Throttle Response & Boost Build-Up

Hello,

As described in another thread, I had to extend my VTG (Variable Turbine Geometry) linkage again. Unfortunately, the car now feels significantly less responsive. It doesn't react to the accelerator pedal as quickly as before. With the shorter setting, it almost felt like driving a gasoline-powered car; even the slightest movement of the accelerator pedal translated into forward motion.
I've noticed that when I suddenly accelerate from mid-range RPMs (above 2000 RPM), it takes approximately 0.5 to 0.7 seconds to reach maximum boost pressure. Before, it was noticeably faster (G3 AFN).
How responsive is your car to movements of the accelerator pedal?

Best regards,
René K.

Hi.

My G3 AFN (with the larger intercooler) responds so well to the throttle above 2000 rpm that I don't feel any turbo lag.
However, it's possible that drivers of TDI vehicles are inherently more tolerant .

I only notice a significant delay in power delivery when in higher gears, below approximately 1400 rpm (depending on the incline and how quickly the engine can rev up from an initial pressure of about 0.3 bar – in that case, I can see how the boost pressure follows the engine speed).

"0.5 seconds to reach maximum pressure above 2000 rpm seems a bit long to me."

The ASV system is also very sensitive to gas movements, definitely more so than my previous 1.4/60 horsepower gasoline engine, although that could also be due to the significant difference in power.

I definitely agree with Ulf regarding turbo lag, and also concerning the engine speeds.

Best regards,

Jan.

Hi,

Thank you for the quick responses.
Here's another question: As long as the engine control unit doesn't deem it necessary to reduce the boost pressure, the VTG linkage is pulled as far as possible into the housing to build up pressure as quickly as possible, right? (This means maximum tension on the control valve?) Or, even at partial load, is it sometimes proactively adjusted back to prevent sudden pressure spikes as the engine speed increases?
What I also noticed after the extension is that my LDA is now wobbling at idle speed, which it didn't do before. However, the vibrations have decreased... which is very strange.

Best regards,
René K.