In my latest pursuit for more power and response for my treasured Nissan S15, I recently embarked down the ECU tuning path by purchasing a Nistune Type 4 daughterboard and installed it into my stock ECU.
The next logical step for most would have then involved paying someone a visit (usually a workshop) to “tune” my car – I went down this route 8 years ago with my GC8 WRX. This time around however, I had better ideas.
Like most of you, I didn’t like the idea of leaving my beloved in someone else’s hands and paying wads of cash for something I had no idea about. Sure, they might be reputable workshops with professional mechanics but spending $1000+ (excluding ECU costs) for work that isn’t really laborious seems a tad exorbitant.
So what exactly is the “tuning” that workshops perform behind the scenes?
It’s no special dark art where ECU sacrificial rituals and voodoo ceremonies are performed just to get those extra “killawasps”. No… on the most basic level it essentially involves watching a gauge, adjusting boost, modifying some values in the tuning software whilst running your car on a dyno and then going for a spin on the road to ensure it’s all running correctly. Yup that’s pretty much all there is to it which makes it easy to question the value of using a workshop to tune your car.
So equipped with our Nistune license, software, laptop consult cable and desire to learn, Jay and I went about creating the “best” tune for my S15. How much power will Pearl get without blowing up anything?
Don’t let the video fool you though, creating the optimal tune didn’t take 2 minutes and 30 seconds… it took several days of road tuning and constant revisions as we didn’t have access to a dyno until the final tune. And now that we have an optimal tune for Pearl’s mods, we can simply apply the same tune onto another S15 with identical mods (cool huh?).
Now you’re probably wondering what we did exactly to achieve this increase in power…
Well in the case of the Nistune software and hardware, it allows us to modify the factory ECU maps on the fly. So whilst I was driving, Jay was on the laptop connected to the ECU monitoring, logging and tweaking parameters.
Without digging too deep into it, the two main variables that are changed are the timing and fuel values. These values are represented in cells within a table spread out across the rev range and load points. These cells need to be updated one by one to get the optimal results.
The idea is to keep adjusting these values ensuring that the air fuel ratio (AFR) is within certain thresholds and there is no knock or preignition. For the former, a wideband AFR gauge is compulsory and for the latter you have to rely on your aural senses unless your ECU has visual knock detection or headphone input.
Staying between 11.2 and 12.5 AFR when your car is on wide open throttle throughout the entire rev range is what every tuner aims for, it’s the sweet spot that makes your ride really come alive. Too rich (low AFR) and your car will lose power and burn more fuel yet too lean (high AFR) you risk detonation and engine damage.
Of course there are other settings like air flow meter scaling and injector scaling that come into the tuning equation but bear in mind this isn’t an in depth guide into tuning, I’m just giving you an idea of what the whole “tuning” process involves.
When it comes time to buying your piggyback or standalone ECU, it is completely up to your needs and budget. For a piece of PCB with some resistors and circuits expect to pay anywhere between $400 and $3000, but you do get what you pay for. On the higher end of the ECU market you will get features like launch control, dual maps, additional auxiliary inputs & outputs, etc..
Question is, do you need all the bells and whistles?
I just needed something simple, stable and proven which is why I chose Nistune.
So after all that hopefully you’ve gained some insight into the world of ECU tuning. The aim wasn’t to criticise the value of workshop tuning but rather elaborate on the work actually done so you know what’s going on because they certainly won’t tell you.
As straightforward as it I’ve made it sound, ensure you get someone who knows what their doing to work on your tune because it’s pretty much brain surgery on your treasured ride.
So Jay, when are you fixing up my tune? 🙂