An age old question of what is better, road tuning or dyno tuning? We won't get too much into that here as we feel they both have their place and a combination of the 2 is always best........and we don't want to start an argument!
The owner of this car came to us for some tuning on his apexi power fc, after we felt his setup had outgrown the apexi ecu we switched him over to a more modern unit, the Ecumaster Black. The car was transformed, even something as simple as starting the car from cold, it was better in every way and drove far smoother after some careful calibration. We took the car as far as we felt safe on the day and it felt fantastic, we were all very happy with the car.
The owner then took the car to a local dyno and did a power run. 326bhp.... not quite what we were expecting for the spec of the car and the way it performed, so has something changed or did we not push the car hard enough to get the best power? Impossible to tell as it has been taken to a different tuner to where the car was tuned, you are never going to get an unbiased opinion and he isn't likely to go looking for faults with the car, of course the tune will end up getting blamed. Not every tuner is like this, but it is the norm rather than the exception which is a shame.
Best way forward? Get the car to a local dyno and we will go over and run the car to see what can be done. We get to J's garage in Attleborough where the car has been dropped off for us to run and investigate, lets go in with open eyes and run the car exactly as it came in. Result? 335bhp, not far from the previous low powered run and to be expected between 2 different dynos on 2 different days but still low.
So lets investigate and see what is going on, a look over the logs did show the car had been running lean, the knock control had been picking up some detonation and retarding the ignition timing. A look over the engine bay and the issue became obvious. A mouse had found a sweet tooth for some silicone hose
It just so happened the silicone hose he liked the look of was the fuel pressure regulator boost source, this meant the car was running rich off boost and lean on boost as the fuel pressure was not referenced against the pressure or vacuum in the inlet manifold. After fixing this and some very minor clean up of the fuelling for a cool day but no other changes we had the following
That is much closer to what we and the owner were expecting from the spec of the car (forged engine, 264 cams, GTX3071r turbo at 1.5bar). Moral of the story is coming to light already, everyone blames the tuner. Thankfully this owner was a very nice guy and definitely wasn't coming at us with the usual attitude that follows a dyno session where the power made isn't what was expected so the process was smooth and pleasant, definitely a nice change!
We then spent the rest of the day creeping ignition timing in where we could, trying different levels of boost to see how it responded. After several hours of work the very best we could manage whilst still keeping a safety margin in mind was 392bhp
What this has showed us, is that we managed to get 97% of the maximum power the car could achieve on the road on a very hot summers day, was the dyno time worth it to find an extra 3%? Well that is for your to decide. If nothing else it's worth the time and money for the knowledge gained, if you are learning something you are not wasting your time. Most importantly, we had fun!
A worthy blog post to show that you shouldn't always blame the tuner when there are so so many things that can contribute to a lower horsepower reading than you were expecting!