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Boost Pressure: Cold Engine & >2500 RPM

 
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Post01-07-2002, 20:30    Subject: Boost Pressure: Cold Engine & >2500 RPM Quote

Hello,
'Recently, I've noticed a phenomenon where the turbocharger pressure is lower when the engine is cold.'
It doesn't start building power until around 2000 RPM. After about 1-2 kilometers, it returns to normal and starts at around 1500 RPM.
At a slightly higher RPM, around 2500-2900 RPM, it drops into a small...
Power drop (no thrust), but it returns to normal after about 2 seconds.

What could that be?

Car: 1997 Volkswagen Passat AFN, 110 horsepower.


Translated on 12-08-2026, 23:14.
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Jan6K

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Post01-07-2002, 20:48    Subject: Boost Pressure: Cold Engine & >2500 RPM Quote

Um... I would never rev up a cold engine, especially a diesel, to 2500 RPM, let alone higher, and certainly not ask for full boost pressure from it.

Best regards,

January.
1Z5 CFHF / AHB H4D


Translated on 12-08-2026, 23:15.
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merlin
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Post02-07-2002, 15:31    Subject: Boost Pressure: Cold Engine & >2500 RPM Quote

It is clear that you should never stress a cold engine,..... but with my 150 HP TDI V6, I also have to rev it up to 2300 RPM when it's cold,... otherwise, it won't move,....... the turbo boost only kicks in around 1850 RPM,....... or how did you imagine it???? icon_smile.gif

Sure, here is the translation of the text from German to English:

'm' translates to 'male' in English.


Translated on 12-08-2026, 23:16.
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Jan6K

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Location: Hagen

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Post02-07-2002, 17:32    Subject: Boost Pressure: Cold Engine & >2500 RPM Quote

Does it still have a wastegate turbo? At least the ASV provides enough power from 1300 rpm to get moving, and it's clear that you can't achieve top performance with it, but that shouldn't be expected anyway. And the AFN (which was the subject of the first post) has a VTG turbocharger, just like the ASV.

Best regards,

January.
1Z5 CFHF / AHB H4D


Translated on 12-08-2026, 23:17.
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merlin
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Post02-07-2002, 17:43    Subject: Boost Pressure: Cold Engine & >2500 RPM Quote

HI JAN6K,...

My V6 TDI from the year 2000 has a VTG turbo,... and it's also a Quattro,... and to get going a bit faster,... it needs some power! Whether or not it's good for the engine,.... when I drive out onto the main road in the morning in heavy traffic,... I sometimes rev it up cold to 2100 or 2300,... I don't know what else I should do! The 4-cylinder TDIs have a clear advantage here, as they offer much more low-end power icon_sad.gif.

Sure, here is the translation of the text from German to English:

'm' translates to 'male' in English.


Translated on 12-08-2026, 23:19.
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