968 Turbo boost problems whilst mapping

Talk and Tech about turbocharged 924/944/968 cars
Rickuk1
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We are having problems making boost on my new 3.0L 16v turbo build. The power delivery is very linear and almost low compression supercharger like in its delivery

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Tom
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Rickuk1 wrote: Wed Mar 19, 2025 8:57 am We are having problems making boost on my new 3.0L 16v turbo build. The power delivery is very linear and almost low compression supercharger like in its delivery
Looking for help? Not a lot to go on there...

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Rickuk1
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Sorry struggling to reply it keeps deleting my comment’s

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Rickuk1
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When we are mapping the car we are struggling to make boost it appears that we are running on spring pressure approx 10psi until we reach about 4500rpm when the boost builds towards the 1 bar threshold we have set. The turbo is an efr 7670 twin scroll setup we have checked the obvious things boost pipes vacuum lines all seems ok. We are running a vems ecu from a similar 968 turbo set up but are not convinced the ecu is set correctly or is faulty the vario cam was not switching in and off and has to be reassigned a new port any ideas or experience with vems

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Rickuk1
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We also didn’t make any more piwer when we increased boost to 12 bar

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Tom
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What are you using as a boost controller?

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Rickuk1
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An N75 valve

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Bergerac
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You could always ditch the electronic boost control and run a manual valve to if its an ECU/valve issue.

What header/crossover/wastegate setup are you running? I would have though you'd be over the limit of the stock setup with a turbo that big.

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Rickuk1
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It’s all custom headers and exhaust and two turbo smart comp gates

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Rickuk1
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