Recently I swapped out my IS38+ for the Mabotech M520H turbocharger.
I already had the Eurodyne Powertap Cable and Eurodyne tunes, so leveraging Mabotech for the tuning of their M520H turbo made sense since they support the Eurodyne tuning platform.
No other significant changes were made to the GTI when I swapped to the M520H turbo, which significantly means the fueling is still “stock” with the exception of an aftermarket HPA high-pressure fuel pump that I installed in 2020 during IS38 custom tuning.
The first tuning effort went straight to using E30 and the first couple of revisions were focused on refining the fuel trims for the Ethanol fraction of the fuel mixture.
Next, a couple of revisions were made so that the Eurodyne ECU tune would operate more smoothly with my customized Stratified TCU tune.
With the groundwork complete attention turned to increasing boost pressure to see what level of pressure the fuel system could support:
(Green lines are my IS38 E30 tune; Purple lines are the M520H E30 tune)
After about six (6) revisions we arrived at the boost curve shown below:
I did a series of ten pulls with this tune revision to record acceleration data to process using the Virtual Dyno application:
Peak wheel horsepower for each pull was then extracted to calculate an average:
Average and Median calculations are 403 WHP.
I was interested in trying to simulate an IS38 boost curve with the goal of producing a compressor outlet air temperature that is similar to an IS38. The reason is that if I want to compare intercooler performance when using the M520H with the data I recorded with the IS38 it would be important to have similar air temperatures leaving the compressor.
Frank at Mabotech made a couple more revisions to create the boost curve shown below:
The compressor outlet air temperature with this boost curve is shown below:
The M520H compressor outlet temperature is roughly 30-40 degrees Fahrenheit lower than the IS38+ turbocharger. A sample of the IS38 outlet air temperature is shown below.
While the temperatures are not drastically different, there’s enough of a difference that I don’t think I’ll be able to fairly compare intercooler performance from the use of the IS38 turbocharger to what is recorded while using the M520H turbocharger.
Mabotech M520H Next Steps:
Tuning progressed very quickly during this first round. It was not uncommon for Mabotech to have a tune revision available for me the same day I sent them data logs.
With fuel supply the current limitation on pushing more boost I’m looking into upgrading the low-pressure fuel pump along with adding multi-port fuel injection.
This will include shipping my candidate fuel injectors to Mabotech for them to perform a flow test to ensure the balance and quantity of fuel delivery are acceptable for the next round of tuning.