Hot Side Torqued

In my previous post I detailed how I planned to run the turbo lines and work around the oil cooler sandwich plate etc. Well, the parts arrived, and it went mostly as planned.

The exhaust manifold and turbo are now torqued up, good to go.

It took a lot of fiddling to get the oil pressure line to work without contacting either the exhaust manifold or coolant line. I ended up just re-using the HKS kit line with a 90 degree M-F swivel off the top of the turbo. The return line was simpler; however it took me 3 attempts to get the height just right. First it was to low (in the oil), too high (no room to weld), just right (I hope..).

I still need to clean the sump thoroughly for welding and drill the locator hole for the bung. Hopefully, how I have it now is above the oil line as I am finding the stainless braided line a real pain to work with. Even when taping the cut location, it still frays quite badly, making the fit up of the nut very difficult. The plan is to fill the sump with water post cleaning to double check the return is above the maximum oil level but I’m quietly confident.

I’m also hoping the coolant line is OK with the heat sleeve around, everyone seems to think so, but time will tell. Doing a walk around, admiring my work I also noticed the wastegate actuator was sitting on the block. I managed to pry it so there is a circa 2-3mm gap – “clearance is clearance”. The ZC31S block must be slightly different in this location as I can’t imagine HKS had this kit leave the factory colliding with the block.

Before:

After:

This marks the end of the “difficult” mechanical scopes, it’s now time to tackle wiring…

Here are some higher resolution images if how the hot side setup looks:

Turbo Lines, Oil Coolers & Timing

I finally dummy-fit the turbo up and tried to fit up per the HKS ZC31S turbo kit manual but I really wasn’t happy with the setup, particularly with the length of the feed line.

The feed line is “AN4″ or 7/16” JIC and the return line is “AN10″ or 7/8″ JIC. If you’re a hydraulically inclined like me these sizes suits 1/4″ and 5/8” tube OD/hose ID respectively.

Personally, I hate how “AN” centric car plumbing is. You pay an insane premium for the anodized pretty parts. The hose fittings are nice and the way all the off the shelf hose options align to AN size is convenient given all the big automotive retailers sell both the fittings and hoses to suit a range of applications. Still, as a mechanical engineer/hydraulic engineer (depending on the day) it still irks me in a weird way. I can’t complain too much though – at work, our fitter and I both like using thread sizing as opposed to tube od/hose id dash sizing. Tomato tomato?

Side note, I love the Taipan Thread Identification Chart. It’s a great point of reference and I use it almost daily at work.

Below is my mud map of how I plan to run the oil lines. The water lines will make use of the lines that formerly served the OEM oil cooler (a very simple, leak-prone, heat exchanger). Excuse the horrible paint work, this was only really used for ordering bits – which have arrived!

The OEM oil cooler as mentioned above isn’t the greatest, the HKS manual calls for it to be rotated but removing it makes much more sense given I’m running a decent size oil cooler anyway. It’s worth noting with the oil cooler I hardly saw temps above 85C, even on 30C+ ambient track days. Unfortunately, removing the factory cooler reveals no “stud”, luckily, I found an option online that should do the trick nicely.

Apart from that I was fairly unwell during the tail end of this week. Today I did bolt up all the timing gear, new sprocket, guides and tensioner. I reused the chain as it looked to be in good condition and the manual states it is OK to reuse.

Once I make the new oil lines, it should all start coming together!

Cometic Head Gasket & ARP Studs

This weekend I removed my head, installed the almost new head, ARP studs and a cometic head gasket.

After removing the head I was generally very happy with the condition of the cylinders, hatching still looks good and for 121,xxx kms, I would say the carbon buildup is pretty good.

Before removing the head, I aligned the timing marks per the manual, for reference, here is what the alignment looks like.

I have new timing components on the way; I will leave the water pump undisturbed as it still turns freely. Will I change my mind in the next week? Probably!

The original head gasket was also in OK shape, not that I expected anything different. Here is a photo of the cometic gasket (1mm) and OEM gasket (?mm) side by side.

The cometic gasket bore diameter is a bit over 2mm bigger than the OEM gasket. As mentioned in a previous post – nobody thinks this is an issue. For shits and giggles, I drew up the difference to see it better visually – agreed – no issues.
– 78.5mm ID is the OEM gasket bore
– 81.2mm is the Cometic gasket bore
both as measured

Installing the head gasket and ARP studs was easy enough, I always hate doing up head studs but thankfully I had experience x4 from the Galant. Interestingly, the ZC32S final torque spec per ARP is 75 ft-lb (102 Nm), the Galant was only 60 ft-lb!

ECU Wiring

As promised, this post will document ECU wiring. I will be wiring in a Link G4X MonsoonX in a “piggyback” style. Below is a wiring table on what I plan to do.

I have seperated the loom and marked the cam and crank sensor. There will be some figuring out to do on the cam and potentially crank signals as I know they differ from the ZC32S (which Haltech has documentation on).

Unfortunately, there is very little information on aftermarket ECUs in these cars and a lot of people report odd issues with cheaper options like AEM and GReddy E-manage (E-Mangle).

I’ll also need to decide what I do about the variable intake runners either:
a) try to remove it
b) replace with ZC31S intake (may require further head drilling, new intake piping)
c) use the Link to control it (looks doable)

If you made it this far, below are images of the ZC32S ECU wiring for your reference. I found these extremely hard to find, hopefully this helps others. I cross checked a lot of the wire colours and it all aligns, will need to check with a multimeter to be sure.

To view in full resolution, right click and open image in new tab.

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:

  1. Suzuki Works Kurume 1.1-way LSD
  2. MFactory 4.312 final drive
  3. TEIN coilovers
  4. TM Square pillow ball strut tops
  5. Hardrace roll center adjusters
  6. Cusco rear stabilizer bar
  7. Monster Sport rear toe and camber shims
  8. X-Force catback
  9. SuperCircuit headers
  10. GReddy AirNX intake
  11. Blitz oil cooler
  12. Unknown brand rear strut bar
  13. Suzuki Sport gauge set (ZC31S) in Monster Sport 3 meter pod
  14. Evo 8 MR / Ralliart Colt Recaro Seats on Bride Rails
  15. R’s Racing brake lines
  16. ZONE TT brake pads
  17. GReddy rear wing extension
  18. GReddy front lip (colour matched)

Below images are in chronological order.