🚀 TRUSTALIGN - Time Attack FL5 Build Journal

[Gambit]

3" single exit titanium exhaust fitted.
11kg saved

Add lightness

 

[tezzasaurusrex]

Added hood vents

 

[Gambit]

Wow mega build update!

 

[Bat1]

Hi all,

This thread will serve as the build journal for my FL5. The car will be moderately modified with the aim to upset higher hp cars on track (namely BMW's) however also serve as a reasonably comfortable road registered vehicle that I can drive daily.

Currently, the modifications are as listed (*updated* Nov 2025)

Engine:
Stock
Motul 0W30 8100 Eco-Clean for street duties
Motul 5W30 8100 Power for ethanol/track use

Turbo:
MHI stage 2

Fueling:
Hondata 1530cc injectors
Full Race HPFP
AEM drop in LPFP

Cooling:
OEM radiator
HKS intercooler with HKS piping kit

Transmission:
Stock Gears
Spoon Mechanical LSD
Motul Gear FF Type 2

Brakes:
Project MU brake pads + Paragon 2 PC discs FR and RR
Motul RBF700 Fluid

Exhaust:
Invidia Catless with hardlagging
Fujitsubo 70mm Front Pipe
Stock with centre (larger) resonator deleted
Hondata mapped flap to always open in engine R mode

Suspension:
Tein Mono Racing 14/12KG Springs
Hardrace FK8 Front Camber Balljoint w/ custom made camber shims, strut pin removed and strut top positioned to max negative.
Eibach Rear Upper Camber Arm
Hardrace rear knuckle Spherical (B arm)
Hardrace hardened rubber Front LCA bushing (rear position)

Alignment:
Camber FR -4°, RR -3° (was -2.7°, -2°)
Combined Toe FR 0mm, RR +3mm (was 0, +2mm)

Body/Aero:
Rear Wiper Deleted
Custom Carbon/ribbed core front splitter with tunnels and end plates, completely curved underside.
Voltex Type 2 rear wing
Front brake ducts blocked off

My fastest lap times currently at various circuits are:
Sydney Motorsport Park GP 1:46.01 (LogR) (Note: Completely stock car only with wheels and tyres)
Winton Motor Raceway Full Circuit 1:34.88 (Natsoft) (Note: Stock springs, FK8 Ball Joint)
Luddenham Raceway 51.9 (LogR)

Update April 2024
Sydney Motorsport Park GP 1:44.44

Update September 2024
Sydney Motorsport Park GP 1:43.95

Update Jan 2025
Sydney Motorsport Park GP 1:42.780
(Main delta has been the extra power from bolt ons and Jester's tune, netting an extra 10kph at the end of Brabham Straight, and further tweaks to suspension, alignment, set up)

Update Nov 2025
Sydney Motorsport Park GP 1:39.865 (WTAC) on Yokohama AD09 (Control Tyre)

I will keep this thread updated as best as possible with modifications and speed secrets that I discover along the way. The aim is to knock those pesky BMW's off the top of the time sheets.

Sorry if I missed it, what wheels set up is in this picture? thank you!

 

[tezzasaurusrex]

Sorry if I missed it, what wheels set up is in this picture? thank you!

Running 18x11 ET44 up front, and 18x10 ET30 rear. With 295/35R18 and 255/40R18 reverse stagger.

 

[Bat1]

Damn, are these Apex wheels?

 

[tezzasaurusrex]

Damn, are these Apex wheels?

Correct. The rear pair have been machined down from ET25 to ET30 though

 

[Jack90210]

Added hood vents

Did you choose those locations deliberately? I've wondered about improving heat evacuation through the hood, specifically about making the center air port larger (and lowered at the rear) and making a larger "scoop" of sorts underneath the port in order to help evacuate the air exiting the radiator. Curious to hear your thoughts, I know that you are big on data acquisition.

 

[HondaHoon]

The TCR H80 racecar is designed the same way and I assume it works for them too.

 

[Jack90210]

Apologies for the lack of updates. Life has been full on since starting up my own alignment shop. The car continues to evolve and the lap times keep coming down.

Latest updates:
HJS catted downpipe (sounds epic)
HKS IC with Piping Kit
Hondata Flashpro + Jester Tuned 98 Octane (equivalent to US 93)

Aero in development - Battle Aero front splitter mounts do not work with the JDM/AUDM steel crash bar, so I got the USDM crash bar instead.
Turns out the aluminium USDM crash bar is heavier than the steel JDM by 2kg! The USDM bar is far more substantial, and extremely beefy, which serves as the ideal mounting point for the splitter. However it is not without its challenges, the USDM crash bar is a completely different profile. Which means the pop up hood actuating system (plastic thing sitting in front of the crash bar) also doesn't work, which then changes the front cooling channels completely as not running it opens up otherwise filled gaps between the bumper and the intercooler/condenser/radiator.
Currently working to close all those gaps to improve the efficiency of the cooling system, air just wants to travel the path of least resistance, so closing up all the gaps is absolute key maximise the volume of air going through the exchangers, and not around them through the gaps!
There are two very large gaps between the OEM glass fibre reinforced plastic radiator support panel and the radiator. So I've now sealed those off as best as possible with 30x30mm thick closed cell foam.

More updates to come.

Regarding the foam around the radiator -- would a high-temp or flame-resistant foam be needed, or is this regular closed-cell foam? Thanks, your build is incredible.

 

[tezzasaurusrex]

Did you choose those locations deliberately? I've wondered about improving heat evacuation through the hood, specifically about making the center air port larger (and lowered at the rear) and making a larger "scoop" of sorts underneath the port in order to help evacuate the air exiting the radiator. Curious to hear your thoughts, I know that you are big on data acquisition.

Yes, the area just after the apex of the bonnet (the major curve from the bumper to the top of the bonnet) receives the lowest pressure. This is the ideal location to position the hood exit vent.
I have not cut the secondary skin of the bonnet directly under the vent since it's positioned over the ECU and fuse box. The secondary skin of the bonnet will act as a port to channel water down to the headlights and also create a net pressure loss in the engine bay. I have zero data to back any of this up, purely just regurgitating my thought process. I could be completely wrong.

 

[tezzasaurusrex]

Regarding the foam around the radiator -- would a high-temp or flame-resistant foam be needed, or is this regular closed-cell foam? Thanks, your build is incredible.

Closed cell is working for me. It's not of a flame retardant type but if you can get your hands on some it would be an ideal choice.

 

[Jack90210]

The TCR H80 racecar is designed the same way and I assume it works for them too.

True. Just wondering if the location is a compromise for heat/aero, because data showed a heat or pressure buildup in that area, etc.

Agree that your reason seems like the most likely one for choosing the vent location. Thanks for the response.

 

[tezzasaurusrex]

Eibach rear lower A arms are nearly half the weight of the Hardrace version.
Since I don't need the adjustability of the a arm at this stage (adjusting from the b arm for now), I'll fit the Eibach

 

[tezzasaurusrex]

RSR/TCR style rear sway bar system fabbed up and installed. Can now do easier/quicker rear roll stiffness adjustments at the track, with a wider adjustment window than on a bar in the OEM location. Many hours of measuring, cutting and swearing but the adjustability should be worth it.