MSefi.com read only forum (Jan.15,2018)

65mm might not be all that much too big. What is the expected HP output of this engine?


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funny, i always justified lots of ignition timing for cruising around for really crappy, poor combustion chambers!!!



Correct! And in fact my old Honda does indeed have really crappy combustion chambers. It's a 3 valve/cyl design with a hemispherical chamber, and practically no squish.


As for ...

I am REALLY surprised at how high of an RPM before the advance kicks in. I would have expected advance to climbing at 2500 to 30 degrees or so for high vacuum.
Am I out to lunch, or just used to really old engines?
thank you for opinions.


Every engine is different but it does look like the ...

Those AFR setting guidelines are just that, guidelines. Every engine is a little different in what it wants for AFR to create maximum HP/Torque. The difference between 12.5:1 and 13:1 is fairly small and I would bet that the dyno won't show much of a difference either. If this is a NA engine set the ...

matt & cygnus.. thanks for your info.. aprreciate it very much :D

i think i will just lock the distributor.. in tight budget >.< then which one should i choose if i wanna run the fueling only..? mS2? version 3..? i will solder it myself..


I think you would only lock the distributor if you want ...

newbie here.. i'm Lawrence from Malaysia.. there not much ppl using MS in m'sia.. so i couldn't get much info from locals..

currently driving 2nd gen 1983' Honda Prelude with stock A18A/ET1 Sohc twin carb engine..
i planned to convert to efi and turbocharge it with 4AG quad throttle & small TD04 ...

How lean you can go under light throttle depends on the engine, but as a general rule for light throttle tuning, if it doesn't ping, it doesn't misfire, and it doesn't count as a pollution controlled vehicle, you're not running it too lean. I wouldn't try this above 50 kPa or so, and my Honda may ...

Yeah, but a "squid" might help to telegraph the math skills and electronics geekiness (is that a word?) that I regularly see here on the forums. And don't get me wrong, I'm impressed and jealous of the math skills and electronics geekiness some of you have.


I'm not getting the connection between ...

Hmm. I like the idea of a mascot. How about an octopus instead of a squid? They're pretty much the same thing and just seem... friendlier? If that makes any sense. I have a picture in my mind of an octopus sitting on top of a V8 with an injector in each of it's arms.


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The default sensor in Megatune is a GM sensor. So if you can find something close to that you know it will work. There is a table in the megamanual that has the temperature and resistance values for the GM sensor.

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I would say that tuning can definitely be challenging, but I wouldn't call it hard. It takes some patience and persistence to learn what all the settings and such are in the tuning software, but once you figure it out the actual tuning process is pretty straightforward. Really the biggest hurdle is ...

The cheapest place to get MAP sensors is a U-Pull-It junkyard. Huge selection and you can use a vacuum pump and voltmeter to map the curve if you can't find any info online.

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It's mostly just trial and error, seeing what works best. I think MAP tends to be more accurate if you have a good MAP signal, but TPS is probably better if your MAP signal is very lumpy. But then if your MAP signal is that lumpy you might be better of with alpha-N fueling instead of speed density ...

I have a TPS connected but it does nothing as far as running the engine. Static fueling is based on RPM and MAP and acceleration enrichment is done entirely with X-tau, which is also RPM and MAP. I could disconnect the TPS and it would make no difference.

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good discussion... how far would this advance be, and how do we know when we hit it? Say we shoot for 100km/hr reference speed. Do we shoot for the lowest kPa we can get while holding that exact speed? What are the safe limits... will it knock audibly while just cruising? I currently run a max of ...

I've been running without that cap for a long time and not had a problem. I can imagine it might cut down on interference with the radio though. Not a problem for me as I don't have a radio in the car.

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Interesting observations. I'll just throw out a couple thoughts.

For engine efficiency, I'm not sure air flow is going to be a reliable indicator. What you really want to look at is brake specific fuel consumption. At a given power output (speed), how much fuel is being consumed? Air is an ...

Looking at the fueling equation we see that Req_Fuel and VE are multiplied together:

PW = REQ_FUEL * VE * MAP * E + accel + Injector_open_time

So if you reduce Req_Fuel by come factor you can simply multiply the VE table by that same factor. 18/16 = 1.125
Multiply the entire VE table by 1.125 and ...

Man that's lean. My Honda would run like crap with that table. Any leaner than 15.5:1 and it starts surging. 16:1 at idle would be really wheezy.
But if you have an engine that can run those AFRs, go for it. Mileage would be very good.

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Hi,
On the bottom of the 6th page there is a draft of an ...

Many thanks , Ken !
NOW: something that still hurts my brain:
The autosport-link it posted tells about "Pumping Losses" because the cylinder is pulling out of a vacuum at part-throttle which is harder to do than being filled by atmospheric pressure at full throttle. This causes a good part of the ...