Clutch and Header

   I was a little nervous having the clutch and other maintenance work done the day before I leave for Lincoln, but my trusty mechanic Rocky specializes in Miatas and all the parts installed were OEM.  Probably the original with 120k miles, the clutch disk was worn unevenly and the flywheel was heat damaged.  The install went smoothly and there were no surprises. Synthetic GL-5 was replaced in both the transmission and differential and the fuel filter was also changed. 

 

  
  The new Racing Beat header fit perfectly and the EGR tube was a breeze to install.  The RB 4-1 design is supposed to generate more power than the OBX 4-2-1. 

Theoretical Weight

  So I rolled my Miata across the scales at the San Diego Tour and the display showed 2168 pounds with 1/4 tank of fuel, helmet, camera, and soft top boot.  This is with the 15x8 6UL / full tread RS3 combination and the quiet Enthuza NB Speeder muffler. Includes NB2 center console. Washer bottle empty and coolant overflow reservoir at 1/3 full.

Helmet 3.5
Camera 1.0
Soft top boot 1.5
Gas (2 gallons) 12.0

  My Odyssey PC545 works great for a daily driver but at over 11 lbs I can save a lot of weight by going with a modern 2 lb. lithium battery.  My complete exhaust is heavy too and it would be easy to save 10 lbs or more with a custom 97+db setup and Maxim header.  Note the wheel / tire weights below also;  I can save 18 lbs if I stay with the 195 Toyos / 7.5" 6UL.  Subtract another 5+ lbs for Bogart, Volk, or SSR wheels.  

   2085# seems like a reasonable weight without going crazy, and in my estimation 2020#  (after some thinking and rough calculating, and with the recent rules change regarding motor mounts, 2020# is probably not realistic. 2055# is closer, maybe.)  would require maximizing the rules with aluminum shock assemblies, custom brakes and rotors, delrin bushings, replacement control arms, billet motor mounts, and so on. How much time and money do I want to spend?  How bad do I want to win?


15x8 / RS3  35.5
15x7.5 / R1R  31.0
Passenger seat  31.0
NB1 console 3.29
NB2 console  3.33
Odyssey PC545  11.5
Maximworks header  11.0
Racing Beat header  15.5
Enthuza XR   12.0
Enthuza NB Speeder 12.5
Roadstersport muffler 17.0
Boomslang and EMUltimate  2.5
Crank pulley 3.85
Complete side power mirror assembly  2.00
OEM fuel filter .50


Rear lower OEM chassis brace
Swaybar reinforcement blocks
Alt & WP pulleys
Intake assembly
Power windows
Power locks
Clearwater speakers
Hardtop latches
Cat / midpipe
Control arms
Motor mounts
Suspension bushings
Differential bushings
Brakes
Lug nuts
Convertible top
Emblems
Shifter
Differential
Filters and Hoses
Frankenstein bolts

Lincoln 'Spring Nationals' Pre-Show

   Recently I've had a few inquiries about my build and the parts I have chosen for my STR Miata.  Aside from being thrifty and on a moderate budget, my idea is to keep it simple, easy to drive, and reliable.  Almost everything added to the car is a readily available off the shelf part, with only minor fabrication needed to fit the driver's seat and to mount the battery.  The only custom parts are the upper shock mounts from PES which have been carefully designed to allow a great balance of bump/rebound shock travel at various ride heights without bottoming out or binding.  Autox is all about minimizing mistakes, both in driving and build execution, and special attention to a few key parts is what can make the car more forgiving and ultimately faster.

http://lateapexphoto.com/

   So a few weeks after the El Toro Pro I find myself unemployed and decide to take a little break and prepare to head off to Lincoln, NE for the "Spring Nationals" which is a four day SCCA event scheduled for the Memorial Day weekend of May 25-28.  Friday and Saturday consist of a Pro Solo with Sunday and Monday being a regular Tour.  I have an appointment to replace the clutch on Monday, May 21st at Rocky's Miatomotive with a planned departure for Lincoln at 6am Tuesday morning. 

   My biggest decision regarding this trip is what tire to use. Actually, tire choice has been my biggest issue during this whole build (aside from the poor ECU service from DPTune). Both the Toyo and Hankook leave me frustrated because neither one is a great tire and both work best at completely opposite temperatures and feel and drive differently.  For this event I will bring my used 75+ run 195 Toyos on 15x7.5" 6UL wheels.

   Although the Miata is one of the few cars in class that can fit the 195 Toyo, I believe the Dunlop SS Z1 is a superior tire and easier to drive in a wider variety of conditions.  Available in a decent 205/50-15 size, actual same day comparison testing is needed to determine if the Dunlop is quicker than its competition.  The 225/45-15 Toyo R1R is also a good tire and I successfully used this tire on a 7.5" wheel on my 1995 STS Miata.  A wider 9" wheel would compliment the 225 Toyo and this could be the combination to have.  In the meantime, I will primarily use the 195 Toyo on a 7.5" wheel because it is relatively cheap, pays contingency, works well in the wet, and is fast on the first lap.

  So while I was typing this post UPS delivers two boxes; one from Mazda containing a 2001 Miata EGR tube and the other from Racing Beat containing a 2001 Miata 4-1 header.  The NB2 (2001-2005 Miata) parts were ordered because the 99-2000 RB headers are not in stock at this time.  The only difference between the two is the connection of the EGR tube to the header; one has male threads, the other is female.

   Due to the poor fitment of my eBay OBX header the original egr tube was bent and modified to fit so a new replacement tube would be needed anyway.  Plus, the new egr tube is compatible with the  2001+ OEM tubular header which makes an easy stealthy swap for SMOG inspection.

 









   I bought the Racing Beat header in anticipation of the upcoming clutch replacement knowing that the header needs to be removed completely to best complete the job.  Since I had to fight the OBX header install, I decided to hit the easy button and get a header that I know will fit the first time without frustration, and of course the RB header has been well developed and proven to make power.

Power

  In my quest for more power and frustration from dealing with Dynotronics Tuning, I purchased a used Greddy Emanage Ultimate and Boomslang harness.  The special plug and play harness meets the rules requirement of no splicing and offers a clean and simple install of the piggyback controller.  Unlike the reflash from DPTune, the Emanage Ultimate gives the user full control over most of the engine management and I will primarily focus on fuel and timing to maximize horsepower and torque.  The rpm limiter can also be changed.  As with my STS car, tuning will be done by Shawn at Church Automotive Testing.

  The install will have to wait until the clutch is replaced, which unfortunately just started slipping as the SCCA Tour and Pro came to SoCal.  A new pressure plate, clutch disc, and flywheel was delivered today thanks to Mazdaspeed Motorsports.  The plan is to have the clutch replaced and engine tuned before the next big regional event scheduled for June 15-17 at El Toro.

STX Mustang Dreaming

Step One:  Find a clean and unmolested 1987 Ford Mustang Sedan (Notchback) 5.0 V8 5-speed or 1988 non-California car. Convert to base model A/C delete, no radio, PS, PW, or Cruise

Step Two: Add the following parts.

Optional 3.08:1 final drive
Steeda 5-Link
Detroit Locker
Koni yellow double adjustable shocks
Maximum Motorsports camber/caster plates
Ebay springs
Front sway bar
Pro 5.0 shifter
Momo Race steering wheel
Sparco Evo seats
Basani long tube headers
Catted x-pipe
Under drive pulleys
Battery relocation
Cold air intake
Moates ecu
Rear disk brake conversion and front Cobra brakes
Bolt-on subframe connectors
17x9 w/265mm Dunlops or 18x9 w/Hankooks
Remove factory side rub strips

After all the hard work it should look something like this and sound fantastic.  

El Toro Pro Solo

I kept the same setup as used the prior weekend at the SD Tour, except for a minor 1/8" rear ride height increase for day two.  Similar tire pressures with the rear going as low as 24 psi.  New coilpack installed.

Ride height is 11 1/2" at all four corners as measured from the center wheel hub to fender.  Pinch weld measurement is approximately 3 5/8" front, 3 1/2" rear.





   Once the tires warmed up the car worked well.  I shifted to third gear in the walloms on Saturday afternoon but did not pick up much time.  Rode the limiter on Sunday and focused on a clean line and dropped some time on both sides.  Could have been quicker on the right but I had trouble slowing for the first pin turn on both runs.  A new clutch and 300 more rpm could be worth another tenth or two.

   Special thanks to my co-driver Jason for warming the tires and giving me positive feedback regarding the car's handling and potential.  Be sure to check out his 67 Camaro build.

Final RESULTS put me in 8th, the final trophy spot and only a half second behind per side.

San Diego Tour

2012 San Diego Solo National Tour

Day 2 finish slalom



Hot Saturday temperatures were favorable for the Hankook tires and I thought I drove very well.  One second out of the lead with the Hondas possibly having a horsepower advantage on the long fast third gear uphill straight.  Clutch is slipping at the 1-2 shift.

Day two the marine layer keeps the sun away and temps are cool and as a result the tires never get hot and I struggle for grip and did not drive well.  Final results put me in seventh place.

Setup

As used at the 2012 SCCA San Diego Solo National Tour:

Koni Race (yellow) shocks front and rear; full stiff front, full soft rear
Custom PES spherical bearing top shock mounts
Front springs - 2.25" diameter x 6" length 750# Hyperco, Koni threaded perches
Rear springs - 2.5" diameter x 6" length 375# Eibach, Ground Control threaded perches
AWR adjustable rear upper control arms
Racing Beat 1.125" diameter, 3/16" wall, hollow front sway bar - no rear sway bar
15x8 +40 949 6UL wheels, 225/45-15 Hankook RS3; 25 psi rear, 27 psi front
Front brake pads OEM
Rear brake pads Hawk HPS
Mazda Competition sway bar end links
Mazda Competition motor mounts
Momo Start bottom-mount seat installed on OEM sliders
MiataRoadster short shifter kit, eBay delrin shift knob
Odyssey PC545 battery
K&N cold air intake
OBX 4-2-1 header
Goodwin Racing midpipe
Enthuza NB Speeder axle-back exhaust
DPTune ECU re-flash with 7500 rpm rev limiter
2168 lbs with 1/4 tank fuel, SCCA scales
Zero front toe, 3/16 total rear toe in, approx -3* camber F&R

Trust, Slip Angle, & One Inch

   The weekend of April 14-15 hosted the last El Toro championship autocross before the upcoming SCCA ProSolo event scheduled for the first weekend in May.  The weather was beautiful with sunny skies and mid 60* temperatures.  I bring my 225 Hankooks out to play and snag a co-driver to help heat them up.  STR runs first group and I have not driven the RS3 tires on this El Toro surface for a couple of years; 2010 SCCA ProSolo in my old 1995 STS car to be exact.

Co-driver warming the tires

 


   I take it easy on my first run but I do not fully trust the tires yet, especially under braking.  Lots of grip at this venue and the Hankooks are much sharper than the Toyos.  Without all the magic Toyo slip angle I am turning in too early and nipping apex cones with the back of the car.  Or it could be from the 1/2" wider wheels.  Or I am just not turning the steering wheel enough on this busy transitional course.

 












    Second run was relatively fast, but drifting the sweeper and getting behind at the finish did not help.  Neither did the three cones; two of which were at the start.  By my third run I was feeling really good about the tires and blown away by the grip and responsiveness, especially compared to the R1R, but I needed a clean run so I backed it down a little.  My 4th and final run was much faster mostly due to staying ahead of the course and from fully trusting the directness of the tires, but I am still a little tight to the cones as seen in the video and I knock down 4 cones (two again at the start).

    I can't complain about my times but I can complain about my driving as I am normally not that dirty.  First place finisher Max H. was on 300+ run Dunlops and I finished second in class.   RESULTS

 




  

Fail

   DP Tune has been a major fail as I have been waiting over 2 months for them to send me an LM2 rental to fine tune the ECU and also bump the limiter up to my requested 7700 rpm.  He keeps saying I am next on the list with a sympathetic email or phone call, but then nothing happens. Last email says it is in the mail and should be here today.  With 2 weeks to go until the San Diego Tour and El Toro ProSolo, I cannot rely on them to process the order fast enough and return it promptly so I will keep what I have and figure this stuff out later.  Besides, my coil pack went bad last weekend with symptoms being minor hesitation and surging under load.  Check engine light is on for low cat efficiency.  Not sure an LM2 tune would be beneficial at this time anyway with the current engine woes.  Coil and plug wires were ordered this morning from Mazdaspeed Motorsports.

  

   











   Some of the coil pack issues could stem from the previous weekend when I changed out the spark plugs and plug wires.  What was supposed to be a simple job turned into stress and frustration when two of the spark plugs threaded out hard the whole way and the number four plug wire ends were fused to the coil and plug. Leftover used NGK blue plug wires from my '95 STS Miata will serve as the replacments in the meantime.  The oil on plug three is from a bad cam cover gasket which will be replaced along with the coil pack.

Bell Engineering Group offers an ECU tuning service similar to what I have, but the cost is a little more and probably well worth it.  After the big California SCCA autocross events, I may seek a refund from DP Tune and explore the BEGI setup.