M520h Tuning Progress

Background:

In August I had reinstalled the Mabotech M520h turbo into my GTI after wrapping up testing with a variety of front mount intercoolers. I decided to give the SimosTools option a try and have been working with Russell Road & Racing on the tuning.

Tune updates have been adjusted for hardware changes, and this post highlights some of the significant changes and results thus far.

Parts:

Recent hardware changes include a switch from the Baun Performance 4″ catted downpipe and 3.5″ midpipe to a Trackslag catless downpipe and Baun Performance 3″ midpipe.

The AWE Track exhaust was changed out for the Baun Performance exhaust.

Baun Exhaust to Trackslag Swap
Baun Exhaust to Trackslag Swap

The intake setup has been changed often, the most recent being the switch from the AMS intake, which is using the lower half of an R600 airbox, to the APR PEX open intake.

AMS Intake / R600 Enclosure Tray
AMS Intake / R600 Enclosure Tray

The APR PEX intake is being used with an MST inlet hose.

APR PEX Intake
APR PEX Intake

Note: For those who are concerned that I am using a “hot air” intake, I’ve previously tested the APR PEX intake, measuring the air temperature inside the inlet elbow, and found the temperature to be comparable to that of the Eventuri closed intake that I sometimes use.

D9 Final Temperature above Ambient
D9 Final Temperature above Ambient

Another change was to install the IE V1 stock location intercooler and a Vibrant 12810 front mount.

Vibrant 12810 Bicooler
Vibrant 12810 Bicooler

Note: The straps are temporary until I can purchase an adequate drill bit to install the IC onto the crash bar.

Results:

Of most interest was how the change would affect the turbocharger wastegate duty cycle:

M520h WGDC - Catted (R7) vs Catless (R7-TS)
M520h WGDC – Catted (R7) vs Catless (R7-TS)

A decent 10% decrease opens up the possibility of raising boost pressure further.

M520h Boost Pressure
M520h Boost Pressure

The boost onset time is reduced some with the catless downpipe.

M520h Boost Onset
M520h Boost Onset

The bicooler is doing well maintaining consistent intake temperature:

IE+Vibrant Bicooler Trend
IE+Vibrant Bicooler Trend

Virtual Dyno estimates of wheel horsepower and torque show some increase, +11 whp/+12 wtq:

M520h vDyno Comparison
M520h vDyno Comparison

Note: A single pull is insufficient to ensure the increases are accurate.

Next:

The hardware setup is finalized for now, and only software changes will be made until I record the “final” numbers for this configuration.


A future update will replace the stock intake manifold with the Mabotech intake manifold.

Mabotech Intake Manifold
Mabotech Intake Manifold

9 thoughts on “M520h Tuning Progress”

    1. The need to use an inlet adapter, elbow in this case, makes the intake choice a tossup. In the future, I’d like to use a turbo that eliminates the elbow, and there are signs that with that setup an open intake might be beneficial.

  1. Kim Laulund Rasmussen

    Impressive build!! Since it is a GTI and front wheel drive, how does it put down the power to the road?? All wheel spin in 1,2 and 3 gear or??

  2. Thanks for the reply.
    Do have any ideas on how to make the spin less?? Reading on MQB tunings sites, many are talking about fitting stiffer and harder springs to the rear. Making the rear drop less under acceleration and the front wheel grip better. The Audi RS3 8V springs will fit our platform. I believe it is worth a try😎👍

    1. Jeffrey Jones

      I don’t know, I get wheel spin at 70 mph in 3rd. I have the Ohlins C/Os and don’t think I’m going to try swapping different springs. I’m interested in knowing if that works though.

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