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Old 07-12-2009, 11:55 PM   #1
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Default Noisy map??

Is my map sensor too noisy? I was looking at some logs from other ecus and they seem to be smoother. I have the motorola map hooked directly to the adaptronic, should I put a small cap in to filter some of the noise?

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Old 07-13-2009, 12:00 AM   #2
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Where do you have the line hooked up?
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Old 07-13-2009, 12:07 AM   #3
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The brake booster fitting that fm used to use. The line has a tiny restrictor in it near the map.
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Old 07-13-2009, 12:10 AM   #4
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Maybe try putting it in with the factory FPR. That's what fixed it for me. I know it's a different ecu but it might be worth a shot.
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Old 07-13-2009, 12:10 AM   #5
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Just for reference, mine is like that. I tried to minimize it by putting a pop rivet in the line as a restrictor to settle it down and it did zero.

Mine is teed straight off the mani that feeds the brake booster line.
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Old 07-13-2009, 12:13 AM   #6
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I have had total success using the ports right at the tb.
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Old 07-13-2009, 12:29 AM   #7
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I guess pick up more vac line and try running it to the TB. I had the link map hooked up there for years and it was fine. Thats why I was wondering if I needed to filter it.
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Old 07-13-2009, 12:36 AM   #8
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Not to be obtuse, but what is the difference between the little port on the TB and the big honkin' 3/8" port on the back of the IM? It all sees the same pressure. Just tryin' to learn here.
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Old 07-13-2009, 12:45 AM   #9
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ITs just the normal oscillation of the pressure in the manifold due to variation in turbocharger RPM, and cylinder pulses. With where the MAP sensor is currently T-d off in the instructions it is probably more susceptible to these oscillations due to high velocity air hitting the back wall and creating a pressure gradient as well as the number 4-cylinder drawing from the end of the plenum when air is only available to replenish it from 1 side.

The frequency of the pressure waves will increase and decrease with RPM and turbocharger performance. It is going to pretty well be impossible to dampen it electronically or mechanically without attenuating part of the signal you don't intend on hitting. So long as the fluctuations don't cause significant changes in cells I wouldn't worry about it. You could try drawing out of the T/B inlet as air velocity is nearly constant here due to that air supplying all 4 cylinders.
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Old 07-13-2009, 12:47 AM   #10
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Some parts of the intake manifold see a lot of turbulence. At least that's what I've read. What he said^^
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Old 07-13-2009, 12:58 AM   #11
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Quote:
Originally Posted by TravisR View Post
So long as the fluctuations don't cause significant changes in cells I wouldn't worry about it. You could try drawing out of the T/B inlet as air velocity is nearly constant here due to that air supplying all 4 cylinders.
Some of the fluctuations are ~5kPa at cruise. That could explain why some of the cells that have been autotuned are randomly ~0.5ms higher/lower than near by cells.
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