The first part that required proper effort as part of the ZC32S turbo build was injector selection, well more injector fitment. Ideally, I wanted to retain the factory fuel rail and find a “drop in” injector solution.
Using Raceworks injector sizing calculator I found I needed approximately 600cc of injector to meet my power goals. However, after speaking my tuner – Rob from RM Performance & Dyno he advised simply go for 1000 cc’s to give me room for future upgrades and to increase my options when it came to physical dimensions.
So, go for the 1000 cc I did.
First point of call was Bosch 1000cc ‘EV14’ injectors. This was because they come in 3 lengths and have publicly available CAD data and decent technical drawings – awesome.
After looking at injectors online for hours and 3D printing some of the Bosch CAD I decided on using the Raceworks modified Bosch 1000cc to suit the “square” lower seal and 11mm o-ring that Suzuki Swift Sport fuel rail has.
The modified 1000cc injectors fit a treat. The only downside was losing approximately 15mm of extended nozzle like the factory injectors have. Speaking with Rob, this is of no concern due to the spray pattern. Additionally, stalking some of the turbo builds in Japan I can see they also use larger injectors with no extended tip, backing up Rob’s advice.
I migrated the upper rubber “seat” and o-ring (making it 2x 11mm o-rings total in the top groove) from the factory injector and added them to the 1000cc injectors, this made it a snug fit in the stem on the factory fuel rail. I am yet to pressure test it but I the engagement feels identical to the factory one.
Due to the slight difference in height between the 2 options, I needed to make a longer plastic spacer to raise the rail circa 4mm to suit the new injectors. I did 3 prints in 0.5mm height intervals based on my measurements, the shortest (19.3mm total height) being the winner.
I also purchase some of these nifty 1pce “USCAR” to Denso adaptors (again from Raceworks), meaning they’re a proper bolt on affair.
