Background:
The Mabotech M720 is a prototype turbocharger that has been installed to record performance data.
This post compares data logged with the M720 turbo with that logged using the Mabotech M520 turbocharger. Significantly, the ECU tune has not been updated for the M720 turbocharger, which is larger than the M520.
Test Process:
The data is recorded during a full-throttle fourth-gear pull, starting around 2,000 RPM and concluding at around 6,500 RPM.
Two pulls are made with each turbocharger, and the measurements are averaged.
Test Results:
In the following charts, the M720 results are shown using red lines, and the M520 results using green lines.
The outside temperature during the data collection for each turbo was unchanged.
The intake air temperature is nearly the same.
Note: This is an interesting outcome, considering the potential effect of compressor size on intake air temperature. This temperature is measured after the intercooler has contributed to cooling the air, and it likely dwarfs any impact that differences in compressor efficiency have on the intake air temperature.
The larger M720 builds boost more slowly than the M520 and holds a slightly higher pressure past 5,800 RPM.
The M720 wastegate is higher than the M520, a finding that was discussed in the first drive post.
The vehicle acceleration data, processed using Virtual Dyno, shows a substantial jump in peak wheel horsepower.
The ~100 whp increase is greater than I was expecting, considering both turbos are operating at approximately the same boost pressure.
| Property | M520 | M720 |
|---|---|---|
| Peak WHP – 1 | 504 | 605 |
| Peak WHP – 2 | 505 | 598 |
| Peak WTQ – 1 | 484 | 504 |
| Peak WTQ – 2 | 478 | 485 |
Conclusions:
A Mabotech prototype turbocharger was compared with a Mabotech M520 turbocharger, where both turbos operate using the same M520 ECU tune.
The larger M720 generated a similar boost curve to the M520 while making approximately 100 whp more.