Boost spike

[Adamwagg]

Hi guys a mate of mine has a 2.5 TDI he has changed maf sensor,map sensor,n75, he is running a hybrid but even on the old turbo it was spiking any ideas what we can look for

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[ozMatt]

does your mate have a tune on the TDI? If the hybrid turbo doesn't have a tune to suit it will probably spike like mad when it comes onto boost.
was the old turbo stock, or another hybrid?

[Adamwagg]

Old turbo was stock and mapped and the old one spiked as well

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[Adamwagg]

Also the old turbo blew after a map which caused him to buy the hybrid do you think it can be the mapper

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[diagnosticator]

Make sure there is no restriction in the N75 control pressure/vacuum hoses and to the DV, and that the DV is working right.

[Adamwagg]

If it's a diesel it won't have a dv??

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[ozMatt]

Also the old turbo blew after a map which caused him to buy the hybrid do you think it can be the mapper

the hybrid will need a different ecu tune. If the tune is written for a stock turbo it won't suit the extra flow coming from the hybrid. Any boost spikes you had before will be worse with the new turbo.

Also, what Diagnosticator said, check the vac lines from the turbo/wastage/N75. If one of these is compromised it could cause/contribute to the boost spikes.

[Adamwagg]

It's been in to get mapped today it's still doing it it's soo odd as the turbo is still boosting as the revs drop 😟

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