Vacuum line for MAP ?

[Got Boooost]

Hey guys,
Im in need of some advise on which vacuum line i should use to install my GM 4 bar MAP sensor. Currently Im running the magnus SMIM, and it has 4 outputs on the back. this is how i currently have them hooked up.
1st output runs to my brake booster
2nd runs to my blow off valve
3rd runs to my PCV
4th runs to my AFPR and Boost gauge inside the car.

I was thinking about putting a "T" connector in the line that Im using for the blow off valve. would this be the best place for me or should i use a different line?

Thanks for the advise guys

Vern

 

[LiquidX]

Optimally you want an individual air source but on this setup you would be best to t into the brake booster as there is "less" activity going on since that line is blocked off during boost but you would need to find the proper T. You can tap into the BOV but make sure it doesn't leak as that can throw off readings.

 

[99gst_racer]

A tee works just fine for this. Just keep the sensor close to the manifold plenum, and you shouldn't have anything to worry about. I'm running 6 different things from the 4 ports on my SMIM.

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[turboglenn]

if you're using your MAP for SD setup and have an ECU with a high resolution then you don't want it hooked to the BOV with a "T" and if you have to as Paul said make sure the "T" is as close to the mani as possible. Reason for this is that the BOV movement will cause fluctuations in the reading of the MAP sensor. I had lots of trouble with this one time and since then i religeously "T" mine into the brake booster line ahead of the check valve

 

[LiquidX]

Damn Paul, got enough stuff back there

 

[99gst_racer]

Yeah, tell me about it. Using 2 T's sure does make it that much more difficult to loosen and tighten everything as well. My next SMIM is going to have at least 6-8 ports on the backside.

 

[Got Boooost]

Thanks for the help guys, Im going to T it into the brake booster.

Cheers

 

[Got Boooost]

hey guys,
so i tried T'ing into the brake booster line but i couldnt find a T that is big enough for the brake line and small enough for the vacuum line to the map sensor. So i used the vacuum line for the PCV, by using the PCV line do you thing i'll run into any problems or issuse? Ive got the sensor installed now but havnt driven the car so Im not sure if it will work effectively.

Thanks for the help

Vern

 

[big_d]

If you want to tee a smaller line, use the fuel pressure regulator source.

 

[Got Boooost]

ive got a line going to the AFPR and it already has a T going to the boost gauge inside the car, if i put another T in there would that be to much for one line ?

 

[bsbllfit7]

i dont think so, the reason you dont want to do the bov is because it could leak and make the readings not correct. The boost gauge should not be leaking and should be fine

 

[jrohner]

i dont think so, the reason you dont want to do the bov is because it could leak and make the readings not correct. The boost gauge should not be leaking and should be fine

If your BOV leaks through the diaphragm, throw it away right now.

 

[viperlp01]

Can you use the first port on the TB?? I also have alot of stuff going on back there and instead of a T I used the first port on the 1g throttle body.

 

[turboglenn]

you can tee the AFPR, The boost gauge, reference for an EBC and the MAP sensor all off one line. The reason is there's nothing to fluctuate like the valve in the BOV, or the solenoid in the EBC's line to the wastegate as the BOV diaphram will fluctuate the signal at idle and low throttle transition when the BOV is recovering from opeing or fluctuating at lower vac's when cruising in a parking lot like a crushed 1g does. the wastegate will effect it's reading at WOT making it bounce up and down as the solenoid lets air through to the gate and as the gate opensand closes regulating the boost

I have mine like this


the brake booster is t'd to a vacuum manifold (air manifold from harbor fright)

off that manifold i have the map, and my EBC's signal on one of the lines . And the other to the AFPR and the gauge tee's into the AFPR, this way if the line comes off the AFPR the guagte tells me by not reading.


then i got another PCV fitting from a spare manifold, put it where the OEM FPR was hooked up and ran that to the wastegate and BOV

 

[Got Boooost]

thanks for all the input guys. so i wont use the line to the BOV how about the line going to my PCV valve?

also as viperlp01 mention below, Ive got a port coming off my accufab throttle body that i dont use, do you think that would be a good source for my map sensor?

Can you use the first port on the TB?? I also have alot of stuff going on back there and instead of a T I used the first port on the 1g throttle body.

Vern

 

[LiquidX]

If your PCV is sealing properly like it shoud then you could use it. Other wise don't use it unless you get an USPlastic check valve. Your reading will be way off if you are trying to pressurize your crank case.

 

[pneumo]

I wouldn't use the PCV line because it won't read vacuum correctly.
T it into the FPR line and make sure the T for the map sensor is closest to the manifold plenum.