DIY_EFI Digest Thursday, September 2 1999 Volume 04 : Number 501 In this issue: Re: Lotus engines and bike TB's Repaired file (was Re: stepped-on..) Re: Stepper/servo motor control.... Ford ECU connector? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 1 Sep 1999 15:11:20 -0700 (PDT) From: "Jon V." Subject: Re: Lotus engines and bike TB's Nic wrote: > >Actually, I liked a lot of the ideas presented. I think the motorcycle TB > >assy is probably too small in the throat, but that was the idea I liked > >best. > > Think about it this way: If you strip a throttle body of a 1300 Suzuki bike > that redlines at 12000rpm and mount it on a 2.5l engine that only does > 6000rpm you are looking at the same flow rate. Yeah, I was thinking about it two ways... assuming that my Internet calculator skills are sufficient to the task, a 2L engine that redlines at 6.8-7.2K (about where mine does/would) needs ~23036 CFM to feed it. The 1300, 12KRPM motocycle engine would need ~26327 CFM (These numbers are pulled from the net, and I didn't check the assumptions that went into them... just CID, RPM, and (a high) 95%VE), which sounds like it is a perfect fit and everything is WONDERFUL and I'm just wishing I could figure out where I'm gonna find a Suzuki without an owner for long enough to... um... anyway... I'm trying to find the parts... That was way one, BUT... That was assuming identical volumetric efficiencies, and I'm not sure that is valid. The high-winding motocycle would gain more from an easy flow path at the top end... but it would also be in some ways less likely to have it, just because street riders are less likely to hit a 12K redline regularly than I am to hit a 6.5-7K redline.... well... I don't *know* that really... my ol'dad used to have a Honda with a redline way out in the stratosphere... like 17K RPM... and he says he used the whole range.... but then again it was a megaphoned 2-stroke racer when he got it (stopped three times driving it home sort of thing) and that sort of breaks most of the rules anyway. > I got a set of throttle > bodies + injectors + FI pump for $40. And they are in mint condition. See, now THAT is what I consider cheap. I've been trying to find that sort of deal... I'll need to try harder. Where/how did you get that deal??? > Quick question: Why does most bikes use individual TB assemblies for > each cylinder while most cars use a single TB? I know how much pain > it is to keep the sync on a bike right, so what is the real gain? I think it is the reason most motorcycles don't have 30Lbs flywheels... they don't need a lot of low end torque, being as light as the are, but a good top end helps a lot. The individual throttle plates are good for better air flow (top end) but don't help with torque the way merged airflow intake systems do. At least, that's what I've mungled my way into believing... ya'might wanna check the reasoning before you go quoting it at parties. The current pair of carbs on my engine would, stock, go into a long flow intake system to get a good air flow going in the mid RPM range. The previous owner torched that and I in my infinitesimal wisdom torched what he did in favor of a pair of air filters from a small ford turbo engine... the result is that I need to unbolt the air filters to check the oil, but I have no appreciable intake resistance, as documented by the fact that the old crankcase breather system which used to attach between the air filter and the carbs and pull a respectable if not all that impressive vacuum now pulls ZIP when attached to just one of the carbs. Most motorcycles seem to have one throat per cylinder one way or another. My Yamaha 1100 has four 34MM carbs feeding it. > I'm not sure which route to go with the bike. I can either make the > Suzuki TB's fit (lots of pain) or simply make a manifold with injectors > at the ports and a single TB at the intake of the surge tank. Will there > be any real difference? > How about the difference between TBI and multipoint injection? Multipoint sounds neater. Actually, TBI injection is really just a snazzy digital way of making a carb that works.... > Does the fact that it is an Turbo affect the answers? Good question! I don't know, but I would ignorantly guess that it makes all of the air flow issues for torque irrelevant. Whatever restrictions a lack of throttle plates would add could be overcome by jumping the boost, and whatever a long air pipe can do for assuring good air flow at low RPMs the turbo will do better. I don't know... but I *like* $40! I gotta find me a deal like that. - -Jon - ----------------------------------------------------------------------------- This was the most unkindest cut of all. -- William Shakespeare, "Julius Caesar" ------------------------------ Date: Wed, 01 Sep 1999 19:09:56 -0400 From: Shannen Durphey Subject: Repaired file (was Re: stepped-on..) I've repaired acsu0024 and put it on the FTP site. Let me know how it works. Shannen Brent Obermiller wrote: > > Okay, yes I'm sorry I was going from memory... I did put 96h in place of the > 00h in the last byte but the symptom is still there. Any ideas? > -Brent > > mailto:ober_b@xxx.com > > ______________________________________________________ > Get Your Private, Free Email at http://www.hotmail.com ------------------------------ Date: Wed, 01 Sep 1999 18:24:32 PDT From: "Bill the arcstarter" Subject: Re: Stepper/servo motor control.... "Michael D. Porter" wrote: >I have determined that I can do what I need with a circuit to control a >stepper or servo motor from a variable resistance. What I need is a >motor/circuit combination which will provide an absolute position for a >given resistance. For reasons of cost, the cheapest means of input for >altitude is a barometric sensor for an L-Jetronic digital fuel injection >system--essentially, the input device is a sealed bellows with a strain >gauge inside. Yes there is a very (sl)easy way to do this. Buy a steering servo for an RC car or plane. This contains the motor, feedback device, and all. You have to feed it a pulsetrain (PWM). The duty cycle determines the shaft position. I'm thinking about doing the same for a buddy's diesel wabbit injection pump. ;) This has been hacked to death in other electronics sites on the 'net. Don Lancaster's for example. Also look around the PIC lists and sites. If you need more help perhaps I can give it? - -Bill ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ------------------------------ Date: Wed, 01 Sep 1999 23:57:02 -0400 From: Jeff Smith Subject: Ford ECU connector? Hi, A friend was showing me the ECU in his Ford Contour, and it appears to have a connector on the back for something. Anyone know what? If you take off the little connector, there is a card edge there, about 30 pins or so, but I don't know what the pinout is, or what it is supposed to do. Anyone know? jds ------------------------------ End of DIY_EFI Digest V4 #501 ***************************** 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".