MAP sensor connection on Kadrons for crank trigger ignition

[TCK123]

I am trying to find the best way to get a manifold vacuum signal to the MAP sensor for a Microsquirt V3 crank trigger ignition. I am thinking that I can tee into the balance tube with a vacuum manifold and then out to the MAP sensor. Or, is it a better signal coming off just one manifold. Any help would be greatly appreciated.

Thanks,
TCK123
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TCK123

[Vanapplebomb]

If the balance tube is big enough (1/2” +), vacuum should be stable enough to tap it right off the manifold.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[clonebug]

You don't need a big line for a Map sensor. A smaller line will give better resolution.
I have a 5/32nds line running from my intake manifold along the passenger side to the front under the buggy hood to the ECU and a boost gauge.
It's been that way for 50,000 miles.
Put a Tee in your balance tube and shrink it down to a small line. Whatever size the fitting is on the map sensor is the size you should use.
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[oprn]

Your balance tube is fine. That way you will get a smoother signal than if you just tapped one manifold. I tapped all 4 on my Webers, ran a 1/8" line from them into a small RC model airplane fuel tank, then another 1/8" line to the MAP sender. Nice smooth signal and has been working this way for 3 years now. You won't need a dampening bottle, your balance tube will do all the signal dampening you require.

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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Vanapplebomb]

[Vanapplebomb]

As for vacuum stability with dual singles, I have measured smoother vacuum at the manifold than off the balance tube. The balance tube was surprisingly bouncy on the gauge, which sort of makes sense given that the air is rapidly oscillating back and forth between the manifolds.

If your balance tube is less than 1/2” ID, manifold vacuum starts to get pretty bouncy. In that case, either use a larger balance pipe, or tap MAP off the balance pipe if it measures smoother.

I find a 1/3” - 5/8” balance pipe to be ideal with dual singles and shorter duration/high vacuum cams. Going bigger doesn’t help, and going smaller reduces vacuum stability.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[boxer74]

[mikedjames]

You would have thought that by now you should be able to tune the filtering on the MAP signal using software in the Microsquirt rather than rigging a hardware low pass filter ( thin tubes and a plenum ..)

I use a MAP sensor created from a Bosch BMP280 mobile phone sensor for my vacuum advance, you can tune the filtering on the sensor. I was using 2Hz .. you could feel the kicks from the timing advance jumping . At 8Hz it is smooth but still filters out the pulses from the engine.
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[oprn]

[TCK123]

A lot of great ideas. I was thinking of putting a 2 way connector off each manifold, one large connection for the balance tube and one small connection for the vacuum line. I was going to run the two small vacuum lines to a vacuum manifold and then out to the MAP sensor. I am a little ways out from getting it running, but I am one step closer now.

Thanks,
TCK123
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TCK123