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Discussion Starter #1
I need to use a map sensor with my engine/ecu setup, however I'm not sure where it is best to place it.


My engine came with two threaded holes in the centre throttle body that had been used for map sensors by the previous owner.



Should I use an external mounted map sensor with a vacuum tube from somewhere connected to it, like this one:

4 Bar MAP Sensor




Or should I get a sensor like the one below and mount it in threaded holes?

AEM 3.5 bar map sensor - EFI-Parts.co.uk: Connectors, Sensors, Trigger wheels, Wideband, Adaptronic, Zeitronix, AEM





You can just make out one of the holes here:




Why are there two threaded holes? Surely you don't need to run two sensors?
 

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Years ago, I was always warned by the most reputable tuners of the rb26 lump that YOU ABSOLUTLY MUST install them in the underside of the plenum to get the best results and avoid significant issues.

I have come to the conclusion in recent years that this advice is ABSOLUTE DOGS CRAP. And meant mearly as a fear tactic to get people to ensure a tuner does the work rather than peeps do it themselves.

It put me off doing what should have been simple mods. I am sure I have seen build threads where map sensors are fitted in accessable areas of the inlet. Do some research of rb26 map sensors, including on skyline aus site andyou should find what you are looking for.
 

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I screwed mine in there the breather goes.
 

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I have got the same 4bar MAP on my car (I work for NZEFI) I have got mine mounted on the firewall next to the factory boost gauge sensor. No you only need one MAP sensor.
 

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Discussion Starter #8
I have got the same 4bar MAP on my car (I work for NZEFI) I have got mine mounted on the firewall next to the factory boost gauge sensor. No you only need one MAP sensor.
They told me that there has been some problems with sensors mounted direct so I'm thinking of using the remote sensor, as long as I can find a neat place to mount it. Its a 260Z, not a skyline and the bay is tucked so everything has to be neat.



The 2 holes were from Apexi D-Jetro PFC instructions.
Blank them and use the breather port on the balance tube.
Thanks, do you happen to have these instructions? Would be useful to know the thread size so I can buy some plugs for the holes.




Just running standard throttle and plenum setup.
 

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They told me that there has been some problems with sensors mounted direct so I'm thinking of using the remote sensor, as long as I can find a neat place to mount it. Its a 260Z, not a skyline and the bay is tucked so everything has to be neat.
We've sponsored a full blown class 3 offroader that has the same 4 Bar MAP sensor for a few years now, never had a problem with it. We have some rubber mounts for them.
 

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Discussion Starter #12
We've sponsored a full blown class 3 offroader that has the same 4 Bar MAP sensor for a few years now, never had a problem with it. We have some rubber mounts for them.
Yeah, I meant the problems were with the ones bolted direct that have problems, not the ones you sell.




Lightspeed - Thanks
 

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Yeah, I meant the problems were with the ones bolted direct that have problems, not the ones you sell.




Lightspeed - Thanks
Cool, no worries:p
 

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Discussion Starter #18
So, having just installed my engine and currently working on setup I realised my map sensor is installed incorrectly, don't know why I didn't think of this at the time.


I have the sensor installed on the bulkhead but the vacuum feed going to it comes from the plenum so obviously it can't be getting any vacuum.




I was thinking of changing this to one of the outlets on the right of the AAC block, currently I have the feed for my boost gauge and BOV coming from them but I can just tee off the line for the boost gauge.





Now I know this will work as a vacuum source but should I really be taking it from somewhere else for better signal/response?

Only places I have seen that can work are the fitting on the balance tube which as stock is for the breather (however I can't see why this would be any better than AAC block) and the other option which is slightly different is to take a line from the back of the throttle plates 3 and 4 and tee it into one line. While this should be easy as I already have the holes drilled I have no idea what the correct thread size is, its not M10x1.25 as previously mentioned in this thread.

I still have the outlets at either end of the balance tube available but from reading on this it seem they offer too weak a signal for a map sensor.


Would also rather keep the top of the engine clean looking.







So, should I change or will it be fine how it is.
 
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