DIY_EFI Digest Friday, October 15 1999 Volume 04 : Number 581 In this issue: Re: DIY_EFI Digest V4 #580 Re: DIY_EFI Digest V4 #580 Re: DIY_EFI Digest V4 #580 RE: MEMS See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Thu, 14 Oct 1999 13:57:47 -0700 (PDT) From: Stuart Hastings Subject: Re: DIY_EFI Digest V4 #580 > > Speaking as a potential customer, the extra belt and air compressor > > used on the Orbital design look like additional parts to break. > > Of course. But a belt driven air compressor is not exactly rocket science... > > > The Ficht design has none of these parts. > > The Ficht has a whole lot of other parts to break. (And it seems to be doing > so with gusto...:)) Hmmm. Oddball injectors, computer to drive them, special alternator, and an oil injector in the crankcase... I guess you have better sources than I do, but I had understood that most (catastrophic) Ficht failures were related to internal engine parts, like pistons, rings, and cylinders. Stuff that was supposed to be well-debugged by now :-) . ... > True. They could have moved the precompression out of the crank case, using > a conventional "wet" crank case, and a screw compressor instead. That would > have given more efficient scavenging, and gotten rid of all oil in emissions. ... I doubt the marine engine manufacturers would fit a compressor unless required by smog regulations. It adds weight, complexity, and cost. But I personally would consider owning such an engine. > > More specifically, EPA is interested only in *air* pollution from > > marine engines. When they mandated oxygenated fuel, they indirectly > > required California fuel to incorporate MTBE, and nobody realized it > > would contaminate the *water*. > > This may be true. I read somewhere that it is doubtful that a significant > amount unburnt gasoline passes into the environment because of the high > temperature of the exhaust gases. It has been definitively shown here in California that most of the MTBE found in surface water (lakes, reservoirs) came from non-DFI two-cycle engines. Here in the Silicon Valley, the local water authority permits powerboats on three of our ten drinking water reservoirs. One of these is open to Personal Water Craft (e.g. Jetskis(tm)) at the beginning of every season, and promptly closed to them after the MTBE concentration rises above a certain threshold. PWC dealers in Northern California have mostly been driven out of business. My four-cycle boat is still permitted on all three reservoirs. When DFI manufacturers claim 25-30% improvements in fuel economy, they're talking about raw fuel that was formerly blown out the exhaust. This is a settled issue. > Since I'm not American, I won't claim to know how the EPA thinks or > works, though. The U.S. E.P.A. is a source of wonderment for us Americans, too :-) . > > Hello, EPA, most marine engines exhaust > > *underwater*, even if most of their smog immediately bubbles to the > > surface! > > That can easily be fixed with a holesaw, if you're worried. :) I'm not worried, because I insisted on four-cycle power when I bought my boat. I'm not a "greenie," but spitting oil (and/or gasoline) into the water dismays me, in spite of all genuine advantages of two-stroke engines on a boat. Most marine engines (in the U.S.) exhaust underwater because it's essentially required by the U.S. Coast Guard for basic safety. Boat-engine exhaust is typically mixed with water shortly after it leaves the engine. Most sterndrives (marinized car engines) have many rubber parts in the exhaust just downstream of the water port; if the water supply fails, the rubber parts promptly melt. If nothing in the boat is hot enough to start a fire, there should be fewer boat fires. Nobody was thinking about ecology when these rules were established. stuart hastings ------------------------------ Date: Thu, 14 Oct 1999 04:33:53 +0200 From: "Espen Hilde" Subject: Re: DIY_EFI Digest V4 #580 > > Mercury delivers a high perf 200 dfi that took 2 place at paris ruoen 24 > > hour (river) race.The ability to run lean burn conditions is great for > > reliability as I see it. > > Do they really deliver it? Given that it has a lower unit that can't > reverse, it wouldn't make much sense for anything but racing. I think they used a standard gearcase, they didnt have to change the lower unit during the race.They saved lots of time that way. I havent sen any pictures or description of the lover unit they used. And as a racer > you get more power per cubic inch from an XR2, 2.5EFI or even a 300 ProMax. > > > I have 2 2.5efi high performance engines that I am reparing, line boring > > Are they any fun? Just problems so far, but nice to look at with mahle forged pistons, lots of ports .aluminium Nicasil treated sleeves. Big reed blocks. and the v8 inspired trottle body.The loverunits are beauties, I have a slightly modified Yamaha 225hp with nose cone that I have to fill with padding all the time, I want to weld it but maybe it will change because of the heat.Maybe the new lowerunits from Yamaha with biger skeg and low water pickups has the same gear and internals as the one I have . I have very modified Yamaha 200 What modifications have you done? that will get an EFI > system if it is still running when I can aford one (eg MADEFI) or find time I have looked at the mad efi myself, no I am hoping that 332 efi would do the trick. I would like to play with the ignition also... Do you have any info on recalibrating the ignition system on the Yamaha engine? > to build something... Performance below 4000 RPM is not exactly stunning when > using carbs. What hp does it make? I read somewhere that the ox66 engine used GM corvette ecu. > > They have analog efi with old d-jetronic peek and hold injectors.(As > > standard) > > Is this the 260hp version? Yes. > > The new 2.5 efis has digital boxes ,Motorolabased. > > The 280hp machines? Yes. Espen Hilde ------------------------------ Date: Thu, 14 Oct 1999 04:33:53 +0200 From: "Espen Hilde" Subject: Re: DIY_EFI Digest V4 #580 > > Mercury delivers a high perf 200 dfi that took 2 place at paris ruoen 24 > > hour (river) race.The ability to run lean burn conditions is great for > > reliability as I see it. > > Do they really deliver it? Given that it has a lower unit that can't > reverse, it wouldn't make much sense for anything but racing. I think they used a standard gearcase, they didnt have to change the lower unit during the race.They saved lots of time that way. I havent sen any pictures or description of the lover unit they used. And as a racer > you get more power per cubic inch from an XR2, 2.5EFI or even a 300 ProMax. > > > I have 2 2.5efi high performance engines that I am reparing, line boring > > Are they any fun? Just problems so far, but nice to look at with mahle forged pistons, lots of ports .aluminium Nicasil treated sleeves. Big reed blocks. and the v8 inspired trottle body.The loverunits are beauties, I have a slightly modified Yamaha 225hp with nose cone that I have to fill with padding all the time, I want to weld it but maybe it will change because of the heat.Maybe the new lowerunits from Yamaha with biger skeg and low water pickups has the same gear and internals as the one I have . I have very modified Yamaha 200 What modifications have you done? that will get an EFI > system if it is still running when I can aford one (eg MADEFI) or find time I have looked at the mad efi myself, no I am hoping that 332 efi would do the trick. I would like to play with the ignition also... Do you have any info on recalibrating the ignition system on the Yamaha engine? > to build something... Performance below 4000 RPM is not exactly stunning when > using carbs. What hp does it make? I read somewhere that the ox66 engine used GM corvette ecu. > > They have analog efi with old d-jetronic peek and hold injectors.(As > > standard) > > Is this the 260hp version? Yes. > > The new 2.5 efis has digital boxes ,Motorolabased. > > The 280hp machines? Yes. Espen Hilde ------------------------------ Date: Fri, 15 Oct 1999 08:50:25 +0100 From: "Rich M" Subject: RE: MEMS Date: Wed, 13 Oct 1999 18:41:28 +0100 From: Ade + Lamb Chop Subject: Re: DIY_EFI Digest V4 #576 At 15:00 12/10/99 -0400, you wrote: >>All MEMS systems use as a minimum the following sensors: >>Additional sensors , depending on application, include: >>Knock >What does the knock sensor do? What does it mean if I don't have one Detects the onset of knocking and dynamically reduces the ignition timing advance to minimise it. Not all the systems implement knock, If you chose to use a system that does, but don't want to use it (or don't have anywhere to mount it) the best would be to have the sensor connected so that it doesn't create a sensor detection fault; the system will never see a knock signal, so will perform normally. >>Fuel rail temperature >Why? I think it's to do with hot start strategy when there could be the possibility of fuel vapourisation in the fuel rail. I've only seen this fitted on MPi applications, where the sensor is mounted on a boss, thermally attached to the fuel rail. >>All MEMS systems control ignition, either single coil or distributorless. >>All systems use a stepper motor controlled throttle stop for idle speed >>control. >Apart from the Mpi (97 on) minis which have a bypass valve which bleeds are >from the filter casing into the manifold. I wasn't aware of that - I've only ever seen steppers.... we live and learn. Rich ------------------------------ End of DIY_EFI Digest V4 #581 ***************************** 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".