DIY_EFI Digest Wednesday, 3 February 1999 Volume 04 : Number 085 In this issue: Re: Love This Re: Love This Re: UEGO IDEA was(Re: More UEGO stuff) Re: VE calculations from torque graph and manifold pressure. OBD II LT1 Engine Swap Gotchas??? Re: OBD II LT1 Engine Swap Gotchas??? Re: Love This Re: UEGO IDEA AutoClutch and manual trans (was: Re: Smooth strategy) RE: Love This Re: Smooth strategy) Re: Love This Re: TC's and manual trans (was: Re: Smooth strategy) Re: Love This RE: Love This Re: UEGO IDEA Re: UEGO IDEA RE: Love This Re: Intake Runner Length Re: PWM motor controller Re: More UEGO stuff Re: Intake Runner Length Re: Intake Runner Length Re: OBD II LT1 Engine Swap Gotchas??? Re: OBD II LT1 Engine Swap Gotchas??? Re: PWM motor controller Re: Intake Runner Length Re: TC's and manual trans (was: Re: Smooth strategy) Re: TC's and manual trans (was: Re: Smooth strategy) See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Gary Derian" Date: Tue, 2 Feb 1999 16:53:45 -0500 Subject: Re: Love This Cooling fans are PWM controlled to minimize noise when full cooling is not needed. Gary Derian > > I thought that cooling fans worked on an on/off system. Under what >conditions would you want PWM control, and what is the pulse width that is >being modulated? You guys really know how to humble a guy; I thought I had >a lock on cooling fans!(:< >>Clarence > > ------------------------------ From: Frederic Breitwieser Date: Tue, 02 Feb 1999 21:59:52 +0000 Subject: Re: Love This > While was mentioned for cooling fans, I was looking for a fuel pump > controller, but a motor issa motor. However, not all motors are the same :) > I thought that cooling fans worked on an on/off system. Under what > conditions would you want PWM control, and what is the pulse width that is > being modulated? You guys really know how to humble a guy; I thought I had > a lock on cooling fans!(:< To vary the speed of the fan :) Faster at a standstill, faster with the A/C on, slower or off otherwise :) A lot of the day-time running lights work the same way, they run at a 50% duty cycle rather than 100%. Beats a large, hot resistor like you said in the chopped out portion of your post. - -- Frederic Breitwieser Bridgeport, CT 06606 http://www.xephic.dynip.com 1993 Superchaged Lincoln Continental 1989 500cid Turbocharged HWMMV 1975 Dodge D200 Club Cab 2000 Buick GTP (twin turbo V6) ------------------------------ From: "Walter Sherwin" Date: Tue, 2 Feb 1999 17:07:09 -0800 Subject: Re: UEGO IDEA was(Re: More UEGO stuff) Yup, I agree. Say 'hi' sometime offline. Walt. - -----Original Message----- From: Tom Sharpe To: diy_efi@xxx.edu> Date: Monday, February 01, 1999 9:22 PM Subject: Re: UEGO IDEA was(Re: More UEGO stuff) > > >Walter Sherwin wrote: > >> Not quite Bruce. Picture the following "Remapping" >> procedure............................... >> >> Create a cal which defeats all of the A/F modifiers such as AE, EGR, ECT, >> etc. Also, disable open loop PE enrichment so that the computer stays in >> closed loop under all conditions. Basically, you would now have a VE driven >> cal, with closed loop correction capability. But, instead of "learning" >> towards stoich, the system would learn towards a safe setpoint (of say >> 11.5:1) defined by the electronic gizmo I had proposed. >> >> > >If we are learning, let's learn 11.5:1 < 10" vacuum (MAP???) stoich at 15"+ >vacuum (could learn lean burn also) and a straight line between them. Come up >with "standard" correction factors for H20 (warm up) and Air Temp and you're >done. > >It's not really that simple, but close..... Tom > ------------------------------ From: "Walter Sherwin" Date: Tue, 2 Feb 1999 17:31:46 -0800 Subject: Re: VE calculations from torque graph and manifold pressure. >Given the fact that I have a DYNO torque curve of a motor over it entire RPM >range for WOT >I should be able to convert torque to VE Assuming you have plugged in the appropriate constants for your engine's displacement and injectors, then yes the shape of the WOT VE table will closely resemble the shape of the WOT torque curve. You might want to aim for 80% VE at peak torque, just to give yourself some headroom to play around in. >With the above results I should be able to build one column in my VE map in >my 808 ECU. >Would it be possible to somehow via math's calculations to work out (roughly) >The VE numbers for all other load conditions. To get close, just use a ratio factor. 50 MAP would lead you to a VE of 50% of the WOT VE table value, at that engine speed. You should be able to start to tune with such a Map. Have Fun; Walt. ------------------------------ From: gervais@xxx.com (Joe Gervais) Date: Tue, 2 Feb 1999 14:37:22 -0800 Subject: OBD II LT1 Engine Swap Gotchas??? I've been quiet on this list for a while. I swapped a 93 LT1 into my early Corvette, and thanks to this list and others, have enjoyed that swap and am about to do a similar swap into a 69 Camaro with a 97 Z28 motor that I couldn't pass up. I know some of the high horsepower guys I know have swapped from OBD II to OBD I PCMs due to difficulties of squeezing 600 HP out of an OBD II controlled motor. For a stock, smog exempt OBD II swap, are there any pitfalls that I should look out for? Anyone else on the list already done such a swap? Joe - -- _________________________________________________________________________ Joe Gervais gervais@xxx.com Product Line Manager (650) 933-7479 voice High Performance Networking (650) 964-0811 fax Silicon Graphics www.sgi.com 2011 North Shoreline Blvd, Mail Stop 08L-855, Mountain View, CA 94043-1389 ------------------------------ From: Roger Heflin Date: Tue, 2 Feb 1999 16:49:30 -0600 (CST) Subject: Re: OBD II LT1 Engine Swap Gotchas??? On Tue, 2 Feb 1999, Joe Gervais wrote: > I've been quiet on this list for a while. I swapped a 93 LT1 into my early > Corvette, and thanks to this list and others, have enjoyed that swap and am > about to do a similar swap into a 69 Camaro with a 97 Z28 motor that I couldn't > pass up. > > I know some of the high horsepower guys I know have swapped from OBD II to OBD > I PCMs due to difficulties of squeezing 600 HP out of an OBD II controlled > motor. For a stock, smog exempt OBD II swap, are there any pitfalls that I > should look out for? Anyone else on the list already done such a swap? > > Joe > If you are swapping in the standard stock unmodified engine you will only need to fake out the sensors that you aren't using, such as the additional O2 sensors behind the cats. Also I believe there are some things that detect a loose gas cap, this will need to be faked out also, and probably several other sensors of the same sort. That is I believe why they generally put a 95 pcm in, they don't have to worry about it. The 96 + pcm does have some nice features, it will count misfires, but this is supposed to get rather confused if you put a cam that is too big in the car, and count alot of misfires and set SES lights and such. If the engine is being modified then the misfire detection seems to be the most troublesome thing, if you are staying in the same car. There are supposed to be "O2" sensors to properly fake out the behind the cat sensors inputs so the computer does not notice. I think it takes the front O2 sensor and makes up the rear signal based on that. And I guess the other problem is not many companies know how to program the 96+ cars, so that is really a problem. Roger ------------------------------ From: Shannen Durphey Date: Tue, 02 Feb 1999 18:02:07 -0500 Subject: Re: Love This Gary Derian wrote: > > Cooling fans are PWM controlled to minimize noise when full cooling is not > needed. > Electrical or acoustic? Shannen > Gary Derian > > > > > I thought that cooling fans worked on an on/off system. Under what > >conditions would you want PWM control, and what is the pulse width that is > >being modulated? You guys really know how to humble a guy; I thought I had > >a lock on cooling fans!(:< > >>Clarence > > > > ------------------------------ From: Ludis Langens Date: Tue, 02 Feb 1999 15:10:16 -0800 Subject: Re: UEGO IDEA Stuart Bunning wrote: > I have removed the carby and > installed the TBI and now (havn't done this yet) are going to keep altering > the VE table until the base pulse width for the injectors will supply the > same amount of fuel as my carby did at idle over the same time period. > Hopefully I will be able to start the car and it will idle. The problem is > if I change RPM or load of the engine ( touch the trottle ) I would > instantly go lean. If I was to set the entire VE map the same maybe your > approach will enable to use BLM numbers to adjust the rest of my map. You won't go as lean as you think. The MAP sensor is used to index into the VE map. But it normally is also multiplied into the fuel calculation. If you had a totally flat VE map, an increase in MAP would still increase the fuel delivered. (Further, an increase in RPM would cause fuel to be injected more often - also increasing the total fuel delivery over a unit of time.) > For example if at 3000RPM I have maximum torque at WOT 100% efficient could > I assume > that at 50KPA it would we only 50% efficient,25KPA 25% etc... I checked the VE table in a production PROM. At most RPM values, there was almost exactly a factor of two increase in VE from 20 KPa to 100 KPa. (Once the MAP gets multiplied in, that means a factor of ten in fuel from 20 KPa to 100 KPa.) Across the RPM range, the highest and lowest VEs varied by about a factor of 1.5. The only exception was the idle "corner" of the table (low rpm, low MAP / high vacuum). In this portion of the table, the VE dropped below what would be predicted by the previous ratios. Perhaps you should do your carb measurement at a load other than idle - and use the results to set an initial (flat) VE table. Regarding tuning with a UEGO: A wide range sensor allows the BLMs to be determined almost instantly. If the sensor indicated a ratio of 12.3 when the ECM wanted 14.6, a little bit of math can jump the BLM to very close to the correct value for the next cylinder cycle. There is no need to bump the BLM (or INT) by one count, wait a while, and perhaps repeat. Of course these smart BLM changes would require a code change in an ECM's program. With appropriate software, the VE table could be tuned fairly well on a dyno with just a quick sweep through the RPM ranges at 10 or 20 different throttle positions. - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ ------------------------------ From: Tom Sharpe Date: Tue, 02 Feb 1999 17:13:09 -0600 Subject: AutoClutch and manual trans (was: Re: Smooth strategy) Why not go all the way and adopt the Ferrari setup. Use the standard friction clutch operated by a power steering pump and cylinder along with the finger switches on the steerring wheel to up/down shift, all controlled by the computer. Copy the ratchet shifter mechanism from a motorcycle. Just two pedals and no shifter..... Let's see.... has anyone seen a Ferrari in the local U-Pull?? Tom ------------------------------ From: "Van Setten, Tim (AZ75)" Date: Tue, 2 Feb 1999 16:10:36 -0700 Subject: RE: Love This > Subject: Re: Love This > > > Could you, or someone, please explain PWM (assuming that PWM=Pulse > Width > Modulation) of cooling fans? > > Subject: RE: Love This > > > Could you, or someone, please explain PWM (assuming that PWM=Pulse > Width > Modulation) of cooling fans? > > Here's my .03 cents worth... Look at it from this angle. The light dimmer > is your house uses PWM to control the intensity of the light. The reason > the "brightness" of the light changes is because the "average power" > dissipated changes, ie. 1/2 bright, 50/50 duty cycle, full bright, 100% > duty cycle. > > In an electric motor, the start currents etc. are very high, so PWM is > used to overcome most of these losses. Again, the reason the motor runs > at 1/2 speed at 50/50 duty cycle is because the average power dissipated > is 1/2 of full power. > > Hope this helps....Tim. > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 2 Feb 1999 16:20:59 -0700 Subject: Re: Smooth strategy) >In a message dated 2/1/99 7:59:36 PM Pacific Standard Time, >cosmic.ray@xxx.com writes: > ><< On Mon, 1 Feb 1999 19:57:53 -0500 "Gwyn Reedy" writes: > >Take a WWII tank or a 40's Chrysler product with 'fluid drive' and you > have > >a fluid coupling with a standard transmission. > > > >Gwyn Reedy > >Brandon, Florida > >mailto:mgr@xxx.com > > Mercedes also uses it in their Unimog 4X4 and 6X6 trucks. > >> >Yes, but why not go for a more violent type, and build a Clutchflite, or does >anyone recall the old clutch conversions for Torqueflites? Kind of a poor mans >Lenco. manual valve body and no missed shifts. They made versions of it in >TH400 too. >Fred Yep. Good stuff!! Greg ------------------------------ From: Tom Sharpe Date: Tue, 02 Feb 1999 17:26:07 -0600 Subject: Re: Love This Gary Derian wrote: > Cooling fans are PWM controlled to minimize noise when full cooling is not > needed. > > Gary Derian > Has anyone reverse eng. the circuits? Any parts available? Tom ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 2 Feb 1999 16:40:05 -0700 Subject: Re: TC's and manual trans (was: Re: Smooth strategy) >> >> > Don't recall whatinell they called it, but for a while Porsche used a >> > fluid >> > coupling AND a vacuum operated clutch (which was triggered by a >> > microswitch >> > on the manual shift lever) in front of a manual tranny in the 911's. The >> > fluid coupling ran in engine oil, IIRC. (A fluid coupling does not >> > multiply >> > torque, has only two elements, called pump and turbine.) > > >TipTronic > >Clive BINGO!!! Greg ------------------------------ From: Roger Heflin Date: Tue, 2 Feb 1999 17:49:44 -0600 (CST) Subject: Re: Love This On Tue, 2 Feb 1999, Shannen Durphey wrote: > Gary Derian wrote: > > > > Cooling fans are PWM controlled to minimize noise when full cooling is not > > needed. > > > Electrical or acoustic? > Shannen > I would say acoustical. On high speed setting the fans on my car are pretty loud. They are pretty quiet on the lower speed. Roger ------------------------------ From: Don.F.Broadus@xxx.com Date: Tue, 2 Feb 1999 17:54:46 -0600 Subject: RE: Love This Actually an AC light dimmer delays the firing of a triac so that only a portion of the sine wave goes to the lamp. For Dim the triac is on for 30 degrees of the 180 degrees positive peak and 30 degrees for the negative peak. PWM deals exclusively with square waves and DC applications. AC Motor control usually are variable frequency drive types. No harm intended. > -----Original Message----- > From: Van Setten, Tim (AZ75) [SMTP:Tim.Van.Setten@xxx.com] > Sent: Tuesday, February 02, 1999 5:11 PM > To: diy_efi@xxx.edu > Subject: RE: Love This > > > Subject: Re: Love This > > > > > Could you, or someone, please explain PWM (assuming that PWM=Pulse > > Width > > Modulation) of cooling fans? > > > > Subject: RE: Love This > > > > > Could you, or someone, please explain PWM (assuming that PWM=Pulse > > Width > > Modulation) of cooling fans? > > > > Here's my .03 cents worth... Look at it from this angle. The light > dimmer > > is your house uses PWM to control the intensity of the light. The > reason > > the "brightness" of the light changes is because the "average power" > > dissipated changes, ie. 1/2 bright, 50/50 duty cycle, full bright, 100% > > duty cycle. > > > > In an electric motor, the start currents etc. are very high, so PWM is > > used to overcome most of these losses. Again, the reason the motor runs > > at 1/2 speed at 50/50 duty cycle is because the average power dissipated > > is 1/2 of full power. > > > > Hope this helps....Tim. > > ------------------------------ From: Tom Sharpe Date: Tue, 02 Feb 1999 19:15:20 -0600 Subject: Re: UEGO IDEA Ludis Langens wrote: > Of course these smart BLM changes would require a code change > in an ECM's program. With appropriate software, the VE table could be > tuned fairly well on a dyno with just a quick sweep through the RPM > ranges at 10 or 20 different throttle positions. That assumes you have a dyno..... Would probably also work on a chassi dyno.... Tom ------------------------------ From: Stuart Bunning Date: Wed, 3 Feb 1999 11:13:36 +1000 (EST) Subject: Re: UEGO IDEA Is the A/F ratio table found at xC4FA (ASBX) in my memcal responsible for part of the fuel supply multiplications that would be experienced even with a totally flat VE table? As my initial thought was if VE was flat it would lean out as load or RPM increased. The map below (hopefully your font it right or it will look like @$#@# ) changes the A/F ratio based on MAP and RPM ... My guess is that the VE table tells the ECU efficiency and the A/F table below tells the mixtures it will try to generate based on the VE table ????? Everyone talks about VE tables and ignition tables.. So what are the other A/F ratio table actuall used for. By looking at them it's pretty obvious 14.7 would = 14.7:1 air/fule ratio and at the right as load starts to get high we want power so the mixtures get righer?? But How mathimatically soes this contribute to adding additional fuel compared to the VE tables. SORRY IF THIS HAS BEEN COVERED !!! I guess I could/will burn a prom with a flat VE and flat A/F ratio table and hook it to my bench ecu and see what the CRO says as I change the MAP voltage or RPM slowly.. xC4FA DC.B 16,0,9 DC.B 140,147,147,147,130,130,130,130,130 DC.B 140,147,147,147,147,147,147,130,130 DC.B 140,147,147,147,147,147,147,130,130 DC.B 145,147,147,147,147,147,135,134,134 DC.B 145,147,147,147,147,147,130,130,130 DC.B 145,147,147,147,147,147,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 145,147,147,147,147,135,130,130,130 DC.B 140,147,147,147,147,135,130,130,130 DC.B 140,147,147,147,147,135,130,130,130 DC.B 140,147,147,147,147,135,130,130,130 > >You won't go as lean as you think. The MAP sensor is used to index into >the VE map. But it normally is also multiplied into the fuel >calculation. If you had a totally flat VE map, an increase in MAP would > Best Regards, STUART BUNNING SALES ENGINEER KENELEC PTY LTD 23-25 REDLAND DRIVE MITCHAM VICTORIA 3132 AUSTRALIA PHONE: 61 3 9873 1022 FAX: 61 3 9873 0200 EMAIL: stuart@xxx.au WEB: http://www.kenelec.com.au/ ------------------------------ From: "Bill the arcstarter" Date: Tue, 02 Feb 1999 17:16:31 PST Subject: RE: Love This Clarence L.Snyder wrote: >> Close... :) SCR's are used for AC applications. An SCR relys on >> the 0V crossing to turn off. And a TRIAC is two SCR's in parallel (sort >> of). :) >> >> Ernst. >Also used (with commutation circuit) on DC controllers like the GE >EV1 motor controller used on forklifts and some electric cars. REAL >tricky getting the suckers to turn off though! Yup. Anyone interested in this particular unnatural act (turning scrs off scrs) can see some scr commutation schemes on my page at: http://www.geocities.com/CapeCanaveral/Hangar/6160/hvtank/hvtank.html (Not for the electrically faint of heart) - -Bill '84 Dodge Ram w/ Rochester 2-G carb from a '72 Chevelle ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ------------------------------ From: "Bruce Plecan" Date: Tue, 2 Feb 1999 22:06:32 -0500 Subject: Re: Intake Runner Length - -----Original Message----- From: Van Setten, Tim (AZ75) To: diy_efi@xxx.edu> Date: Tuesday, February 02, 1999 4:47 PM Subject: RE: Intake Runner Length I worked at an R+D shop, and for a while Ollie Morris (one of the great of manifold designers), and find Smokey Yunick's quote of "square ain't as bad as it seems" (or words to that effect) meaningful. While many ports look like beautiful sculptures, sometimes it's just better to take you licks, and be done with it. Specially with a dry manifold. Considering at 6,000 rpm from butterfly to intake valve the "air" is only in the intake for like .008 (and possibly much lesss) of a sec. it ain't there long enough to estabish boundry layers/laminar flow enough to matter (for other than all out race applications). Worry about the bowl, and valve, the most. Specialy if were still talking about a turbo VW. Then we can get to keeping the total valve diameters not to exceed 85% of the bore, or shrouding gets to be an issue (non-hemi heads).. Sir Harry Ricardo, just realised I hadn't mentioned him in two weeks. Cheers Bruce Well, if the smoke alarm batteries fail, the Fire Dept is a distant second for a Food Timer. Gotta teach Doc to use the microwave. Least we got new windows in the Kitchen outta the deal. > I can understand air speed >in the runner, etc., but where it goes out the window for me is when you see >the runner, where it attaches to the plenum, is a square corner! A lot of >plenum / runner combinations are shaped like a "T". Believe me, I'm not >trying to make an issue out of this, just trying to understand and make the >best setup feasible. > Thanks.....Tim. ------------------------------ From: "Bruce Plecan" Date: Tue, 2 Feb 1999 22:29:43 -0500 Subject: Re: PWM motor controller - -----Original Message----- From: rauscher@xxx.com> To: DIY_EFI@xxx.edu> Date: Tuesday, February 02, 1999 4:04 PM Subject: PWM motor controller Thanks Bruce > >Ok, have it done up. Find in the incoming directory >a couple of files: > Pwm.txt Write up on circuit > pwm1.gif Image of schematic >Have fun, and let us know how your experiments work out! >BobR. ------------------------------ From: Raymond C Drouillard Date: Mon, 1 Feb 1999 21:38:26 -0500 Subject: Re: More UEGO stuff On Tue, 2 Feb 1999 16:37:48 +1100 "Ross Myers" writes: > > >>Hi all, >> I checked out the motec site (autronics also sell one) but these >>are too expensive for me .That is why I was hoping one could be built (even >>as a kit) at a fraction of the cost.Motecs unit is just right with the >>screen and sensor. >>Some of us race people are on tight budgets! >>PAUL > > >I know what you are saying Paul, but my point was if they felt the need for >a 32bit micro to run the thing something must be tricky. > >Regards > >Ross Myers Either that, or they want you to believe that it's tricky and pay the $$$$. Even if there is a pressure and thermal sensor, it wouldn't take much processing power to calculate a true lambda reading from all of that. Even if they are doing data logging... Ray ___________________________________________________________________ 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] ------------------------------ From: "Tony Bryant" Date: Wed, 3 Feb 1999 16:58:57 +1200 Subject: Re: Intake Runner Length Bruce says: > > I worked at an R+D shop, and for a while Ollie Morris (one of the great of > manifold designers), and find Smokey Yunick's quote of "square ain't as bad > as > it seems" (or words to that effect) meaningful. While many ports look like > beautiful > sculptures, sometimes it's just better to take you licks, and be done with > it. > Specially with a dry manifold. Considering at 6,000 rpm from butterfly to > intake valve the "air" is only in the intake for like .008 (and possibly > much lesss) of a sec. it ain't there long enough to estabish boundry > layers/laminar flow enough to matter (for other than all out race > applications). Worry about the bowl, and valve, > the most. Specialy if were still talking about a turbo VW. Then we can > get to keeping the total valve diameters not to exceed 85% of the bore, or > shrouding > gets to be an issue (non-hemi heads).. Sir Harry Ricardo, just realised I > hadn't mentioned him in two weeks. > Cheers Speaking of shrouding issues, I've just finished porting a head for my EFI Datsun L20B (2 valve non crossflow head). I made a cylinder sized pedestal extension for my flow bench, to attempt to simulate the shrouding effect of the cylinder walls (I have a 92% combined valve dia/bore ratio). To my amazement the flow went up as compared to the vastly unrealistic unshrouded situation I had before that. A quick investigation with the 'flow direction and velocity indicator' (a piece of sewing cotton tied to some welding wire), revealed that the flow patterns had changed from being concentrated on the ceiling, to being concentrated on the outside wall of the port, with the flow curling around the valve stem . I found the optimum port shape changed significantly. A completely different approach needed to be taken, than in my previous setup. I had always heard and read about how ports set low in the head don't flow worth a damn, but now I'm not so sure; my small low rectangular exhaust ports almost outflow my high, round smooth intakes! I also have a theory that low intake ports add significant swirl to the incoming mixture, for very little cost in flow. My 2c ------------------------------ From: "Ord Millar" Date: Tue, 2 Feb 1999 23:01:13 -0500 Subject: Re: Intake Runner Length Bruce, can you explain the 85% diameter thing? It's not fitting into my brain too well... Ord - -----Original Message----- From: Bruce Plecan To: diy_efi@xxx.edu> Date: Tuesday, February 02, 1999 10:52 PM Subject: Re: Intake Runner Length > >-----Original Message----- >From: Van Setten, Tim (AZ75) >To: diy_efi@xxx.edu> >Date: Tuesday, February 02, 1999 4:47 PM >Subject: RE: Intake Runner Length > >I worked at an R+D shop, and for a while Ollie Morris (one of the great of >manifold designers), and find Smokey Yunick's quote of "square ain't as bad >as >it seems" (or words to that effect) meaningful. While many ports look like >beautiful >sculptures, sometimes it's just better to take you licks, and be done with >it. >Specially with a dry manifold. Considering at 6,000 rpm from butterfly to >intake valve the "air" is only in the intake for like .008 (and possibly >much lesss) of a sec. it ain't there long enough to estabish boundry >layers/laminar flow enough to matter (for other than all out race >applications). Worry about the bowl, and valve, >the most. Specialy if were still talking about a turbo VW. Then we can >get to keeping the total valve diameters not to exceed 85% of the bore, or >shrouding >gets to be an issue (non-hemi heads).. Sir Harry Ricardo, just realised I >hadn't mentioned him in two weeks. >Cheers >Bruce Well, if the smoke alarm batteries fail, the Fire Dept is a >distant > second for a Food Timer. Gotta teach Doc to use the >microwave. > Least we got new windows in the Kitchen outta the deal. > > >> I can understand air speed >>in the runner, etc., but where it goes out the window for me is when you >see >>the runner, where it attaches to the plenum, is a square corner! A lot of >>plenum / runner combinations are shaped like a "T". Believe me, I'm not >>trying to make an issue out of this, just trying to understand and make the >>best setup feasible. >> Thanks.....Tim. > > > ------------------------------ From: "David A. Cooley" Date: Tue, 02 Feb 1999 23:10:37 -0500 Subject: Re: OBD II LT1 Engine Swap Gotchas??? At 02:37 PM 2/2/99 -0800, you wrote: >I've been quiet on this list for a while. I swapped a 93 LT1 into my early >Corvette, and thanks to this list and others, have enjoyed that swap and am >about to do a similar swap into a 69 Camaro with a 97 Z28 motor that I couldn't >pass up. > >I know some of the high horsepower guys I know have swapped from OBD II to OBD >I PCMs due to difficulties of squeezing 600 HP out of an OBD II controlled >motor. For a stock, smog exempt OBD II swap, are there any pitfalls that I >should look out for? Anyone else on the list already done such a swap? You may want to go Pre-OBD_I as well... All of the OBD_I PCM's from GM I have seen on V8's have a pre and post cat O2 sensor... Pre OBD_I didn't. =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 I am Pentium of Borg...division is futile...you will be approximated. =========================================================== ------------------------------ From: "David A. Cooley" Date: Tue, 02 Feb 1999 23:15:42 -0500 Subject: Re: OBD II LT1 Engine Swap Gotchas??? At 04:49 PM 2/2/99 -0600, you wrote: >If you are swapping in the standard stock unmodified engine you will >only need to fake out the sensors that you aren't using, such as the >additional O2 sensors behind the cats. Also I believe there are some >things that detect a loose gas cap, this will need to be faked out >also, and probably several other sensors of the same sort. That is I >believe why they generally put a 95 pcm in, they don't have to worry >about it. The 96 + pcm does have some nice features, it will count >misfires, but this is supposed to get rather confused if you put a cam >that is too big in the car, and count alot of misfires and set SES >lights and such. I was on the Impala SS list for a while... The 94/5 pre-OBD_II pcm's still have the dual O2 sensors for each bank, pre and post cat. According to several list members, the 94/5 Vette and camaro/firebird also had the pre-post cat O2 sensors. =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 I am Pentium of Borg...division is futile...you will be approximated. =========================================================== ------------------------------ From: Tom Sharpe Date: Tue, 02 Feb 1999 22:21:34 -0600 Subject: Re: PWM motor controller > Pwm.txt Write up on circuit > pwm1.gif Image of schematic > > Have fun, and let us know how your experiments work out! > > BobR. > > Any questions, just post... I got out my rusty Tech America catalog and foundall the resistors and capacitors. I'm not a EE so I need lots of help. 1. What is a 18-24v 1Watt Zenier (I think I know but I need a PN). 2. IRFZ44 (pg73) T220 or IRFP044 (pg74) 4 pin package and 180W - 57 amps. 3. IN4753A or IN4755A (pg62) 36v 7ma - 43v 6ma 4. 470 uf 25V -- only electrolytic ??? 5. For the .1 uf and 3.3 uf cap, use electrolytic? can't find disk cap. What voltage?? 16? How do you convert pf to uf?? 6. I want to run it from a stamp computer (or possibly a HC11 SBC) driven from a Fuel pressure sensor and the tach lead. What do I need to change?? I think the input is 0-1 volt or 0-5 volts. Help 25 psi <= 2K rpm, 75 psi >= 6K rpm, rising rate from 2K to 6K rpm I could drive it directly from the 0-5V fuel pressure sensor. ------- the lights just went on again... Thanks in advance - I will test it with a pot - what wattage??? will a small one work? Tom Sharpe ------------------------------ From: "Bruce Plecan" Date: Tue, 2 Feb 1999 23:36:13 -0500 Subject: Re: Intake Runner Length - -----Original Message----- From: Ord Millar To: diy_efi@xxx.edu> Date: Tuesday, February 02, 1999 11:20 PM Subject: Re: Intake Runner Length Cylinder Bore x .85= some dimension. The sum of both valves head diameters should about equal that. 4" borex .85= 3.4 1.9" intake, and a 1.5" exhaust would work very well. None hemi type head. Not an absolute, but a good guide. Yates, and them NASCAR guys are now getting around that. But, they spend a ton of money to do it. Angle cutting the heads to get the stems more parrael to the cyl bore works to. Bruce >Bruce, > >can you explain the 85% diameter thing? It's not fitting into my brain too >well... > >Ord > >-----Original Message----- >From: Bruce Plecan >To: diy_efi@xxx.edu> >Date: Tuesday, February 02, 1999 10:52 PM >Subject: Re: Intake Runner Length > > >> >>-----Original Message----- >>From: Van Setten, Tim (AZ75) >>To: diy_efi@xxx.edu> >>Date: Tuesday, February 02, 1999 4:47 PM >>Subject: RE: Intake Runner Length >> >>I worked at an R+D shop, and for a while Ollie Morris (one of the great of >>manifold designers), and find Smokey Yunick's quote of "square ain't as bad >>as >>it seems" (or words to that effect) meaningful. While many ports look like >>beautiful >>sculptures, sometimes it's just better to take you licks, and be done with >>it. >>Specially with a dry manifold. Considering at 6,000 rpm from butterfly to >>intake valve the "air" is only in the intake for like .008 (and possibly >>much lesss) of a sec. it ain't there long enough to estabish boundry >>layers/laminar flow enough to matter (for other than all out race >>applications). Worry about the bowl, and valve, >>the most. Specialy if were still talking about a turbo VW. Then we can >>get to keeping the total valve diameters not to exceed 85% of the bore, or >>shrouding >>gets to be an issue (non-hemi heads).. Sir Harry Ricardo, just realised I >>hadn't mentioned him in two weeks. >>Cheers >>Bruce Well, if the smoke alarm batteries fail, the Fire Dept is a >>distant >> second for a Food Timer. Gotta teach Doc to use the >>microwave. >> Least we got new windows in the Kitchen outta the deal. >> >> >>> I can understand air speed >>>in the runner, etc., but where it goes out the window for me is when you >>see >>>the runner, where it attaches to the plenum, is a square corner! A lot of >>>plenum / runner combinations are shaped like a "T". Believe me, I'm not >>>trying to make an issue out of this, just trying to understand and make >the >>>best setup feasible. >>> Thanks.....Tim. >> >> >> > ------------------------------ From: "Clarence L.Snyder" Date: Tue, 02 Feb 1999 23:40:24 -0500 Subject: Re: TC's and manual trans (was: Re: Smooth strategy) Gary Derian wrote: > > I am defining a torque converter as a device that multiplies torque. If > there are only 2 elements, where does the torque multiplication come from? > If one element is attached to the engine and the second element is attached > to the transmission, there is no way the second element can have more torque > than the first. This two element thing you are describing may be a very > nice device and it may have been called a torque converter but it cannot > multiply torque. For that, you need a reaction member. > > I never took auto mechanics in high school. > > Gary Derian > > >Gary Derian wrote: > >> > >> A torque converter must have at least three elements. The extra torque > >> comes from the reaction at the stator. Its the hydraulic equivalent to a > >> lever and fulcrum where the extra force comes from the fulcrum. A torque > >> converter is not more efficient than a fluid coupling but it does > multiply > >> torque when it is slipping adding an extra gear for starts. At low > slippage > >> (cruise conditions) the stator freewheels and a torque converter reverts > to > >> a fluid coupling. A 4 or 5 element converter would be the equivalent of > a > >> compound lever. > > > >Reference Wm Crouse - Automotive mechanics- fifth edition - Webster/Mc > >Graw Hill. > >Torque converters with only 2 elements DID exist. The definitive > >difference between a fluid coupling and a TC is the shape of the vanes. > >Note, a 3 element fluid coupling also existed. > > > >You took auto mechanics in high school - I taught it :} Compared to a straight vane fluid coupling, it did a wonderful job - -redirected SOME of the oil back onto the turbine instead of colliding with the pump. I always considered only the 3 element or more as torque converters too, but the fact remains, two element "torque converters" did exist - however few. ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 2 Feb 1999 22:52:16 -0700 Subject: Re: TC's and manual trans (was: Re: Smooth strategy) >Gary Derian wrote: >> >> I am defining a torque converter as a device that multiplies torque. If >> there are only 2 elements, where does the torque multiplication come from? >> If one element is attached to the engine and the second element is attached >> to the transmission, there is no way the second element can have more torque >> than the first. This two element thing you are describing may be a very >> nice device and it may have been called a torque converter but it cannot >> multiply torque. For that, you need a reaction member. >> >> I never took auto mechanics in high school. >> >> Gary Derian >> >> >Gary Derian wrote: >> >> >> >> A torque converter must have at least three elements. The extra torque >> >> comes from the reaction at the stator. Its the hydraulic equivalent to a >> >> lever and fulcrum where the extra force comes from the fulcrum. A torque >> >> converter is not more efficient than a fluid coupling but it does >> multiply >> >> torque when it is slipping adding an extra gear for starts. At low >> slippage >> >> (cruise conditions) the stator freewheels and a torque converter reverts >> to >> >> a fluid coupling. A 4 or 5 element converter would be the equivalent of >> a >> >> compound lever. >> > >> >Reference Wm Crouse - Automotive mechanics- fifth edition - Webster/Mc >> >Graw Hill. >> >Torque converters with only 2 elements DID exist. The definitive >> >difference between a fluid coupling and a TC is the shape of the vanes. >> >Note, a 3 element fluid coupling also existed. >> > >> >You took auto mechanics in high school - I taught it :} > Compared to a straight vane fluid coupling, it did a wonderful job >-redirected SOME of the oil back onto the turbine instead of colliding >with the pump. I always considered only the 3 element or more as torque >converters too, but the fact remains, two element "torque converters" >did exist - however few. No way--a two element torque converter is a violation of Newton's laws!! Regards, Greg ------------------------------ End of DIY_EFI Digest V4 #85 **************************** 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".