DIY_EFI Digest Friday, May 21 1999 Volume 04 : Number 298 In this issue: Re: Simple Injection Questions Re: Mr Helmholz - simple model Clues Needed Re: alternative engines, now Hemi Re: Clues Needed Re: Clues Needed Re: 1227749 Re: alternative engines, now Hemi Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: O2 Volts Re: Mr Helmholz - simple model Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: Clues Needed Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: alternative engines, now Hemi Re: Mr Helmholz - simple model Re: Simple Injection Questions Re: Simple Injection Questions Re: Simple Injection Questions Re: Simple Injection Questions Re: Simple Injection Questions Re: Mr Helmholz - simple model Re: alternative engines, now Hemi 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 07:59:18 -0400 From: "Gary Derian" Subject: Re: Simple Injection Questions 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 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. To answer your second question, no, you don't need to include ignition timing although there are advantages associated with electronic spark timing. Gary Derian > Hi, I've been lurking for a little while and have a couple of questions. > It seems this list is very detail oriented, my questions are more specific. > > I would like to know how to make a very simple injection system, possibly the > simplest > available design, with the caveat that it must be closed loop, and have > reasonably good > performance. My current plan revolves around a 68HC11 or '332 with an O2 > sensor. This will be targeted at a 650cc single cylinder motorcycle engine. I > assume I will also need a tach sensor, throttle position sensor, and some kind > of manifold sensor. What is the minimum subset of sensors that you need? What > kind of manifold sensors exist? > > Do I have to take over ignition as well? What's the cost/benefit of this > integration? I already know that this particular engine lacks a rev limiter so > I'd want to incorporate that feature. > > It seems the list focuses mostly on control systems. I'm wondering where to buy > things in small quantities like throttle bodies with TPS, mass flow sensors, > pumps regulators, injectors. In short, all the goodies I don't already have ( > computer guy if you hadn't guessed). > Thanks folks! > Beez > ------------------------------ Date: Fri, 21 May 1999 08:28:24 -0400 From: "Gary Derian" Subject: Re: Mr Helmholz - simple model I race go-karts which use centrifugal clutches so I have done some thinking here. If you change your gears, you have changed your top speed at max rpm. If you are pulling stumps, use as low a gear as you can but still set the clutch stall at max torque. For a drag racer, not traction limited, you need to maximize the "power under the curve" for the 1/4 mile and must choose a gear that does this without blowing up the engine before the traps. Once you are close on a gear, the clutch setting can be calculated. Since a sliding clutch transmits all the torque input (there is no where else for it to go) and converts power into heat, it stands to reason the more torque input, the more torque output. Therefore set the stall to the max torque rpm. If you want to change your gearing, you still must set the stall to the max torque rpm. For a drag run with a sliding clutch (again, not traction limited), start out at max torque rpm while the clutch is sliding, as speed builds up, the clutch will lock up and rpm increase to max power rpm and beyond. At this point, you can shift gears if you have them. One would hit the traps at an rpm between max power and the rev limit. This is only for a sliding clutch or fluid coupling. A snowmobile uses a CVT so does not absorb power. For this case, operating the engine at max power rpm will be faster. A torque converter multiplies torque and absorbs some power so it operates somewhere in between. Gary Derian > On Thu, 20 May 1999, Gary Derian wrote: > > > If one has a sliding clutch, it should be set to hold the engine at max > > torque rpm, not max power rpm. > > I disagree, because of the effects of gearing. > > A hypothetical engine makes 300 ft.lbs at its torque peak of 4000 RPM. > At that RPM it makes 228.5 HP. > > Let's say it makes 201.3 ft.lbs at its HP peak of 6000 RPM. At that RPM > it makes 230 HP. This is an engine that could probably use a new cam. :} > > Even so, once gearing is taken into consideration, it is better to use the > HP peak. You can have a 33% lower gear ratio at the higher RPM, which - > more or less by definition - outweighs the decrease in torque at the HP > peak. Once we gear this engine down by 1/3 it makes the same 300 ft.lbs > of torque that it did at its torque peak. > > But let's say we have an engine that doesn't have its torque fall off so > badly. Let's say, instead, the engine makes 220 ft.lbs at 6000 RPM, > instead, for an HP rating of 251.3. This engine, when gearing is taken > into consideration, can generate an effective 328 ft.lbs of torque - a > noticeable improvement. > > This is why engines are rated mostly in HP. Torque is of course the most > important component in acceleration, but what RPM the torque is generated > at is just as important. HP is a better measurement of torque at RPM, > although of course a full printout of the torque curve is the best :} ------------------------------ Date: Fri, 21 May 1999 09:00:26 -0400 From: "Bruce Plecan" Subject: Clues Needed Being new to the scope world, and after reading a scope manual, I'm still at a lose, and hope someone could clear these meanings up for me. When using the triggering mode selection there are these options. Auto + Internal - - Internal +External - -External Auto-seems to mean that the pulses are displayed as they occur, and the trigger sense lead need not be connected. ALSO, for these 4 other options where would one hook the sense lead to. Any help here appreciated. Bruce Happy used to, really chase the skirts. But, having visited Scotland last weekend, has left him confused...... ------------------------------ Date: Fri, 21 May 1999 06:08:37 -0700 (PDT) From: Squash Subject: Re: alternative engines, now Hemi - --- Greg Hermann wrote: > Well--'tis true that rats end up rather FLAT (and do > not run very well at all) after an elephant has > stepped upon them!! I suppose they do! But aren't elephants scared of mice? Andy _____________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Fri, 21 May 1999 10:16:33 -0400 From: "David A. Cooley" Subject: Re: Clues Needed > Being new to the scope world, and after reading a scope manual, I'm still at > a lose, and hope someone could clear these meanings up for me. > When using the triggering mode selection there are these options. > Auto This triggers the synchronization of the scope from whatever signal is fed into the normal vertical input. > + Internal > - Internal These are similar to auto in they pick up off the signal sent to the vertical input, but the level it sync's at is adjustable with the trigger level control. + and - are for which slope of the waveform it triggers off of. > +External > -External These require the external trigger input to be hooked to it's own source... On the PCM, you could hook the trigger input to the 18X or TACH signal and hook the vertical probe to whatever you want and see it in relation to the 18X or TACH signal. ------------------------------ Date: Fri, 21 May 1999 10:32:31 -0300 From: "Ord Millar" Subject: Re: Clues Needed +/- internal - usually means triggers off the 50 or 60hz ac supply, either on the rising or falling zero volt cross. (could mean that the trigger is extracted from the signal input in some cases) +/- external - triggers off the the sense lead, either on the rising or falling edge. There should be a setting for level - whenever the input voltages cross this level the scope makes a trace. Auto - just triggers as soon as one h-sweep is finished. When using a seperate trigger, hook it to something that's in sync with what you want to measure - think of it like a timing light. - -----Original Message----- From: Bruce Plecan To: diy_efi@xxx.edu> Date: Friday, May 21, 1999 11:05 AM Subject: Clues Needed >Being new to the scope world, and after reading a scope manual, I'm still at >a lose, and hope someone could clear these meanings up for me. > When using the triggering mode selection there are these options. >Auto >+ Internal >- Internal >+External >-External >Auto-seems to mean that the pulses are displayed as they occur, and the >trigger > sense lead need not be connected. >ALSO, for these 4 other options where would one hook the sense lead to. >Any help here appreciated. >Bruce > Happy used to, really chase the skirts. > But, having visited Scotland last weekend, has left him confused...... > > ------------------------------ Date: Fri, 21 May 1999 08:55:11 -0700 From: "Todd....!!" Subject: Re: 1227749 Right place at the right time so it seems! ey? Will definitely remind ya about the web site thing... LATER! Todd....!! Frederic Breitwieser wrote: > > > HOW in the world didi ya find out when and where this auction was going > > to be? > > I dunno, this was back in the early 90's, but they have them every so > often. Read the papers, car mags, etc, sometimes they advertise in the > back. Those "Jeep for $10" government ads are information about > auctions... waste of 10 bucks really, but thats your worse case > scenario. > > We should prolly take this offline too since its a carb based truck at > the moment, and I don't have the time to EFI it, too many other EFI > things going on. > > > I'd pay $700 for a hummer shell! > > Yeah, that goes without saying. I really wasn't in the market for one > at any price, however I was visiting a friend in LA, he was going, I > tagged along, I found this carcass, and couldn't help myself. > > > Did ya use the caddi transaxle and make IT a mid engine! or is it setup > > in the normal front engine rear wheel drive, or 4 wheel drive or what? > > 4wd using hummer diffs, 5 speed out of a commercial GM box truck of some > sort (junkyard), engine/trans adaptor. > > > Hope I can find this e-mail when your firewall's fixed! > > Remind me every few weeks. ------------------------------ Date: Fri, 21 May 1999 08:53:28 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi Hey Andy, The diagonal dual quad bathtub type intake on a HEMI and other Mopars is what's known as a Rat roaster type intake, now that ya mention it, it does have the word Rat and Roaster in the name, maybe they named it that cuz it actually DOES what it's name mentions...? Thanks for sharing the distinction about the name.... LATER! Todd....!! Squash wrote: > > --- "Todd....!!" wrote: > > I'll probably use a RAT ROASTER when I inject my > > twin turbo 426 Hemi, > > What is a RAT Roaster?? Is this a mopar anti-chevy > slang term? > > Andy > _____________________________________________________________ > Do You Yahoo!? > Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Fri, 21 May 1999 09:01:39 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi COOL, Thanks for the info! Later! Todd....!! Bill Edgeworth wrote: > > Hemi's do not use siamesed intake ports like the B engine heads. Most stuff > from the bottom end is interchangeable i.e..) timing chain or gear drive, > timing cover, water pump, oil pump, NOT the cam, oil pick up on hemi is 1/2" > instead of 3/8" pipe (can be changed on 440 block to Hemi specks), cranks, > NOT main caps, NOT blocks. > > Bill Edgeworth > > "Todd....!!" wrote: > > > 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'll probably use a RAT ROASTER when I inject my twin turbo 426 Hemi, > > how bout you? > > > > If ya think ya want some Hemi parts go to my link page at: > > http://www.c-com.net/~atc347/toddlnk.htm > > and go to the Swapmeet stuff, there's quite a bit of VERY TRICK HEMI > > stuff there for sale! Like Hemi Alum rods, 8 titanium keepers or > > retainers, can't remember which, gear drive, etc.. Some of this stuff is > > usable on our NON hemi BB Mopes... > > > > LATER! > > > > Todd....!! > > > > Frederic Breitwieser wrote: > > > > > > > Anyhoo.. I believe ya, the Hemi heads really flow alot, even in stock > > > > form, add that to the shape of the combustion chamber and where the > > > > > > They also look cool and sound cool. However, they suck gas. Good > > > candidate for EFI :) > > > > > > -- > > > > > > 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 09:18:31 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model 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 once saw on TV a REAL TIME graph of a TOP FUEL DRAGSTERS' rpm's during an ENTIRE 1/4 run, all 3.x seconds of it! The rpm's stayed right around 7,000 the whole time! Pretty cool, ey? LATER! Todd....!! - ------------------- Gary Derian wrote: > > If one has a sliding clutch, it should be set to hold the engine at max > torque rpm, not max power rpm. > Gary Derian > > > > The rpm's aren't held constant unless you have some sorta newfangled > > clutch setup like the top fuelers have that hold their rpm's at PEAK > > power the whole run! THAT would be nice!! > > ------------------------------ Date: Fri, 21 May 1999 09:22:44 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi Hi Gary, Thanks for the clarification about the dual plug setup on the hemi being more efficient than the single plug version... Hence, why I stated 'plug(s)'.... 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... Kinda makes ya wonder, ey? Later! Todd....!! Gary Derian wrote: > > 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 > lots of ignition advance and high octane for a given compression. Now the > Dick Landy twin plug heads really hastens the combustion and makes an > already strong engine much stronger. Other mfgs have used twin plugs since > then. > > Gary Derian > > > Anyhoo.. I believe ya, the Hemi heads really flow alot, even in stock > > form, add that to the shape of the combustion chamber and where the > > spark plug(s) are located within the cylinder and you have one power > > packin pachyderm! > > > > > > Todd.... ------------------------------ Date: Fri, 21 May 1999 09:28:12 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model I'll post the e.t.'s for the day, hope I kept the slower one's... I'm not sure if anyone broke or not, maybe some newby to the strip did a MAJORLY HAIRY burnout while standing IN the bleach box and threw water all up in his rear fenders and then lined up to race and left a puddle for me and everyone else who ran after him...? Could be... However, I ran a LOT of runs, with hardly ANY time inbetween them, most of the runs that night were within about 10-30 mins of each other! Hardly anyone else was out that night! I just kept on goin around and around and around.... Will try n find all those slips, put em in my picture book.... Thanks for posing the question about track conditions versus octane booster... Didn't think of that, and I think I kept runnin on the same side of the track... Later! Todd....!! Gary Derian wrote: > > Todd, what did your mph do in the 1/4 when the octane boost increased power > so much your ET's got longer? Maybe some dew condensed onto the track, or > someone blew their engine. > > Gary Derian > > > > I then proceeded to not EVER gain traction for the rest of the > > night, about 5 runs in all with the octane boost in the tank, E.T. NEVER > > even dropped to mid 14's again! Due to wheel spin.... > > ------------------------------ Date: Fri, 21 May 1999 09:30:52 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi Are ya sure that the cranks don't interchange? What's the diff? Besides the Hemi having 8 flywheel bolt holes vs the 440/383's 6 flywheel bolt holes Are the main journals a different size? or the rod journals? what? The stroke is 3.75, same as a 440... And as for the caps, jsut cuz there's an extra bolt hole in the main caps for the cross bolt, does that mean ya still can't use em in the 440? Just wonderinnnnnnnnn............!! Thanks! Todd....!! Greg Hermann wrote: > > >Hemi's do not use siamesed intake ports like the B engine heads. Most stuff > >from the bottom end is interchangeable i.e..) timing chain or gear drive, > >timing cover, water pump, oil pump, NOT the cam, oil pick up on hemi is 1/2" > >instead of 3/8" pipe (can be changed on 440 block to Hemi specks), cranks, > >NOT main caps, NOT blocks. > > > >Bill Edgeworth > > > Yep--the 2,3, &4 caps are cross bolted on a Hemi. Cranks do not interchange > either. > > Greg ------------------------------ Date: Fri, 21 May 1999 09:33:54 -0700 From: "Todd....!!" Subject: Re: O2 Volts FYI - I've SEEN my headers glow while idling at night.... I'm pretty SURE they glow while at WOT and any where inbetween.... How hot are headers when they begin to glow? Is there some sorta formula or somethin to tell us this, i've never heard of it, but I bet there is a specific temp when a specific metal (Like Iron, FE) glows... LATER! Todd....!! Bruce Plecan wrote: > > I *added* heat with the lighter earlier, and no changes were noted. > On the cars being used in really cold temps, the exhaust on several models > the tubing would not crack spit. Meaning while over 210dF, was not really > hot. > On some vettes, the O2s are probably 4' away from the ports. On a really > cold day, at idle, with mechanics gloves (nomex type)(none operative cat) > you can hold the exhaust back there. > If the temp was a major concern why is't there a true strategy to > compensate for it?. > This when hot enough, is this the 800-900dC temp?. When does an average > engine reach an EGT of that?. > When speaking of a catalyst, fine, but without knowing what it is, and > what it's properties are, is gets again rather mute, as I see it. > By the way, in all my testing I was using a strategy where by I know to > some degree what the actual heater temperature is. So I can duplicate this > on car, and then see what is going on. Without quessing. > While oems, are doing this O2 work as a emission law mandated issue, I'm > just trying to figure out enough to do what I want to do. Other issues > don't matter, other than as a point of interest, or maybe concern for > others. > Grumpy > > > > The useful facts as I see them are: > > > In cold weather, a none heated O2 sensor can go open loop. due to the > O2 > > > sensor being too cold. A heated O2 develops enough heat so that it can > > > "properly sense" the needed gases to operate. > > > The O2 sensor, as tested responds to HC rather than O2. > > > While you might be able to change things, or define other operating > modes, > > > I know that if I mount the sensor far enough away from the engine that > being > > > heated is neseccary, then I know what gases matter, and thus what the > sensor > > > is seeing. > > > There are a couple of things I'd like to throw in the mix here. > > > The heater on the heated sensor is a helper to get the sensor up to > > temperature... it's probably still relying on hot exhaust gases to > > be at working temperature... it may not be hot enough when testing with > > room temperature gases. > > > There is a catalyst on the electrodes which may well promote the > > combustion of gaseous hydrocarbons with the O2 that diffuses thru > > the sensor, hence the reaction to gaseous hydrocarbons. > > > The sensor itself, when hot enough senses the relative concentrations > > of O2. This is not necessarily the O2 concentration in the exhaust > > gases as measured by other means due to the catalytic action of the > > sensor electrode... > > > Orin. ------------------------------ Date: Fri, 21 May 1999 09:38:01 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model FYI - In addition to the top fuel dragsters' engine being held at 7,000 rpm by the clutches engaging without spinning the tires(which is the goal, there's a VERY fine line in tuning them clutch packs as you probably know)... His rear gears were only like 3.73's or so! So they stated.... EVEN with those HUGE REAR SLICKS! Wierd, ey? LATER! Todd....!! William T Wilson wrote: > > On Thu, 20 May 1999, Gary Derian wrote: > > > If one has a sliding clutch, it should be set to hold the engine at max > > torque rpm, not max power rpm. > > I disagree, because of the effects of gearing. > > A hypothetical engine makes 300 ft.lbs at its torque peak of 4000 RPM. > At that RPM it makes 228.5 HP. > > Let's say it makes 201.3 ft.lbs at its HP peak of 6000 RPM. At that RPM > it makes 230 HP. This is an engine that could probably use a new cam. :} > > Even so, once gearing is taken into consideration, it is better to use the > HP peak. You can have a 33% lower gear ratio at the higher RPM, which - > more or less by definition - outweighs the decrease in torque at the HP > peak. Once we gear this engine down by 1/3 it makes the same 300 ft.lbs > of torque that it did at its torque peak. > > But let's say we have an engine that doesn't have its torque fall off so > badly. Let's say, instead, the engine makes 220 ft.lbs at 6000 RPM, > instead, for an HP rating of 251.3. This engine, when gearing is taken > into consideration, can generate an effective 328 ft.lbs of torque - a > noticeable improvement. > > This is why engines are rated mostly in HP. Torque is of course the most > important component in acceleration, but what RPM the torque is generated > at is just as important. HP is a better measurement of torque at RPM, > although of course a full printout of the torque curve is the best :} ------------------------------ Date: Fri, 21 May 1999 09:40:01 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model Hi CL, I've never messed with a snowmobile, being from Houston, Texas n all... What, may I ask, is a two stage helix, and HOW can a snowmobile hold the rpm's like that? What's the technology involved! Very interested in this... Thanks! Todd....!! CLsnyder wrote: > > ----- Original Message ----- > From: Gary Derian > To: > Sent: Thursday, May 20, 1999 6:52 PM > Subject: Re: Mr Helmholz - simple model > > > If one has a sliding clutch, it should be set to hold the engine at max > > torque rpm, not max power rpm. > > Gary Derian > > > > > > The rpm's aren't held constant unless you have some sorta newfangled > > > clutch setup like the top fuelers have that hold their rpm's at PEAK > > > power the whole run! THAT would be nice!! > > > > >On a snowmobile it holds at max HP rpm at wide open throttle. With a 2 > stage helix it can hold max torque atpart throttle. > > > > ------------------------------ Date: Fri, 21 May 1999 11:27:19 -0400 From: "David A. Cooley" Subject: Re: alternative engines, now Hemi > 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. ------------------------------ Date: Fri, 21 May 1999 11:00:05 -0500 From: steve ravet Subject: Re: Clues Needed Bruce Plecan wrote: > > Being new to the scope world, and after reading a scope manual, I'm still at > a lose, and hope someone could clear these meanings up for me. > When using the triggering mode selection there are these options. > Auto It may mean that the scope triggers constantly, ie as soon as it finishes drawing a trace it immediately draws another. Or it may look at the current signal and auto generate a level and slope trigger for it. Some HP scopes do that, in addition to setting the time base and vertical scale automatically. > + Internal > - Internal This setting means that the signal you are looking at generates a trigger. There should also be a level setting associated with these. The level is specified in volts. When the signal that your probe is connected is at that voltage then the scope triggers and generates a waveform. +/- sets the slope of the trigger. If it's set to + the scope triggers when the waveform rises through the trigger voltage. If it's -, it triggers as the voltage falls through the trigger voltage. > +External > -External Probably means that there is a probe connection that can be used to trigger the scope only. +/- and level are same as for internal, but the waveform on the external trigger can't be viewed. You could, for example, put the external trigger on the tach signal and use the other channels to observe spark traces. > Auto-seems to mean that the pulses are displayed as they occur, and the > trigger > sense lead need not be connected. > ALSO, for these 4 other options where would one hook the sense lead to. > Any help here appreciated. > Bruce > Happy used to, really chase the skirts. > But, having visited Scotland last weekend, has left him confused...... - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ Date: Fri, 21 May 1999 08:59:58 -0700 From: Bill Edgeworth Subject: Re: alternative engines, now Hemi > > 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 09:08:00 -0700 (PDT) From: Squash Subject: Re: Mr Helmholz - simple model - --- "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 12:15:18 -0400 From: Frederic Breitwieser Subject: Re: alternative engines, now Hemi > 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 12:18:29 -0400 From: "David A. Cooley" 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. ------------------------------ Date: Fri, 21 May 1999 12:52:16 -0400 (EDT) From: William T Wilson Subject: Re: Simple Injection Questions On Thu, 20 May 1999, Christopher J Beasley wrote: > Do I have to take over ignition as well? What's the cost/benefit of > this integration? I already know that this particular engine lacks a > rev limiter so I'd want to incorporate that feature. It is possible to use a regular distributor (or whatever you've got on a single-cylinder engine) in conjunction with a fuel computer. It is also possible to build in a rev limiter with the fuel computer by cutting fuel, instead of spark, when you hit the rev limit. ------------------------------ Date: Fri, 21 May 1999 13:19:56 -0400 From: Frederic Breitwieser Subject: Re: Simple Injection Questions > It is possible to use a regular distributor (or whatever you've got on a > single-cylinder engine) in conjunction with a fuel computer. It is also > possible to build in a rev limiter with the fuel computer by cutting fuel, > instead of spark, when you hit the rev limit. 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). Just a thought. - -- 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 13:32:51 -0400 From: "David A. Cooley" Subject: Re: Simple Injection Questions > 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 10:42:55 -0700 From: Christopher J Beasley 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 12:57:20 -0500 From: steve ravet Subject: Re: Simple Injection Questions Christopher J Beasley wrote: > > 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? Alpha-N is the simplest FI possible using only throttle position (alpha) and engine RPM (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. PE=power enrich, more fuel when you stomp the pedal, er, twist the handle. - --steve > > > > > > > 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 - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ Date: Fri, 21 May 1999 12:32:40 -0700 From: "Todd....!!" Subject: Re: Mr Helmholz - simple model 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....!! - ------ Gary Derian wrote: > > I race go-karts which use centrifugal clutches so I have done some thinking > here. If you change your gears, you have changed your top speed at max rpm. > If you are pulling stumps, use as low a gear as you can but still set the > clutch stall at max torque. > > For a drag racer, not traction limited, you need to maximize the "power > under the curve" for the 1/4 mile and must choose a gear that does this > without blowing up the engine before the traps. Once you are close on a > gear, the clutch setting can be calculated. Since a sliding clutch > transmits all the torque input (there is no where else for it to go) and > converts power into heat, it stands to reason the more torque input, the > more torque output. Therefore set the stall to the max torque rpm. If you > want to change your gearing, you still must set the stall to the max torque > rpm. > > For a drag run with a sliding clutch (again, not traction limited), start > out at max torque rpm while the clutch is sliding, as speed builds up, the > clutch will lock up and rpm increase to max power rpm and beyond. At this > point, you can shift gears if you have them. One would hit the traps at an > rpm between max power and the rev limit. > > This is only for a sliding clutch or fluid coupling. A snowmobile uses a > CVT so does not absorb power. For this case, operating the engine at max > power rpm will be faster. A torque converter multiplies torque and absorbs > some power so it operates somewhere in between. > > Gary Derian > > > On Thu, 20 May 1999, Gary Derian wrote: > > > > > If one has a sliding clutch, it should be set to hold the engine at max > > > torque rpm, not max power rpm. > > > > I disagree, because of the effects of gearing. > > > > A hypothetical engine makes 300 ft.lbs at its torque peak of 4000 RPM. > > At that RPM it makes 228.5 HP. > > > > Let's say it makes 201.3 ft.lbs at its HP peak of 6000 RPM. At that RPM > > it makes 230 HP. This is an engine that could probably use a new cam. :} > > > > Even so, once gearing is taken into consideration, it is better to use the > > HP peak. You can have a 33% lower gear ratio at the higher RPM, which - > > more or less by definition - outweighs the decrease in torque at the HP > > peak. Once we gear this engine down by 1/3 it makes the same 300 ft.lbs > > of torque that it did at its torque peak. > > > > But let's say we have an engine that doesn't have its torque fall off so > > badly. Let's say, instead, the engine makes 220 ft.lbs at 6000 RPM, > > instead, for an HP rating of 251.3. This engine, when gearing is taken > > into consideration, can generate an effective 328 ft.lbs of torque - a > > noticeable improvement. > > > > This is why engines are rated mostly in HP. Torque is of course the most > > important component in acceleration, but what RPM the torque is generated > > at is just as important. HP is a better measurement of torque at RPM, > > although of course a full printout of the torque curve is the best :} ------------------------------ Date: Fri, 21 May 1999 12:43:53 -0700 From: "Todd....!!" Subject: Re: alternative engines, now Hemi 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 etc, etc... Just as a thought, if your believe the limitation of runnin a non spark plug engine using the block and head as the anode and ground instead of a spark plug is because of the bolts and the water between em creating a connection, then we must insulate em, maybe even run two seperated(isolated) radiators, one for the head, one for the block... 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.... 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. ------------------------------ End of DIY_EFI Digest V4 #298 ***************************** 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".