Braking into the next chapter

Another long break from the previous post, work has been hectic but thankfully my efforts seem to be bearing some real fruit ultimately allowing me to look into the brakes on the S2000. Since my first foray onto the track, I've been reliant on upgraded brake pads on the stock calipers. The clear favorite for me has been the Project Mu Racing 999 with it's excellent characteristics when hot and feel during threshold braking. I've managed to stave off brake pad & fluid during track with custom brake ducts channeled to both disc and caliper on each corner. This has worked tremendously with virtually no brake fade after many laps at a go, what seems like extended brake pad life, extended brake fluid life, little to no instance of brake disc cracking and apparent long life of the rear hubs which are prone to failing due to heat soak from the solid rear disc.

Ultimately when I chose to upgrade my wheels, the consideration to move to a big brake kit was key in my selection of the face of the wheel. The Enkei Racing GTC02 wheel has generous convex curved spokes which allow enough clearance for a big caliper despite a slightly higher offset than my previous GTC01. Some barrels are also narrower around the hub but the GTC02 has plenty of space for me to maximize the disc diameter. 

Sourcing for a brake kit for the S2000 comes with a few considerations even after the wheel selection issue has been resolved.

A) There are no front and rear big brake kits sold jointly to ensure optimal brake balance is maintained. Rear big brake kits usually eliminate the handbrake which is not suitable for road going cars.  This leads to people having to buy a brake kit for the front and trying to custom something for the rear as well as playing around with brake pad compounds in an attempt to optimize brake balance. Most rear brake kits consist of stock bigger rotors from other cars combined with an Mazda RX7 or RX8 brake caliper. Clearly this variable of brake balance is an important attribute to maintain as the S2000 has excellent stock brake balance for trail braking in my view.

B) Brake cooling even with a big brake kit can be an issue as evidenced by the experiences of a friend of mine who was on an Alcon big brake kit with 330mm discs experiencing fade on race pads just after 5 laps. The larger diameter discs of the big brake kit do help but even with much larger vanes than the OEM rotors, one can easily begin running into the upper limits of the heat capacity of the system.

Ducting then becomes a necessity to stave off brake fade over multiple laps but running the ducting then has its own issues of which I have had my fair share of negative experiences over the years. At full lock, there is the tendency to crush and rub the brake cooling hoses until they eventually fail which leads to dragging of pipes everywhere. Being rather low, the S2000 also would quickly end up having ducting get damage from items on the road or collect gravel during an off track excursion which ends up obstructing the funnels or getting lodged in the piping.

In this picture you can see the brake duct piping dangling from my car after being damaged in an off track excursion.

C) The S2000 in naturally aspirated form doesn't put out too much power so balancing the braking needs with weight is also a key consideration. Some brake upgrade kits use large OEM discs from other cars but both such calipers and discs are usually heavy which is to be avoided considering how adding unsprung weight is detrimental to both braking and acceleration. 

All things considered, much like any part of setting up a car, performance is a balance of resources available as well as limitations. Considering all these factors, here are some of the outcomes I sought in my choice of brake kit:

i) To seek a brake setup that has been proven in competitive events for reliability and endurance. This helps me minimize the risk of brake failure which is highly dangerous for obvious reasons. In this department, I also want to reduce the reliance of unnecessarily complicated ducting which I've had come loose far too many times. Getting brake ducting components which have come loose stuck in my brakes would not be my idea of a good time.

ii) To look for a brake kit that has good brake balance balancing the changes made to braking power. This will allow me to exploit the strength of the S2000 in its cornering ability in areas like trail braking.

iii) To consider the availability of replacement parts for service life. A slightly overlooked point has been how easily available spares are and with the age of the S2000, it's become more front of mind. Certain brands start off at a cheaper price point but longer term users of these brands now face a potential issue of lack of supply of replacement parts due to supply chain disruptions or even the winding up of the brand itself.

iv) Having used my previous brake setup which allowed me 10-15 laps of fade free performance, I've thoroughly appreciated how more fuss free seat time helped me get improve. I definitely am looking to find a brake kit that can keep me on the track for a similar amount of time without succumbing to the heat buildup. This attribute is something I would be willing to sacrifice some amount of reduced outright performance for. 

With these points in my mind, the Sakebomb Garage AP Racing Competition Brake System https://www.sakebombgarage.com/ap-competition-brake-system-s2000/ and the Competition Rear Brake System https://www.sakebombgarage.com/sbg-competition-rear-brake-system-s2000-rear-rx8-caliper-retrofit-kit/ ticked every box in my book. 

Here's how the front looks 

Pics of the rears

Friend of mine from Japan helped me get these used RX8 calipers which are in great condition at a solid price!

Availability of replacement brake pads is pretty important to me so when I saw I could get the D50 radial depth pads from Endless, which I can source fairly easily from Japan, it was a great point of reassurance. 

I chose the N35S / CC43 pads which came recommended by a friend who has run these.

The performance upside realized from this entire braking setup would be:

1) An unsprung weight saving of about 1 kg per side up front.

2) From feedback from a bunch of users, no need to run any ducting front or rear if I'm just running the usual roughly 30 min runs that I make. This massive heat capacity increase benefits fluid, pad and disc lifespan as well as the performance of all these areas. From a safety aspect, this is pretty much priceless.

3) Great reliability of a proven brake system in both caliper & disc performance. Cracking discs or stuck calipers would probably be a thing of the past.

4) Readily available spares for all components of the brake system from disc, to caliper hardware and brake pads. Spares are also reasonably priced and upsizing of the components means the replacement cycle is not so frequent.

My car is currently in the midst of the full refresh of performance and I'm eagerly awaiting the completion of the entire car to experience the new lease of life it's been given. Upgrading the braking system was pretty much essential to being able to extract as much of the full performance potential of my S2000 as I can and has been long overdue. 

Thrilled to move to the next chapter of performance!

Thoughts about my tyres and wheels

Ever since I made my change to the Advan A052, I've been searching about for a good baseline pressure to run and I thought it might be good to summarize some of my thoughts about what I've come across relating to setting up a tyre for my use.

Tyres are after all probably the most complex part of the car and changes in technology have clearly dramatically changed our view on what works the best. One example of this shift in acceptance in how we view tyres might be seen in cyclist tyres where for some time it was accepted that a thinner tyre with a higher pressure would result in a lower rolling resistance and thus be quicker but now a wider tyre on a properly sized wheel would actually be proven to be quicker.

Wheel Width:

Clearly tyre performance must taken in consideration with the wheels they will be run on. Here's a summary of steps I would take to choose the wheel I will need to run:

a) Pick the tyre you want in the width you want

b) Check the tyre tread width

c) Look for a wheel that matches as closely for the specific tyre tread width 

Clearly some compromise might need to be made with respect to the wheel that can clear your current (or planned) big brake kit and clearance within the wheel well.

Some wider wheels do end up rubbing against the inside of the arm at full lock and I found  Rob Robinette's blog (check out https://robrobinette.com/S2000Alignment.htm ), which has a wealth of information regarding S2000 modification, highlighted these OE Ford steering rack spacers which could be fitted to the S2000 for limiting lock enough so it doesn't contact the arm at full lock.

Some of the helpful info from Rob Robinette's blog, read his blog directly for more detail

Picked up the items for myself through Amazon

Tyre Pressure:

This is a tricky topic so I'll relate a bit from where I come from to lead into the thought process. 

Back when I was running the Hankook RS3 in square 255/40/17, the first tyre that in my opinion began the 200TW tyre "war", I was told that the go-fast pressures would be about 29-30 psi hot. When I mentioned how others ran about 34-35 psi hot, it was rubbished as being way off the mark and me reading too much of forum knowledge. 34-35 psi hot did eventually yield me great wear and good lap times much to the surprise of those who had written my setup off. Going lower to 32-33 psi hot didn't feel particularly good maybe due to the rather soft sidewalls.

Moving to the Achilles 123S in square 255/35/17, I began experimenting with slightly lower pressures based on the wear patterns I noticed from the use on the track. I eventually settled at about 33 psi hot which seemed to yield the best results, going lower to about 31-32 psi would tend to let the tyres rollover a bit too much.

Now moving to the A052, I started seeking a new baseline to begin my fine tuning as I had totally departed from the realm of 17 inch tyres. Unfortunately, even before COVID 19, there is no neighborhood track I can use to fine tune my settings so finding a baseline to begin from which is closest to optimal would be important. Taking a step back, I observed that my car had progressively shed some weight through lightweight seats and removal of the soft top which I now realise definitely did impact the optimal tyre pressure to run.

Currently my car would be about 1200kg fully loaded before the driver so I started looking around for comparable cars weighing about the same, having modest power output and being known for exemplary handling. I came across the series 3 Exige which had rather interesting factory specifications for the tyres used. The Exige owners have a choice between Pirelli P Zero Trofeo and the Michelin Pilot Sport Cup 2 but both have very different recommended pressures namely 38 psi for the Pirelli and 32 psi for the Michelin.

Clearly the difference of the construction of the tyre is significant enough to warrant a large change in tyre pressure to be run. I would consider the construction of the carcass of the A052 in the lower profile sizing I am running to be much closer to that of the Michelin Pilot Sport Cup 2 than the Pirelli. This information combined with some real world user input from old timer S2KI members who have actually used the A052, I got a reasonable range to start playing around with pressures. The car didn't handle too well using the same pressures as I had previous run on the RS3 or the street driving pressures I ran for the 123S which were a touch higher than the optimal hot pressures but a bit lower and there was a marked improvement in overall handling.

I'll still be messing around to find the best middle ground to run the tyres while I sort out some of the minor fender rubbing I'm still experiencing. Stay tuned for more updates :)

Credit to:

Rob Robinette for information and screenshots from his blog, go check it out! https://robrobinette.com/S2000Alignment.htm

Dyno results for the PracWorks Carbon Intake Manifold, a missed opportunity

So the dyno is done and here are some noises to satisfy your VTEC urges (if I stood by any longer my eardrums would have burst lol)

I've been scratching my head on how to get these dyno numbers out in a way fair to everyone and I guess the best way is just to be brutally frank on the mistake I made which can be summed up in one statement:

A dyno comparison for the gains of the mods especially flow related stuff like an intake manifold should never be done on a STOCK THROTTLE BODY, STOCK EXHAUST WITH CATALYTIC CONVERTER AND STOCK HEADER.

Why? Because NO GAINS will be apparent. 

Yeah I messed it up big time. Just think about this from a common sense perspective:

You introduce 5% more air, increase more fuel to match and allow 0% more exit volume.

I'm kicking myself for not thinking this out beforehand but I've got to live with my error.

That said, I do have positive results for the PracWorks item to report on, so read on and find out.

Before I show the dyno charts I need to preface with questions that will inevitably come:

Q1) Why don't you show the full numbers? 

Ans: I'm not keen in getting distracted by the absolute numbers nor will the numbers be of practical use to anyone unless they are running EXACTLY the same setup as I am dyno tested under EXACTLY the same conditions. If you still want to know, you are welcome to look for me on FB or IG to ask about it.

Q2) What happened to the first benchmark run that I can compare with using the same free flowing exhaust?

Ans: The dyno database got corrupted and the file was lost. I cannot do an on screen comparison on the dyno software with the current run. 

Q3) What dyno is it and is the dyno operator reliable?

Ans: It is a Mainline dyno and if you know dynos this is as reliable/repeatable as it gets. The operator is undoubtedly reliable as they do many different cars and have always been praised for consistency. The only "negative" is that this dyno is known to read low or a "heart breaker", not a concern to me as I am only looking for consistent results and the nett gains.

Red Line: Stock Exhaust, Stock TB with Catalytic Converter, Password JDM Air intake, 

Carbon Intake Manifold 

Blue Line: Stock Exhaust, Stock TB with Catalytic Converter, Password JDM Air intake, 

Stock Intake Manifold 

Horsepower

Observation:

a) Loss in power & torque from midrange from 3000rpm - An expected result from a larger manifold volume.

b) Slight bump in Mid range but negligible difference until maybe 7500 rpm - Restriction in exhaust flow caps all gains

Swapped out the stock exhaust for a free flowing exhaust and did some comparisons with the Password JDM intake, 3 inch short ram pipe without velocity stack and 3.5 inch short ram pipe with velocity stack.

 

Red Line: Free flowing Exhaust, Stock TB without Catalytic Converter, Carbon Intake Manifold, 

 Password JDM Air intake

Blue Line: Free flowing Exhaust, Stock TB without Catalytic Converter, Carbon Intake Manifold, 3.5 inch short air ram with 4 inch velocity stack 

Horsepower

Observation:

a) 3.5 inch short air ram outperforms across the powerband but especially from 6000rpm - High cam loves the bigger air flow. Peak gains of about 3-5 whp 

b) Curve shows no sign of flattening even past 7000rpm - Much more airflow to exploit at higher rpm 

Red Line: Free flowing Exhaust, Stock TB without Catalytic Converter, Carbon Intake Manifold 

 3.5 inch short air ram with 4 inch velocity stack

Blue Line: Free flowing Exhaust, Stock TB without Catalytic Converter, Carbon Intake Manifold, 3 inch short air ram with no velocity stack 

Horsepower

Observation:

a) 3.5 inch outperforms around 6500 rpm for a bit - probably more airflow to optimize but maybe getting choked beyond 7500 somewhat

With these preliminary results I settled on a longer 3.5 inch intake piping with 4 inch velocity stack cleaned up into a compartment.

So you might be asking: Hey wait a minute, does this mean the PracWorks Carbon intake manifold does not make gains?

Ans: This manifold ABSOLUTELY makes gains.

Although the dyno file of the first run with free flowing exhaust plus stock intake manifold was lost, I still kept a picture of it thankfully and orange graph below is a snap shot I took off the dyno. I extrapolated the numbers for a comparison that is imperfect but the best effort I can muster.

Blue Line: Free flowing Exhaust, Stock TB without Catalytic Converter, 

Carbon Intake Manifold, 3.5 inch short air ram with 4 inch velocity stack

Orange Line: Free flowing Exhaust, Stock TB without Catalytic Converter

Stock Intake Manifold, 4 inch very long silicon pipe for max flow 

Horsepower

Observation:

a) The power curve steepens significantly after 6000 rpm - Although I don't have a exact overlay, the steepening suggests mid range gains.

b) The peak power of the orange line was achieved with maximum airflow possible > 8300 rpm. The peak power of the blue line was measured at around 8100 rpm and compared to the orange line at the same 8100 rpm was around 11 WHP higher with >6% higher peak torque . The only other variable to cause some possible variation is the orange line having the 4 inch long pipe (proven to make about 3-5 whp over the Password JDM) and the blue line having the 3.5 inch pipe with velocity stack (also probably making 3-5 whp over the Password JDM) so they pretty much cancel each other out in this comparison.

I will fully admit that this comparison wasn't perfect but I am after all, just an enthusiast with limited time to hang around running different setups on the dyno for the perfect comparison. With the limitations, the best I can share is my thoughts on how this setup might work for your own rides as each of our setups are probably running different compression ratios, head ports, piston designs, combustion chamber shapes, cams, ecu tunes and many other factors so it's expected that such results are probably not exactly repeatable in your own rides.

I've already set out to get supporting modifications to do this intake manifold and engine setup some justice to unlock as much of its potential as I can muster. Please keep a look out for my next update which I expect to be soon and if you have further questions on this post you can always chat me up on Instagram or Facebook. 

Enkei Racing GTC02 plus Advan A052 test fit on my S2000, you never know if you don't try...

It fits. Well... kind of! 

So how did we get here? I rolled up to YHI HQ in my Achilles 123S shod Enkei GTC01 and took some pics to have a sense of how much different the change would be.

So contrary to what many might think, my choice was made on the basis of the TYRE FIRST. 

Yes, the tyre choice is number 1 in the overall scheme of things simply because it is probably the most complex piece of engineering on the car which pretty much determines the result when the literal rubber hits the road. You get the tyre first, get the wheel that suits it and then make it work.

Do reference this article by Billy Johnson which states what the priorities should be:

How to PROPERLY select and size TIRES for PERFORMANCE

Advan A052 is probably the quickest tyre out there so being able to secure a regular source of tyres through YHI was the key point. Testing overseas has proven it to be potentially quicker than the RE71R (this depends very much on the overall setup) with equal if not higher wear rates so it was critical for me to get the entire setup done correctly. This performance edge comes about in my view due to the relatively grippier compound and lower weight of the tyre.

So that's how much more grip I am looking to optimize

Have I made a mistake going too wide? That's something that can't be easily answered and the only real answer to that lies in the performance results I achieve. I know from past experience that I was on the wrong path and the subject of jeers when I fitted a big front splitter, a big rear wing, squared tyre fitment, running higher than the common wisdom of tyre pressures and the list goes on. Somehow the very novel experiments I am called out for eventually became the de facto standard setup.

How could this be? Well. the answer is simply that nothing that I was doing was actually novel but setups that were already proven to work and were widely adopted. This case of tyre choice is a bit different in that there is still some debate out there due to the scarcity of people running this setup on an naturally aspirated S2000. In this area, I've really had to thank the kindness of the people I've chatted with on social media who so openly shared without any agenda save to help a fellow owner achieve success. With their input, I was able to balance the conditions of the kind of track, event, power and weight to make a choice of a starting point regarding tyre choice.

All in all, although I have some degree of confidence that this setup is going to work, the experimentation with size will continue because that's really the only way to tell.

So what are the drawbacks of this setup? 

a) Fitment is challenging, I'll let the pics explain.

Barely clears the splitter

Tight fitment in the front wheel well at full lock even with 2 steering rack spacers

Some rubbing on the rear tyres over bumps in the road despite a not overly low ride height and stiff suspension

b) The overall wheel and tyre weight is heavier. It is encouraging though that the penalty is relatively small in my view despite the large increase in tyre width. I think the trade off is reasonable

GTC01 weight

GTC02 weight

I did have a custom brake duct on one side that rubbed pretty hard on the wheel and have to be removed but these are all things that I think can't be avoided with customized setups so I'm taking in my stride. I'm looking forward to visiting the local body work legend to get the fenders tweaked as necessary, put on my louvers, mount my splitter and adjust the brake duct as necessary (some of it has been messed up over the years). Hope I can get to that soon!

Thanks to:

YHI Singapore for helping get the install done right despite the hiccups

Desmond for helping me ferry the wheels back and forth, thanks bro!

Billy Johnson and MotoIQ for use of their writeup

First look at the Enkei Racing GTC02 wheel, new grip setup in progress...

Yes, there's something new under the cover!

I've spent more than 13 years on my S2000 and through that time, I've been running these wheels on the track:

Stock wheels from Day 1

Enkei RPF1 which I used for about 

Back in 2014, as I sought a stronger wheel for long term use, I made the switch from RPF1 to the Racing GTC01 which I still use until today

My current Racing GTC01

The Racing GTC01 has served me remarkably well and despite being heavier than the RPF1 by about 2-3 kg due to wider width plus more rigid construction, which could be felt through the steering, has taken all my track abuse without hardly anything to show for it. I've always prioritized wheel strength for the following reasons:

a) At Sepang Circuit, which is the track I frequent, there is sometimes a need to hop curbs to get the best line 

b) The peak G forces achieved by the tyres increase with development of tyre technology and thus the corresponding the load on the wheel increases so from a reliability standpoint a more robustly construction wheel would provide long term use

c) A more rigid wheel would possibly lessen the need for increases in camber angle to compensate for the deformation of the wheel. Any additional negative camber increases for such compensations are not ideal for tyre lifespan or the overall track performance.

With the help of YHI Singapore, I managed to source the latest iteration of the Racing GTC series: the Enkei Racing GTC02 in Hyper Silver. This wheel was seen at the 2020 Tokyo AutoSalon Enkei Booth and has been making its rounds in roadshows in Japan.

Official launch on Facebook in August 2019

Here is my video wheel reveal

Ken Nomura having fun at the Tokyo Auto Salon Booth

Promotional roadshow in Japan to highlight the wheel have been ongoing

Here is my own video reveal of the wheel

The key reasons for the choice of this wheel would be:

a) robust construction for strength and rigidity to a higher limit than the current wheel I run

You can see how beefy the spokes are and the evenly dispersed split spoke design helps ensure load is not concentrated at only a few points

The thick flange at the rim edge helps hold the tyre in place through high load events

b) Lightweight construction 

This wheel will be much wider than the current wheel I run but weighs about the same, around 10kg. This means there is no weight penalty to running this wider wheel which allows me to run a wider tyre size.

Here you can see a close up of the lightening done on the spokes

These dimples machined out of the block reduce weight and improve heat dissipation from the wheel to avoid additional heat being transferred to the hubs. Such heat buildup is often not considered but can lead to premature failures of hubs. The centre bore also looks to have a reduced amount of material in the lugnut area.

The back face of the wheel has also had some shaving of the spoke done with material removed from the centre hub 

c) Big brake kit clearance

The barrel of the wheel is generously formed and allows for clearance of large calipers should I wish to upgrade my brakes down the line

The curvature of the spoke and where it ends on the wheel face helps the brake caliper face fitment

d) Excellent quality and design which is what Enkei is known for

The greyish portion is where the edge of the tyre sits and Enkei has put anti-slip paint to prevent slip between tyre and wheel which happens more than many realise. Patented M.A.T process to form the Enkei wheels has also evolved to M.A.T Dura II for added strength.

This part is just pure Japanese craftmanship character, guess Mr Suzuki signed off that this wheel met his inspection standard!

e) Price point of the wheel 

The Enkei Racing GTC02 has a retail price 60% that of a similar sized forged wheel. Wheels are a consumable over the long run such as when an off the track event happens, you can't avoid that big pothole at speed and long term use will slowly but surely bring the wheel ever so slightly out of round. Any wheel and tyre shop owner who levels with you will tell you that even forged wheels do deteriorate over time. In view of that, the Racing GTC02 is excellent value for money.

I'm really looking forward to bring my grip setup to the next level with this new wheel and YHI Singapore was a great help to help order this wheel in. I'll be approaching them as well for tyre choice, as I'd like to pair this high performance wheel with a top tyre to prep for what looks to be an exciting evolution for my S2000. Stay tuned for the next update with fitment pics and tyre selection!

I would like to specially thank again YHI Singapore for helping me source this wheel in the specific fitment I was looking for.