Manual Boost Controller

[Verkmiester]

Hello all,
I have an S3 8L ive imported from Japan to Canada. Been fixing everything up for 4 months and have the car almost perfect. The last issue I have is my wastegate spring has become weak with age and has started opening too early. The car has a stage 2 tune now which is requesting 22psi, however, my actual boost is closer to 16psi.

I have a manual boost controller from my old car I was going to try and use to get the boost closer to the requested amount. Because the car is tuned for 22psi I figure this would be a one-off situation a MBC might actually work with our cars.

The question at hand is how would I hook it up with the N75 to accomplish my goal?

Any input would be greatly appreciated.

 

[MrAudi2017]

Why don't you just get a new actuator rather than going thru all the faff of doing this? Also are you sure it's not something like a boost leak?

As you already know that these engines don't like it you've kinda answered your own question.. it's better to nut up and replace the actuator

 

[desertstorm]

As above, fix the problem , don't try and codge it. There can be other issues that will cause low boost such as boost leaks, Have you had the car smoke tested ?.

 

[Stuart B]

Considering the N75 controls the actuator and will hold back actioning the actuator until hitting the desired readings. Putting an MBC there instead surely won't make any difference will it? Isn't actuator pressure 6psi ?
Most 22psi maps are only 22psi for a few revs aren't they say 4-5k rpm?

 

[<tuffty/>]

If your map is requesting 22psi but the turbo can only make 16psi then an MBC won't fix the issue...

Replace the actuator...

Do not fit anything uprated though as the map is expecting to see a standard one... fitting something stiffer can result in a boost spike followed by rods exiting the block...

MBC's serve no purpose on a modern car like the S3... I have used one in the past on my big turbo setup before there was a better understanding of how to map boost over 22psi (ECU can't see boost over 22psi)..

The S3's ECU and map strategies are very different to older turbo cars where you would have needed to use an MBC...

Fix the hardware issue... log the car in VCDS... it may not just be the actuator as the turbo's get tired too...

I assume you are only getting 16psi max? as K04's won't hold 22psi much past 5.5k/6k rpm

<tuffty/>

 

[badger5]

Hello all,
I have an S3 8L ive imported from Japan to Canada. Been fixing everything up for 4 months and have the car almost perfect. The last issue I have is my wastegate spring has become weak with age and has started opening too early. The car has a stage 2 tune now which is requesting 22psi, however, my actual boost is closer to 16psi.

I have a manual boost controller from my old car I was going to try and use to get the boost closer to the requested amount. Because the car is tuned for 22psi I figure this would be a one-off situation a MBC might actually work with our cars.

The question at hand is how would I hook it up with the N75 to accomplish my goal?

Any input would be greatly appreciated.

if the ecu's trying to achieve the requested boost on block 115, and the actual n75 duty cycle on block 118 is >95% and still not achieving it, then an mbc will achieve nothing. The actuators gone soft and needs replacing.