DIY_EFI Digest Friday, March 10 2000 Volume 05 : Number 097 In this issue: Turbo throttles and Speed sensors RE: Electronic Transmission Control Re: Turbo speed sensor going to use optics instead ? Re: Turbo speed sensor going to use optics instead ? Re: Turbo speed sensor going to use optics instead ? Re: 700R4 merits (was Re: Electronic Transmission Control) Compact Flash - how to drive it? Re: 4 Bar MAP sensor for DFI Re: 4 Bar MAP sensor for DFI See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Thu, 09 Mar 2000 23:29:21 -0500 From: Frederic Breitwieser Subject: Turbo throttles and Speed sensors Howdy, I have responded to several items in the digest, in this one message, since the topics seem to cross one another. Hope no one minds. SIMULATED CRANK TRIGGER: > If you're in a hurry, check out National Semiconductor's site at > http://www.national.com/pf/LM/LM555.html This is good. The 555 timer not only can be configured to adjust frequency, but pulse width. It puts out a fairly nice square wave too, which can be changed using smallish capacitors. The link Charles posted is an excellent starting point. TURBO SPEED: There are many ways of doing this, and optical is probably the least intrusive IMHO. We tried several ideas, one being a small slotted disk attached to the turbo shaft, which worked well. Of course, this is fragile hanging off a hot turbo, vibrating inside the engine compartment when you slap the throttle shut :) We even got real clever (har har) and used reflective paint, painting the intake side of the turbo wheel with little dots, then using an IR emitter/detector pair we were able to count dots, i.e. speed. Worked fine until the device loosened up and was sucked into the turbo. Also, this arrangement has the IR pair sitting in your airstream. Another option is if your turbo's shaft hangs out of the housing slightly. Some do, some don't. Our T03's do. We cross drilled a small hole side to side on the shaft, and put the same IR pair (pre ingestion into turbo) on either side of the shaft ends, using little aluminum brackets painted black we were able to shield stray IR light, and everytime the hole through the shaft lines up, the detector emits a trigger into a device which conditions it and then it can be counted. Two light beams per rotation (hole on both sides of shaft, all the way through). PRE/POST TURBO THROTTLES: I probably should have said pre/post plenum. :) Pre plenum you can get away with one or two throttle bodies, which is much easier to obtain/fabricate/tape together, where as post plenum throttles you need one per cylinder, aka weber. Bitch to set up. The disadvantage of the pre-plenum throttle, is if your plenum is sized appropriately (cid of engine or larger), you have this giant air cavity containing air to be sucked into the engine, forming a vaccuum. Thus, when you close the throttle after high boost runs, you have plenty of air to go into the engine for a period of time. Small amounts of time, but its noticable when dropping off a 8000 RPM "yank" to idle. The reverse is also true - the larger the plenum, the longer it takes to build pressure, as the plenum acts as a resevior, much like the vaccuum booster "stores" vaccuum for your brake system. So, turbo lag is slightly more pronounced. Also, having a 80,000 RPM turbo suddenly have its output plugged might be rude to the turbo bearings. Worn ones have made a slight "clunk" kinda sound when this occurs. At least in our testing, so since we are not scientists, anything could be wrong. With individual throttles per cylinder, post plenum, I see advantages. If you back off the throttle abruptly, the air in throttle body underneath the throttle plate is all the air your engine gets, so its decelerates much faster. Also, if the plenum has any pressure left in it when you open the plates (i.e the turbos are still pressurizing the plenum), you have a higher level of boost right off the line. This assumes the throttles in both examples do not leak at all. Obviously, they do, or the car wouldn't idle at all - no air. Using the plenum as a cushion to the turbo also seems logical. Which is better? Jeeez, Not sure. Just sharing some testing we have done on a Buick V6. The individual throttle bodies were an absolute BITCH to make, even with fancy CNC machining equipment. RUNNER LENGTH: As with the TPI engines, the longer the runners, the more torque you generally get in the low-end. This is why camaros/vettes have about 17" of runner length (curved, but long), because off the line, you want the torque. Shorter runners with a larger plenum also achieve this same goal, however there is a lot of math involved. We determined our runner length by doing 5 dyno pulls, then changing the runner length, and repeating. The longer-runner-more-torque-down-low theory does in fact apply to shorter runners with a larger plenum (throttles pre plenum). However, the longer runners do more than provide an "air battery" on the low end, it also directs the airflow. If you were to inhale some cigar smoke, and blow into the air, you get a cloud (or a ring if you truly have a talent). If you were to blow the same smoke through a paper towel cardboard tube, the smoke coming out is more directed. Longer runners do this for your engine. At higher RPMs however, its not as necessary because there is enough flow/pressure that the air tends to go somewhat more straight than at lower RPMs. More kinetic energy in the air molecules, and they continue to flow in one directions. Turbos enhance this even more. The ideal runner length (without displaying all the engine specs) on our twin turbo V6 (252 + .030 overbore engine) turned out to be 12.7 inches for each runner, and a plenum equal in size to the cid of the engine (ours was 260cid, close enough). The last comment I will make about turbos before I turn in for the evening (just got home from a 15 hour work day) is it was our experience that the most significant gain (for the dollars) is with the intercooling. Longer/shorter runners, port work, runner shape, valve size, etc, all are factors in increasing your volumetric efficiency, however the most % gains were with intercoolers. The more you can cool the air post turbo, the more air you can fit into the cylinder. We had significantly higher power gains by using a water-based intercooler attached to a garden hose (which attaches to a well, so the water is prolly 40-45 degrees tops) over an air to air intercooler, which has ambient air flowing through it at best. Of course, the latter is much easier to install, less to break, and easier to fix when it does. two hoses and an intercooler and a few clamps. Easy. Another comment... while I don't have facts in front of me to support this... we found through experimentation that smaller displacements with higher boost to produce more power, generally, keeping everything else equal (stroke, etc). I'm unsure if this is because there is less surface area in the chamber for detonation so the timing doesn't retard so much, or the piston top is much narrower in diameter its stronger since there is less pressure being exerted on surface of the piston (because the skirts of the piston are closer together they can absorb more load?). I dunno, one of those funky things I guess. Though I have violated most of my suggestions by building a twin-turbo large displacement mopar stroker motor with a reasonable amount of boost (10lbs max). Idles nice and revs nice to 4000 rpm. Stump puller. As far as cams go... my advice is this - get as much air into the engine as possible. You can do this two ways... low lift with long open time, or high lift and short open time. Both will do approximately the same thing, and a slew of math can tell you which is right for you based on where your normal rev band will be. OVERLAP is not your friend. Anytime we added overlap, more and more air/fuel blew by the exhaust valve. With turbo, it flew out faster. The more overlap you have the less boost pressure you will realize in your engine because more of it flows out the tailpipe. Roller cams would be a good choice because you can have high lift and long open times and have the lifters follow the cam lobes. Just some random thoughts, feel free to thump upon. - -- Frederic Breitwieser Xephic Technology 769 Sylvan Ave #9 Bridgeport CT 06606 Tele: (203) 372-2707 Fax: (603) 372-1147 Web: http://xephic.dynip.com/ - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: 9 Mar 2000 21:14:09 -0800 From: "Eric Aos" Subject: RE: Electronic Transmission Control > I'd like to see some hard data to go with this, as there's none in my > GM info. I wonder if there are different scales. Will the 4T60E to > withstand as much torque as the 4L60E? > Shannen OHHHH ME ME... I got that answer... http://www.gmpowertrain.com/transmissions.htm 4L60E - 350 lb-ft 4T60E - 280 lb-ft 4T65E - 280 lb-ft 4T80E - 300 lb-ft 4L80E - 440 lb-ft Eric (Happy to finally have an answer, instead of a question) - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 2000 00:05:52 -0600 From: "Robert W. Hughes" Subject: Re: Turbo speed sensor going to use optics instead ? You might want to check your laser pointer first. Most of these are are pulsed, apparently to extend battery life. Point it at a wall and shake it back and forth. If it draws dotted lines, it is pulsed. Another possibility is the laser from a busted CD player. They are mounted on a small driver board and operate at near infrared, about 680nm. Check polarites on power to driver board before removing it from player, a lot of these things use a negative supply voltage. This is not a problem for something like this, as long as you connect to power with the proper polarity - negative input to ground, positive input to voltage in other words. - -- Robert W. Hughes (Bob) BackYard Engineering 29:40.237N, 95:28.726W Houston, Texas rwhughe@xxx.net - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 2000 14:44:58 From: "Mike (Perth, Western Australia)" Subject: Re: Turbo speed sensor going to use optics instead ? At 12:05 AM 10/3/2000 -0600, "Robert W. Hughes" wrote: >You might want to check your laser pointer first. Most of these are are >pulsed, apparently to extend battery life. Point it at a wall and shake >it back and forth. If it draws dotted lines, it is pulsed. Yeah good point, mine is a $15 cheapy 3 cells, no cct - just resistor to laser led, I'm getting a fast slew rate opto transistor sensor in next few days - so will rig it up with a CRO to check, tah >Another possibility is the laser from a busted CD player. They are >mounted on a small driver board and operate at near infrared, about >680nm. Check polarites on power to driver board before removing it from >player, a lot of these things use a negative supply voltage. This is not >a problem for something like this, as long as you connect to power with >the proper polarity - negative input to ground, positive input to >voltage in other words. I suppose I'm considering that if the laser pointer works it might be a good kit project - depends on what sort of output it has though that would make it usable for most systems, Tah :) Mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 100 15:08:57 +0800 (WST) From: Bernd Felsche Subject: Re: Turbo speed sensor going to use optics instead ? Mike writes: >At 12:05 AM 10/3/2000 -0600, "Robert W. Hughes" wrote: >>You might want to check your laser pointer first. Most of these are are >>pulsed, apparently to extend battery life. Point it at a wall and shake >>it back and forth. If it draws dotted lines, it is pulsed. >Yeah good point, mine is a $15 cheapy 3 cells, no cct - just resistor to >laser led, I'm getting a fast slew rate opto transistor sensor in next few >days - so will rig it up with a CRO to check, tah Keep in mind that most "consumer" electronics bits are only rated to just 55C. The laser diodes can get hot by themselves I hear - though I've never noticed it on the few occasions where I've used a laser pointer. A large proportion of consumer stuff dies if you leave it in the car, in the sun. Not just plastic warping, etc, but semiconductors "blowing" if you try to use them before they've cooled. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 08 Mar 2000 22:05:15 -0600 From: MysticZ Subject: Re: 700R4 merits (was Re: Electronic Transmission Control) clayb wrote: > > You're supposed to have so much darn horsepower, that first gear is correct, but > the overdrive takes you from 70 mph up to 160 mph. I love it when that happens :) I laugh real evil like every time I drive my Z, which isn't very often. Slam the gas to the floor at any speed below about 30 and white smoke pours out of the tires :) > Only downside is you've gotta drop into third if traffic on the freeway drops > below 60 mph. > Good horsepower makes three gears between 0 and 60 mph more than sufficient. Unless I really want to move RIGHT NOW it doesn't downshift above 55 or so. There's enough power there to pull in 4th faster than most grocery getters can in 2nd. The notable exceptions are some of the more exotic BMWs, Lexuses (Lexi? ;), Impala SSs, and the likes. - -- Steve 97 Chevy Camaro Z28, Mystic teal, A4, not stock 90 Kawasaki EX500A4, black, M6, not even CLOSE to stock! lt1_z28@xxx.net/~lt1_z28 Aluminum, steel, carbon fiber, titanium, and two cast iron balls. McMillan Motorsports- http://www.mmsbikes.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 100 16:36:51 +0800 (WST) From: Bernd Felsche Subject: Compact Flash - how to drive it? Time for another dumb question ... How hard is it to drive a compact-flash? I'm considering it as an option for data-logging using the SPI from an Atmel 8535... Any definitive URL's with spec's and supplies for connectors, etc. would be welcome. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 2000 11:11:33 +0200 From: "John Andrianakis" Subject: Re: 4 Bar MAP sensor for DFI I have seen 4 bar map sensors with 0-5v output in a Bosch racing products catalog. Unfortunately I dont have the catalog so you will have to locate a Bosch dealer. - ----- Original Message ----- From: Flanagan, Stephen CECOM RDEC STCD To: Sent: 10 Μαρτίου 2000 00:59 Subject: 4 Bar MAP sensor for DFI > Does anyone have info on a 4 Bar MAP sensor that can be used to replace > a 3 Bar sensor on a ACCEL DFI system. I am running an excess of 35 lbs of > boost and the DFI is only mapped up to 3 Bar or roughly 30 lbs of boost. > I would like to substitute the 4 bar sensor for the 3 bar sensor, and lie > to the map. My one concern is if the output of the 3 Bar sensor is relative > to > the output of the 4 Bar sensor. I am guessing here but for Example: on the > 3 Bar sensor, voltage output is 0 - 5 volts which equals 0 to 3 Bar. For > the > 4 Bar sensor, 0 - 5 volts should equal 0 - 4 Bar. > > I am looking for a specs on the 3 bar and 4 bar sensors and some > feedback if anyone has tried something like this in the past. > > If anyone can educate me on this it would be greatly appreciated. thanks in > > advance. > > sf - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 10 Mar 100 18:06:01 +0800 (WST) From: Bernd Felsche Subject: Re: 4 Bar MAP sensor for DFI John Andrianakis writes: >I have seen 4 bar map sensors with 0-5v output in a Bosch racing products >catalog. Unfortunately I dont have the catalog so you will have to locate a >Bosch dealer. >----- Original Message ----- >From: Flanagan, Stephen CECOM RDEC STCD >> Does anyone have info on a 4 Bar MAP sensor that can be used to >> replace a 3 Bar sensor on a ACCEL DFI system. I am running an >> excess of 35 lbs of boost and the DFI is only mapped up to 3 Bar >> or roughly 30 lbs of boost. I would like to substitute the 4 bar >> sensor for the 3 bar sensor, and lie to the map. My one concern >> is if the output of the 3 Bar sensor is relative to the output of >> the 4 Bar sensor. I am guessing here but for Example: on the 3 >> Bar sensor, voltage output is 0 - 5 volts which equals 0 to 3 >> Bar. For the 4 Bar sensor, 0 - 5 volts should equal 0 - 4 Bar. >> I am looking for a specs on the 3 bar and 4 bar sensors and some >> feedback if anyone has tried something like this in the past. Try http://www.mot-sps.com/senseon/pressure_SG.html Integrated sensor, compensated with ranges up to 700kPa or 1000kPa. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #97 **************************** 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".