So I'm thinking I'm gonna run megasquirt, but am wondering if I'll be able to pass emissions. These are here in washington, so I should be fine w/ the m52 but what all do I need to keep for emissions. I know cat and exhaust for one, but what else do I need?
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these are probably questions for msefi.com / msextra.com forums rather than r3v
megasquirt docs have instructions on how to tune for best emission readings (HC, NO2, CO)
theoretically, you should be able to MS tune it for better emissions than the stock Motronic tune. (MS2 recommended, WBO2 sensor is a must) -
near the bottom of the page:
you should read all of it though.Comment
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Thanks much, forgot to look there, I appreciate the help.Comment
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when i ran my m52 through emissions in oregon it was way below average. max limit was 220 the car ran at 70. but i was using motronic, 3.5 maf, s52 cams, s50 midpipes with cats and a UUC catback. hope that helps a lil.Comment
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oh c'mon man, let's not let this negativity make its way from bf.c please.
Noone is talking about the precision here. I am just saying that tuning for best performance/economy and for best emissions are two different tunes. With motronic you have to have two different chips for two tunes (which is ok if you know how to tune motronic, have an emulator/software and have a chip burning device), with MS, it's a click of a mouse, or flip of a switch.Comment
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Do what? What negativity?
I quoted what I was replying to. Someone said that "in theory" you could tune a MS for even better emissions than a motronic. This is simply not true. To do so (be it better emissions, better economy, better performance, or all 3) you would need to at least match the injection capabilities. This means sequential injection and good injection timing control. MS has neither. (well, it doesn't have the latter because it doesn't have the former.)
A tune for best performance (usually done at WOT) and best economy (usually cruise) would NOT be different chips or tunes. Just different parts of the map. This goes for MS or motronic. Best emissions and best economy may not be identical, but best emissions wins on a car with a cat.
Given the lack of sequential injection though, you won't be able to do any more than match the emissions capability of the stock chip in the ECU. You'd be darn lucky to get there too.
Precision is important given the bit that I quoted.Comment
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don't worry static, pissmachine isn't here.
jk
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ok techno, point taken (even though you've misread my post, where i said different tunes for "best performance/economy" OR "best emissions", NOT for "best performance" OR "best economy", the latter can clearly be one tune)
i just want to know and i would be very thankful if you can provide some substance to your claims (something more than just using words like "sequential" or "precision").
Like, for instance, do you have solid figures of comparisons between the injector timing control between MS2Extra and Motronic? (MS2E has down to microsecond precision, which seems to be more than enough for even an avid MS tuner)
Have you spent significant amount of time tuning semi-seq injection EMS (like MS2 that can do say 6 alternating injections per engine cycle) and tried to match the economy of motronic sequential?
I am not arguing that seq inj is inherently better, but exactly how much better? anyone quantified it? enough to put up with proprietary nature of motronic? buying extra hard/software to be able to tune it? giving up MS2E features and great community support? etc.Comment
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My point was that best economy cannot be achieved on a vehicle with a catalyst and emissions still met.
Buying the hardware/software to tune motronic is less expensive than buying a MS. so I'm not sure why that would be an issue. Even if you "go all out" and buy an emulator ($175) and register your copy of tunerpro ($30), you're well under half the cost of any viable megasquirt solution.
You may be giving up "features" but gaining functionality and reliability.
The best a MS can do injection wise will be 2 pulses per intake event, spaced 360 apart, of ~1/2 the calculated fuel. Still no control over the injection timing though, and the calculated fuel can change quickly. You also have the problem of possibly spraying sometimes with an open valve, sometimes with a closed valve, etc... so you have the possibility of actually missing your intake event.
Ideally you want to always spray on the back of a closed valve. You want a single spray as close to the intake event as possible, but you want all of your injection time to happen before the valve opens. that is not an easy task in itself as calculating your injection start time is then somewhat complicated. add in a "moving target" of an intake cam like VANOS and you're now well out of what is currently MS territory. Hopefully that will be fixed soon, but for now, there's a large gap between the MS and the motronic in that regard.
The "open valve" issue alone makes for some serious tuning issues beyond just emissions.Comment
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these are some good points here.
couple of corrections: MS2 can do variety of different injection patterns. One i experimented with and found best for is 6 alternating squirts per cycle (one can do up to 8 on a V8). With this setting, each injector gets 3 squirts per cycle, one of which will most likely be made on the open valve with 2 others on the closed one. The response with 6 alternating squirts per cycle should theoretically be very close to sequential (which i've proven on my car), but the atomization (as you mentioned) and especially useful range of injector ratings would be perhaps not as good as sequential - question is by how much?
Even though not perfectly timed, the amount of fuel sprayed in semi-sequential mode still makes its way into the chamber (maybe not as well atomized) and it's not like the squirts are randomly timed or in random order, so i don't think that some cylinders get more fuel than others.
btw, is there a cheap emulator available supported by tuner-pro that would have the trace capability? (i.e tuner pro would be able to highlight the cells that ECU is reading from currently, while the emulator is hooked in)Comment
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