GM 3Bar MAP Sensor Install on S14 SR

[speedfiend]

Alright guys Im getting my SR back together and will be running PFC D-jetro. I decided to utilize the GM sensors after researching that they respond quicker then the standard Apexi sensors do.

Anyways I have hit a snag on installing the MAP sensor. I know most people will tap the center of the plenum and run a vacuum line to a remote location where the sensor is mounted. This is fine but I am trying to keep things a little more hidden and clean looking, so I have come up with another idea that I wanted to run by you guys and see if my thoughts are in order.

Here is the sensor I am working with.

http://i848.photobucket.com/albums/ab42/yashios14/20160227_152034_zpsrhuthz3i.jpg

As you can see the place where the vacuum line would mount is very short. Reason being on the Vette's and CTS-V's, these sensors come on, they mount directly to the manifold. This is why there is an o-ring on that nipple. So, since I would have to drill a hole in the plenum anyways to accommodate the 3/8's fitting needed to run a vacuum line, I was thinking of mounting it directly to the manifold in the same manor as they are on the Vettes and such. One of the two vacuum fittings on the bottom side of my mani is plugged off. So I will drill that out to 3/8's and the nipple with the o-ring will be inserted there. I will then drill another hole next to it to bolt the sensor in place so that it will not come lose and leak. Below you can see what I am talking about.

http://i848.photobucket.com/albums/ab42/yashios14/20160227_152054_zpsvl03aj44.jpg

Does anyone see this as being a bad idea? Of course if the hole I drill for the bolt breaks through then I will use some thread sealant to prevent any vacuum leak from there as well. I figure the o-ring should be plenty on the actual nipple. Ive seen guys run 25+ psi of boost on vettes on the same sensors with no issues. Let me know what you guys think.
Thanx, Cameron

Edit: Sorry for the giant pix!!! What happened to Zilvia's image resizing deal?

[Kingtal0n]

I think its alot of extra work when you could just run a short line from a manifold source instead. You can hide it wherever you want, just use a dedicated line, and be sure its facing the right way (many map sensors are directional, i.e. gravity has an influence on the wire inside so they need to be installed in the right orientation)

That said, check the orientation before you drill any holes. It would suck to install it permanently into the manifold only to find it reads incorrectly because of its positioning. Also I would configure it before drilling any holes also, test it and verify you can get it to work first. Just in case.


And finally, if you do decide to go forward with the drilling/tapping idea, you will preferable weld a boss (just strike an arc with the tig welder and add some filler material, let it cool, then file it flat) before any drilling/tapping. Make sure you drill the exactly right size hole for both the tap and the sensor O-ring. You do NOT want to rely on sealant in this location. At most some teflon tape, but it depends on the sort of thread.

And one more thing. I notice in the pic you have it near other vacuum sources. Ideally the map will be ALONE, placed WELL away from any other vacuum sources, where signals in the manifold may influence the map sensor. For example, do not place it near any single plenum runner; the runners are each dedicated to a cylinder and each cylinder has a harmonic associated with it's runner, as well as a strong differential pressure (a fast rate of change of pressure) that the map will pick up and make a bunch of noise/garbage in your map voltage. Ideally the sensor will be somewhere along the big open tank of the plenum, well away from other lines leading out of that plenum, and well away from any runners that lead to cylinders.

[speedfiend]

Thanx a lot for the info Kingtalon! Im still contemplating what I want to do. Ill keep you guys posted if I go through with the idea or if I just choose a remote location to mount it and put a nipple in the manifold plenum.
Thanx, Cameron

[speedfiend]

Well ive decided against mounting the sensor on the bottom of the manifold for two reasons Kingtalon mentioned above. My main concern was the moisture building up in the nipple of the sensor and causing it to go bad. Also, I couldn't really find any info about mounting orientation but just to be safe Id rather the sensor not be upside down.

So now I think Im going to utilize the same idea but on the rear of the plenum. There the sensor will not build moisture in it, and ive seen plenty of people with them mounted with the nipple horizontal to the ground. Granted there is a port on the rear for the pcv but considering there are ports all over the manifold it would be hard to find a spot that isn't near a port, unless you drilled on the very top which I am not gonna do. Plus, i feel that the pressure in the manifold will be fairly equal in this area also.

What do you guys think?
Cameron

[Kingtal0n]

Well ive decided against mounting the sensor on the bottom of the manifold for two reasons Kingtalon mentioned above. My main concern was the moisture building up in the nipple of the sensor and causing it to go bad. Also, I couldn't really find any info about mounting orientation but just to be safe Id rather the sensor not be upside down.

So now I think Im going to utilize the same idea but on the rear of the plenum. There the sensor will not build moisture in it, and ive seen plenty of people with them mounted with the nipple horizontal to the ground. Granted there is a port on the rear for the pcv but considering there are ports all over the manifold it would be hard to find a spot that isn't near a port, unless you drilled on the very top which I am not gonna do. Plus, i feel that the pressure in the manifold will be fairly equal in this area also.

What do you guys think?
Cameron

should be ok, just test it in that orientation before you mount it, and keep it away from runners that lead to cylinders.

[Jorgs_7]

Bought 3 bar GM map sensor to mount remotely. 35$

Removed TB,

drilled/tapped 1/8" NPT a few inches away from TB flange,

installed barbed fitting with nipple,

ran vacuum line from hidden sensor to nipple.

Bam

[RB25GUY]

nah dude cast holds heat in. drill a hole like jorgs said a few inches away from your tb on your ic piping alum dissipates heat better.... more accurate readings......