DIY_EFI Digest Tuesday, May 18 1999 Volume 04 : Number 291 In this issue: Re: LT1 Spark info wanted Re: O2 Volts SAE articles 950003 & 950004 Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Re: O2 Volts Re: O2 Volts Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Re: O2 sensor and water VE tables Re: O2 sensor and water Re: LT1 Spark info wanted Mr Helmholz - simple model Re: radiators? Re: 1227749 Re: 1227749 Re: thank you Re: alternative engines, WARPED Re: alternative engines, WARPED Re: alternative engines, WARPED Re: alternative engines, WARPED Re: Misc Electronics / barrier coat / reverse cool./ Part2 Re: O2 sensor and water Re: O2 sensor and water RE: VE tables Re: O2 sensor and water New Person Re: Mr Helmholz - simple model Re: alternative engines, WARPED Re: O2 sensor and water See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 18 May 1999 07:34:31 -0400 From: Ken Kelly Subject: Re: LT1 Spark info wanted Shannen, I sent both last night, but sent them on gmecm by mistake. The original request is on the office PC, and I responded from home. Knew what you wanted, just not which list you requested it on! Ken Shannen Durphey wrote: > > Manual, 94-95 fine, much obliged. > Shannen > Ken Kelly wrote: > > > > Shannen, > > I can print out the tables for the stock 94-95 PCM for you. > > The advance curves look different for the AUtomatic and > > Manual, which do you want? Is 94 - 95 a good year? I have > > the 96 Auto Image too, but I'll have to confirm that I have > > that table loction for the 96. > > > > Ken > > > > 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: Tue, 18 May 1999 07:32:56 -0400 From: Shannen Durphey Subject: Re: O2 Volts Christopher J Beasley wrote: > > CLsnyder wrote:snip > > > produced at this point is programmed into the ECU. If the voltage goes low, > > the ECU richens the mixture. When the voltage goes high it leans the > > mixture, and the ECU counts crossing points to determine if the system is > > correcting properly. > > > > > Exactly, except the other way 'round, right? > b No, more O2 in exhaust=lower voltage = need for more fuel. Hence the rich on ignition based misfire problem. Shannen ------------------------------ Date: Tue, 18 May 1999 21:49:58 +1000 From: Peter Gargano Subject: SAE articles 950003 & 950004 I can't find SAE articles 950003 & 950004 anywhere! I had a looked at all the Australian University OPAC library systems and I cannot find these two SAE articles (published in SP-1082 pages 9 to 19 and 21-28). If anyone has a copy of these articles (or SP-1082, with ISBN = 1056091632X) I'd like to know -- please. regards, - -- Peter Gargano mailto:peter@xxx.au ------------------------------ Date: Tue, 18 May 1999 07:44:50 -0400 From: "Gary Derian" Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Two stroke pipes are tuned by injecting water. I think its common in personal water craft. They just use a constant stream. I think there may be a little to be gained by timing the water but that would be a small improvement, maybe using less water for the same effect, compared to using the water in the first place. This talk of fancy tuning is interesting and certainly improves the power per displacement but my question is does all this work actually make a better vehicle. Isn't it easier to just use a larger engine with appropriate gearing to achieve the same power and economy without all the extra parts? For sure there is some small fuel economy gain in city driving with a small displacement engine because it uses less fuel at idle. But in cruise mode or WOT, specific power is not really affected by fancy tuning. Gary Derian > The majordomo deleted portion proposed active acoustical tuning using a > "microphone" or a sensitive pressure sensor well filtered and positioned near > the valve to observe the exhaust acoustical pressure and in conjunction with a > camshaft angle sensor, we would have the feedback mechanism to actively > measure and time the arrival of the negative going pulse. > Since the sole purpose of the water is to vary the resonance by varying the > temperature it becomes very interesting on how to administer the water. > Probably the simplest is to vary the temperature of the gas in the collector. > But would timed injection into the exhaust port just before the exhaust valve > opens be more effective or just trailing the major pulse or perhaps even into > the exhaust pulse itself. ???? Floors open. > ------------------------------ Date: Tue, 18 May 1999 08:35:49 -0400 From: "CLsnyder" Subject: Re: O2 Volts - ----- Original Message ----- From: Christopher J Beasley To: Sent: Tuesday, May 18, 1999 2:52 AM Subject: Re: O2 Volts > > > CLsnyder wrote:snip > > > produced at this point is programmed into the ECU. If the voltage goes low, > > the ECU richens the mixture. When the voltage goes high it leans the > > mixture, and the ECU counts crossing points to determine if the system is > > correcting properly. > > > > > Exactly, except the other way 'round, right? > b > No, when the voltage goes high you have too little O2 in the exhaust, so it leans the mixture to compensate. When the voltage goes too high you have too much O2, so it richens the mixture. A missfire allows O2 to flow through unburned, and forces the engine rich. From my understanding and experience anyway. Been wrong before - but I think I got it right this time.> ------------------------------ Date: Tue, 18 May 1999 08:56:32 -0400 From: "David A. Cooley" Subject: Re: O2 Volts > Ahh... Now I see. Technically speaking, the O2 sensor should be > called an O2 differential sensor. Or maybe a "lack of O2" sensor. ; > ) No, the sensor doesn't make a voltage when there is oxygen on the > sniffer side of the sensor. It makes a voltage when there is no > oxygen on the sniffer side. Now the Argon thing, I'd like to know > more about. IIRC, the ecm supplies a bias voltage to the sensor to > prevent false readings like the ones you got in plain air. Actually, It provides a bias voltage so it knows when the sensor either is shorted or open. If it see's 450mv for a preset time and the engine is running etc, it sets a defective O2 sensor code... if it see's 0v for a long enough time, it set's a defective O2 code and a lean exhaust code. ------------------------------ Date: Tue, 18 May 1999 09:08:04 -0400 From: "David A. Cooley" Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz > This talk of fancy tuning is interesting and certainly improves the power > per displacement but my question is does all this work actually make a > better vehicle. Isn't it easier to just use a larger engine with > appropriate gearing to achieve the same power and economy without all the > extra parts? > > For sure there is some small fuel economy gain in city driving with a small > displacement engine because it uses less fuel at idle. But in cruise mode > or WOT, specific power is not really affected by fancy tuning. There is a lot to be said for proper tuning at WOT *AND* cruise. I had a 1985 Buick GN, 3.8liter V6, turbocharged and NON-intercooled. It ran 15.92 at 88MPH stock in the 1/4 mile and got 20mpg on the highway. I manufactured a lot of mods myself and bought some others... I had it running mid 12's and highway cruise increased to 25-27MPG with the A/C on! A 455 buick big block, mildly warmed over would have gotten me the 12 second time slips, but MPG would have probably been close to half what the little V6 was getting... You have to keep in mind that more CI = more fuel at stoich. you have to feed what you have. ------------------------------ Date: Tue, 18 May 1999 06:13:26 -0700 (PDT) From: Squash Subject: Re: O2 sensor and water My O2 sensor has been completely under water and mud for long periods of time, while operating. It never seemed to fail for me... Andy - --- Raymond C Drouillard wrote: > > On Sun, 16 May 1999 23:56:56 +0200 "Nils Björkman" > writes: > >Hello > > > >Im working on an EFI project. The purpose of this > project is converting > >and modifying an Volvo B230F engine to be used in a > boat. > > > >Now the turn has come to attach the O2 sensor. The > following problems > >occure: > > > >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. > > Car exhaust is mostly water vapor. I have never > heard of that bothering > an O2 sensor. Liquid water might be another story, > however. > > ___________________________________________________________________ > You don't need to buy Internet access to use free > Internet e-mail. > Get completely free e-mail from Juno at > http://www.juno.com/getjuno.html > or call Juno at (800) 654-JUNO [654-5866] > _____________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Tue, 18 May 1999 09:15:58 -0400 From: "David A. Cooley" Subject: VE tables I have a question... My 95 buick LeSabre basically uses the same code, but with different option bits set and different table values, as the Supercharged 3800V6. The engine is using MAF and no MAP for air flow. It has tons of MAF tables, but also has VE tables. (Engine efficiency VS RPM). What effect do the values in the VE tables have if you change say 80% at some RPM to 95%? increase fuel delivered at that point or decrease it? Thanks, Dave ------------------------------ Date: Tue, 18 May 1999 09:17:10 -0400 From: "David A. Cooley" Subject: Re: O2 sensor and water > My O2 sensor has been completely under water and mud > for long periods of time, while operating. It never > seemed to fail for me... > Yes, but that's the outside... It's designed to get wet and survive. If you get water on the active element inside the exhaust stream, it's toast. ------------------------------ Date: Tue, 18 May 1999 09:54:42 -0400 From: Shannen Durphey Subject: Re: LT1 Spark info wanted 'Sokay, they arrived at my mailbox all the same. Thanks. Shannen Ken Kelly wrote: > > Shannen, > I sent both last night, but sent them on gmecm by mistake. The original request > is on the office PC, and I responded from home. Knew what you wanted, just not > which list you requested it on! > Ken > ------------------------------ Date: Tue, 18 May 1999 14:58:24 GMT From: bob@xxx.com (Robert Harris) Subject: Mr Helmholz - simple model The Helmholz resonating system was originally developed for wind acoustical instruments as a model. We now routinely use it to create and size resonant intake systems. But some may still have trouble visioning it. The pure model is a ball "resonating volume" with a pipe "tuning pipe" attached. Changing the temperature changes the local speed of sound within the resonator - and thus the frequency of resonance changes. Changing the volume within the resonating volume changes the frequency - larger lower. Changing the area/length of the tuning pipe changes the frequency. So everyone should see a ball with a pipe. We now add some pipes - sort of like porcupine spikes sticking out of the resonating volume - but part of the resonating volume. N -1 spikes are of the length and volume of the header pipes running to the collector. The Nth is the length and volume including the volume of the cylinder with the exhaust open during overlap N is the number of cylinders firing into the common volume. The headers/runners can be individually ram tuned to a frequency somewhat higher than the highest helmholz frequency and thus extent the top end as this resonance swamps the helmholz effect. When a pulse of sound ( exhaust gas acoustic pressure front ) hits an open volume it generates a negative pressure wave that travels back up the header to the exhaust valve. We want the negative peak of this wave to arrive at the time both valves are open "overlap" to gain maximum effect. That is the theory behind ram tuning exhaust. With the ability to swamp that effect with the Helmholz resonance, think ringing a bell - with a variable sized bell - we can retune the resonance downward as much as practical. Since the only thing that matters ( assuming a reasonably well designed otherwise exhaust system ) is the arrival of this negative pulse, we need only measure the instantaneous port pressure in this crankshaft angle region and then tune the system to a maximum negative pressure. Adding blind volume to the resonating volume simply lowers the resonant frequency - a good thing since the additional volume does not have to flow gas. Adding area/shortening the length of the tuned pipe raises the resonant frequency. Perhaps multiple switched exhaust pipes? ------------------------------ Date: Tue, 18 May 1999 08:38:49 -0700 From: "Todd....!!" Subject: Re: radiators? Hello Mike, If ya go to your local auto parts store, they should have a HUGE book full of pictures of radiators, with the dimensions under each pic! Just choose the one you want and maybe put up a bit a cash and it's yours!! LATER! Todd....!! P.S. - COOL project, that car must not weigh more than 1,500 lbs. if THAT! Buddy bought one a while back, was gonna put a s.b. chev or ford in it, but he didn't have the drive or the desire to even start the project! He got the idea to do the mini-vette opel GT after I did my 81 Pontiac T1000 (Che-Vette) with a 400 s.b.c. and TH375 all outof a big ol impala wagon... That thing booked and it weighed in at 2,345 after the install... Used the STOCK rear-end, luckily it wasn't a posi ot I would SURELY snapped it, it ran fine with the stock rear end, I think it was like an 8 bolt or so(LOL) it was geared up for the lil 4 banger that it came with so the 400 was pretty much wrappin out for any period of distance at about 40 mph! I used an ol chev nova style radiator... Didn't run a hood at first, but then the base security said somethin about the hood being safety equipment????? can you BELIEVE it! That's SO BOGUS!! So I cut the hood where the radiator and stock fan was stickin up and hittin the hood and pinned it in the front with hood pins, whalaa, prob solved, except at higher speeds the back of the hood would tend to rise and flap a bit due to the engine air and fan wind blowin some SERIOUS cfm underhood! LATER! Todd....!! http://www.c-com.net/~atc347/toddlnk.htm - ---------- Mike Pilkenton wrote: > > I know this is a little off topic for the efi list but I'm finishing up my > 3.1L V6 engine transplant project into my Opel GT and it's time to think > about cooling. Can anyone suggest a decent OEM radiator that would be > sufficient for the GM 60 degree V6 and fit in a tight area say about 13 in > tall by 16 in wide? > > Mike ------------------------------ Date: Tue, 18 May 1999 08:28:14 -0700 From: "Todd....!!" Subject: Re: 1227749 Hi Fred!, This is good to know about alum tubing!! What diameter and wall thickness was the tubin ya used? Aren't they usually billet rails? or are the billet rails just show stuff... Keep the tidbits coming mang.... I'm learnin, I'm sure others are as well! LATER! Todd....!! - ------------- Frederic Breitwieser wrote: > > Greetings, > > After spending most of the morning wandering around two local junkyards, > I lucked out and found two of the elusive 7749 ECMs, one passed my > "power up" test, the second one didn't, and the yard I got them from > said they'd exchange the bad one when they get a wrecked turbo sunbird > in later today (which means middle of next week to everyone else). Also > picked up a 2-bar MAP sensor using GM part numbers as a reference, for > $15. It was sitting on a shelf believe it or not, so that piece is > done. Coincidentally, the body harness I snagged to give my old beater > truck power everything (windows, locks, cruise, digital dash) plugs > right into two of the three underhood ECM harnesses with ease, and I > have to verify the wiring to ensure I don't have any ground and batt > leads interconnecting. At least the connectors fit... moving wires > around has become quite easy after all the practice I'm getting! > > Sorry for the cross post... so many people have given me help and advice > I wanted to make sure you all know I appreciate it !!!! > > Oh, and I pressure tested my homemade fuel rails this morning and they > leak right through the aluminum tubing. I found that odd. I know > aluminum is somewhat porous compared to other metals, but 100psi of air > pressure on the end of the fuel rail, submerging it into a litter box > full of water resulted in small bubbles forming on the surface of the > aluminum. When the pressure is released, the bubbles appear to receed > back into the aluminum. Very odd. Just thought you'd all get a kick > out of it. > > --- > > Frederic Breitwieser > > Xephic Technology > "Leadership in IT" > Bridgeport, CT 06606 > > Web: http://www.xephic.dynip.com > Voice: (203) 372-2707 > Fax: (603) 372-1147 ------------------------------ Date: Tue, 18 May 1999 08:30:34 -0700 From: "Todd....!!" Subject: Re: 1227749 Sounds like Fred got one of his from a TURBO SUNBIRD... Good luck.... I haven't seen many of them runnin around much.... LATER! Todd....!! - ---------- Thomas Martin wrote: > > I have a decent contact at a local boneyard (he owns it!), what vehicles should I be > on the lookout for to find a 1227749 ECM? > > He has a large stack of ECM's, and many 80's cars. > > Thomas Martin ------------------------------ Date: Tue, 18 May 1999 08:40:14 -0700 From: "Todd....!!" Subject: Re: thank you If you're stil there, hope not, WHERE may I ask are ya goin for your trip? LATER! Todd....!! Marc Piccioni wrote: > > Just a short note to say that I am dropping off the list for a while, due > to an extended trip. I wish to thank all the members who have answered my > newbie EFI questions. > > Regards > > /Marc ------------------------------ Date: Tue, 18 May 1999 08:53:50 -0700 From: "Todd....!!" Subject: Re: alternative engines, WARPED I hear ya, My Dana should be able to hold up to WHATEVER I can dish out to it... We'll see how she holds up with the twin wutrbo FI'd 440 and/or 451 stroker 400... I'm sure the Dana will hold up to 900+ hp... Have ya'll ever seen the axles in one of these things? They're HUGE! especially in comparison to the 8 3/4, will have to look at a 9 inch and see what the diff is as well... And yes, it SURE would be nice to swap out the ol 4.10's for say some 2.73's for a long cruise across the country or even across TEXAS which is about half the trip from Houston to Canada! Later! Thanks for the input all... Todd....!! Tom Sharpe wrote: > > Just wanted to say that 9" Fords are easier to work on than Dana 60's.. Mopar 8 > 3/4 are fine unless you need a new Posi. Tom S ------------------------------ Date: Tue, 18 May 1999 09:15:43 -0700 From: "Todd....!!" Subject: Re: alternative engines, WARPED All you mentioned is foreign to me... I am not of that era and have no friends with any of the good ol flat heads... Do have a friend with a couple a Hemi's buit they're all 426's and souped in the ol Cuda's... 28 mpg seems UNREAL to me right now.... What's the trick? throw a one barrel on it and highway gears and a LOT of air in some REALLY skinny tires and MAYBE I'll be in the teen's but I don't see 20 ANYTHING for gas mileage coming outa my pig! As for gear ratio, the goal is to hit red line in top gear when ya cross the finish line, that's the all around goal of gearing for best e.t... As for the AAR 340 in another car, in my mind the AAR Cuda deserves to have it's engine back! It deserves it and it DEFINITELY looks TOTALLY AWESOME! I passed up snaggin an AAR Cuda for $1,000 back in about 1988, STILL kickin myself! I had JUSt bought the BEE so I didn't think I needed another Mopar pig in the shed! The thing sold right before I found out what it was worth! It had a blown engine(Thrown rod) and the heads and 6 pac intake and carbs were stolen off of it, the body was in SUPER shape, it was orange with the black AAR strip kit! still had the turnouts in front of the rear tires as well as the cool 'glas? single scoop hood! As for the 440 turnin the rpm's... FYI, if'n ya don't already know... A small block chev 302 engine's bore is 4 inches, stroke is 3.00 inches A small block chev 327 engine's bore is 4 inches, stroke is 3.25 inches A small block chev 350 engine's bore is 4 inches, stroke is 3.50 inches A small block chev 400 engine's bore is 4.125 inches, stroke is 3.75 inches A BIG block chev 427 engine's bore is 4.25 inches, stroke is 3.75 inches A BIG block chev 454 engine's bore is 4.25 inches, stroke is 4.00 inches If we took, for example, a Big Block chev engine with a 4.25 inch bore, like say a 454 block and DE-STROKED the crank to in between a 327 and 350 at say about a 3.37 stroke, this would give you the dimensions of a 383 Mopar engine! Can you imagine what a cehv 454 destroked to a shorter stroke than a 350 chev would rev like? Well, you know what it could sound like whenever ya here a 383 Mopar engine rev! Super quick! Then ya have the 440 Mopar which comes from the factory with a 4.32 inch bore and a 3.75 inch stroke (Same as the 427 Chev b.b.) A 400 Mopar engine has even a BIGGER bore than the 440 at 4.34! AND the stroke is the same as the 383!!! which again is abotu 3.38 inches! a 400 Mopar engine is like taking a 454 engine with a 4.25 inch bore, boring it out .090, which is hardly ever done on the B.B. Chev due to cyl wall thickness and safety THEN DE_STROKIN the sucker to a shorter stroke than a 350 chev!! The 400 Mopar is where it's at if ya want a high revvin engine! What some people do to the 400 Mopar is throw the 3.75 inch 440 crank into the 400 block and create a REALLY lightweight internal 451 stroker motor! http://www.musclemotors.com sells the kit for this build in various forms and completedness... One of the GREAT things about these Mopar engine's is that they cost less at the bone yards than even the s.b. chevs or Ford's, I assume due to the law of supply and demand, more people but chev's and Fordsouta the yards than Mopars... I picked my 440 up for $135 at the local Pic-Ur-Part self-help junk yard... Rebuilt it and had it in the car for about $1,300 TOTAL including the price of the junkyard engine! Sure I'm only runnin low 13's so far, but I have my probs and it's not the engine itself, it's the ignition system, i.e. cheap plugs and wires, as well as carburetor 'issues'... Tippin the scales at 3,710 lbs. without driver doesn't help things much! Will be in the 12's soon, after installin new Accel 8 mm wires and accel non resistor plugs and buddies race 750 and losin the rest of the junk in the car after a good cleanout.... Hopefully she'll hook up this time, maybe use some VHT this time as well!! And some octane booster or race fuel! LATER! Todd....!! http://www.c-com.net/~atc347/toddlnk.htm CLsnyder wrote: > > ----- Original Message ----- > From: Todd....!! > To: > Sent: Thursday, May 13, 1999 1:54 PM > Subject: Re: alternative engines, WARPED > > > CL, > > > > It takes a LOT of gear to get a behemoth like our b-body Mopars outa the > > hole, 2.xx gears just doesn't cut it, as compared to 4.xx gears, no > > comparison... > What is your low gear ratio? With a close ratio box you need 4+ gearing - > with the wide ratio box and the long gears you get the same overall ratio > (within a few points) - you just need a bit wider power band because you > have to wind it a bit tighter before shifting or you can bog it out. > > > > The torque of the Big Blocks still may feel strong even with the highway > > gears but it's not as effective as when ya use quicker gears such as the > > 4.10's.... > > Again, it is overall ratio that counts - don't matter a hill of beans where > the gearing is done, and a big block has a nice fat power curve so it pulls > strong in second without floating the valves in low. > > > > I drove my 70 Bee with the ol 383 and 4.10's with an automatic 727 from > > Cheyenne, Wy to Houston, Texas back in June of 1989, got 15 mpg goin 50 > > mph most of the way... with 100+ mph jaunts about every 10 to 30 minutes > > to clean er out... Windows were down the whole way, except for when it > > rained in the hill country of Texas... That trip was with an 800 spread > > bore single feed dbl pmpr jetted pretty rich for Cheyenne's > > altitude(Over 5,200 ft).... > > > > And NO I didn't use ear plugs as I should've.... I was runnin dual > > cherry bombs only, straight off the headers, and couldn't go to sleep > > the night I arrived in Houston due to my ears ringing.... > > > > Have since acquired a LOt of single packs of those sponge roll up ear > > plugs for passengers and myself on those long trip days... > > > > Am about to install a set of 3 inch pipes with 3 inch 2 chambered flows, > > they're in the trunk, I need to have the muffs welded back onto the > > pipes, wonder how it'll sound, as compared to the current 2.5 inch pipes > > with el cheapo turbo's... > > > > Thanks fo rthe stories mang... > > > > LATER! > > > > Todd....!! > > > If you want sweet ya gotta drive a 264 flatty with a short Thrush from > Waterloo Ontario to Tulsa Oklahoma in August. The big six barks real nice - > about 28MPG in an air conditioned '57 half ton. Pulling away from a stop in > second was no problem either. > > The trip from Waterloo to Murray Harbour PEI in the 53 Hemi Coronet Sierra > (373 gears and overdrive) made 18 hours of fantastic music as well at about > the same mileage. Both were quiet enough to get by the coppers without any > trouble, yet healthy sounding enough to be "cool". The 264 P'up was a bear > in the rain or hot weather, pulling away without squeaking the tires took > some practice, or second gear. The guy who has it now has a 340 AAR in it > and about 48" of rubber under the bed. > > > > > > CLsnyder wrote: > > > > > > ----- Original Message ----- > > > From: Todd....!! > > > To: > > > Sent: Wednesday, May 12, 1999 3:17 PM > > > Subject: Re: alternative engines, WARPED > > > > > > > I hear ya Harold, makes sense to me... > > > > > > > > However I have a Dana 60 with the 4.10's and it takes a bit longer to > > > > swap out the gears in that baby, it'd probably be quicker to swap ou > > > > tthe entire rearend!? > > > > > > > > Good idea though. My friend with another 70 Bee which DOES have a > Dana > > > > swapped his 4.10's out for some 3.23's and MAN does it HAUL on the > > > > highway! > > > > > > A friend has a '69 'Runner with the 383 Magnum, 2.7? gears and wide > ratio > > > box. Good out of the hole with the steep low gears, and excellent > mileage > > > driving half sensibly in 4th. Pretty well bury the needle in third at > > > redline. > > > > > > > > > > ------------------------------ Date: Tue, 18 May 1999 09:19:02 -0700 From: "Todd....!!" Subject: Re: alternative engines, WARPED The 56 should be in at cruisin speeds on the highway, right? I tested the mechanical and vacuum advance settings with a timing light and all ligned up correectly when doin the timing tests, i.e. removing the vac line and holdin the r's above 2,600 rpm adjusted for 38 degrees BTDC, then applied vac to vac advance and got 56 degrees....just like the mopar book says... Current 750 dbl pmpr has no vac tubes to hook to so I'll wait till I get another carb on it to see how she runs with vac adv hooked up, hopefully better MPG, well see! Thanks for the input! LATER! Todd....!! Gary Derian wrote: > > You won't see all 56 deg. while driving. It is a lot but will only occur at > max vacuum and rpm above the full advance rpm. > > Gary Derian > > > > The Manual calls for 38 degrees total mechanical advance and lik 56 > > degrees advance with the vacuum hooked up... > > > > Does this sound right to ya'll? > > > > Seems a tad bit much to me! > > > > Thanks again! > > > > Really appreciate the help! > > > > LATER! > > > > Todd....!! ------------------------------ Date: Tue, 18 May 1999 09:20:29 -0700 From: "Todd....!!" Subject: Re: alternative engines, WARPED So Shannen, do ya think I could get away with the 2 sizes bigger since I'm at or below sea level? What size exactly IS two sizes bigger than what ya had(What are your current jets in the carb right now?) Thanks! Todd....!! Shannen Durphey wrote: > > Todd....!! wrote: > > > > I have a 72 Buick 455 in my 72 Jaguar, but the carb that was on it was > > jetted for Cheyenne, Wyoming, I already messed up my first 455 that I > > put in the Jag due to this carbs' pretetonation causing lean > > condition... broke a couple of peices of ring crowns off the top of a > > couple a the pistons.... Damage was already done long before I swapped > > out the carb for a sea level configured rochester... > > Well, I don't believe Cheyenne is too much higher than Hardin, MT. > Before I left Hardin, I swapped the primary jets for jets that were 2 > sizes larger. Once I arrived here (900 ft above sea level) I had to > retard the timing slightly. The car is slightly rich now, but I don't > use it much so I haven't finished the tuning. This is a 455 buick, > 3.08 rear gear, 18mpg on the highway. > Shannen ------------------------------ Date: Tue, 18 May 1999 09:51:14 -0700 From: "Todd....!!" Subject: Re: Misc Electronics / barrier coat / reverse cool./ Part2 Get/find a bigger oven mang! Thanks for the ideas too! Todd....!! Bruce Plecan wrote: > > OK, now, what really needs/can be done right. > Since mileage is an issue, it's batch fire, vaporization ain't a bad thing > for that, > I'd be willing to leave the intake runner, and back side of the valve undone > Do the combustion chamber (cylinder head, and piston top). > Exhaust valve, face, and backside. > Then the exhaust runner > Then the exhaust manifold inside and out. > Barrier coat the bottom of the intake manifold to keep the oil heat off of > it. > What's wrong/right with this picture > Block too large for oven so is a no doer > Bruce ------------------------------ Date: Tue, 18 May 1999 08:51:47 -0700 (PDT) From: Squash Subject: Re: O2 sensor and water - --- "David A. Cooley" wrote: > Yes, but that's the outside... It's designed to get > wet and survive. If you > get water on the active element inside the exhaust > stream, it's toast. Yes, this is the outside. I would have big problems if I had enough water inside to do in the sensor. Would an inactive (cold) sensor get ruined by submersion in water? If the any engine is running, I don't think that you would have much of a chance of water coming up the exhaust. Andy _____________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Tue, 18 May 1999 08:51:49 -0700 (PDT) From: Squash Subject: Re: O2 sensor and water - --- "David A. Cooley" wrote: > Yes, but that's the outside... It's designed to get > wet and survive. If you > get water on the active element inside the exhaust > stream, it's toast. Yes, this is the outside. I would have big problems if I had enough water inside to do in the sensor. Would an inactive (cold) sensor get ruined by submersion in water? If the any engine is running, I don't think that you would have much of a chance of water coming up the exhaust. Andy _____________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Tue, 18 May 1999 11:52:24 -0400 From: "David A. Cooley" Subject: RE: VE tables Ah.. So Peter Wales bud's (Superchips) increased VE to richen the mixture... They richened the mixture from 3800RPM and up and it is at 100-105% across the board... stock was 85-90% I may set that back and just play with the PE and timing. > > An increase in VE requires an increase in fuel as a higher VE > > indicates more air flow (or a better ability to flow air). > > > > A 100% VE means you are pumping 3800cc's of air every 720 degrees. > > > > -Mike > > > > -----Original Message----- > > From: owner-gmecm@xxx.edu > > [mailto:owner-gmecm@xxx. Cooley > > Sent: Tuesday, May 18, 1999 9:16 AM > > To: DIY_EFI > > Cc: gmecm@xxx.edu > > Subject: VE tables > > > > > > I have a question... > > My 95 buick LeSabre basically uses the same code, but with different > option > > bits set and different table values, as the Supercharged 3800V6. The > engine > > is using MAF and no MAP for air flow. It has tons of MAF tables, but also > > has VE tables. (Engine efficiency VS RPM). What effect do the values in > the > > VE tables have if you change say 80% at some RPM to 95%? > > increase fuel delivered at that point or decrease it? > > Thanks, > > Dave > > > > > ------------------------------ Date: Tue, 18 May 1999 11:59:19 -0400 From: "David A. Cooley" Subject: Re: O2 sensor and water > Yes, this is the outside. I would have big problems > if I had enough water inside to do in the sensor. > Would an inactive (cold) sensor get ruined by > submersion in water? If the any engine is running, I > don't think that you would have much of a chance of > water coming up the exhaust. I think the only way you'd see it on the inside was in a marine app where water is pumped into the manifolds/headers to cool them... maybe some reversion could suck enough water up to kill the sensor. ------------------------------ Date: Tue, 18 May 1999 12:38:50 -0400 From: "SPECTRO COATING CORP." Subject: New Person Hi - My name is Jason & I recently started subscibing to this list. I'm sure I will learn something here as my efi knowledge drops off a cliff at the ECU connector.(going in - not out ;) My current projects are a V8 AWD S10 Blazer & an 8V-71 supercharged & injected 440 Chrysler (on the engine stand). I'll hang out & watch for awhile. Thanks - J ------------------------------ Date: Tue, 18 May 1999 12:50:11 -0400 From: "Bruce Plecan" Subject: Re: Mr Helmholz - simple model If this opens a whole new box of problems, just ignore. But, I've noticed what a huge change expansion chambers have had of VE in 2 strokes, and after seeing the Mercedes Benz GT (Sedan, whatever they call em) with the v-6, and 3 into 1 exhausts, and running 2 expansion chambers (one per side), I just wonder, how they came up with that... Is it the shape of the cones or volume that makes a "E.C." work, or both?. Grumpy > The Helmholz resonating system was originally developed for wind acoustical > instruments as a model. We now routinely use it to create and size resonant > intake systems. But some may still have trouble visioning it. > > The pure model is a ball "resonating volume" with a pipe "tuning pipe" > attached. Changing the temperature changes the local speed of sound within > the resonator - and thus the frequency of resonance changes. Changing the > volume within the resonating volume changes the frequency - larger lower. > Changing the area/length of the tuning pipe changes the frequency. > > So everyone should see a ball with a pipe. We now add some pipes - sort of > like porcupine spikes sticking out of the resonating volume - but part of the > resonating volume. N -1 spikes are of the length and volume of the header > pipes running to the collector. The Nth is the length and volume including > the volume of the cylinder with the exhaust open during overlap N is the > number of cylinders firing into the common volume. > > The headers/runners can be individually ram tuned to a frequency somewhat > higher than the highest helmholz frequency and thus extent the top end as this > resonance swamps the helmholz effect. > > When a pulse of sound ( exhaust gas acoustic pressure front ) hits an open > volume it generates a negative pressure wave that travels back up the header > to the exhaust valve. We want the negative peak of this wave to arrive at the > time both valves are open "overlap" to gain maximum effect. That is the > theory behind ram tuning exhaust. With the ability to swamp that effect with > the Helmholz resonance, think ringing a bell - with a variable sized bell - we > can retune the resonance downward as much as practical. > > Since the only thing that matters ( assuming a reasonably well designed > otherwise exhaust system ) is the arrival of this negative pulse, we need only > measure the instantaneous port pressure in this crankshaft angle region and > then tune the system to a maximum negative pressure. > > Adding blind volume to the resonating volume simply lowers the resonant > frequency - a good thing since the additional volume does not have to flow > gas. Adding area/shortening the length of the tuned pipe raises the resonant > frequency. Perhaps multiple switched exhaust pipes? > ------------------------------ Date: Tue, 18 May 1999 12:47:13 -0400 From: "Gary Derian" Subject: Re: alternative engines, WARPED Just use manifold vacuum. Carb vacuum is ported so there is no vacuum at idle. This can help or hurt the idle quality. Try it and see. Gary Derian > The 56 should be in at cruisin speeds on the highway, right? > > I tested the mechanical and vacuum advance settings with a timing light > and all ligned up correectly when doin the timing tests, i.e. removing > the vac line and holdin the r's above 2,600 rpm adjusted for 38 degrees > BTDC, then applied vac to vac advance and got 56 degrees....just like > the mopar book says... > > Current 750 dbl pmpr has no vac tubes to hook to so I'll wait till I get > another carb on it to see how she runs with vac adv hooked up, hopefully > better MPG, well see! > > Thanks for the input! > > LATER! > > Todd....!! > ------------------------------ Date: Tue, 18 May 1999 13:49:01 -0400 (EDT) From: Pat Ford Subject: Re: O2 sensor and water Previously, you (Squash) wrote: > --- "David A. Cooley" wrote: > > Yes, but that's the outside... It's designed to get > > wet and survive. If you > > get water on the active element inside the exhaust > > stream, it's toast. > > Yes, this is the outside. I would have big problems > if I had enough water inside to do in the sensor. > Would an inactive (cold) sensor get ruined by > submersion in water? If the any engine is running, I > don't think that you would have much of a chance of > water coming up the exhaust. no but the sensor is exposed to outside air, and I've cracked then on my landie and subarus ( the subies are right at the bottom of the y pipe anything more then 8" would flood the outside of the sensor and the thermal gradient popped them (they would leak exhaust). the landrover had its sensor about 3' off the ground, go into water that deep and pop ( I ended up removing the sensor for that reason) they also don't like mud 8-( > > Andy > > _____________________________________________________________ > Do You Yahoo!? > Free instant messaging and more at http://messenger.yahoo.com - -- 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 ------------------------------ End of DIY_EFI Digest V4 #291 ***************************** 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".