# My turn to delete the SAI system



## stickman007 (Apr 21, 2015)

I dreaded the day that I would have a vacuum leak and would have to trace down the source. Well, the day came this morning. I'm planning to just delete the whole SAI system. I've already found a tuner that can delete the MIL light, found the vacuum diagram, and a butt load of research.

Just one more question before I start, since my car is AMU, none of the guides I cam across discussed what to do with the hose that goes to the "Vacuum box for pressure control valve" from the N122. I will be deleting the combo valve, so do I just vent the vacuum box line to atmosphere?

Its the hose with the alternating blue strip


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## Huw403 (May 3, 2015)

stickman007 said:


> I dreaded the day that I would have a vacuum leak and would have to trace down the source. Well, the day came this morning. I'm planning to just delete the whole SAI system. I've already found a tuner that can delete the MIL light, found the vacuum diagram, and a butt load of research.
> 
> Just one more question before I start, since my car is AMU, none of the guides I cam across discussed what to do with the hose that goes to the "Vacuum box for pressure control valve" from the N122. I will be deleting the combo valve, so do I just vent the vacuum box line to atmosphere?
> 
> Its the hose with the alternating blue strip


As a newby, what is SAI, AMU, and N122? I've done loads of EU talk but can't figure this out!


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## stickman007 (Apr 21, 2015)

SAI = Secondary Air Injection (includes the Combi-Valve, Secondary Air Pump, and the N122 Valve)
N122 = is the valve that sends vacuum to "activate" the combo-valve allowing air from the pump into the exhaust
AMU is the engine code for North America spec 225q (maybe else where? I don't know)


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## Gone (May 5, 2009)

SAI injects air into the exhaust upstream of the cat when the engine is cold. The idea is to provide extra oxygen into the exhaust to complete the oxidation/combustion of the fuel after the cylinders, to compensate for the lower catalytic converter efficiency when cold and reduce hydrocarbon emissions while the engine and exhaust warms up.

It's one of those things that was put there with good intent but a cynic may argue its a lot of extra trouble for very little real gain, and in some cases can lead to more trouble. On some GM models for example, the no return valve on the SAI line can fail open under the heat and this then lets exhaust gases flow back up the line into the breather system, which ultimately then sludges the sump. Never heard of that on a TT though.


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## stickman007 (Apr 21, 2015)

No body can help?


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## Grahamstt (Jul 22, 2008)

You seem to have an extra pipe to your wastegate - could be North American spec.
The SAI should be straight forward to delete, use a blanking plate(Forge) at the engine end remove the motor and trunking and relevant pipe work. You can put a resistor into the connector to stop the mil from coming on, then you can remove the breather pipes from under the manifold and lead one from the large block breather pipe to the cam cover breather (Tpiece) then to the rest of the breather system or to a catch can/tank if you want to fit one.

This doesn't address the other pipes under the manifold to do with the n247 to the diverter valve. Search for a "how to"

Mine is a APX engine code but yours will be similar


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## stickman007 (Apr 21, 2015)

Thank you!

I think the AMU euro equivalent is APX? After doing some more reading, I think the hose in question causes the waste gate to open allowing SAI air into exhaust whenever vacuum is applied. Still no confirmation though. I will be deleting the SAI system as you described, and run with MIL until my tuner can mod the map. I will leave the hose in question to atmosphere just in case.


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