Ok consider this to be my research diary. And that to be a working title until I think of something better. Which I won't because **** you.
My car is at a very nice place atm in terms of performance and practicality so it will take quite a lot to make me want to do anything further to it, but I want to compile a list of mods, costs and reported benefits in order to properly educate myself about where to throw my money next time I feel like I am starting to collect too much of the stuff. Once compiled this should also serve as a good source of information for others that want to tweak this car for use at the track.
Mission: Make the MPS as much of a time attack weapon as possible without forgetting that it's still only a Mazda3.
The hierarchy for money spent vs lap time improvement goes:
1. Driver skill, experience and size of testicles
2. Tyres
3. Brakes
4. Suspension
5. Power output
Power:
No Brainer here, DP, Intake and ECUTEK tune have given me all the power I reasonably need without going over the top.
Interesting tidbit: My second tune produced LESS power than my first one did, but it had a more useable torque curve and actually produced faster times.
I have since upgraded to an ETS TMIC along with a BNR Stage 1 Turbo.
Manley H beam Rods, Cp-e Stage 2 Pistons, Cp-e Injector Seals along with EGR delete and an Oil Catch Can for good measure.
One thing people don't talk about much: Race fuel. Look into octane boosters and race fuel for track day shenanigans.
Suspension:
Rear Swaybar - first handling mod anyone should do with their MPS.
Springs/Shocks/Lowering: (2) (3) (4) (5) (6)
Some Further reading on suspension tuning: (10) (11) (12)
I know of a LOT of suspension jobs that have utterly ruined cars, from bad geometry to downright stupid tyre scrubbing bullshit. Suspension needs to be done right. Tread lightly.
I have KW V3's (9) with custom made adjustable strut tops, front swaybar, bump steer kit and rear camber kits all fitted now. I can honestly say that this setup is MORE comfortable than stock on the street and way more stable at the track. KW clearly know what they are doing. These have height, (low speed) bump and rebound adjustments.
The settings I am using are:
For the Street:
Bump: -10 clicks front/rear
Rebound: -9 Clicks front/rear
For the track:
Bump: -5 clicks front/rear
Rebound: -9 clicks front -8 clicks rear
1 click harder on rear bump = epic sideways action.
There is all kinds of stuff to learn on suspension about Bump/Rebound settings, corner weights, front/rear natural frequencies and how everything interacts. When I get a better first hand feel for it I will write more down but the basic setup guide for this car is low and soft in the front end, high and firm in the rear. You want to add Caster and Camber to the front, front toe in for stability and toe out for twitchy responsive cornering.
Weight Reduction:
I remove the rear seats at the track and strip everything else (spare, jack etc) out.
Running light fuel loads helps as well, I take a couple of 10L Jerry Cans to the track with me, typically I will use about 8-10L per session. Be careful tho, I started getting fuel surge when I was running very light on and that can blow your engine up. I fill up when my fuel light comes on now.
Carbon fiber bonnet? Looks rice but saves a lot of weight!
Aerodynamics:
Does the rear wing on the Gen II even do anything? I think it creates more drag than downforce just by looking at it.
Aero mods usually look stupid and provide no measurable benefit unless the car is stupidly fast.
Brakes:
Pads: I am currently using Carbotech XP10 Brake Pads with DBA4000 slotted Rotors for the racetrack - I changed to these from Project Mu Club Racers recently and imo, they are better in every way. I have been hugely impressed with the XP10's. They squeal ridiculously on the road tho. If you're not tracking your car, REMSA pads are fantastic. Theyre cheap, quiet and have great feel.
Fluid: Penrite SIN, flushed after every second track day. I like this because it has the same boiling points of AP racing fluids and others but it is half the price.
Big Brake Kits: Potentially grabby stopping power, and can ruin the brake pedal feel as well as screw up your brake bias. 2 good options are out there, Corksport or the Willwood kits that both use the stock rotor and fit under the stock rims. Or Stop Tech/Brembo kits that have different Rotors but also need spacers and/or different wheels.
A little note on brakes - You will be tempted to remove the backing plates on the front wheels to help with heat dissipation. This is ok to a point, I found semi slicks + racing brake pads produce so much heat that it started melting my ABS sensor plugs, if you are going as aggressive as I do on brakes, keep the backing plates on.
Wheels/Tyres:
Lightweight wheels, reducing unsprung/spinning mass has a disproportionately good effect on handling. I have a set of 18x8 Enkei Fujin for my track rims, theyre a couple of kilos lighter than the stock rims
Tyres: I have A050 Semi Slicks and AD08's depending on what class I am running in. Good tyres are the single biggest upgrade you can get if you are chasing faster lap times
Drivetrain:
The MPS comes with a pretty good (Viscous) LSD from the factory compared to most other hatches on the market, but it can still be improved upon.
Quaife - Saitek on MSF has done this (7) - Torque biasing type that works by biasing torque away from the wheel with low traction which should help the MPS's tendency to spin its inside front wheel coming out of corners. It's main weakness is that it doesn't lock so it won't give you any drive if you lift a wheel off the pavement. This is a very good diff for the road as well as it's smooth in its operation, and is a very common upgrade for other hot hatches that come with shitty open differentials.
Cusco, Kaaz (13) and OS Gieken (14) make proper clutch type 1/1.5/2 way LSD's as well. These are probably the best options out there for track running, but do sacrifice some daily comfort with NVH and slightly jerky low speed manoeuvring. They also need more maintenance and take considerable time and effort to get them dialed in just right.
A note on 1/1.5 and 2-way diffs for those that don't understand:
A 1-way diff behaves like an open diff under braking and deceleration, they only lock when you are accelerating and under power. This is the best option for a FWD car as the tendency to lock under braking will often induce a huge amount of understeer. You are better off having your fronts free wheel under brakes and turn in, and only want the diff to lock when you are trying to put the power down.
A 1.5-Way diff will lock fully under acceleration and only lock half as strongly under deceleration. If tuned correctly this will probably be the fastest option but you need to spend a lot of time tweaking the locking function and every time you want to make a change, you need to remove the transaxle in our cars.
A 2-Way diff locks equally under acceleration and deceleration, these are ideal for RWD drift cars but are no good for fasts and even worse for FWD cars.
The best of both worlds is the Wavetrac diff (15), which is similar to the Quaife in operation but actually has a locking ability. The frustrating thing is that it isn't available for the MPS!
The main thing to conclude out of the diff debate is this: Unless you are a serious racer then a Quaife or (ideally) Wavetrac will be the best option in nearly all cases. A Kaaz or Cusco type diff will in theory give you the fastest lap times but it can take a lot of tweaking to get them set up just right, and if they are set up wrong then they can make things really terrible. A torque biasing diff is the best option for 95% of owners and even
I ended up buying a Quaife and have been loving its operation so far. Very smooth and grip exiting corners is excellent. The car doesn't understeer at all anymore provided both wheels stay on the pavement, if you lift a wheel then you lose drive but when it's hooked up - WOW.
I also bought a NPC clutch + flywheel combo that spins very nicely along with the engine now being fully balanced.
Servicing:
Proper wheel balance & alignments
I use Castrol Edge Ti 5w-40 engine oil in my car.
Castrol VMX80 in the gearbox
Regular servicing matters, caining your car at the track WILL reduce its servicable life. Take care of it and it won't give you any trouble.
Driver Skill
Learn to drive. Learn how your car behaves, learn the track, practice in racing sims, read about it, watch professionals, take lessons with driving instructors at track days. Experience and knowledge in this area helps educate you to make decisions about what parts of the car need to be modified to fix up weaknesses.
Good Reads:
1. [NSFW] MSF vs 8thGen - FW - Forzda vs the World & Beyond - Mazdaspeed Forums
2. http://www.mazdaspeedforums.org/foru...-plates-82220/ Corksport Camber Plate thread.
3. http://www.ozmpsclub.com/forum/tech-...tml#post176648 Epic Suspension Tuning Compendium.
4. http://farnorthracing.com/autocross_secrets6.html Shock absorber theory
5. http://farnorthracing.com/autocross_secrets18.html Suspension "Not Crap" list.
6. http://www.gofastadventure.com/?tag=willowsprings
7. http://www.mazdaspeedforums.org/foru...tml#post860859 - Post about effects of putting a LSD in.
8. http://www.heasmans.com.au/new_site3/main.html - Suspension specialists, recommended by LW
9. http://shop.kw-suspensions.eu/index....&pg=160&page=1
10. http://www.kw-suspension.com/us/kw_faqs.php
11. http://www.rapid-racer.com/suspension-tuning.php - Some good, simple reading on suspension dynamics and what adjustments affect what aspects of handling.
12. http://www.se-r.net/car_info/suspension_tuning.html
13. http://www.kaazusa.com/lsd_mazda.html
14. http://www.edgeautosport.com/manufac...d-3-2007-2013/
15. http://www.wavetrac.net/technical.htm
16. http://www.trackhq.com/forums/f295/l...you-have-2319/ - The best online discussion I have found so far about different LSD types
17. https://www.youtube.com/watch?v=JEiSTzK-A2A - Another good Explanation on how Torsen type differentials work.