April 2025 – Maxim's Blog

Further Disassembly

A lot more progress tearing down the motor ready for the thicker head gasket and head studs. As you can see the condition is great for 121,000kms and a lot of track days.

The head gasket I purchased is to suit an 81mm bore whereas OEM size is 78mm. Speaking with my tuner, a machinist and Cometic (gasket manufacturer) they all advised this oversizing will be fine. This does slightly concern me as R’s Racing Products and Monster Sport both list 81mm bore as “bore up” or oversized bore spec for us non-Japanese.

I also fit the baffled sump plate from R’s Racing Products that I’ve been holding on to for almost 5 years now…

I managed to find the ECU pinout in an obscure Facebook group buried in the comments of a post from 2014. God bless Ka Po W and his Yellow Power Ranger. Wiring diagram table to come in my next post.

Teardown

I had a good day today tearing down everything in order to remove the engine and make way for turbo related parts.

The oil cooler will need to be relocated and the exhaust system up for sale at some point. It’s SuperCircuit headers, RRP mid-pipe and an X-Force catback.

During disassembly I noticed the passenger side gearbox driveshaft seal was weeping a little gearbox oil. As this constituted an order from Suzuki, I also go the opposite side, the OEM oil cooler o-ring, rear main seal and axle nuts.

The engine is now ready to come out, only the mounts remain. Working on the Cube and this car compared to the VR4 really makes you appreciate modern engineering and design for assembly (and disassembly). Both the ZC32S and the Cube allow the engine harness to be disconnected at the ECU, the front bolts off and the drive assembly can simply come out the front – beautiful.

Head Drilling

Unfortunately, the ZC32S head doesn’t have all exhaust manifold holes drilled and tapped – unlike the ZC31S. I only heard about this reading the documentation from the shop in NSW (One Stop Mechanical) that originally fit the turbo to the ZC32S I purchased the kit off. I later confirmed this was the case when I removed my extractors from my current setup.

I did my best to mark out holes but wasn’t entirely happy with how I had measured and drilled.

With how tight the holes on the HKS manifold are to the M10 studs, you don’t get much allowance for error. With this in mind, I decided to only tap the 4 extra holes to M8 (instead of M10) to give myself a bit more room to play with. This worked out great.

My only remaining concern is the depth of one of my drillings. It’s 1-2mm deeper than the factory drillings. Looking at the casting, I think we are fine. Famous last words?

Injector Selection

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.

My Suzuki Swift Sport ZC32s

Purchased in late 2020 with 67,000 kms this car was to be my new daily.

I attended a track day at MTA Wodonga (Logic Center) one week after purchase to get an understanding of the car in factory trim. This ZC32S was to build on learnings from our previous two swifts and become a street registered “track” car. You can read about my previous cars here.

In 2025 I picked up a HKS turbo kit suit ZC31S that had previously been fitted to a ZC32S. A large driver for this blog was the documentation of this phase of the build.

Current mod list: