LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

MAP relocation

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Old Dec 21, 2007 | 05:02 AM
  #1  
1982z28with18s's Avatar
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MAP relocation

Has anybody moved the map sensor to the rear of the intake? Or ran it on a vacuum line and moved it under the dash? I'm deleting all the vacuum ports on the side of my intake to clean up the engine bay and running a custom setup on the back of the intake, but I still have the map sensor I would like to relocate. Any downsides to doing this?
Old Dec 21, 2007 | 11:17 AM
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I always thought the MAP on the LT1 was integrated very nicely
Old Dec 21, 2007 | 11:46 AM
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If you move the MAP sensor remote by adding a hose, you will "dampen" the readings. The longer/smaller diameter the hose, the slower the pressure changes will reach the sensor. The slower the MAP sensor responds to manifold pressure, the less accurate the ignition and fueling will be, since they are both affected by engine load, which the PCM bases on the MAP reading. The stock LT1 location is as good as it gets.
Old Dec 21, 2007 | 01:15 PM
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1982z28with18s's Avatar
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Originally Posted by Injuneer
If you move the MAP sensor remote by adding a hose, you will "dampen" the readings. The longer/smaller diameter the hose, the slower the pressure changes will reach the sensor. The slower the MAP sensor responds to manifold pressure, the less accurate the ignition and fueling will be, since they are both affected by engine load, which the PCM bases on the MAP reading. The stock LT1 location is as good as it gets.
This is what I was worried about, I just am trying clean up the engine bay even more and not having the map sensor in the stock location would help a lot. You think it would be that slow of a response that it would case issues?
Old Dec 21, 2007 | 02:17 PM
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Directionally, it hurts. I have no idea whether it would screw up the readings enough to hurt the way the car runs. I personally would not even consider risking the loss of accuracy for "looks". I'd choose "performance" over looks every time.... but that's just me.
Old Dec 21, 2007 | 06:05 PM
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why not install a hand held vaccuum guage and run it to the inside of the car. Compare the readings to the map sensor if the readings are the same I would say you would be ok with moving the map to the same length as the guage.
The differences I think would be unnoticeable.
Old Dec 24, 2007 | 10:37 AM
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Megasquirt uses an internal map sensor with a vacuum line so I think I'll be fine.

No vacuum hoses at all will be on the side of the intake, and only wires on top of the the intake will be the injectors, the iac/iat/tps will be routed underneath.
Old Dec 24, 2007 | 02:42 PM
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Originally Posted by 1982z28with18s
Megasquirt uses an internal map sensor with a vacuum line so I think I'll be fine.

No vacuum hoses at all will be on the side of the intake, and only wires on top of the the intake will be the injectors, the iac/iat/tps will be routed underneath.
Make sure to post up some pics when your done
Old Dec 24, 2007 | 04:21 PM
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1982z28with18s's Avatar
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A lil preview of how it looked as it was going together...

Old Dec 25, 2007 | 03:39 PM
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*redacted

I had a problem once using a softer hose on a wastegate and overboosted... not good.

Last edited by Godchsr; Dec 26, 2007 at 02:37 PM.
Old Dec 26, 2007 | 11:16 AM
  #11  
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The factory LT1 MAP sensor does not use any hoses. The end of the pressure sensor nipple inserts directly into the manifold. For a remote location, obviously the hose has to be strong enough to resist deformation under full vacuum. My MoTeC ECU install manual recommends that the hose be no more than 1 meter in length, and that the sensor itself has to be located higher than the port on the manifold, in order to prevent any moisture buildup. The port on the plenum should be facing downward. No other devices should be connected to the same vacuum line as the MAP.
Old Dec 26, 2007 | 11:49 AM
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1982z28with18s's Avatar
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Originally Posted by Injuneer
The factory LT1 MAP sensor does not use any hoses. The end of the pressure sensor nipple inserts directly into the manifold. For a remote location, obviously the hose has to be strong enough to resist deformation under full vacuum. My MoTeC ECU install manual recommends that the hose be no more than 1 meter in length, and that the sensor itself has to be located higher than the port on the manifold, in order to prevent any moisture buildup. The port on the plenum should be facing downward. No other devices should be connected to the same vacuum line as the MAP.
Thanks, I think I can keep it under a meter in length easily and will keep it facing down.
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