Words & Snaps by Ben
If you've been following this thread, you'll know the parts we got (POWAA Build Part I), how we assembled the engine (Part II), and how we got the first results with a traditional intake design (Part II).
149hp and 166.7Nm of torque was fun, but we still had an ace up our sleeves to squeeze even more power out of the 1.5L mill of my Vios NCP42.
With the help and R&D from the RZCrew Garage, it was time to install the individual throttle bodies (or quad throttles) and dyno the final results of the POWAA Build!
First up was the assembly and adaptation of the 4A-GE silver top throttle bodies to match the 1NZ-FE.
We machined a custom manifold and after some measuring, cutting, grinding, measuring again and more fiddling, it was ready to be installed.
While we were preparing the intake, the mantlepiece of the build finally reached: Link G4+ Storm ECU.
The Toyota factory ECU was giving us way too many issues - after a couple of weeks running the E-Manage Ultimate, it was already correcting the values given by the piggyback, and the car was running more and more rough. On top of that, the EMU wasn't going to be able to handle the tuning needed to run the ITBs.
The only way to fix this issue once and for all was to go for a standalone ECU. We chose the Link G4+ Storm over Link's other ECUs for its capacity to control the VVTi. As ITBs are known to rob the torque, we were planning on catching some back thanks to the VVTi. Full control over this system was also going to allow us to set its maximum angle setting and adjust the exhaust cam accordingly, without the risk of having the valves kiss.
We pulled in a couple of late nights to install the ITBs with the aim of being able to drive the car around until we finalised the last bits.
A selection of groovy '70s tubes later, and each cylinder had its own breathing hole.
While we were at it, we also installed the SARD aluminium radiator modified to make space for the intake, along with a slim Billion fan, to make sure the engine stayed cool when being abused.
With the throttle bodies in place, we were able to take the final measurements for the velocity stacks. For now, we used the stock angled scubas that came with the Toyota ITB so that I could drive my car to work and back while waiting for the trumpets to be machined.
We benched the car without the trumpets and got around 130hp. The measurements were not too accurate as this wasn't the usual bench, and a lot of parameters and parts were still missing. The aim was just to lay a temporary base map.
A week later, the velocity stacks were ready, and I quickly chucked the angles tubes aside for their shiny, straight counterparts.
With very little clearance between the velocity stacks and the hood, I couldn't fit an air box to prevent dirt, sand and any other unwelcome objects getting sucked in the engine. I had to improvise some filters, first by clamping some wire mesh between the throttle bodies and the velocity stacks, and then cutting an HKS foam filter and wrapping it around each intake.
The result wasn't sexy to look at, and after a couple of days I realised that the foam was being cut by the edge of the trumpets. I rethought the idea and decided to sandwich the foam between two layers of mesh, and clamping the assembly between the throttle bodies and the velocity stacks.
A much nicer setup to look at, but, as I was to learn later, a very problematic one too.
I drove the car this way for a couple of weeks, before I was finally able to bring it to Torque Racing for the final tune.
The moment of truth had come.
With the wiring fully done, my car was loaded on the bench and we let the pros at Torque Racing do their magic.
Before long, they started doing the power pulls and the result: 70bhp. Yes, you read it right. We checked the compressions, double checked the values, and it didn't change: an ultra low 70bhp.
It was as if the engine didn't breathe properly... And indeed, it didn't. Remember the filter sandwich I made? It turned out that it got dirty, and with the dirt clogging the foam, there was simply almost no air flowing through.
We quickly removed the filters and did a pull, that gave a healthy 140bhp. From there, the tuner dialed in new values, as this time air did get into the combustion chamber. Then we finally got the final results: 160bhp@ 7,900rpm and 169Nm@ 4,400rpm of torque at the crank (140.8hp and 148.1Nm at the wheels)!
That's a healthy 106 hp per litre, and a 47% horsepower increase from the stock 109bhp. Not too shabby for a 1.5L NA build!
The next natural step was to release the full stables on track, and boy do these horses pull hard! My previous record around the Johor Circuit was standing at 2:04.46. Upon my first outing with this new setup, I was already hitting 2:02.546.
I hit a new 2:00.829 personal record, but I know the car can go much faster, it's now up to me to practice up to her level!
I couldn't resist taking part in the 5-lap challenge at the end of the track day, see the race below and enjoy!
I finished the race in second position, right in between two pro racers in their race-ready Proton Sagas. Next time I'm aiming for no less than 1st! I can't wait for the next track day!