Td5 Intake Manifold Tap Location

I want to move my Boost Pressure Sending Unit location from the turbo hose to the Intake Manifold.
I am not familiar with the casting design of the Td5 Intake Manifold, but does anyone know what the actual function of what looks to be a "blow out plug" on the rear of the Td5 Intake Manifold?


Secondly, does anyone know if it would be a bad or good idea to tap that area with a 1/8 BSP tap?

Here is a pic of the area in question. I prefer to do tap this area since it would eliminate the need to run the sending unit wires down the length of the manifold.

IMO that's not a bad ideea

I'm gonna give it a shot, unless someone tells otherwise.
Worse case, If it is not think enough, looks like I can re-TIG the "plug" area with some thicker material.

Use a rivet nut with the proper interior thread and screw the probe in that

I hadn't seen that before. Looks like a good option!

IMO rivnuts are a very good solution when you want to screw something into a thin plate i used them in various applications with great results

Actually, I've never used them, but thank you for bringing them to my attention.
We'll give it a shot.

i drilled my manifold to install a boost gauge for a better and true reading plenty of meat to drill and tap leave that core plug alone as they are not that thick .... not to sure how a map sensor will react as these are mostly calibrated
however its worth a try or even installing a sampler tube or a wider band sensor

i have been caught out in the past doing this on other types of engines as some map sensors and ecus are callibrated differently to others different euros etc

ozzyboydeano said:

not to sure how a map sensor will react as these are mostly calibrated
however its worth a try or even installing a sampler tube or a wider band sensor

Click to expand...

i'm not getting your point here

Thanks for the input, ozzyboydeano!
I agree the "core plug" doesn't seem all that thick. I just like that location best. I am leaning toward drilling a hole in the "plug" and TIGing a beefier aluminum plate atop the plug and tapping that.
I purchased a "spare" Intake manifold from the wrecking yard so if things don't work out, I'm not screwed.
I don't see this affecting the MAP sensor signals to ECU.

Where exactly did you drill and tap your manifold?

sierrafery said:

i'm not getting your point here

Click to expand...

i m unsure if there a different rates in map sensors for the td5 this is not my area of work not really clued up on the td5 management system so please go easy on me mate

i know for other diesel engines in my line of work they use different bar rated sensors running off a sample tube from the manifold or turbo preassure line and each sensor can vary between euro

to be honest i really think its a good idea that all map sensors should read manifold pressure as its true reading as well as inlet manifold temps

D90Don said:

Thanks for the input, ozzyboydeano!
I agree the "core plug" doesn't seem all that thick. I just like that location best. I am leaning toward drilling a hole in the "plug" and TIGing a beefier aluminum plate atop the plug and tapping that.
I purchased a "spare" Intake manifold from the wrecking yard so if things don't work out, I'm not screwed.
I don't see this affecting the MAP sensor signals to ECU.

Where exactly did you drill and tap your manifold?

Click to expand...

i drilled the top and towards the front of the manifold and taped in a fitting

if your going to tig in alloy plate you could do this any where even over the core plug area

A bit late in the game though for what it's worth...

Would not mess about with the core plug as it is jammed in place and not that thick.

Rivnuts are non-sealing plus require a flat surface & constant material thickness to set properly.

Was planning to tap into the manifold just aft of where the MAP sensor sits (there seems to be a fair bit of meat in that area) but chickened out in the end.

My EGR blanking pipe (aluminium made) has quite a thick base flange (±12mm or so), so tapped a 1/8” NPT thread and installed a 90° elbow push-to-connect fitting for ¼” nylon tubing (pic below).

Used air brake nylon tubing (SAE J844, good for up to 10 bar & 90 °C) to take 'intake pressure signal' to the back of the turbo boost gauge (mechanical type).

Not ideal as strictly speaking sampling point should be mid-manifold but orders of magnitude better than upstream of intercooler.

Have a spare intake manifold on the shelf just waiting for me to get braver.

It is never too late. Thank you for your input, MTurri! I haven’t tapped the Intake Manifold yet as I am knee deep into a head gasket replacement. After this is all settled, I’ll tackle the Boost Sensor location.

Thanks again, Great Info!
Cheers,
Don