MAP line

[svranger25]

after reading the whole "what have you done to your obs" thread i had a lot of things to do, one thing i dont get though, on my intercooler piping i have a pipe that is tapped right after the turbo before the intercooler (hot or cold side?) that runs to my boost gauge and the gauge only, i dont have a sensor for the truck to read boost psi?? kinda worried about this. ben raining all day and going to be for most of tomorrow but hopefully i'll get out there and check it out, any insight into this, PO had the intercooler installed and may have to fix this...

[backwoodsboy]

On the banks intercooler kit, you should have a line running from the passenger side firewall into the 'y-pipe' (cold side of intercooler) prior to heads.
Here is a picture of the sensor and line. The picture is a 99+, which came factory intercooled but the MAP sensor location is essentially the same.
http://img151.imageshack.us/img151/3...tt73llgwd6.jpg
Disregard the caption for a boost gauge 't'. Boost reading for a gauge can be attained either by tapping into the existing MAP line, or by drilling a new hole in the intercooler plumbing. Sounds like the previous owner opted for the second route.
Hope this helps.

[erics diesel]

If he didn't move the map line it should still be connected to the passanger side plenum.

[svranger25]

thanks ya'll
i think i freaked out for nothing i see a line that goes from the map sensor to the passenger side of the y pipe.
is the mod moving this line to the hot side? pros? cons?

[terryknight]

the truck will have more accurate MAP pressure and therefore more accurate fueling. on my truck Boost now gets higher and gauge is more sensitive and smoke is less

[backwoodsboy]

Terry, how does moving the MAP line from cold to hot side give a more accurate reading? Reading from cold side would reflect the psi drop across intercooler, and be closest to what is actually present at the heads.

[BigFuel]

I agree with backwoodsboy in that moving the MAP line to the hot side of the IC system will show the PCM a false representation of the air moving in the system. My best thought as to why it works for you and Elmo (I think) is that your tunes are not as good as the tuner thought as to when it comes to a truck that is not supposed to have an IC but does. My truck has great acceleration and no smoke with the MAP line where it is (except for the boost fooler).

[EDIT: on rereading that I didn't mean it to come out that much of a dick to you or the tuner. I just meant to imply that the tune you are running _may_ not be tuned correctly for an OBS with a IC]

[CELAYORK]

When you move the map line to the hot side of the y pipe you get less turbo lag and some claim better performance.

[Fordman247365]

I can tell you I moved my map line to the hot side right after the turbo and I now have zero turbo lag and a steady boost needle.

Dont move the line if you don want to, but I am damn happy that I did, runs like a different truck down the road

[Fordman247365]

Originally Posted by BigFuel

I agree with backwoodsboy in that moving the MAP line to the hot side of the IC system will show the PCM a false representation of the air moving in the system. My best thought as to why it works for you and Elmo (I think) is that your tunes are not as good as the tuner thought as to when it comes to a truck that is not supposed to have an IC but does. My truck has great acceleration and no smoke with the MAP line where it is (except for the boost fooler).

[EDIT: on rereading that I didn't mean it to come out that hard on you or the tuner. I just meant to imply that the tune you are running _may_ not be tuned correctly for an OBS with a IC]

Just read what you said....dont really know, but it made a huge difference on my truck and I aint movin it back