30 Nov 2017

DIY Unichip Re-Tuned Innova Crysta

In one of my earlier posts I wrote about getting the Unichip for my Innova Crysta, which at that time was the first Toyota 2.8 GD Diesel engine in the country to get a proper custom tune. Being the first to experiment with a particular make/model in a country not known for tuned cars or tuner culture has its downsides and being a guinea pig is one of them. Unichip is a universal piggyback ECU and not a pre-programmed Diesel tuning box. And being a universal piggyback ECU the tune will only be good as the tuner, and chances of getting a crappy tune is quite high and I got a not so great tune from the tuner.

Re-tune upto my satisfaction never really happened. But all was not lost because I could tune it myself now (read below). In my installation and the tune I finalised Unichip was programmed to do these functions only 1) Rail pressure, 2) Boost control, 4) Injector duration and 5) SOI. The rest including safety features were turned off.

I was interested in becoming a Unichip agent myself since I believed the kit has potential if tuned well and I talked this with the main dealer and signed up as the Unichip agent in my region. This also gave me access to Unichip software.

Now I had Dastek's software and some very limited amount of documentation to get me started with reprogramming my Unichip. Each Unichip plug and play installation is specific for that particular make and model of the vehicle and often the kit will have additional modules apart from the main Unichip and the tuner gets access to the documentation relevant for that kit. Unfortunately I did not have access to the documentation for this kit or the Diesel specific information. But when you get a lemon you make lemonade Any how I decided to work with what I have and see what I can do, for now.

The tough part was the closed nature of Unichip and there was not much information available on it outside their network and this is a system that is new to me and the lack of relevant documentation put me in a spot. I went through whatever relevant documentation I could get my hands on even if that was for another manufacturer's piggyback. Once I gathered all the info I could possibly get I got on with programming, testing, reprogramming, and retesting. Lucky for me I chanced upon a Unichip competitor documentation and decided to try a different approach and made a completely new map based on what I learnt there. This proved to be a huge success and used this approach to build a new base map, rest is easy now.

If more power is needed a larger bang needs to be made inside the combustion chamber and for a larger bang more fuel and air needs to be delivered. While making larger bangs be careful otherwise engine would just go bang.

I had to burn a lot of midnight oil and Diesel doing the testing but the perseverance paid off finally I made a tune for my Crysta that I am kind of proud of. With Unichip my guesstimate would be around 230BHP and 450NM at the crank. Its time to put it on a dynamo-meter and measure the actual power output.

This is what I paid for when I decided to get the Unichip, if I never had the software it would have been a huge loss. But in hindsight would i buy the Unichip again? The answer is a big NO. The tune is only good as the effort the tuner in India puts into the tune.


Update: 230BHP and 450NM at the crank was a consevative figure when i guessed?!! I am surprised by the results myself. It made 214BHP 567NM at the wheels!