Porsche 944 2.5 litre gravel rally car projectMay 28, 2015
In 2011 after successfully rallying a Peugeot 504 in multiple outback and local rallies, we decided to build a Porsche 944 rally car using parts left over from the various race and tarmac rally cars that we had prepared over the years. This Porsche to be driven in gravel rallies.
Was this madness? I occasionally thought so at the time, but I went along with the idea, thinking that if it doesn’t work the car will be a good for classic tarmac rallies, pre 1985.
I picked up a very rough non-runner on ebay and bid for it sight unseen. From the photos the body looked OK and I fully expected to need to rebuild most of the mechanicals anyway. After collecting it, we had it running within an hour and it generally seemed OK. We proceeded to strip the interior, fit a roll-cage, seats and other safety equipment and most importantly fitted a custom made under-tray/sump guard. This proved to be the Achilles heel for the first few rallies as we had to bring the tray up high at the front to mount to the solid bumper-bar and air being very lazy, refused to go through the vents we had created, instead it decided to go around and so we had a few overheating problems. We cured this by creating an air dam, forcing air into the radiator and oil cooler and hence no more issues.
The engine was rebuilt with 10.5:1 compression, new rings, bearings and a flowed head and intake manifold. This resulted in a lift from 167bhp to 200bhp. All the other parts were re-used, even though the engine was full of sludge it had managed to remain in pretty good condition, a credit to Porsche quality.
Once all of the mechanicals were sorted over time, we decided it was time to put it to the ultimate test: the 2013 Classic Outback Trial !!! Two thousand five hundred kilometres through outback NSW, with around one thousand being competitive. After having thrashed the Peugeot through a few of these I knew that “suspension” was critical. We were pretty sure about the rest of the cars reliability but our suspension was inadequate for the rigours of the outback. The Porsche was designed as a road or occasional track car, not for outback Australian roads/tracks!!
We consulted the guru, Murray Coote of MCA Suspension in Queensland. He was delighted to help. The car went to Murray for a few weeks and he measured and calculated and produced a suspension to die for, I couldn’t wish for better, it is superb.
We were now ready for the big one, the Classic Outback Trial and the car did not disappoint. I have described the rally elsewhere, so I will not go into detail here, suffice it to say that the car performed amazingly, in most part due to the suspension. The only issue we had for the entire rally was lower control arm bushes which were early Porsche type and not up to the rigours of getting pounded over rough roads, (we have now replaced these with a later larger type bush). We used about 200ml of oil, several rally tyres and petrol of course and nothing else for the entire event. The car did the job beautifully.
The great thing about rally cars is you never stop fiddling with them, this is all part of the fun, so onto the NEXT PROJECT:
MrBrakes being a Bosch Car service Centre we have a very good association with Bosch Motorsport in Melbourne, so the engine management system or ECU on the 944, is being revolutionised with the help of engineers at Robert Bosch Motorsport (BMS). After an assessment, the guys at BMS recommended fitting a Bosch ECU and various sensors to drive this. We removed the old airflow meter and ancillary gear from the engine and fitted all nice new sensors, as well as plugs, injectors, a wide band oxygen sensor, fuel temp and pressure sensor and so on to bring the ECU into the 21st Century. This, as I write, is still ongoing and we are just waiting for crank angle and TDC sensors to be fabricated and fitted and we’re ready for the dyno and tuning.
I am very much looking forward to the next phase of this magic 944’s life, with its new technology.
The rally calendar for this car is: The State Bank of SA Re-Run in August, the Alpine Rally in December, the Classic Outback Trial in June 2016 and the Silver Fern in New Zealand in November 2016, as well as other minor events and test days that we can fit in. All the above are long distance events that the car and the drivers will revel in.
Stay tuned for more developments.