NefMoto

I'm re-doing my front mount pipe work and don't have a take off nipple anymore for the N75 valve.

I'm thinking I'll just run it to the inlet manifold instead. In my head it might actually run better. My main concern is that it's the other side of the throttle body, and the N75 will also see vacuum.

Will this be a problem? Anyone tried it? Thoughts?

Cheers

It'll dick with pressure control. If you have a part throttle / high boost situation, the waste gate won't open to release boost pressure. If anything, it'll be getting 'sucked' shut which will increase the cracking pressure.

Drove the car for the first time today, appears to be OK at the moment. I will keep a keen eye on the boost gauge and see what happens

Just went it to atmosphere if you have no place to put it, DON'T plug it into the intake manifold.
For the boost reference it HAS to be from the turbo compressor cover or worst case past that pre-intercooler....

In part throttle situations you have the potential to blow up your intake tract with huge boost pressures. I don't see WTF your boost gauge has anything to do with that, when the pre-tb and pre-ic pressure will be insane.

To anyone reading this, DON'T be like this guy.

It's the boost source of the N75 I moved to the inlet manifold - if I vented it to atmosphere it wouldn't work.

Has anyone used these boost hose nipple take offs before? Do they seal OK?

IMO the main question is of how tolerant the new setup is of large boost spikes.

Using the manifold as a ref pretty much limits how extreme those can be

Plumbing the ref before the throttle plate can present the n75, the wg, and possibly the intake (if vented to intake) with large spikes.

Neither are a good thing, IMO. N75s are already notoriously failure prone.

PRJ has me worried now, so not driven the car hard at all. I've pretty much kept it off boost.

I don't understand how it could be a bad thing. In my mind, the boost pressure inside the manifold is more important than the pressure at the turbo.

I'm obviously incorrect in my thinking, so if anyone could explain, it'll be much appreciated.

I thought prj did a fine job explaining why.

It doesn't explain it well enough for me to understand.

At partial throttle, the throttle plate will restrict flow, but surely it wouldn't affect the pressure. Is this where I'm incorrect?
Perhaps it's the time difference between the turbo producing the pressure to the N75 seeing it?

I'm not saying I'm right, your wrong, or I don't believe you, I just want to understand it - and at the moment, I can't.

At the end of day, if you experienced and knowledgeable people say it's no good and I need to change it, I will.

The wastegate pressure control system does not want to see vacuum. Also, yes there is some delay from the outlet of the turbo, and the inside of the manifold. Earlier input to the wg is better. Lastly, those boost taps work fine. What's the big deal with adding a nipple somewhere close to the turbo?

Nothing wrong with adding a nipple, it was just easier to use an empty nipple on the intake.

I'll get a nipple ordered up and change the setup.

That's exactly what you're incorrect about. The very basic physics.
Flow restriction provides a drop in pressure across throttle plate depending on opening angle.
You can have vacuum in the intake manifold and 1.5 bar pressure pre-throttle in some cases. Ponder on that and now think why what you are doing is a HORRIBLE idea.

I have connected the 1.8T N75 boost pressure source input to the intake after the intercooler before the throttle body. The primary effect was to raise the boost pressure reference by the same amount of pressure drop through the intercooler core. Running stock and APR 1+.

Why though? N75/WG is used to keep shaft speed of the turbo sane. ( limiting boost) That drop/pressure before throttle is modelled in ME7 with the intake manifold model.. If you put boost reference after intercooler you gonna be pushing the turbo more than you should. KO3 has very high shaft speed at 18 psi + or so and you also run off the efficiency map at high rpm and using it as a heater, so if you run 18 psi after intercooler you are essentially spinning the turbo even more....

I still use K03-026 in my 1.8T (1984cc stroker), 10,4:1 CR, E100, boosting up to 24psi peak. Using this setup for 18 months now.
I'm impressed of how strong this oem turbos are.

Its strong until the shaft literally shatters and destroys the engine. You are literally asking for it with those boost levels. Atleast upgrade to a KO4/hybrid with k16 comp wheel/turbine , to get same boost & better perfomance/flow with  lower shaft speed.

Yeah, I'm aware of that. In one or two weeks, I'll start disassembling my car to finish the project. K03 was never in my project, its just that here is Brazil things are so expensive, and in this time I was doing another thins to the car.
Soon I'll be with 400whp, with a proper turbo, etc... if you have instagram, see my project at @a3stroker.