วันจันทร์ที่ 18 กุมภาพันธ์ พ.ศ. 2556

Sneak Peek: Daigo Saito's Achilles Tire SC430

Sneak Peek: Daigo Saito's Achilles Tire SC430

copy from http://www.motoiq.com/magazine_articles/id/2698/sneak-peek-daigo-saitos-achilles-tire-sc430.aspx

 

Sneak Peek: Daigo Saito's Achilles Tire SC430
By Mike Kojima

After two years of rumors and plenty of gossip, it finally happened, Daigo Saito, reportedly the best drift driver in the world arrived on our shores with not just a splash but a bang.  Daigo, 2008 D1GP champ and 2011 Formula D Asia Champ came out of the gates hard at the Long Beach season opener with a third place.  Daigo has fought hard on foreign soil maintaining a solid second place in Formula D standings for much of the year.
There are many rumors surrounding Daigo's car which has been reported as having as much as 1300 hp.  The fact that Daigo and his crew don't speak English and that they are somewhat secretive about their car, has kept many fans wondering about what makes it tick.  We don't directly know all of the car's specs either, but we have photos and I will attempt to give you a technical tour around the car.  It is an interesting blend of both Japanese and American Technology.
Daigo took the old guard of US drifting by storm with surprisingly strong performances.

Daigo sometimes runs the SC430 with the hard top on if it is raining or to shield him from smoke.

Perhaps the best follow driver in the world, Daigo's aggressive, super close proximity, in your face driving style has angered some drivers like Luke Lonberger and Justin Pawlak.  A lot of Daigo's controversial driving tricks are probably due to the differences between what is acceptable in D1 vs FD in part and the fact that he is a rookie and just getting to learn some of the courses that many other drivers have been driving for years.


2011 FD champ Dai Yoshihara has been able to defeat Daigo with each encounter in the 2012 season so far.

Conrad Grunewald has had more battles with Daigo than any other driver, fighting numerous one more time bouts from road Atlanta to New Jersey.  The battles have been controversial and have resulted in some motions by FD to more clearly define scoring and DQ criteria for the season.

 

This is the most powerful engine on the Formula Drift Circuit by far. The engine that strikes fear in the hearts of LS swapped drift cars everywhere.  Daigo's SC430 is powered by a 2JZ rumored to have as much as 1300 hp.  Personally we think 900-1000 hp is much more realistic but there is no doubt that Daigo's car is very powerful.  Daigo's engine uses a Brian Crower 3.4 liter stroker kit which has a billet 94mm stroke crank and 87mm JE pistons using a 2618 alloy asymmetrical forging with a contoured undercrown, hung on BC 5.59 center to center H beam rods.
The engine uses a 2JZGE cylinder head, presumably to take advantage of the VVT-i variable cam timing system on the intake cam.  This can give needed faster spool and a wider powerband, we think as much as 100 lb/ft in some parts of the powerband.  Daigo uses Brian Crower cams and HKS timing gears with all the related valve springs by Brian Crower as well.  A heavy duty HKS timing belt is also used.  The heads are probably mildly ported with a good valve job.
The engine has a rear mounted radiator so the layout of the plumbing for the engine's front mounted Greddy core tube and fin intercooler can be very simple and straightforward for minimal volume while still being large diameter for good flow.  All couplers and hoses are burst resistant 4-ply HPS silicone parts.  HPS also supplied all of the postive locking stainless T-Bolt clamps as well.
The secret behind Daigo's awesome power is a Garrett GTX4294R turbo.  It uses a billet compressor wheel with better aero and maximum compressor efficiency with a ball bearing CHRA for faster spool.  It has an exhaust A/R of 1.2 with a divided housing to speed spool time with a pulse converter exhaust manifold.  The turbo can provide enough airflow for over 1100 hp.
A fabricated intake manifold with a large surge tank is used to feed the big stroker engine.  An enlarged throttle body feeds the big plenum.
An HKS GT50 wastegate is used to regulate boost pressure.  The exhaust manifold is an HKS tubular stainless piece designed for pulse conversion with a  twin scroll exhaust housing on the turbo.  This speeds spool by over 500 rpm.
The unusual stainless mesh air filter is made by Blitz.  It filters better than you might think and has very low restriction.
A Greddy RZ 40mm blow off valve helps reduce turbo compressor surge.
Greddy also supplied the oil cooler adaptor.  The adaptor has ports for oil pressure and temperature sending units for the Racepak dash.
The exhaust is a large 4" in diameter stainless part.  To flow enough gasses for mega power you need a big exhaust!
Yes, Daigo's car has nitrous.  It's probably the reason why the rumors of 1300 hp started.  The 10 lb bottle has a heater and one bottle lasts a FD weekend.  We think that the nitrous is only used to spool the turbo quickly and shuts off once a certain boost pressure is reached.  Daigo typically does not use the nitrous in an event's early practice sessions and you can really hear the difference in exhaust note and how fast his engine responds when he turns it on in later sessions once he learns the basics of each track.  The nitrous is the key factor in levelling the playing field against the V8's.  With nitrous, you can have the low end power of a big V8 with the tremendous top end power of a turbo.  Daigo's power is one of the key factors in his success this year.
Under the dash, Daigo's car has typical Japanese style engine management which is a somewhat confusing bundle of magic tuning boxes.  The basic fuel, spark and cam control maps are controlled by the large gold box which is an HKS V-Pro stand alone ECU. The next box is an HKS part that converts the stock waste spark ignition system to an individual coil direct fire system and  the final box is a Greddy Profec boost controller.  There is another box we think it's a Racepak multiplexor for data logging.  Bulkhead terminations for the wiring and plumbing would be safer as well.
The rear of Daigo's car is almost more interesting than the engine!  In the interest of having as much weight rearward as possible, nearly every moveable component is relocated to the rear of the car.  This offsets the forward weight bias of the long 2JZ.
The back of the car contains the heat exchangers for coolant, and oil as well as their attendant surge tanks.  The fuel cell, nitrous bottle, rear wing supports, battery and reservoir for the interooler and radiator sprayer are also located back here.
The whole back of the car is supported by a delicate, super light bird cage arrangement of small diameter aluminum tubes bolted to the frame rails.  Although the construction is exquisite, we feel that this is much too fragile for the rough and tumble world of pro drifting and it leaves many critical components exposed to potentially crippling damage.  Most typical FD cars use larger diameter seamless or chromoly tubing for the front and rear fabricated subframes.
The critical heat exchangers are also the most rear mounted components and prone to damage.  A good hit can cause the car to be taken out of action.  Koyo makes the radiator and oil cooler and you can see the electric Davies Craig water pump back here as well.  Don't get us wrong, this is beautifully made, super trick stuff but it makes the car less robust in a semi contact motorsport.
The cooling fans are located under the car.  The screen was added after Long Beach as it was found that debris could easily fly up and hole the radiator.
An Odyssey dry cell battery provides power for the car's systems in a safe lightweight package.
This fabricated aluminum tank is the water reservoir for the intercooler and radiator sprayer.
 A high pressure AEM water injection pump is used for spraying the radiator and intercooler.
Water is added every round to the rear mounted tank to help keep things cool.
Daigo's car runs on VP C16 fuel.  C16 is really good turbo and nitrous fuel.  The fuel is transferred from the fuel cell to the engine via twin Bosch 044 fuel pumps.
Like the rear of the car, the front has a beautifully fabricated aluminum sub structure.  We feel that this is easy to damage.  Fortunately since the radiator is in the back, it can crush quite a bit before it gets into critical components.  On most drift cars this structure is made of seamless mild steel or 4130 chrommoly for better impact resistance.  This lightness of construction probably contributed to the car's heavy damage suffered in the Las Vegas round.
The roll cage is Formula D compliant and is sort of minimalistic.  Many Japanese drift teams feel that the cage should be flexible to help the car find traction.  This is the opposite of what many of the better American teams feel who build stiffer cages with more triangulation.
The cage is minimalistic lacking the triangulation seen in many of the top US cars.  This is an area where a lot of US built cars are triangulated.
The pedal system is very simple as it is just using modified stock Toyota components.  This is very different from most US drift car that use racing pedal boxes with dual brake master cylinders and balance bars to adjust brake proportioning fully.  Daigo's car uses a stock master cylinder and power brake booster.  The lightweight clutch pedal operates a Spec twin disc clutch using metal discs and a lightweight flywheel.
Daigo can adjust his brake bias to some degree with this hydraulic proportioning valve.  Unlike dual master cylinders and a balance bar where you have full control of the brake bias, the valve can only adjust the slope of the rear brake pressure curve after the knee point.
Daigo uses a driver controlled drift brake operated by this lever attached to a Willwood master cylinder.  The shifter goes to an exotic sequentially shifted Holinger dog type, close ratio, six speed transmission from a GT300 JGTC car.  The close ratio six speed reduces the need for a quick change rear end like many US drift cars run. US thinking is to use a strong and light 4 speed NASCAR style gearbox with fine tuning of the final drive ratio via a quick change rear end.
The rear brakes and the drift brake are Wilwood Dynapro 4 piston calipers.  We were looking at the offset in the rear brake rotor hat and are pretty surprised that the cars track was widened so far by spacers.  This puts a lot of strain on suspension components and wheel bearings.  A wave type, solid sprint car rotor is used.  On a sprint car this helps clear dirt from the brakes but we suspect that Daigo uses these rotors for lighter weight and looks.
The front brakes use a 6 piston Wilwood Dynapro caliper with a solid wave rotor.  When using the stock master cylinder, careful attention has to be spent on caliper fluid capacity and the ratio of caliper piston sizes.  It is interesting that this works out Ok.
Daigo's office is very straightforward, all RHD using the stock Toyota dash shell and carbon panels.  Note how the cage does not extend past the dash. This is not good for stiffness or footwell intrusion protection but is consistent with the JDM chassis flexibility line of thought.
The switch panel contains the master cut off switch, ignition kill, start button, dash, lights, nitrous system and fuel pump switches. it also has a nitrous bottle pressure gauge and a Blitz boost controller.  The Blitz boost controller is the primary boost control and the Greddy Profec under the dash is a back up boost control.  We are uncertain as to why the team feels that two boost controllers are needed.
A PLX Devices M-300 wide band a/f ratio gage is used.
This is the arming switch and sprayer button for the intercooler and radiator water spray.
A deeply dished Prodrive steering wheel is mounted to he stock steering column.  A Racepak digital dash and data logger is also used.  The red T-handle is the activation lever for the Safecraft fire system.
The Safecraft fire system employs FE36 extinguishing agent.  FE36 is the replacement for Halon 1211.  It does not damage the ozone layer like Halon and is less toxic while still extinguishing better.
A Seibon dry carbon hood saves a bunch of weight and has functional vents that help keep the 2JZ cool.  The hood has survived some pretty decent impacts without breaking!  The front fascia, rear bumper, fenders and side skirts are also Seibon dry carbon.
 
Daigo sometimes runs the gutted out stock top.  On some occasions this is for rain and on others to reduce the amount of smoke in the cabin.  The doors are lightweight and strong Seibon dry carbon fiber parts that save about 80 lbs off the total weight of the car.
 
A huge rear wing is run, presumably to help contain the massive power the engine produces.  Sturdy mounts for the wing attach directly to the rear support structure not the trunk.  The trunk lid is a Seibon superlight dry carbon part.  Seibon parts take around 150 plus lbs off of the SC430.
 
The stock configuration diff is run, not a quick change like US drift cars typically use.  An OS Giken LSD splits the power.  Daigo runs a 3.7 final drive.  An oval section exhaust flows enough for all the power while maintaining ground clearance.
 
Ikeya Formula adjustable links are used in the rear suspension.  These links are fully adjustable and replace the squishy rubber bushings with bearings.  The rubber bushings in the uprights are pressed out and replaced with spherical bearings as well.  Stock Supra axles are run and they hold up well.
 
DG 5 adjustable coilovers are used with Swift Springs.  The stock rear antisway bar is run.  The rear crossmember bushings are locked in place with aluminum top inserts.  Note that the motion ratio of the coilovers can be adjusted as can the position of the swaybar end links.  Also note the full seam welding treatment that has been performed on the unibody.
 
Look at the extreme wheel spacing used to fill out the widebody.  This puts a lot of stress on the wheel bearings and suspension.  The Ikeya Formula lower arm is adjustable for length on the inboard end and has an additional eccentric on the outboard end for adjusting camber.  Cool stuff!
Currently Daigo's car runs super sticky and super smoky Achilles 123S tires in 265/35-18 in the front with the Achilles ATR Sport 2 also in 265/35-18 in the rear.  The Achilles 123S is a really grippy tire and we are looking forward to evaluating it on some of our project cars.
The front suspension also runs adjustable Ikeya Formula arms.  A Cusco non adjustable front sway bar is used.  The stock Lexus electric over hydraulic power steering is used.
To get more steering angle, the lower part of the spindle is replaced with a shorter piece to increase the steering ratio.  What's cool is that this part unbolts from the upright part of the spindle making getting more angle a simple job. A DG-5 front coilover is used with a Swift spring.  The front hub uses a thick spacer to space the wheel out to fill the widebody.  Unfortunately this really increases the scrub radius which affects turn in.  From the look of things, the rear steer rack position is set up for minimal Ackerman.
Increasing the track can increase rear grip while sliding sideways by reducing weight transfer to the outside wheel.  When the tires sizes are restricted like they are in Formula D, this is a trick that helps.  The Achilles 123 is currently only available in a 265 width but we think the car can probably run a 275 or wider under the FD tire width to weight rule.  When wider sizes of the 123S come out, the car will get faster!
Lightweight Prodrive forged wheels are used.
Currently Daigo is in second place in Formula D points heading into the last event at Irwindale.  Daigo's performance this year has been amazing.  Just wait until next year now that he has experience with the US circuit and knows the tracks.
We have shown that Daigo's Achilles Tire SC430 is an interesting mix of JDM and US technology.  The car's stellar performance is the result of tremendous power provided by the Garrett boosted, Brian Crower large displacement, nitroused 2JZ and grip of the Achilles 123S tire.  Combined with Daigos suburb driving skill, the Achilles team has been very competitive in their inaugural season and we expect that to increase as the team becomes more experienced with US tracks and driving protocol.
We can't wait to see what Daigo has in store next year, especially now that he is more familiar with the Formula D circuit

Sources

Achilles Tire

Design Craft Fabrication
Bridges Racing
   

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