3.5 Bar MAP sensor vs 1 Bar sensor

Discuss which Sensors work best with these ECUs and share how you are using inputs and outputs

3.5 Bar MAP sensor vs 1 Bar sensor

Postby VR6Turbo » Tue Jan 10, 2012 10:58 am

I've gone back to a normally aspirated engine with a map sensor. I'm using the same Kavlico 3.5 bar MAP sensor that was on my turbo engine and it seems to work fine with DTA's standard pressure compensation map applied.

I say runs OK, but I have a niggling doubt it could be better with a 1 bar sensor.
I know you would get more resolution in the sensor scaling page, but does that really matter? I'm not so familiar with mapping n'asp engines.

Just trying to keep costs down :)
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby stevieturbo » Tue Jan 10, 2012 2:04 pm

I doubt it will make any difference you'll notice.

Maybe if something seemed odd, check for stable voltages from the sensor. Worst case it may fluctuate a bit more.
But as they work perfectly fine on a boosted engine, they'll work perfectly fine on a n/a

Is it a temp change or permanent ?
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby VR6Turbo » Wed Jan 11, 2012 4:54 am

Yeah permanent. I've gone back to n'asp tuning. High hp turbo motoring just crippled me at the pumps every month :?

The KPA reading does fluctuate a little at idle actually, but not a huge amount.

It's odd readings I'm getting that make me wonder. Such as 6KPA at over-run, 20KPA at very light throttle on motorway and mid 30s KPA for idle. I'm used to seeing much higher numbers than that (off boost).

This motor is DBW though and when the plate is closed, it's REALLY closed. Which may explain the high vaccum I guess.

I might try a 1 bar anyway tbh as it's makes more sense for n'asp really.....
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby stevieturbo » Wed Jan 11, 2012 6:59 am

readings dont sound that odd really. Id expect a mild cammed engine to pull 30-40kpa at idle.

Why not just get a mityvac or similar and test the map sensor readings ?

Where is the signal line taken from ? It always needs to be from a central plenum or intake pulses can affect the stability of readings. Damping the line can also be needed sometimes. Filtering may achieve a similar result, although Ive never used much filtering.
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby VR6Turbo » Wed Jan 11, 2012 5:06 pm

Good idea on the Mityvac, I'll look into that.

Here is the MAP sensor and it's manifold connection. It's right at the back of the plenum well away from the runners, so I figured that would give a stable enough feed.

Image
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby stevieturbo » Wed Jan 11, 2012 5:26 pm

Looks like a decent enough position
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Re: 3.5 Bar MAP sensor vs 1 Bar sensor

Postby VR6Turbo » Fri Jan 13, 2012 4:16 am

Cheers Stevie. Got the Mityvac this morning. Nice bit of kit 8-)
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