Garrett Turbocharger Issues with VW Engines?

Hello everyone,

Yesterday, I happened to come across the page http://www.egarrett.com/products/gt_15_25.jsp, and it raised a few questions for me. Perhaps the 'turbo' experts could help me identify where the logical fallacies lie.

The GT17 (=VNT15) is specified in the diagram up to a maximum of 72 kW, and it only achieves this maximum value with a compression ratio of approximately 2.45. This would translate to a relative boost pressure of 1.45 bar at an atmospheric pressure of one bar.
For example, the AFN uses this type of loader. However, it only operates at a pressure of 1-1.1 bar, but still delivers an output of 81 kW.
Should I understand that Volkswagen is operating the charger completely outside of its specifications?

The same principle applies to all other types of chargers.

It also raises my suspicion that the text recommends the GT25 for gasoline-powered vehicles with a maximum output of 210 hp (154 kW). However, in the diagram, I only see a reading of 135 kW for the GT25.

I would be grateful if someone could explain this to me.

Regards,
Private.

PS: Initially, I wanted to know what additional modifications could be made to the VW chargers. Now, however, I'm leaning more towards reducing the boost pressure.

Should I understand that VW is operating the charger completely outside of its specifications?


Um, power has absolutely nothing to do with boost pressure...
My 1.9 TDI engine produces 66 kW of power at a boost pressure of 0.9 bar.
The Koleos 1.8i also produces 66 kW of power and has absolutely no turbocharger boost, but it revs much higher.
The air mass is typically displayed on the x-axis.

The power curves at Garrett are complete nonsense because you can't simply choose a turbocharger based on a rough estimate of the required power output.

The charger must be sized to provide the desired charging pressure even under the most unfavorable flow conditions.
Therefore, it must not exceed its maximum RPM (which corresponds to the maximum air mass).
It must not be operated beyond its maximum pressure ratio, otherwise it will start to surge. Therefore, always operate within the compressor operating range.
And in that case, I don't see any problems with engines that haven't been serviced.

CU Gremlin.

Does anyone perhaps have the correct charger identification fields?

Best regards, Rudi.

...and I don't really see any problems with engines that haven't been tuned.
Okay, I honestly didn't think Volkswagen was that clueless. But this is specifically about tuning with increased boost pressure. That's why I'm looking for suitable diagrams showing the compressor map, so I can better estimate at what engine speed (air mass) you can safely apply a certain amount of boost to the turbocharger. I'm hoping to find areas where Volkswagen doesn't push the boost as high as the compressor map would allow.

...the charger must be sized such that it can deliver the desired charging pressure at the most unfavorable flow rates.
Therefore, it must not exceed its maximum RPM (which corresponds to the maximum air mass).
He must not be loaded beyond the maximum pressure ratio, otherwise he will start to surge... so always operate within the compressor operating range.
That is exactly what I intend to do, but as close as possible to the edge of the compressor detection field .


...the curves at Garrett are complete nonsense because you can't simply use a turbocharger with a rough estimate for a specific power output... the x-axis usually represents the air mass .
Thank you for summarizing it so clearly again . That's exactly how I would have envisioned it. However, I haven't been able to find any corresponding identification fields for our loaders yet.


@Everyone:
Does anyone perhaps have compressor maps for common turbochargers (Wastegate, VTG 15, 17, 19, 20) and would be willing to send them to me? (Also happy to receive them via PM/email)

I would really appreciate it and would be happy to return the favor.

Regards,
Private.