DIY_EFI Digest Friday, March 26 1999 Volume 04 : Number 195 In this issue: Catalog downloads Re: EFI Intake Conversion (1 of 2) Re: 454 TBI for 350 Spark Retard vs overlap Re: MAF GM systems identifying a Chevy 350 block and Trans Re: MAF GM systems Re: 454 TBI for 350 Re: identifying a Chevy 350 block and Trans Re: 454 TBI for 350 Re: A '747 for ignition only Re: identifying a Chevy 350 block and Trans Re: MAF GM systems Re: identifying a Chevy 350 block and Trans Re: Spark Retard vs overlap Re: O2 Sensor Current? Re: A '747 for ignition only (tested) MAF airflow numbers Re: O2 Sensor Current? Holley to GM EFI Re: A '747 for ignition only (tested) Re: Holley to GM EFI ECU6 8051 to 80552 conversion Re: "Negative Overlap" or more commonly known as Pressure Balance cams See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 26 Mar 1999 07:53:58 -0500 From: Shannen Durphey Subject: Catalog downloads Accell, Mr. Gasket, more http://www.mrgasket.com/fuel.htm#anchor13169 Shannen ------------------------------ Date: Fri, 26 Mar 1999 13:29:12 +0000 From: Frederic Breitwieser Subject: Re: EFI Intake Conversion (1 of 2) > Does anyone have dimensions for various injectors? I know that there > are a few designs, but what are the differences? If a bud of mine has 8 > ford injectors, will they fit a GM injector manifold, etc, etc? I found most of the OEM injectors, Ford and GM, fit the same injector bungs, and have the same connectors. Most are Bosch *I think*, though I'm sure someone will correct me. I milled my bungs out for the Ford injectors (o-rings top and bottom) and found that pretty much any GM or Ford injector I've found _so far_ in the junkyard have fit snugly. Real snug! - -- Frederic Breitwieser Bridgeport, CT 06606 http://www.xephic.dynip.com 1993 Superchaged Lincoln Continental 1989 500cid Turbocharged HWMMV 1975 Dodge D200 Club Cab (soon to be twin turbo 440) 2000 Buick GTP (twin turbo V6) ------------------------------ Date: Fri, 26 Mar 1999 09:34:04 -0500 From: "Bruce Plecan" Subject: Re: 454 TBI for 350 - -----Original Message----- From: cwagner@xxx.net> To: diy_efi@xxx.edu> Date: Friday, March 26, 1999 12:42 AM Subject: 454 TBI for 350 There is a bunch of stuff on the 747, here, p rogramming 101 is all about it. Off the home page in DIY_EFI is a summary of it. But still go thru the archives, and there is more. You have to hunt for it, but there is lots of info around for the 747. Bruce I have recently acquired a throttle body for an 89 GMC pickup with a 454 in it. I plan on using it on a 76 Chevy 350 in a 1/2 ton 4x4. I don't know if I could use this throttle body using the bin for a 350 engine or not. Hopefully I will be receiving a programmer so I could reset some values but don't know what to reset to. I am certain that the injectors will flow more fuel than is needed during normal driving but will need that extra during WOT because the throttle body flows more air also. I could use some expertise on this project. I will be using the well known 7747 computer. ------------------------------ Date: Fri, 26 Mar 1999 15:01:11 GMT From: bob@xxx.com (Robert Harris) Subject: Spark Retard vs overlap Its an aftermarket thing. The Buick GN/T Type home pages/mailing lists can point to more info. For the quarter milers, the best I can understand it is a two stage rev limiter. Stage I - you bring the engine up to launch RPM - say 3800, kick the first stage in and nail it to the floor. This "stutter fire" rev limiter works by progressively severely retarding the spark in selected cylinders. The result of limiting by spark retard is just prior to launch you have the turbo spun up to heavy boost, fuel flowing accordingly, launch rpm set, and making virtually no power. The turbo does not need to spin up - its there and the throttle is WOT. All dressed up with all the air/fule flow possible and no spark to make it go. Dropping the rev limiter instantly restores the engine to full power at a high boost making for a very hard and consistent launch. The rev limiter then resets and behaves in a conventional manner. Since the boost was already very high at this point, turbo lag on launch does not enter the equation - no way to lag if you are already there and no way to improve when you are there so anti-lag is meaningless for this app. I don't suspect valve life is much concern vs winning the race. P.S. It works. On Fri, 26 Mar 1999 05:00:02 -0500, you wrote: >Date: Thu, 25 Mar 1999 13:25:36 -0500 >From: "Bruce Plecan" >Subject: Re: Valve Overlap > >- -----Original Message----- >From: Robert Harris >To: diy_efi@xxx.edu> >Date: Thursday, March 25, 1999 11:03 AM >Subject: Re: Valve Overlap > > > >>Now if you want to spin the turbo up in a hurry, you might consider >selective >>spark RETARD. Buick GN's do it all the time. > >Can I ask where in the program this is incorporated?. >> >>By momentarily retarding the spark, say to 30 degrees after TDC, combustion >>starts way late and slow and the majority of the charge burns and expands >in >>the exhaust manifold greatly increasing the volume of gas to spin the turbo >>which greatly increases the inlet charge ..... > >Wouldn't that be kinda hard on the exhaust valve?. >Bruce > 1963 Ford C-600 Prison Bus Conversion "Home" 1971 Lincoln Continental 460 "Christine" 1972 "Whale" Mustang awaiting transplant 1978 Dodge Long Bed Peeek Up "Bundymobile" Habaneros - not just for breakfast anymore ------------------------------ Date: Fri, 26 Mar 1999 11:19:05 -0500 From: Frederic Breitwieser Subject: Re: MAF GM systems Aloha MV, > if you have big cubes and twin turbos, could you put one MAF > sensor on each turbo, have the turbos totally separate, say, > each turbo pumping into the opposite bank from what's driving > it, and make the ECM reference only one of the MAF sensors? I had tried that actually on the Buick V6... I needed two MAF sensors simply because the twin turbos flowed more than one MAF was going to tolerate, so I split it like you had suggested. Didn't really work well, especially at idle to 3k RPM range. Ran rough as hell. I attempted to create a little circuit to combine the MAF frequencies, summing them, then generating a new frequency. Eeeeeh, didn't work either, didn't start at all. At least with the OEM ECM. I was trying to lie to it :) With aftermarket stuff it might be much easier. Just move all the fuel tables up! > Since the other side of the engine is the same displacement > and (hopefully) running at the same speed, you could base One would hope! > your calcs on *half* the actual air flow, no? Makes sense.... > Actually, it is to provide the identical restrition to the *real* > unit on the other side of the engine. That makes sense also. I would suggest not to bother trying to merge the signals - didn't work well for me. Though the GM parts I used ouput a frequency rather than a voltage, so it was more complex than it needed to be. > for high volume applications... What is on the Hummer? Two edelbrock throttle bodies and a haltech EFI system. 10lbs of boost, no more. No OEM ECM :) - -- 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, 26 Mar 1999 09:09:09 -0800 From: "Stowe, Ted-SEA" Subject: identifying a Chevy 350 block and Trans hi. I just bought a jag with a Chevy 350 engine and Chevy trans. it is a constrained motor with what looks like a single barrel Rochester and those rams horn exhaust manifolds. but I believe the manifolds need to stay there to fit in the engine compartment. The engine might have some height restrictions maybe that's why that carb is there. I would like to identify the engine for tune up purposes. Also the egr valve is disconnected, and there are the usual 2-3 plugged up vacuum ports on the carb and manifold. I believe that having a working egr valve is a good thing, exactly where was that attached ? thanks, Ted Stowe ------------------------------ Date: Fri, 26 Mar 1999 12:14:59 -0500 From: "David A. Cooley" Subject: Re: MAF GM systems I wonder... Run the inlet of both turbos to a Plenum and have the 2 sensors in the Plenum before they vent to the aircleaner... It was probably rough because one sensor being used is sensing 3 pulses per 2 rev's instead of 6... air flow was probably bouncing up and down and it didn't know how to handle it. - -----Original Message----- From: Frederic Breitwieser To: diy_efi@xxx.edu> Date: Friday, March 26, 1999 12:03 PM Subject: Re: MAF GM systems >Aloha MV, > >> if you have big cubes and twin turbos, could you put one MAF >> sensor on each turbo, have the turbos totally separate, say, >> each turbo pumping into the opposite bank from what's driving >> it, and make the ECM reference only one of the MAF sensors? > >I had tried that actually on the Buick V6... I needed two MAF sensors simply >because the twin turbos flowed more than one MAF was going to tolerate, so I >split it like you had suggested. Didn't really work well, especially at idle >to 3k RPM range. Ran rough as hell. I attempted to create a little circuit >to combine the MAF frequencies, summing them, then generating a new >frequency. Eeeeeh, didn't work either, didn't start at all. At least with >the OEM ECM. I was trying to lie to it :) With aftermarket stuff it might >be much easier. Just move all the fuel tables up! ------------------------------ Date: Fri, 26 Mar 1999 12:27:38 -0500 (EST) From: David J Kennedy Subject: Re: 454 TBI for 350 I was wondering the opposite, I have a TBI 350 (1989) and would someday like to step up to the 454. What I want to know is what can I keep of my current TBI set up. Will I just need the 454 throttle body? It'd be great if I could keep all my sensors/ecm and just move them to their new homes on a big block. I'd offer a trade, but I am not ready for that project yet- I don't think:) David Kennedy ------------------------------ Date: Fri, 26 Mar 1999 12:33:43 -0500 From: "Gary Derian" Subject: Re: identifying a Chevy 350 block and Trans EGR can be a good thing on a late model engine that advances the timing when the EGR kicks in. It reduces pumping losses and improves economy at part throttle. On an old carbureted engine, EGR kills throttle response and reduces economy. Those old engines with no electronic controls work best when the vacuum advance is connected directly to the carb, ported vacuum is usually best, and no EGR. Of course if you have to meet emission standards, you have to hook it all up. The EGR valve hooked up to a special vacuum port on the carb that has a long slot in the carb throat. As the throttle is opened, more of the slot is under the plate increasing the vacuum signal as the throttle is opened. Gary Derian > hi. I just bought a jag with a Chevy 350 engine and Chevy trans. > > it is a constrained motor with what looks like a single barrel Rochester and > those rams horn exhaust manifolds. but I believe the manifolds need to stay > there to fit in the engine compartment. The engine might have some height > restrictions maybe that's why that carb is there. > > > I would like to identify the engine for tune up purposes. Also the egr valve > is disconnected, and there are the usual 2-3 plugged up vacuum ports on the > carb and manifold. I believe that having a working egr valve is a good > thing, exactly where was that attached ? > > thanks, Ted Stowe ------------------------------ Date: Fri, 26 Mar 1999 13:04:45 -0500 From: "Bruce Plecan" Subject: Re: 454 TBI for 350 - -----Original Message----- From: David J Kennedy To: diy_efi@xxx.edu> Date: Friday, March 26, 1999 12:52 PM Subject: Re: 454 TBI for 350 I'm assuming this is a truck application: The give away BBC to SBC TBs is the BBC has 2" butterflies, and the SBC have 1.8"s. Some variances in connetors for TPS. Large and not so large injectors, for BBC Early bigger. MAP, CTS, all the same. 87-91 all were 747s, Bruce I was wondering the opposite, I have a TBI 350 (1989) and would someday like to step up to the 454. What I want to know is what can I keep of my current TBI set up. Will I just need the 454 throttle body? It'd be great if I could keep all my sensors/ecm and just move them to their new homes on a big block. I'd offer a trade, but I am not ready for that project yet- I don't think:) David Kennedy ------------------------------ Date: Fri, 26 Mar 1999 13:28:55 -0800 From: rr Subject: Re: A '747 for ignition only Well, it works, so far so good. I have an entire '747 system, sanes TBI under the hood. Only thing with the TBI is that I plugged a TPS into the connector and it's laying on the intake manifold. Disabled the O2 & TPS error codes, setup the spark map as though it was a centrif distributor only, put the original carb on, and fired it up. (Other misc changes in the PROM also). No error codes, data stream looks good, I'm going for a test drive as soon as I'm off the PC here... This is also the first (FIRST!) firing of any efi system that I've ever done! Yea, I'm a little excited, Yaaa-hoooo. BobR. P.S. As soon as I'm done playing with this, I'll get that high pressure fuel system and the TBI on. rr wrote: > > Bruce Plecan wrote: > > > > -----Original Message----- > > From: rr > > To: diy_efi@xxx.edu> > > Date: Wednesday, March 24, 1999 11:55 AM > > Subject: A '747 for ignition only > > > > >Bruce, I remember that you had mentioned this before. Whether a '747 > > >could be used for a computer ignition system only. As my install is > > >right at the point of needing an EFI fuel system. And the carb system > > As for needing just the EFI fuel system, I was actually meaning, > the pump/filter/lines to the TBI. I have an entire '747 system from > a truck currently installed in/on the engine/vehicle. > > Only take a minute to pull the TBI and throw the carb back on. > > > >is still in place, I think I'll try it out. > > >Off the top of my head, the one thing that needs to be done, it to > > >zero the error bit map for all the O2 stuff. Burn the prom with > > >some spark tables, and try it. > > >Anything else you can think of? > > > > On a CCC: > > You'll need the right MAP, > > TPS, Seems likely to be shareable. > > TPS, hmmm, that I'll lose removing the TBI. Maybe it won't > matter much, I should still get some PE due to the MAP. > > > ESC, and KS probably different. You'd have to call Chev or Parts House > > for accurate info., I'm not sure. > > For the intial fire it up to see of it runs, I'd disable all the malfunction > > flags. > > Set the timing, and immediately try a chip with like you said 13-44-45 > > disabled, and closed loop/learn temps set to FF. > > Yep, good idea's here. > > > Depending on what you actually doing, you'll need the fuel pump signals > > wired in. > > Done. > > > > > None CCC: > > gonna need a TPS, in addition to the above.. > > Bruce > > > > > >BobR. > > I'm thinking that the main spark table is RPM vs MAP, it's > the little things that might mess me up. > > I'll let everyone know how this goes... Yea, I'm gonna > try it. Why not! Gotta' learn somehow. > > BobR. > > Ya' sure Doc's not up for a ride under the hood with a > timing light? LOL > > -- ------------------------------ Date: Fri, 26 Mar 1999 13:47:27 -0500 From: "Clarence L.Snyder" Subject: Re: identifying a Chevy 350 block and Trans > t is a constrained motor with what looks like a single barrel Rochester and > those rams horn exhaust manifolds. but I believe the manifolds need to stay > there to fit in the engine compartment. The engine might have some height > restrictions maybe that's why that carb is there. I've never seen a single barrel carb on a small-block chevy. My guess would be a standard rochester 2 bbl, meaning the engine is NOT from a truck and is not a 4 bolt main, in all likelihood. ------------------------------ Date: Fri, 26 Mar 1999 14:48:37 -0500 From: Frederic Breitwieser Subject: Re: MAF GM systems > It was probably rough because one sensor being used is sensing 3 pulses per > 2 rev's instead of 6... air flow was probably bouncing up and down and it > didn't know how to handle it. That could be... I also had the MAF sensors very close to the plenum - just in front of the throttle bodies which were mounted to the plenum directly. The plenum might have acted as a giant reverberator. - -- 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, 26 Mar 1999 13:52:27 -0600 From: "David" Subject: Re: identifying a Chevy 350 block and Trans Ted, If you can give me the casting numbers on the block, heads, intake, etc., I can look them up and tell you more about the engine. David Edwards - -----Original Message----- From: Stowe, Ted-SEA To: 'diy_efi@xxx.edu> Date: Friday, March 26, 1999 11:38 AM Subject: identifying a Chevy 350 block and Trans |hi. I just bought a jag with a Chevy 350 engine and Chevy trans. | |it is a constrained motor with what looks like a single barrel Rochester and |those rams horn exhaust manifolds. but I believe the manifolds need to stay |there to fit in the engine compartment. The engine might have some height |restrictions maybe that's why that carb is there. | | |I would like to identify the engine for tune up purposes. Also the egr valve |is disconnected, and there are the usual 2-3 plugged up vacuum ports on the |carb and manifold. I believe that having a working egr valve is a good |thing, exactly where was that attached ? | |thanks, Ted Stowe | ------------------------------ Date: Fri, 26 Mar 1999 16:23:14 -0500 From: "Bruce Plecan" Subject: Re: Spark Retard vs overlap - -----Original Message----- From: Robert Harris To: diy_efi@xxx.edu> Date: Friday, March 26, 1999 10:12 AM Subject: Spark Retard vs overlap That is just a 0 MPH rev limiter. Now if the control was for boost then that would be something else. Least to my way of thinking, but I've been wrong before (least twice today). Bruce Doc's been upset. He's out waxing the boat and trailer. Had water in everything. After reading a blonde joke the other day, he found out the boat might be much faster if he takes it off the trailer when in the water.. >Its an aftermarket thing. The Buick GN/T Type home pages/mailing lists can >point to more info. For the quarter milers, the best I can understand it is a >two stage rev limiter. Stage I - you bring the engine up to launch RPM - say >3800, kick the first stage in and nail it to the floor. This "stutter fire" >rev limiter works by progressively severely retarding the spark in selected >cylinders. > >The result of limiting by spark retard is just prior to launch you have the >turbo spun up to heavy boost, fuel flowing accordingly, launch rpm set, and >making virtually no power. The turbo does not need to spin up - its there and >the throttle is WOT. All dressed up with all the air/fule flow possible and >no spark to make it go. > >Dropping the rev limiter instantly restores the engine to full power at a high >boost making for a very hard and consistent launch. The rev limiter then >resets and behaves in a conventional manner. > >Since the boost was already very high at this point, turbo lag on launch does >not enter the equation - no way to lag if you are already there and no way to >improve when you are there so anti-lag is meaningless for this app. > >I don't suspect valve life is much concern vs winning the race. > >P.S. It works. > >On Fri, 26 Mar 1999 05:00:02 -0500, you wrote: >>Date: Thu, 25 Mar 1999 13:25:36 -0500 >>From: "Bruce Plecan" >>Subject: Re: Valve Overlap >> >>- -----Original Message----- >>From: Robert Harris >>To: diy_efi@xxx.edu> >>Date: Thursday, March 25, 1999 11:03 AM >>Subject: Re: Valve Overlap >> >> >> >>>Now if you want to spin the turbo up in a hurry, you might consider >>selective >>>spark RETARD. Buick GN's do it all the time. >> >>Can I ask where in the program this is incorporated?. >>> >>>By momentarily retarding the spark, say to 30 degrees after TDC, combustion >>>starts way late and slow and the majority of the charge burns and expands >>in >>>the exhaust manifold greatly increasing the volume of gas to spin the turbo >>>which greatly increases the inlet charge ..... >> >>Wouldn't that be kinda hard on the exhaust valve?. >>Bruce >> > > >1963 Ford C-600 Prison Bus Conversion "Home" >1971 Lincoln Continental 460 "Christine" >1972 "Whale" Mustang awaiting transplant >1978 Dodge Long Bed Peeek Up "Bundymobile" > >Habaneros - not just for breakfast anymore > ------------------------------ Date: Fri, 26 Mar 1999 15:25:50 -0600 From: Thomas Martin Subject: Re: O2 Sensor Current? Static is set to 22 degrees, factory spec is 20 with 87 octane. 22 is MORE than acceptable with 93 Oct. No, it is CCC, computer controls the advance. No mech advance. No carbon buildup in the EGR tubes, I have run some X-66P down about 2 months ago, no change. If I run 89 oct, she pings like I am advanced to 30 degrees and have lean mixture!! I means she rattles! This is my concern, I would like to run 87 oct again, and not have to use the Cat or AIR. The carb was rebuilt last summer, and is VERY clean inside. She purrs at idle, does 0-60 in 9.3 with 2 people in the car and all my tools, and with 2.14 gears and 205 75 R 14 tires (taller than stock). I was still in first gear! She was running very rich at the high rpm end. I will start to work on the unity gain op amp this weekend, hopefully that will cure the whole problem and give me some tunability without code. I did not see anything about the 27S181 on the http://www.cruzers.com/~ludis/ website, am I blind? Does the carb CCC setup use the 27S181 or am I getting wrong info? I got it from someone who has programmed one for a 442. I have a ECM, Service Number 1226454, this is NOT from my Cutlass, but can it be used for it? I think it came from a 84 and older 3.8L Chevy V6 car. The letter code is BDB. Does this mean much? There is numbers 16027811, and 867811, and 46370568 also. What do they mean? I appreciate the help of the members of the list on this, even though it is not an EFI car, yet. I am planning on this summer building up a TBI system for it. I can justify a lot of money in this car, but my 80 Turbo Trans AM with a 70 400 in it will get SFI, that is my goal there. Thanks! Tom Martin > > Tom, > I have an 81 307 "Y". It is completely stock, but it isn't > even EFI. It's got the Feedback Carb. I've never played with > it, just been driving it since 85. I don't have a part > throttle ping problem. Maybe you have too much static > advance, carbon buildup, or are running lean. I need to look > at mine, but I actually thought it still had mechanical > advance in the distributor. I thought only the Vacuum > advance was computer controlled. I could be wrong, I've only > replaced the rotor and Cap once on that distributor. I agree > the Feed back carb needs to be replaced, It needs rebuilt > every 2 years, and I've about worn mine out, from > rebuilding. > > Ken ------------------------------ Date: Fri, 26 Mar 1999 16:11:51 -0800 From: rr Subject: Re: A '747 for ignition only (tested) OK, back from the test drive. Quick re-cap: I'm trying a complete '747 ECM/sensor/distributor system, minus the TBI in a small block chevy. This is a hot-rodded setup: headers, duals, cam, al. heads, cold air, gears, all the stuff to go fast. Oh, I'm using a Carter 625CFM AFB carb, aftermarket, on an Edelbrock Perf. RPM manifold. The other thing is, that this is a first for the entire system. It has been installed over the last 4 months, and first fired up today. It started with the first click of the key, the grin on my mug gives that away. (I'm still smiling). I used an 8-in-1 EPROM that I can switch between programs. This I was able to do without shutting off the engine. (a '256Kb prom, with eight dip switch selected banks). I burned in 3 different programs, with just the timing tables changed between them. One table is what B.P. used in one of his vehicles, the other two being what a centrifugal advance distributor would be like. One of which has 6deg more timing, across the board, than the other. I set the intial advance to 6deg, and the warm bias in the prom to the same. Cold bias to 12deg. It hot cranks just fine, this is good. The timing table is along the lines of: 14 initial, 36 total, in by 3200 RPM. The other table has 6 deg more across the board. This table did give some knock counts, but without a feeling of lost power. The knock filter I used is from a 4.3L Astro van, as the bore size matches (4"). I have one from a 305 to try, but that is a smaller bore engine. The engine runs as good as, or better than it did with the electronic distributor and CDI ignition. Under WOT, the power was good. I don't have a performance measuring device (well, my butt), but I'll do something here soon. B.P.'s table was interesting, it was lazy at low engine speeds, and came on with a bang. Our cams are two differents beasts anyway. I'm running an Isky 280 Mega cam: 224deg @xxx. That and I'm running a 5-spd, while B.P. has an auto. Oddly, I am getting a trouble code 33, MAP sensor high. This might be due to the battery being shot, and a reset occuring during crank. I do know that the ALDL scanner resets at crank. I'm not too worried about it. (might also be an interaction of the TPS, which isn't moving). The system does go into closed loop and learn mode. Along with the INT and BLM moving. It even sees cross-counts, as the carb is fairly well tuned. But, this doesn't seem to have any effect on the system as it's now being used. The VSS is reporting correct mph, along with the map at 57.5-60KPa at idle. The ECM even reports that I've hit the A/C switch. Man this is great. It has a better cold idle than the orig system. I have no choke on the carb, but additional advance occurs during warm up, due to the ECM control. I made other minor changes to the prom maps, as far as knock retard degrees and PE mode. For the above testing, I disabled the error codes for the O2 sensor and TPS. Sometime down the road, I'll get the TBI on it, along with the high pressure fuel system. Well, in closing, I'm going to leave the system like this for a while, and do some futher testing. If anyone has any ideas or requests, let me know... BobR. - -- ------------------------------ Date: Fri, 26 Mar 1999 16:39:26 EST From: A70Duster@xxx.com Subject: MAF airflow numbers The test was done at an elevation of 5300 ft. at a temp of 69 F. I couldn't draw any more air from the setup. That's why it stops at 2.19 volts (sorry). I measured feet per minute from the aneometer. Ane. MAF FPM volts 113 0.200 145 0.300 187 0.470 228 0.605 251 0.665 270 0.720 420 0.995 481 1.085 580 1.210 605 1.245 710 1.375 840 1.515 920 1.595 1170 1.770 1220 1.805 1530 2.025 1810 2.190 Plot the data.... It looks parabolicish to me :) See ya, Mike ------------------------------ Date: Fri, 26 Mar 1999 16:53:27 -0500 From: "David A. Cooley" Subject: Re: O2 Sensor Current? At 03:25 PM 3/26/99 -0600, you wrote: > >I did not see anything about the 27S181 on the >http://www.cruzers.com/~ludis/ website, am I blind? Does the carb CCC setup >use the 27S181 or am I getting I just looked too... Remember seeing it a while back... Just did an archive search on 27S181 at the DIY web site and came up with several messages, one had the instructions on how to read it from Scot Sealander (I believe). Will look later and send them. =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 I am Pentium of Borg...division is futile...you will be approximated. =========================================================== ------------------------------ Date: Fri, 26 Mar 1999 14:01:25 -0800 From: Vinnie Moscaritolo Subject: Holley to GM EFI Hi; I was thinking about converting my Holley EFI TBI unit (the old analog 2bbl) to work with the GM ECU. As I understand this is what Howell does, but they use an idle air control unit instead of the solenoid that Holley uses. I have a few questions that the list might be able to help with. Can someone tell about Howells idle air control ? Where can I get one to make my Holley (2bbl) compatible? Is the GM ECU a good idea? I am using it on a International Harvester 304 and I have modified a manifold to accept the TBI unit directly, Although I might mount a 1" spacer under the TBI to give it more clearance. I hear that this is good for low end power, since the IH motor only revs about 4000 rpm I think this would be fine. but I would like to know if this is an OK idea? thanks again. ------------------------------ Date: Fri, 26 Mar 1999 17:17:51 -0500 From: "Bruce Plecan" Subject: Re: A '747 for ignition only (tested) - -----Original Message----- From: rr To: diy_efi@xxx.edu> Date: Friday, March 26, 1999 4:42 PM Subject: Re: A '747 for ignition only (tested) If ya wouldn't mind, I'd like a copy of the bin, just incase someone tries this. I was concerned that it would have been in limp home mode. Interesting, that it works that well. Bruce nacelp@xxx.net >OK, back from the test drive. Quick re-cap: I'm trying a complete >'747 ECM/sensor/distributor system, minus the TBI in a small block >chevy. This is a hot-rodded setup: headers, duals, cam, al. heads, >cold air, gears, all the stuff to go fast. Oh, I'm using a Carter >625CFM AFB carb, aftermarket, on an Edelbrock Perf. RPM manifold. > >The other thing is, that this is a first for the entire system. It >has been installed over the last 4 months, and first fired up today. >It started with the first click of the key, the grin on my mug gives >that away. (I'm still smiling). > >I used an 8-in-1 EPROM that I can switch between programs. This I >was able to do without shutting off the engine. (a '256Kb prom, with >eight dip switch selected banks). > >I burned in 3 different programs, with just the timing tables changed >between them. One table is what B.P. used in one of his vehicles, the >other two being what a centrifugal advance distributor would be like. >One of which has 6deg more timing, across the board, than the other. I >set the intial advance to 6deg, and the warm bias in the prom to the >same. Cold bias to 12deg. It hot cranks just fine, this is good. > >The timing table is along the lines of: 14 initial, 36 total, in by >3200 RPM. The other table has 6 deg more across the board. This table >did give some knock counts, but without a feeling of lost power. The >knock filter I used is from a 4.3L Astro van, as the bore size matches >(4"). I have one from a 305 to try, but that is a smaller bore engine. > >The engine runs as good as, or better than it did with the electronic >distributor and CDI ignition. Under WOT, the power was good. I don't >have a performance measuring device (well, my butt), but I'll do >something here soon. > >B.P.'s table was interesting, it was lazy at low engine speeds, and >came on with a bang. Our cams are two differents beasts anyway. I'm >running an Isky 280 Mega cam: 224deg @xxx. >That and I'm running a 5-spd, while B.P. has an auto. > >Oddly, I am getting a trouble code 33, MAP sensor high. This might be >due to the battery being shot, and a reset occuring during crank. I >do know that the ALDL scanner resets at crank. I'm not too worried >about it. (might also be an interaction of the TPS, which isn't moving). > >The system does go into closed loop and learn mode. Along with the >INT and BLM moving. It even sees cross-counts, as the carb is fairly >well tuned. But, this doesn't seem to have any effect on the system as >it's now being used. The VSS is reporting correct mph, along with >the map at 57.5-60KPa at idle. The ECM even reports that I've hit >the A/C switch. Man this is great. > >It has a better cold idle than the orig system. I have no choke on >the carb, but additional advance occurs during warm up, due to the >ECM control. > >I made other minor changes to the prom maps, as far as knock retard >degrees and PE mode. For the above testing, I disabled the error >codes for the O2 sensor and TPS. > >Sometime down the road, I'll get the TBI on it, along with the >high pressure fuel system. > >Well, in closing, I'm going to leave the system like this for a >while, and do some futher testing. If anyone has any ideas or >requests, let me know... > >BobR. > >-- > ------------------------------ Date: Fri, 26 Mar 1999 14:49:01 -0800 (PST) From: andy quaas Subject: Re: Holley to GM EFI I don't think howell ever used the projection 2bbl. Howell has used the 4bbl w/iac and the GM replacement by holley (also has an IAC). Andy - --- Vinnie Moscaritolo wrote: > Hi; > > I was thinking about converting my Holley EFI TBI > unit (the old > analog 2bbl) to work with the GM ECU. As I understand > this is what > Howell does, but they use an idle air control unit > instead of the > solenoid that Holley uses. > > I have a few questions that the list might be able to > help with. > > Can someone tell about Howells idle air control ? > Where can I get one to make my Holley (2bbl) > compatible? > Is the GM ECU a good idea? > > I am using it on a International Harvester 304 and I > have modified a > manifold to accept the TBI unit directly, Although I > might mount a > 1" spacer under the TBI to give it more clearance. I > hear that this > is good for low end power, since the IH motor only > revs about 4000 > rpm I think this would be fine. but I would like to > know if this is > an OK idea? > > thanks again. > _________________________________________________________ Do You Yahoo!? Get your free @xxx.com ------------------------------ Date: Fri, 26 Mar 1999 18:39:57 -0500 From: "Ord Millar" Subject: ECU6 8051 to 80552 conversion Al, I got my CD for the Phillips 80C51 series, and looked at the assembler code that you sent me. For the A/D conversion, it looks like the CPU you had before did an 8 bit conversion. The Phillips converter is 10 bits. It looks like the basic code that goes with this would only know how to read 8-bit. Did you want to change the basic, or should we store only the high 8 bits? For the Flash stuff - I need some specs on the 5 volt system, I have only ever programmed for 12V ones. - -----Original Message----- From: Al Lipper To: Ord Millar Date: Saturday, March 20, 1999 4:24 PM Subject: Re: 8051 programming >Ord, >Thanks so much for your interest! I don't think we need too uch assembly >programming, but some. Basicially, we've changed over from an Intel >80C51GB (that is no longer made) to a Phillips 80C552. They have similar >features, but the capture/compare timers and A/D converter have different >register structures, so the old software needs to be modified to work with >the philips chip. The other thing we need done is to revise our old flash >memory loader to work with a new 5v flash (we used to use a 12v version). >All the current code is well commented. I've attached the files that >contain it, so perhaps you can look over them and tell me what you think. > > Al > >At 02:23 PM 3/20/99 -0500, you wrote: >>Al, >> >>I do a lot of 8051 programming, mostly in assembler (with a little MCS basic >>for fun now and then). >> >>Perhaps I can help you with the ECU6 software. I can not spend too much >>time with it, but if you have some specific problems to solve, or algorithms >>that you need let me know. >> >>Ord >> >> > ------------------------------ Date: Fri, 26 Mar 1999 15:56:32 -0800 From: Vogt Family Subject: Re: "Negative Overlap" or more commonly known as Pressure Balance cams On Tue, 23 Mar 1999, bob@xxx.com (Robert Harris) wrote: > > The concept is quite simple and Dave Vizard in his book about Chevy Cams > covers it extensively. Like all his books - more fact and theory than brand > specific. > > The assumption is that since their is both positive manifold pressure and much > higher exhaust manifold pressure thru much of the power region, use no > overlap. > > Overlap in a NA engine used the exiting exhaust gasses to draw fresh charge > into the cylinder and if the negative pulse from the exhaust is coupled to the > intake, create even more flow. With a turbo, because of back pressure, for > much of the throttle, the exhaust back pressure is higher than the intake > pressure - so overlap actually forces exhaust up the intake manifold. > > So you time the closing of the exhaust valve to get maximum exhaust extraction > and then delay the opening of the intake valve until well past TDC to about > the point where the downward moving piston has reduced the residual exhaust > pressure to the intake pressure. At this point - about 30 after TDC - you > open the valve and the intake pressure - being marginally above the residual > exhaust - forces charge into the engine. Absolute minimum exhaust charge > dilution. > > Closing of the intake is about normal depending on boost pressure - but long > duration late closing is not optimal - pressure fills cylinder and holding > open late reduces the trapped charge and works the intake pressure against the > rising piston. > > What results is a pure otto cycle engine - short cam on intake and normal > exhaust. Very torquey on the low end - Vizard reports 1000+ hp with enough > boost on a 350 chevy so there is no lack of top end power. Bob, are you on the Ford Trucks list also? Very good explanation, thanks a lot. This is what I have been waiting to hear for some time now. I am building a Ford 429 for my projectmobile 4-wheel drive truck. Basically the major concern is maximum torque right off idle. My question is, would this type of cam be a good idea without a turbo, since I am of the limited funds, or should I buy a normal "torque" cam for the first stage of the build, and get a turbo grind later? Also, I have been wondering about the suitability of an automatic transmission with this type of power delivery. My major intended use is super slow crawling. The turbo idea is to also make it "mud-bog-able". Any thoughts, anyone? Birken ------------------------------ End of DIY_EFI Digest V4 #195 ***************************** 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".