected for temperature and exhaust O2. But why do you > insist on closed loop? As far as I know, that is most useful for making a 3 > way cat work. Without a cat, you actually want a lean cruise and rich PE. > Neither of which are well indicated with a normal O2 sensor. What's PE? The reason I want some sort of closed loop is that in bike applications, people are always changing things like different exhaust, air filters, modified airbox, etc. I want the injection system to compensate and I've been instructed that MAF with O2 will compensate for modifications like this. > > > To answer your second question, no, you don't need to include ignition > timing although there are advantages associated with electronic spark > timing. Well, most bikes already have CDI now so it might be pretty easy to take over triggering. What are the advantages/disadvantages? Thanks! Beez ------------------------------ Date: Fri, 21 May 1999 15:36:04 -0400 From: "Bruce Plecan" Subject: Re: alternative engines, now Hemi | > They used to think it was impossible to travel to the moon, much less | > mars.... we've done it... Depends on if you beleive the news. | > They used to think a 4 minute mile was impossible... Done | > As well as a sub 4 second 1/4 run outof a piston engined dragster... | > Done Hear of sub 5, but not sub 4. Wouldn't sub 4 mean 3.xx | snip | > Most obstacles are easily overcome, if ya think the 'right' way.... Cold Fusion. | why not have a spark plug with a very long nose and no side electrode Saab done it already, trouble was erosion at top of ring pattern when spark occured. Grumpy | ie | the nose clears the threaded part by .5" to .75" and sparks to the | piston due to proximity | a problem I could see is the oil insulating the return path | > Anything else? | > LATER! | > Todd....!! | > David A. Cooley wrote: | > > > Makes ya wonder why they don't just use the piston as the electrode and | > > > the head as the ground or vice versus and omit the spark plug all | > > > together due to not having a need for em anymore! | > > > The block and/or pistons can be electrically isolated from the heads | > > > fairly wasily with nonconductive head gaskets, etc... | > > Actually, they can't. Head bolts are metal, water in the cooling jacket is | > > conductive etc... | > > It's basically an impossibility. | Pat Ford email: pford@xxx.com ------------------------------ Date: Fri, 21 May 1999 15:38:33 -0300 From: "Ord Millar" Subject: Re: Mr Helmholz - simple model HP = TQ * RPM / 5252 (When TQ in lb-ft) So crossing at 5252 isn't really a surprise... - -----Original Message----- From: Todd....!! To: diy_efi@xxx.edu> Date: Friday, May 21, 1999 3:55 PM Subject: Re: Mr Helmholz - simple model >Squash, > >Ya just HAD to make me go and look at a bunch of different tq/hp graphs, >didn't ya! > >Will research a bit and let ya know, someone in here probably already >knows... > >LATER! > >Todd....!! > >Squash wrote: >> >> --- "Todd....!!" wrote: >> > Hey Gary, >> > >> > More actual TOTAL POWER is produced under the power >> > curve, I believe, >> > where the Torque curve meets the HP curve... Ya >> > think? >> >> I don't know, but don't hp and torque curves always >> cross at 5252 RPM? How would that work on any engine >> that has a peak HP over 5252 RPM? >> >> _____________________________________________________________ >> Do You Yahoo!? >> Free instant messaging and more at http://messenger.yahoo.com > > ------------------------------ Date: Fri, 21 May 1999 16:25:09 +0000 From: xxalexx@xxx.com Subject: Re: More Lists IATN has a mail list and web forums http://www.iatn.net I have not seen anything for internal repairs. alex > Hi folks > Would anyone have more mailing lists to recommend? > While I enjoy this list about 98% of this I dont understand and I am > looking for something still to do with engine management systems > but maybe closer related to the repair of these systems rather than > reprogramming > Cheers > Geoff > > > ------------------------------ Date: Fri, 21 May 1999 16:25:09 +0000 From: xxalexx@xxx.com Subject: Re: Opel Omega Diagnostic Conector I was looking at a GM Tech-2 scan tool manual circa 1996 a few days ago. There were many optional adapters and languages including Opel. Also I recall adapter pin outs. I will check back in a few days. I have a OBD2 protocol GM tool that should work if you have pin 2 of a 16 pin D shaped connector under dash near stearing wheel. Also a ISO protocol if uses a pin 7 alex http://www.obd-2.com > Hi, > > I am "listening" this list for some time, since I bought EFI cars. > > I have two EFI cars, they are made in Brazil, by Chevrolet, following > the original design by Opel (Germany) (with some litle changes, maybe). > They are an Omega Sedan (1994) 2.0, and a Corsa (1998) 1.0. > > How I always make the services, only in my cars, by myself. I'm > searching for technical information about it (in portuguese, english, > french, spanish or italian; I don't understand anything in german). > > Specially about their EFI systems (Bosch Motronic, I think) and the > diagnostic conector. I am thinking about an interface to PC. > > I found a conector in the Omega, wich I think that is the diagnostic > conector, but it doesn't looks like an ALDL conector, in fact, I'm not > sure if that conector with 10 pins (2 lines of five pins), positioned in > the engine compartment, in a cable comming from the main cable of the > EFI system, is the diagnostic conector. > > So, my questions are; if there are anybody in the world who can answer > this. > > 1) where are the diagnostic conectors, in these two cars? > 2) what are their pin functions? > 3) what are the codes and the protocol to "talk" with the ECM? > > Thanx in advance > > Aron L. Petrucci > aron@xxx.br > > Londrina - Pr > Brazil. > > > > > > > ------------------------------ Date: Fri, 21 May 1999 16:40:53 -0400 (EDT) From: William T Wilson Subject: Re: Simple Injection Questions On Fri, 21 May 1999, Frederic Breitwieser wrote: > It would be my preference to cut spark rather than fuel, simply > because cutting fuel would result in a lean condition at higher RPMs You'd think so, but many production rev limiters work this way. I know there's a reason for why they do it this way, but I cannot remember what it is. In any case, a fuel cut doesn't creat detonation provided you really cut the fuel off all at once. ------------------------------ Date: Fri, 21 May 1999 14:28:45 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi Good'n Bill, ouch... What new CAR is even SOLD with a Rat these dayzzzz.... Anything?... Just wonderinnnnnnn.........!!!! Todd....!! Bill Edgeworth wrote: > > > > > I suppose they do! But aren't elephants scared of > > mice? > > > > Andy > > > > Common misconception, the elephants are just trying to stomp on the > rodents, not dancing around scared. To eliminate this image Doctors at > mopar genetically engineered a new animal. It is one that swallows > rodents whole rather than squashing them. They called the new animal a > Viper. > > Bill Edgeworth ------------------------------ Date: Fri, 21 May 1999 14:30:46 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi You're correct Fred, Didn't Popular Science already 'do' the plastic engine article quite a few years back(10-15 years ago?) I forgot about it... ALSO, thanks for the enlightment/distinction about the coolant merely being a chemical issue... GREAT point as well! LATER! Todd....!! =------- Frederic Breitwieser wrote: > > > Actually, they can't. Head bolts are metal, water in the cooling jacket is > > conductive etc... > > > It's basically an impossibility. > > At this moment in time, yes. However, with composites coming into the > market over the next several years, its theoretically possible to have > non ferrous heads, blocks and fasteners. And the coolant being > conductive is merely a chemical issue. > > Give it a few years :) > > -- > > Frederic Breitwieser > Bridgeport CT 06606 > > 1993 Supercharged Lincoln Continental > 1989 HWMMV w/turbocharged 500cid Caddy > 1975 Dodge D200 Club Cab soon to have 431 stroker + turbos > 2000 (I hope) Buick GTP (Mid-Engined Sports Car) ------------------------------ Date: Fri, 21 May 1999 15:29:23 -0700 From: "Todd....!!" Subject: Re: Simple Injection Questions Some kids in a big truck did that 'trick' to me back in the late 80's! But they didn't blow anything up, that I noticed anyways... Why not just cut BOTH Spark AND Fuel!!?? Teh bigshot dragsters cut only ignition and they seem to not have many probs....better than the alternative of NOT using ANY type of rev limiter, ey? KABOOOMMMMM.... LATER!! Todd....!! - --------------- David A. Cooley wrote: > > > It would be my preference to cut spark rather than fuel, simply > > because cutting fuel would result in a lean condition at higher RPMs > > and possibly cause detonation. No spark results in fuel cooling off > > the combustion chamber while you're above the RPM limit, but I know > > there are other factors (unburnt fuel into the cats, etc). > > Eww... Cutting fuel, since it sn't reducing it, but turning it off > completely, wouldn't make a lean condition... > Cutting spark, cats or not, may cause more problems, as raw fuel into the > exhaust makes a rather spectacular explosion! > I blew a pair of Hemi mufflers off a 68 Pontiac Bonneville... Turned the key > off for about 2 secs while under way at 70MPH and when I cut the key back on > it blew the exhaust system apart! > Scared the hell out of me! ------------------------------ Date: Fri, 21 May 1999 15:37:43 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model I call the no trans setup a direct drive setup, how bout you? Never actually driven a vehicle with it! COOL! LATER! Todd....!! Frederic Breitwieser wrote: > > > Gary what's a CVT...? > > Constantly Variable Transmission, whereas the engine maintains an RPM > in its optimal torque curve, and the transmission, via a belt of some > sort, adjusts the axle speed. This is typically done with two > interlaced pulley halves that mate together. The closer the pulley > halves are together, the larger diameter the pulley is. The reverse > would also be true, whereas the pulley halves pulling apart would > yield a smaller pulley diameter. Works great in go-karts, and been > used for years. Some of the carm manufacturers have been making units > for electric powered cars, and nowadays even small gas engine powered > cars. > > Problem has been (to date) belt tearing under high power applications. > > > ALSO a TOP FUEL dragster is still traction limited, doesn't have more > > than one gear, and the clutch slides the entire run... > > Our funny car has *no* gears. Engine, flywheel, clutch, giant > lubricated spherical bearing, driveshaft. > > We worship our SFI rated bellhousing :) > > -- > > Frederic Breitwieser > Bridgeport CT 06606 > > 1993 Supercharged Lincoln Continental > 1989 HWMMV w/turbocharged 500cid Caddy > 1975 Dodge D200 Club Cab soon to have 431 stroker + turbos > 2000 (I hope) Buick GTP (Mid-Engined Sports Car) ------------------------------ Date: Fri, 21 May 1999 15:41:49 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi WOW PAT! GREAT IDEA! Will research... May I patent this if it all works out? Spark gap should be set at .065, right? I DID do a quick experiment with what would happen to a spark plugs spark if the grond electrode was cut totally off flush with the rest of the threads... I heard this is what the drag racers do... The spark this setup produces is HUGE! Anyone every try it? Do it and see, you'll be amazed! I would have to see how this setup sparks under at least 200 lbs. of pressure of air n fuel to see if it's truly beneficial under real world conditions n all... Thanks again for the idea(s) mang! LATER! Todd....!! Pat Ford wrote: > > Previously, you (Todd....!!) wrote: > > C'mon David...., > > > > They used to think it was impossible to travel to the moon, much less > > mars.... we've done it... > > > > They used to think a 4 minute mile was impossible... Done > > > > As well as a sub 4 second 1/4 run outof a piston engined dragster... > > Done > > > > snip > > > > > As for the bolts, use isolated anchors within the block or merely secure > > the heads onto the block via some sortof external mechanism...(like a > > vice) > > > > Most obstacles are easily overcome, if ya think the 'right' way.... > > why not have a spark plug with a very long nose and no side electrode > > ie > the nose clears the threaded part by .5" to .75" and sparks to the > piston due to proximity > > a problem I could see is the oil insulating the return path > > > > > Anything else? > > > > LATER! > > > > Todd....!! > > > > David A. Cooley wrote: > > > > > > > Makes ya wonder why they don't just use the piston as the electrode and > > > > the head as the ground or vice versus and omit the spark plug all > > > > together due to not having a need for em anymore! > > > > > > > > The block and/or pistons can be electrically isolated from the heads > > > > fairly wasily with nonconductive head gaskets, etc... > > > > > > Actually, they can't. Head bolts are metal, water in the cooling jacket is > > > conductive etc... > > > It's basically an impossibility. > > > > > > -- > Pat Ford email: pford@xxx.com > QNX Software Systems, Ltd. WWW: http://www.qnx.com > (613) 591-0931 (voice) mail: 175 Terrence Matthews > (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Fri, 21 May 1999 16:59:14 -0400 From: "David A. Cooley" Subject: Re: alternative engines, now Hemi At 02:28 PM 5/21/99 -0700, you wrote: >Good'n Bill, ouch... > >What new CAR is even SOLD with a Rat these dayzzzz.... Anything?... > >Just wonderinnnnnnn.........!!!! Suburban's, pickups, tahoe's etc... =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 Sponges grow in the ocean... Wonder how deep it would be if they didn't?! =========================================================== ------------------------------ Date: Fri, 21 May 1999 17:02:26 -0400 From: Frederic Breitwieser Subject: Re: Mr Helmholz - simple model > I call the no trans setup a direct drive setup, how bout you? Works for me. > > Never actually driven a vehicle with it! ------------------------------ Date: Fri, 21 May 1999 14:31:18 -0700 (PDT) From: senator@xxx.edu (Bill Bradley) Subject: Re: Mr Helmholz - simple model > > I don't know, but don't hp and torque curves always > > cross at 5252 RPM? How would that work on any engine > > that has a peak HP over 5252 RPM? > > Yes they do... Just means that as the Torque and HP cross at 5252, the HP is > rising and the torque is falling. > they don't stay the same above 5252. Wrong. The torque curve could very easily be rising, HP=torque(lb*ft)*rpm/5252. They always cross there. As far as the Max torque vs. Max Hp issue. Torque =Force x radius so the maximum force accelerating the car is directly proportional to the maximum torque. Power=Work/time, but it also equals Force*velocity, so the maximum force at any given speed is at maximum horsepower (the gearing is irrelevant) So for maximum acceleration you want the revs to be at peak hp. For those of us with normal transmissions, the usable power curve is more important than peak, which is where the maximum torque is a factor. Bill ------------------------------ Date: Fri, 21 May 1999 15:30:32 -0400 From: "Gary Derian" Subject: Re: alternative engines, now Hemi Saab has already shown an engine where they run the spark from the plug to the piston. Gary Derian > Makes ya wonder why they don't just use the piston as the electrode and > the head as the ground or vice versus and omit the spark plug all > together due to not having a need for em anymore! > > The block and/or pistons can be electrically isolated from the heads > fairly wasily with nonconductive head gaskets, etc... ------------------------------ Date: Fri, 21 May 1999 15:45:00 -0400 From: "Gary Derian" Subject: Re: Mr Helmholz - simple model CVT is continuously variable transmission. If you are traction limited, your control scheme becomes keep the tires at the hairy edge all the way down. This would be trivial if NHRA would allow traction control. Gary Derian > Gary what's a CVT...? > > ALSO a TOP FUEL dragster is still traction limited, doesn't have more > than one gear, and the clutch slides the entire run... > > LATER! > > Todd....!! ------------------------------ Date: Fri, 21 May 1999 15:41:58 -0400 From: "Gary Derian" Subject: Re: Mr Helmholz - simple model Power in horsepower and torque in ft-lb always have the same value at 5252 rpm. That is because a horsepower is defined as 33,000 ft-lb per minute and to go from linear to rotary we have to divide by 2 pi. The result is 5252.1131002 yadda yadda Power in kW and torque in Nm would cross over at some other rpm. To maximize power under the curve, you have to operate your engine so the average hp is as high as possible. This means revving past the hp peak to a point that after you shift, the engine has the same power but on the rising side of the curve than before you shifted. Because rotational inertia has less effect in higher gears, it is better to shift a little sooner than this. Gary Derian > --- "Todd....!!" wrote: > > Hey Gary, > > > > More actual TOTAL POWER is produced under the power > > curve, I believe, > > where the Torque curve meets the HP curve... Ya > > think? > > I don't know, but don't hp and torque curves always > cross at 5252 RPM? How would that work on any engine > that has a peak HP over 5252 RPM? > > _____________________________________________________________ > Do You Yahoo!? > Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Fri, 21 May 1999 14:35:43 -0700 From: Bill Edgeworth Subject: Re: alternative engines, now Hemi "Todd....!!" wrote: > Good'n Bill, ouch... > > What new CAR is even SOLD with a Rat these dayzzzz.... Anything?... > > Just wonderinnnnnnn.........!!!! > > Todd....!! > No cars that I know of but an option for Pick up trucks. Bill Edgeworth ------------------------------ Date: Fri, 21 May 1999 18:26:58 -0400 From: "David A. Cooley" Subject: Re: Mr Helmholz - simple model At 02:31 PM 5/21/99 -0700, you wrote: >> > I don't know, but don't hp and torque curves always >> > cross at 5252 RPM? How would that work on any engine >> > that has a peak HP over 5252 RPM? >> >> Yes they do... Just means that as the Torque and HP cross at 5252, the HP is >> rising and the torque is falling. >> they don't stay the same above 5252. > > Wrong. The torque curve could very easily be rising, >HP=torque(lb*ft)*rpm/5252. They always cross there. My answer was for if the HP peak was over 5252 RPM... Even if the torque was still rising, the HP would be rising at a greater rate and they would not stay the same after 5252 RPM =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 Sponges grow in the ocean... Wonder how deep it would be if they didn't?! =========================================================== ------------------------------ Date: Fri, 21 May 1999 17:56:55 -0500 From: Don.F.Broadus@xxx.com Subject: RE: Simple Injection Questions The main fear if you cut the ignition is that the fuel will build up in the intake manifold or mufflers, when you switch the ignition back on... BOOM there goes the intake or muffler. > -----Original Message----- > From: William T Wilson [SMTP:fluffy@xxx.org] > Sent: Friday, May 21, 1999 3:41 PM > To: diy_efi@xxx.edu > Subject: Re: Simple Injection Questions > > On Fri, 21 May 1999, Frederic Breitwieser wrote: > > > It would be my preference to cut spark rather than fuel, simply > > because cutting fuel would result in a lean condition at higher RPMs > > You'd think so, but many production rev limiters work this way. I know > there's a reason for why they do it this way, but I cannot remember what > it is. > > In any case, a fuel cut doesn't creat detonation provided you really cut > the fuel off all at once. ------------------------------ Date: Fri, 21 May 1999 19:08:04 EDT From: AL8001@xxx.com Subject: Re: alternative engines, now Hemi In a message dated 99-05-21 16:57:28 EDT, atc347@xxx.net writes: >You're correct Fred, > >Didn't Popular Science already 'do' the plastic engine article quite a >few years back(10-15 years ago?) > >I forgot about it... > > Yes, it was based on the Ford 2.3L 4 Cyl engine. It was also raced for a time in IMSA in a GTU car. Harold ------------------------------ Date: Fri, 21 May 1999 19:14:47 EDT From: ECMnut@xxx.com Subject: Re: Mr Helmholz - simple model, top fuel Man, I AM a fossil... When did they scrap the 2 speed lenco? MV > > ALSO a TOP FUEL dragster is still traction limited, doesn't have more > than one gear, and the clutch slides the entire run... > ------------------------------ Date: Fri, 21 May 1999 19:30:45 EDT From: ECMnut@xxx.com Subject: Re: Simple Injection Questions Hi Frederic, I gotta agree. The GMC Syclone has a 4600 RPM fuel cut from the factory. When ya hit it, it bucks like a bull, as fuel is turned off, then back on, and there is definitely detonation when this occurs under boost. I've heard all the theories about turning the fuel off then back on, but they don't seem to apply with 16psi of boost.. There is *significant* detonation as the injectors come back on.. It's not pretty. It would be good if they'd kill both spark & fuel Mike V > It would be my preference to cut spark rather than fuel, simply > because cutting fuel would result in a lean condition at higher RPMs > and possibly cause detonation. No spark results in fuel cooling off > the combustion chamber while you're above the RPM limit, but I know > there are other factors (unburnt fuel into the cats, etc). ------------------------------ Date: Fri, 21 May 1999 19:50:21 -0400 From: "Bruce Plecan" Subject: Re: Mr Helmholz - simple model, top fuel When that guy from the Eagles sang with that other group.. Hohoho Doc | Man, I AM a fossil... | When did they scrap the 2 speed lenco? | MV | > ALSO a TOP FUEL dragster is still traction limited, doesn't have more | > than one gear, and the clutch slides the entire run... ------------------------------ Date: Fri, 21 May 1999 19:53:29 -0400 From: Frederic Breitwieser Subject: Re: alternative engines, now Hemi > Would your FI setup for the 440 intake bolt onto the 426 Hemi's intake? > (i.e. are the runners located in the same position? I know the intake > bolts are verticle on the hemi vs. the 440 has the angled intake bolts, > but other than that, I've never noticed any diff? I don't think they line up... I remember reading something about lack of intakes that mate with hemi heads on a wedge block... But I'm often wrong. ------------------------------ Date: Fri, 21 May 1999 19:54:48 -0400 From: Frederic Breitwieser Subject: Re: alternative engines, now Hemi > Actually, the plug location in a Hemi is bad because it is off to one side. > Its the best you can do with a Hemi but its still bad. As a result it needs >From what I've read a not so uncommon mod for all out racing is to drill and tap another spark plug hole... but I've not found anything on the net about it. Someone who was slightly intoxicated mentioned this to me in a bar a year or so ago. ------------------------------ Date: Fri, 21 May 1999 19:56:19 -0400 From: Frederic Breitwieser Subject: Re: alternative engines, now Hemi > block (383-400) has smaller mains and you cannot use the Hemi crank without > cutting down the mains. This is actually what I did with my 440 wedge steel crank into the 383 block.. instead of boring out the mains I had the crank turned... a mere $125 bucks. Not too bad, and because you're taking off a lot of material, even a scoured/scratched crank (which is cheap!) can suddenly become a good core crank for the project. As long as it passes magnafluxing, it should be okay. ------------------------------ Date: Fri, 21 May 1999 19:57:58 -0400 From: Frederic Breitwieser Subject: Re: alternative engines, now Hemi > You're correct Fred, My, how rare :) > Didn't Popular Science already 'do' the plastic engine article quite a > few years back(10-15 years ago?) Might have, I don't read that magazine all that often... just occasionally in line at the supermarket while getting yet more cat litter. > ALSO, thanks for the enlightment/distinction about the coolant merely > being a chemical issue... GREAT point as well! I'm actually waiting patiently for ceramics and composites to become "regular". Most of these materials don't retain or reflect heat as well as aluminum/iron/steel, and certainly weight a lot less. Less heat retention = less detonation = more boost :) ------------------------------ Date: Fri, 21 May 1999 19:58:56 -0400 From: Frederic Breitwieser Subject: Re: Mr Helmholz - simple model, top fuel > Man, I AM a fossil... > When did they scrap the 2 speed lenco? Different classes allow different things. Lenco's are good units, but if the class allows less parts to break, you have less to go wrong. ------------------------------ Date: Fri, 21 May 1999 20:04:07 -0400 From: "Bruce Plecan" Subject: Re: Simple Injection Questions | Hi Frederic, | I gotta agree. The GMC Syclone has a 4600 RPM fuel cut from the | factory. When ya hit it, it bucks like a bull, as fuel is turned off, then | back on, and there is definitely detonation when this occurs under | boost. I've heard all the theories about turning the fuel off | then back on, but they don't seem to apply with 16psi of boost.. | There is *significant* detonation as the injectors come back on.. | It's not pretty. It would be good if they'd kill both spark & fuel Ya, but look at the drivetrain inertia your taking about. Your syclone with it's 4WD is over twice as much as any other vehicle so when it drops off, and back on it is violent, and would be under any strategy, IMHO. Probably a Saab ATP (?) Running a boost cutoff, overspeed management, and then a fuel cut.. Don't let things turn back on at 16 PSI of boost. Also, depends on driver. Hitting a fuel stop in a drag car can mean something failed, and the run should be aborted. So the driver ends the run by lifting, rather than keeping his foot in it. I wouldn't use it a signal to shift or to flat foot thur it (not lifting). Grumpy | Mike V | > It would be my preference to cut spark rather than fuel, simply | > because cutting fuel would result in a lean condition at higher RPMs | > and possibly cause detonation. No spark results in fuel cooling off | > the combustion chamber while you're above the RPM limit, but I know | > there are other factors (unburnt fuel into the cats, etc). ------------------------------ End of DIY_EFI Digest V4 #299 ***************************** 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".