Grand Prix Circuit

3 min read Original article ↗

This page contains projects about the game Grand Prix Circuit (GPEGA to its friends), and links to useful resources.

Don Matrelli’s Legacy

Don Matrelli’s Legacy is a mod featuring:

  • Three new tracks
    • Circuit de Spa-Francorchamps
    • Baku City Circuit
    • The Möbius Space Dragstrip
  • Three new cars
    • Rivella, with great maneuvrability and acceleration
    • Anglo-German, the fastest car but with tricky handling
    • Gastón Martini, for people who like hard challenges
  • A full set of new opponents, stronger than the original ones
  • A 23-letter German word

For more images and videos, see the release announcement.

As for any good game of the past century, reading the manual is an important part of the experience.

Making of

Stressed – GPC edition

The tool stressed (STunts RESource EDitor) is an application by Daniel Stien (“dstien”) allowing to edit the resource files of various games developed by DSI. Here we present an extended version supporting the .PES files of Grand Prix Circuit. Further developments targeting .PCS files (CGA graphics) and Test Drive might be possible in future.

Note: Set Options / Compression Format to the correct value before opening a file.

  • Stressed for Windows, 2026-06-24 (password-protected, password = stressed)
  • Stressed for Linux, 2026-06-24 (password-protected, password = stressed)
  • Source code
  • Wikipage The page concerns the base version, which only supports Stunts, but should still be regarded as the official reference.

The Linux release is offered as best effort. It should work on several distros, but building from source is advised.

Vehicle editors

There are two editors able to customize the performance of Grand Prix Circuit’s cars.

CyclesMod

CyclesMod is a Java tool by “albertus82”. It works by patching the GPEGA.EXE executable and creating a new one with the modded cars

GPC Vehicle Editor

The tool used to develop the cars in Don Matrelli’s Legacy. Made in C++ and Qt, mostly vibe-coded using cyclesmod as base. It reads and writes the 444-byte array containing the data of the three vehicles. One can start with an empty array, or extract the baseline from a dump of the data segment when the game is running:

dd if=data-segment.bin of=vehicles-array.bin bs=1 skip=$(( 0x75f2 )) count=444
 
The McLaren engine data in the base game. Notice the innatural boost between 9 and 10 krpm: likely a last-minute adjustment by the game developers.

Comments

No GitHub account? You can also send me your comment by mail at [email protected]