DIY_EFI Digest Monday, May 17 1999 Volume 04 : Number 288 In this issue: Re: O2 sensor and water Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Re: LT1 Spark info wanted Re: BMFC, Tiiming, and Coatings programming 101 Re: BMFC, Tiiming, and Coatings Re: I'm BACK...but NOW as a VENDOR Re: BMFC, Tiiming, and Coatings Re: BMFC, Tiiming, and Coatings Re: Variable Restrictiveness Exhaust I'm BACK...but NOW as a VENDOR Re: Variable Restrictiveness Exhaust Re: O2 sensor and water RE: BMFC, Tiiming, and Coatings Re: O2 voltz See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sun, 16 May 1999 22:50:31 EDT From: EFISYSTEMS@xxx.com Subject: Re: O2 sensor and water In a message dated 99-05-16 18:04:59 EDT, you write: << Now the turn has come to attach the O2 sensor. The following problems occure: Hi Nils, It has been my experience that water will kill the heater in a heated o2 sensor.....never tried an unheated version.........most water cooled exhaust manifolds have an area a couple inches long from the flange outwards where there is no water jacket, this is where I usually install them on port efi apps.....a tip though...if the cam is lumpy at all it will pull some water back down on the sensor at idle, killing it.......I have had good luck with a rpm switch and delay timer to start the heater in the sensor........I thought someone here was experimenting with the o2 sensor in the intake manifold exhaust crossover.....did anyone ever try this???? - -Carl Summers SNIP> 1. If the O2-sensor gets in contact with water (in the exhaust manifold), will it be destryoed, how does it work and so on. 2. How near the exhaust port can it be placed to be 300-800 DegC hot? The exhaust manifold is water cooled and the outside of the cast iron thing is not more than you can touch with your hand and not get burned. Please let me know if anyone knows or thinks anything Thanks Nils Björkman Sweden >> ------------------------------ Date: Mon, 17 May 1999 03:00:49 GMT From: bob@xxx.com (Robert Harris) Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz To review the basics A Helmholtz resonant intake consists of a largish diameter intake pipe, a resonating volume (plenum) and individual cylinder runners. The individual cylinder runners are length/diameter tuned to the highest power rpm desired and the helmholz resonator extends the rpm range downward. Reverse it. Individual cylinder runners, resonating volume ( collector ) and a largish tunable pipe. Size the exhaust cylinder runners for the high rpm diameter and length. Fire them into a collector and then out a pipe. Most exhausts can be reduced to an inverted helmholz resonator. We all know about sizing the collector by running a high power run on a freshly painted collector and cutting the collector off an inch past where the paint burned off to establish the size. With the awareness that the exhaust system is essentially a helmholz resonator, we can progress past simple length diameter tuning and begin to draw strange and exotic systems that baffle and befuddle and yet work incredibly well. >From Advanced Engine Technology Heinz Heisler ISBN 0-340-56822-4 5.12.2 Helmholz Resonator Cylinder Charging C / A Helmholz N = --- / ------- 2pi V L V N = resonant frequency Hz C = velocity of speed of sound m/s ( at the temperature of the gas ) A = cross sectional area of tuned pipe m2 L = length of tuned pipe m V = Resonating volume m3 RPM to HZ Rpm x number of cylinders divided by 120 ( 4cycle ) 5.14.4 Velocity of sound in a gas. Excellent discussion of calculating the velocity of sound in a gas. In essence, the velocity is proportional to the square root of the absolute temperature. For an initial play value, he recommends 518 m/s for a 400c average system exhaust temperature. Your milage may vary . Th individual runners are included in the resonating volume as well as the collector "plenum". Again, looking at the exhaust as a Helmholz resonator, we immediately see that by varying the volume we can tune the resonant frequency. This can be done by using a small collector and coupling blind volumes in and out. It can also be accomplished by butterfly valve switching in/out tuned stubs or using a vacuum headlight actuator to vary the length of a slippy pipe stub coupled to the collector. We can also change the effective rpm that this resonance affects by varying the number of cylinders - say split banking such that we feed two or four or eight cylinders into each chamber. Finally, we can change the temperature of the exhaust and change the resonance. http://www.msdignition.com/2new.htm#Switch This switch just might be the ticket for thinking - if you can twist your sister and put on a strange hat. Water injection for exhaust gas temperature control - not anally extracted - but from a reputable manufacturer in production - just for another application. The control system only needs look at four items . Feed Forward or predictive: RPM and EGT at the resonator Feed Back or corrective : Camshaft angle and pressure applitude/sign Set point - sign and camshaft angle of peak pressure. Should be very doable if someone cared to try to take advantage of maximum scavenging thru a very wide region. But then - who would want to do that? Habaneras - not just for breakfast anymore ------------------------------ Date: Sun, 16 May 1999 23:18:52 -0400 From: Shannen Durphey Subject: Re: LT1 Spark info wanted That might work. I was thinking of some tables from the prom, but Diacom runs might show the general idea. Shannen Roger Heflin wrote: > > Do you want some diacom runs from a LT1 at cruise? > > Roger > > On Sun, 16 May 1999, Shannen Durphey wrote: > > > I'm looking for spark timing vs rpm, temp, map for an LT1 engine. > > I've got the notion that this engine uses a large amount of advance at > > cruise and would like to confirm it. Thanks. > > Shannen > > > > ------------------------------ Date: Sun, 16 May 1999 22:36:28 -0500 From: Tom Sharpe Subject: Re: BMFC, Tiiming, and Coatings My oil analysis was > 5000 ppm silicon (off scale) -- from sand thru the carb.. 300 yard sprinter in sand... Tom S Jim Davies wrote: > On Sat, 15 May 1999, Greg Hermann wrote: > > > POR-15 is also recommended by the mfgr for the inside of blocks. Painting > > them is wise--condensation does happen in there! > > > I once had access to a well equipped test lab and they would routinely do > engine oil analysis for me. What was interesting [to me] was that although > the engine in question was several years old at the time, the silicon > leached out from casting was pretty high... ------------------------------ Date: Sun, 16 May 1999 23:55:33 -0400 From: "Kevin" Subject: programming 101 Hey all, I'm a newbie to programming and am trying to learn as much as I can... I've been looking through the 101 files... but when I do a search for "101" I get the topics all over the place with no periodical order... by date, as they were written. Is there any way to get these articles by date so that I can read them as they were written? Regards, Kevin ------------------------------ Date: Sun, 16 May 1999 23:49:50 -0400 From: Shannen Durphey Subject: Re: BMFC, Tiiming, and Coatings Please do. I've heard some good results, and read more. I will be pulling the heads in a couple weeks, and I'll get a good look at the chambers and pistons at that time. This isn't a "quick and easy hp gain" like lots of gimmicks, there's a damn site more work goes into applying this stuff than installing a "fuel saving cow magnet". Shannen Programmer wrote: > > Shannen, > > Guess I'll have to look into this some more--I'm young and prejudiced to > gimmicks, so I'll have to do some research on this. Maybe I can find someone > that's working on this to throw on our dyno...be patient with me guys !! > > Lyndon IPTECH > -----Original Message----- > From: Shannen Durphey > To: diy_efi@xxx.edu> > Date: Sunday, May 16, 1999 7:17 PM > Subject: Re: BMFC, Tiiming, and Coatings > > >Well, in answer to the last question, ceramic thermal barrier coatings > >stick in the combustion chamber. They've been around for years, and > >are starting to gain popularity. Here's a company that makes DIY > >coatings, which some list members have used succesfully. > >http://www.deskmedia.com/~techline/Index.html > > > >I have thermal barrier coatings and dry film lubricant in an engine I > >run daily, and have had mixed results. DFL is available on piston > >skirts through TRW, and GM is now applying it to pistons for the 3.1l > >engine. > > > >Shannen > > > >Programmer wrote: > >> > >> What about seat contact width ? Seat/valve contact location ? What kind > of > >> coating sticks to anything in the combustion area ? > >> > >> Lyndon IPTECH > >> -----Original Message----- > >> From: Robert Harris > >> To: diy_efi@xxx.edu> > >> Date: Sunday, May 16, 1999 9:47 AM > >> Subject: BMFC, Tiiming, and Coatings > >> > >> >Dave Vizard reports that simply coating the combustion face of the > intake > >> >valve lowers the intake air charge temperature by 60 degree F or more > and > >> is > >> >worth typically two octane numbers increase in the effective octane of > the > >> >fuel. > >> > > >> >Remember that the intake valve face is exposed to combustion > temperatures > >> for > >> >at least 50% of the cycle and reaches the same temperatures as the > exhaust > >> >face. Further the back side temperature reaches 600+F in a normal > engine. > >> >The majority of the intake valve cooling comes from HEATING the intake > air > >> >charge. > >> > > >> >Insulating the valve from most of the combustion temperature > significantly > >> >reduces the intake valve temperature and reduces the amount of heat the > >> valve > >> >can reject to the incoming charge. > >> > > >> >The intake valve coating is so important that Vizard recommends that if > you > >> >only coat one thing, it should be the intake valve. > >> > > > ------------------------------ Date: Sun, 16 May 1999 20:44:19 -0700 From: "Steve" Subject: Re: I'm BACK...but NOW as a VENDOR Welcome Back Gar! Steve - -----Original Message----- From: Gar Willis To: DIY_EFI@xxx.edu> Date: Saturday, May 15, 1999 10:52 AM Subject: I'm BACK...but NOW as a VENDOR ------------------------------ Date: Sun, 16 May 1999 21:00:52 -0700 From: "Steve" Subject: Re: BMFC, Tiiming, and Coatings It is a very common thing to do on a race engine that is rebuilt on a regular basis that is cast iron. When I worked at Electramotive all of the cast iron engines were painted to speed up the clean up time during rebuilds and to prevent casting sand from being shaken out of the knooks and crannies. Yes you can grind out and polish the inside, which we did to the major nasties, but we still painted it. Steve - -----Original Message----- From: Programmer To: diy_efi@xxx.edu> Date: Saturday, May 15, 1999 8:15 PM Subject: Re: BMFC, Tiiming, and Coatings >Ted, > >It's been done in the past--I don't know if any real "dyno'd" results ever >made some publications, but >the best results wouldn't have made the extra work worth the bother. > >Lyndon >-----Original Message----- >From: Stowe, Ted-SEA >To: 'diy_efi@xxx.edu> >Date: Saturday, May 15, 1999 12:40 AM >Subject: RE: BMFC, Tiiming, and Coatings > > >>here's a thought, has anyone ever given any thought to painting the inside >>of an engine ? before you hit delete, consider how easy it is for dirt etc >>to stick to the inside of the block, under a microscope the surface must be >>like velcro. I suspect oil would return a little quicker to the pan. just a >>thought, you can flame me now. >> >>-----Original Message----- >>From: Bruce Plecan [mailto:nacelp@xxx.net] >>Sent: Friday, May 14, 1999 9:31 PM >>To: diy_efi@xxx.edu >>Subject: BMFC, Tiiming, and Coatings >> >> >>Has anyone run any "independent" testing on these barrier coatings for what >>they actually have seen as an improvement pre+post coating?. >> Has any one run any endurance tests?. >>Do I need mention that this might need a complete recal to get right. >>Bruce >> > > ------------------------------ Date: Sun, 16 May 1999 21:05:27 -0700 From: "Steve" Subject: Re: BMFC, Tiiming, and Coatings When you test the same engine combination over and over you find that the oil temp is within a few degrees for that given combination. If it is different and the combination is the same then something is wrong or there was a change. I find this very easy to believe as I have witnessed hundreds of dyno runs over the years. My turbo V6 I just built with coatings takes twice as long to warm up now that it is coated. Also I have seen a 200 degree F increase in EGT at low speed. I haven't done full load testing yet so I can't report on that yet. Steve - -----Original Message----- From: Programmer To: diy_efi@xxx.edu> Date: Saturday, May 15, 1999 8:24 PM Subject: Re: BMFC, Tiiming, and Coatings >Greg, > >The only problem with testing like that is the motor had to be torn down to >perform the experiment. I'd put little faith in a 15 degree change when a >complete teardown would have had to be done to perform the work. > >Lyndon IP TECH >-----Original Message----- >From: Greg Hermann >To: diy_efi@xxx.edu> >Date: Saturday, May 15, 1999 8:11 AM >Subject: Re: BMFC, Tiiming, and Coatings > > >>>Has anyone run any "independent" testing on these barrier coatings for >what >>>they actually have seen as an improvement pre+post coating?. >>> Has any one run any endurance tests?. >>>Do I need mention that this might need a complete recal to get right. >>>Bruce >> >>A fellow I spoke with at HPC told me that they ran a dyno test of a fairly >>typical hipo 350 CID Chebby first with no coatings, then with coating only >>on the piston crowns. Said that--with no other changes, the steady state >>oil temperature at sustained full load dropped 15 degrees F. >> >>Greg >> >> >> > > ------------------------------ Date: Mon, 17 May 1999 00:20:37 -0400 From: "Gary Derian" Subject: Re: Variable Restrictiveness Exhaust I don't really know how these mufflers work. I think the Mitsubishi had a vacuum valve that blocked part of the muffler's outlet. This changed the tuning and made it quieter. According to this month's Car and Driver, the Maxima has a spring loaded valve that opens up at some set backpressure. There is no active control. Gary Derian > 1) > Gary, > can you elaborate on how that muffler varies? > > > Gary Derian wrote: > > > > Adding backpressure just for the sake of it won't improve low speed torque. > > Having small diameter ports which happen to add backpressure will. Its not > > the backpressure that improves torque. Its the low rpm tuned components > > that do. Now, having a variable restrictor that quiets the car when > > cruising is a good idea. The new Nissan Maxima has such a muffler. > > Mitsubishi 3000's have had them in the past. > > ------------------------------ Date: Sun, 16 May 1999 21:39:00 -0500 From: dave.williams@xxx.us (Dave Williams) Subject: I'm BACK...but NOW as a VENDOR - -> Hey maties, (and the rest of the diy resident "stoidi") My, my. A fetid breath from the past, toidi-boy. ------------------------------ Date: Sun, 16 May 1999 22:38:56 -0700 From: GARY Subject: Re: Variable Restrictiveness Exhaust I just found a July, 1969 issue of Car and Driver magazine. It has a "max blue" rs camaro on the cover. A story of a Car and Driver tuned Camaro is in there with a psychedelic picture of one. On the back cover, a very cool ad. for a super bee 440 with 4.11 rear end and a four bolt hood. There is an advertisement for goodyear tires that looks like something out of the movie "Austin Powers, International Man of Mystery." - -- GARY mailto:hobiegary@xxx.net ------------------------------ Date: Mon, 17 May 1999 01:52:53 EDT From: AL8001@xxx.com Subject: Re: O2 sensor and water In a message dated 99-05-16 22:55:13 EDT, EFISYSTEMS@xxx.com writes: >It has been my experience that water will kill the heater in a heated >o2 sensor.....never tried an unheated version...... It will kill a unheated one as well. Early EFI Chevy Astro vans had a recall involving replacement of the y pipe. The Astro has its O2 sensor on the top of the pipe ~ 18" from the engine. Condensation during a cold start/warmup would drip down onto the sensor causing the coating to crack. The replacement pipe had a sheetmetal shield to collect the water. Some vans even had one exhaust manifold replaced to accomidate the sensor. ( The old sensor was left inplace but it's wire was cliped off. Harold ------------------------------ Date: Sun, 16 May 1999 21:42:00 -0500 From: dave.williams@xxx.us (Dave Williams) Subject: RE: BMFC, Tiiming, and Coatings - -> And when the paint all flakes off, and ends up in the oil pan... Doesn't seem to be an issue, at least if the block is properly clean before you paint. I prefer white epoxy myself. ------------------------------ Date: Mon, 17 May 1999 01:49:46 -0500 From: "G. Scott Ponton" Subject: Re: O2 voltz Ok guys I have sat back and waited for awhile for you all to get this straight. The sensor "compares the amount of oxygen in the exhaust stream with the amount in the outside air. The reason it doesn't seem to work this way is two or three fold. 1. The sensor needs to be at a "reasonably" stable temp before its output is "reasonably" stable. 2.The sensor only works in a very narrow A/F ratio. As the amount of oxygen climbs above a certain point it can't drop the voltage any lower and the oppisite is just as true. The output voltage is also limited by the design of the sensor. After a point removing more oxygen can't effect a voltage change. Much has been said and made of the "wide band" sensors too. After reading much on the "wide band" sensor it works exactly the same way as a "normal" sensor. The difference is through outside influences, either a standard sensor or electronics atached to the output, are used to create a "current pump" when the sensor cross stoich the "outside" control device switches the current in the sensor so that it breaks oxygen atoms away from the oxidized gases in the exhaust. By know at what rate this happens chemically we can use the output of the sensor to "roughly" ( better than what we started with) determine the amount of oxidized fuel (and other such nasties as NOx) in the exhaust stream. Notice the word normal used to desribe combustion as we currently use it on a daily basis. This doesn't include off the wall or experimental engines which use some sort of modifided combustion cycle. Why not you ask? This is going to get very long if I have to get into everything that can effect this. Simply put: Within the range of "normal" combustion, a little either side of stoich, the leaner the mixture the greater the amount of free oxygen in the exhaust stream as there isn't enough fuel to combine with all the oxygen in the cylinder. As the mixture is enrichened the amount of free oxygen drops for exactly the opposite reason. If you go to the point of misfire all bets are off. Although a lean cylinder will tend to dump more free oxygen into the exhaust than a rich one as until the mixture is extremely rich some part of the air charge ingested will be used as the fuel attemps to oxidize ( burn) whereas in a extremely lean cylinder next to nothing oxidizes as our current ignition system cannot produce the energy needed to properly promote combustion of these mixtures. Testing a sensor with argon and other similar gases doesn't work very well unless they are in an enclosure with only the tip of the sensor exposed to the "inert" gas. I won't try to get into ther chemistry involved at this moment as I will have to research the chemistry of inert gases before I can explain it in those terms. At this point my chemistry is rusty to say the least. At least that part of it which doesn't deal with the above as I use this nearly every day. OK let the flames begin!! LOL :-) Scott ------------------------------ End of DIY_EFI Digest V4 #288 ***************************** 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".