V8Rspec build

I will make an effort here to document my build specifically a “V8R Spec” car. I hope you find this helpful if you are considering a build such as this or maybe considering a GM GEN3 engine swap project of your own.

So why this build. Quite simple really. I want a car that will perform at the next level when compared with a Spec Miata, will handle, is tunable, is reliable, and is at a price point that is within my means. I want to do as much of the work myself as possible. I also want to use proven, tested, and supported products that are not going to put me on the bleeding edge. I would also like to compete with like cars on a level playing field.

While I have found it difficult to quantify there has also been several trains of thought around “price to performance ratio” or “price to fun factor”. I have looked into other platforms to achieve similar design or performance objectives. These have included a C5 Corvette that later became a super charged C5 Corvette, a Pontiac GTO 5.7 that later was also super charged, a late model Mitsubishi all wheel drive turbo charged sedan, Honda S2000, a FFR Cobra replica, a Ford Mustang GT, Numerous NA (1990 - 1997) and NB (1999 - 2005) Miatas.

During all of theses builds, street and track projects alike I keep coming back to the same simple facts. The Miata is cheap to operate, has great support both from Mazda and the aftermarket, has great handling characteristics and is a tough platform. The only issue I have with this platform was cubic inches. I have worked on and or owned numerous Turbo and or super charged Miata’s and have always found ways to work around the inherent limitations of a blown small engine. Then I built my first GM GEN 3 Miata that was a street and track car. In short it opened up my eyes to a new world of possibilities and performance that was within my budget, home workshop facilities and mechanical abilities.

So after much research, numerous bench racing sessions with friends and fellow racers and numerous calls with the V8Roadsters staff, I have made the decision to build a V8RSpec. I am not for a second suggesting that the selections I have made are the only way to get this job done. You may have different experiences and or preferences. I will however share with you my selections the associated reasoning and in the end how it all works together.

The specifics:

Donor

A 99 Miata will be the base for this build. The NB (1999 - 2005 Miata) is a platform that I am very familiar with, has great suspension geometry, can handle life as a track duty car, has amazing after market support, and per my last build will fit a GM GEN3 small block and still maintain the great Miata handling as when stock. The Miata handling DNA if you will.

Engine
I will be using an L33 (GM GEN3 small block from a 2005 - 2007 Chevy Silverado) The L33 option is essentially a LS1 that has a reduced stroke giving it a 5.3 liter capacity vs the LS1’s 5.7 liter capacity. The L33 uses the LS1 799 or 243 heads (head casting number) from the LS1 and can be found at a significantly reduced price when compared to the LS1. While my experience in finding a serviceable LS1 has been limited; I believe you will find the price range for a good serviceable engine to be in the $2500 - $4500 range. I was able to find a comparable L33 long block engine assembly locally for $700. The price range for the L33 engines seems to be in the $500 - $1500 range.

The L33 will need a few extra bits and pieces to fit this application. During this build I will document the parts we have found to work and also give you a few alternative ideas and or reference points from others who are building similar cars. As a brief introduction to the engine section of this build. The L33 will be mated to an LS6 intake with the associated fuel rails and injectors with a cable operated throttle body. I will also be using a combination of front drive pulleys and accessories from other GM vehicles. I hope to save you the many hours of time, several of us have spent testing numerous configurations, bolts, pulleys etc. In short the final engine accessory drive setup is inexpensive, and provides a reduced engine bay foot print (almost 3/4” less) right where you will need it in front of the radiator. The CAM is supplied by V8Roadsters for this specific application. Engine assemblies are a personal preference item (especially when selecting vendors) I have chosen to go with known suppliers and parts that will meet my design and performance objectives, namely reliability and simplicity.

Transmission

One of the many advantages of working through this build with a vendor like V8Roadsters is their driveline knowledge and experience. My last build I used a T56 transmission. While I found it to be robust, it was also heavy, had a very low 1st gear and a 6th gear over drive ration that was all but worthless in my application. V8R had been working for some time on a T5 solution to address their customers needs. In short the T5 with a Ford road race gear set and a modified gear ratio cluster will provide a usable 1st - 5th gear close ratio solution that is also about 70 pounds lighter. I am aware of numerous racers who have concerns about the strength of the T5 transmission. Upon digging into these issues and the racing experience base I have available to me (that is the local racing community). I was able to find that the stock T5 gear set in 3000 plus pound cars, running high horse power (in many case north of 400hp) is an issue. However in this application with a sub 2400 pound car and 350 or so HP we believe we will not have an issue.

Differential

I will again be using a Getrag differential. Again this may not be the perfect differential for all applications. There are numerous threads out there on the issues with this differential in other applications. The CTSV being the main one. Again however in a light weight car (such as this application) without rear wheel hop stresses and lack of associated rear end binding have all contributed to this being the differential of choice for this application. The rear end ratio with the transmission gear set was also reviewed in detail. In short I will be using a 3.23 rear end ratio with a limited slip. The most popular OEM application for this differential is the Cadillac CTS automatic. Why 3.23? I am using the ford road race close ratio gear set in my transmission, and wanted a usable 1st gear. The 3.23 ratio when mated to this transmission gear set will provide over 170mph (calculated from engine RPM, associated gear set ratios and wheel rolling diameter)

ECU

The L33 ECU (or Silverado ECU) was found to not be the best for this application. I will again be using a 2002 Camaro ECU. The engine harness and connections to the ECU are provided by a custom harness vs. the OEM engine harness. Weight and simplicity were the main selection criteria here.

Fuel

During my last build (Twice as Nice) I had numerous lessons learned to include setting up the fuel system. Nathan (http://www.swaptastic.net) has done a great job of documenting several options with part numbers for AN fittings and or hard line fuel system configurations. I will be using AN fittings from the tank to a Corvette fuel filter pressure regulator and then a 3/8” hardline through the passenger compartment to braided line and finally to the fuel rail. Why through the passenger compartment? I have reviewed my options here and believe this routing to be the safest in the long run considering this application and the close proximity of the headers to the other engine bay routing options.

Cooling

I will be using a custom radiator and swirl pot on this build. (more detail to follow) The thought here is to avoid the lower hose having to cross the lower engine bay (when using a radiator designed for a Miata application one of the radiator hose inputs is on the drivers side the GM Gen 3 motors water pump connections are both on the passenger side).

Wiring

I have removed all of the stock Miata wiring harness from my donor Miata. That is more than 25 pounds of wiring. As this is a dedicated track car only the required electrical elements will be added back during the build process. The rule book will specify what electrical functions we must utilize. We will use brake lights, wipers, cut off switch, after market ignition panel, cool suit, cooling fans, fuel pump. I have created a elementary wiring diagram that should suit my needs. The dash board will be replaced with a racing oriented digital dash with a sweeping digital tach, shift light, warning lights, oil temp, oil pressure, and water temp.

Steering

The Miata steering rack in my donor car was a powered unit. While I prefer the ratio of the powered rack work must be done to “de-power” this unit. I will try to document this process and also provide the adjustment process and end result analysis.

Suspension

I will initially be using a “Spec Miata” suspension kit. I had a new kit on hand, have experience tuning this setup and wanted to be able to use our tuning experience with this suspension kit to later determine if we need additional rebound, spring rate etc.


Roll Cage

I had a “Miatacage.com” roll cage kit on hand so will be using this kit for this build. Frankly I would have bought another one of this kits if I did not have one on hand. The ability to customize the roll cage to fit my needs, its compliance with the major racing bodies safety regulations and the quality of materials, computer located bends etc make it the best available for this application.

Seating, Fender Flairs, Hard Top, Wheels, Tires, Exhaust etc

While on the surface the selection of these parts and their fitment is a personal preference, I will attempt to show how these parts were fitted and why they were selected.

Can't wait to see where this goes!

Keep it up Mark! Steve and I just got the ball moving again... Now I just need to catch a flight up and finish build a few more custom parts. We need a middle ground to meet and play once we are all up and running. Kick Mac in gear you're going to need a bump drafting partner

The Donor 99 Miata

The donor car was picked up in Dallas, it had been set aside for a Spec Miata build that simply did not occur. The drive train had already been pulled saving me considerable time and effort. Not just from having to pull the motor, transmission and diff, but also in getting rid of them. I was able to also secure 2 new front fenders and a hard top.




I then set to work on stripping the car down to a bare tub. Every nut, bolt, screw, wire, rubber grommet, and plastic fitting was removed from the car. I also removed the windshield and all other glass from the doors etc.

One the car was torn down to a bare tub I removed the rubberized material from the foot wells. This was done with dry ice. I found that when I broke up the dry ice into small pieces and then let it sit on the floor boards for a few minutes the rubberized floor insulation material came out in large chunks.

I then set to removing the seam sealer in the areas where the roll cage was to be installed. This is not a fun project but taking my time paid off and in the end I was able to have all of the 6 roll cage weld in points cleaned up to a clean bare metal finish. At the same time I also removed the seam sealer around the transmission tunnel where the tunnel would later be widened for the new bell housing.

The front and rear sub frames were also removed from the car and the fuel tank and all of the associated lines and fittings also pulled. I did not want to do all of this welding (roll cage install) on the car with the fuel tank still in the car. I was also going to have to upgrade the fuel system pump and lines and this is easier with the tank out of the car.

I then made a chassis cradle. I went to a local metal scrap yard and purchased $40 worth of scrap steel. I then welded up a cradle with casters that would allow me to move the now bare chassis tub around the shop and on and off the lift. The cradle mounts to the factory sub frame mount points allowing full access to the under side of the car for the needed roll cage and transmission tunnel work.




Roll Cage

The next big job was the roll cage installation. I decided to tackle this first as I did not want to alter the chassis tub until it had the additional reinforcement that the roll cage would provide.

Beside being VERY careful not to paint myself into a corner where ever possible (during the cage install it would be very easy to get ahead of yourself). The rear landing perches were installed first. This was not as bad as it could of been as the area had been prepared as mentioned above. Any and all surface contamination will affect the weld quality. That is any paint, seam sealer, rubberized sealant etc. The landing perches were trimmed to fit where needed and then welded into the chassis tub.

The main roll bar hoop was then tacked into place at the recommended angle, then the seat back bars, diagonal braces, and rear bars. This whole assembly was then pulled from the car. I was able to do this as I had cut long slots into the rear parcel tray.


This allowed me to remove the whole rear cage assembly in one piece weld all of the joints with much easier access and then reinstall the now fully welded assembly back into the tub.

On to the front half of the cage. The upper door bars were fitted and tacked into place. Then the NASCAR door bars were fitted and tacked into place. Once everything was aligned I then removed each (left and right) completed assembly and again did the finish welding outside of the car. The completed assemblies were then welded onto the front landing perches and then welded to the rear main hoop.


Now the fun part. The over the windshield bar and the bars that provide overhead protection were measured 3-4 times and then notched long as the angles (some of these bars require two notches per end that must line up to form the corner). In the end I cut them long and then slowly trimmed them to fit.


Once cut to length sliding the bars into place was a real challenge. There is only one way to get them into place and even then it was a delicate time consuming task. The trick here is to fit the end with the two cuts into the rear passenger corner first and then slowly trim until you can get the bar into the front drivers side corner.

Once this was in pace and welded in I realized I was in trouble. The Upper door bars were now covering the front hardtop attachment bolt holes and there was no way to get bolts into these holes. I should of installed the front upper hardtop mounting brackets first (no this was not in the instructions) There was really only two options. Undo all of the side and top bars (which were now finished welded) or come up with a new way to mount the front of the hardtop to the upper windshield frame.

The SCCA GCR (General Competition Rules) no longer allow the hard top to be mounted to the roll cage. I therefore would have to purchase a metal hardtop bolt in bracket set (seems almost all of the after market hardtop mount brackets are aluminum) and extend them so they could be mounted to another location on the windshield frame. All in all a lot of extra work due to a dumb mistake that you do not want to make.

A center net is now required by most racing organizations. I then thought through the center net mounting at the dash end. I have used an extension strap to the center net and then wound it around the under dash bar on other Miatas (this seems to be the common way to install the center net). I knew there had to be a better way as in a accident the dash becomes the holding point for the center net strap. I decided to mount a bar through the left center AC vent and added a nut plate and eyelet to the end of the bar to attach the center net.


Once all of the bars were finished welded I then went to work on gussets and side window net mounting points etc.

Transmission Tunnel

The next major task was to widen the transmission tunnel. As I am using the T5 transmission and custom steel (safety item) bell housing from V8R I did not have to widen the tunnel as much as I did before for the T56. The T56 was close to 4” wider where as the T5 needs less than 3”. I did want to ensure I was able to gain access to all of the bell housing bolts and was able to remove the transmission and bell housing without having to pull the engine to service the clutch etc.

I started on the inside of the car and removed the two transmission tunnel inner braces with a plasma cutter. I then cut the joint where the floor meets the firewall from inside the car





I then moved to the engine bay and removed the two upper side tabs with a 4” cut off wheel. Must cleaner than using the plasma. I then finished the transmission tunnel to firewall cuts from the engine bay side. Once all of this was complete the firewall was wrapped around the tunnel in the new location and welded back into place. The inner braces were then trimmed to fit the new tunnel location and welded into place. I then used 3M seam sealer on all of these new joints and gave all of these joints a coat of primer.


The drivers side floor

The stock floor board has four small humps used to mount to the stock seat sliders. As I would be using a race seat and low profile sliders I no longer needed these stock mounting points. So they were removed. I then cut into the transmission tunnel where it met the drivers side floor board and also made two vertical cuts.



Why? This allowed me to get a race seat onto the floor board with sliders that allowed for 7” of forward and rear movement. I then measured and bent a piece of sheet steel to 37 degrees and welded it into position. The drives side floor is now a little wider, fits the seat in the lowest position possible and allowed for forward and rear movement. I did check before this modification that there would be enough room for the exhaust and as you will see later did not have an issue.


Fixing the body damage

The donor car had a bit of body damage that had to be addressed next. The radiator core support was missing from the car. I had received with the car a replacement piece that had to be fit and then spot welded into place. While Working on the front of the engine bay I cleaned numerous of the engine bay high stress panel joints. I then seam welded these panel joints.

I found a useful guide on where to seam weld the Miata tub for strength and used this for reference to seam weld the tub.

It was then off to the paint shop. I first reviewed with the painter the car in primer to ensure the body work had been addressed. Any and all small dings had been repaired.











So how did it look when it came back from the painter and was all of the time and effort worth it. In a word YES !!!






While the car was off at the painters I focused my time on assembling the front and rear sub frame assemblies so that when the car returned from the painters I could begin assembly.

More to come.

WOW!

That looks amazing! Can't wait to see more!

What's that hole in the driver's floor board?

Engine

The engine started life in a 2006 Chevy Silverado. While the truck itself did not fair to well (wrecked) the engine will soon live again.

So how do you source an engine and what should you look for? In 2005-2007 Chevy made a 5.3 liter Vortec engine that was called the “L33” option and was primarily installed in Crew Cab 4 wheel drive Silverado pickups. You may also find one in an Envoy, Trail Blazer, SSR etc. All of these trucks will have a “B” in the 8th digit of the vehicle identification number (VIN). Why the L33 5.3 V8? This is the engine that the V8RSpec series has standardize on, is inexpensive (when compared to an LS1-6) is an alloy block (less weight) and is essentially a reduced stroke (6mm less) LS#. How can you be sure you are getting an L33? Head casting numbers and alloy block is the key. You should verify that the heads have a casting number of 799 or 243, this is an LS6 head and was installed on the L33. The head casting number is on the top of the head in the outer front or rear corner depending which side of the engine you are viewing.

After calling numerous wrecking yards, going to local junk yards, doing the EBAY and craigslist searches, I finally found a good serviceable engine via car-parts.com. I found this particular engine an hour from my home base and was able to strike a deal @ $700.00 for the complete long block minus starter and alternator.




I picked up the engine and dropped it off at my favorite LS engine builder. While the engine was there I added the specV8R cam, ARP studs or bolts in all of the high stress locations, replaced the push rods with a better fitting (because of the new cam) high strength pieces. We also added the new V8R oil pan, an new LS6 intake with cable throttle body and new injectors.





Once the engine was back from the rebuild process it was time to complete the assembly process and add all of the accessories before matting it up to the new front subframe.

The front engine assembly (accessory drive pulleys etc) needed to be changed out to pull the front of the engine back 3/4”. (same as the last build “twice as nice” )

The only differences this time was the use of the CTSV alternator bracket and alternator. The CTSV alternator bracket has an extra mounting bold (3 instead of 2). I have had issues with the alternator moving under load with the other 2 bolt bracket. This then also required a different alternator to fit this bracket. The CTSV alternator is an expensive piece. I was able to find a remanufactured unit for just over $200 vs. a new alternator was in the $450 range.



The steam vent line has also changed. I will be using a swirl pot and have incorporated the stem vent line. This will assist in the drawing of steam out of the heads and will vent via the radiator cap.




The flywheel, clutch and pressure plate are from Exedy. They were kind enough to assemble a special unit for me. Special? As I am using a GM engine and a Ford T5 transmission this is not an off the shelf piece. The Pressure plate and flywheel are their Corvette parts and the clutch disc was sources to fit the transmission input shaft and to work with the Flywheel and pressure plate. I was very happy with the quality of the parts as received and look forward to testing them once the car is running.

The transmission as mentioned above is a Ford road race close ration unit. The 5th gear modification was also made to this box. That is the 5th gear is now a lower ratio that will allow it to be used on track vs. the normal over-drive 5th gear.



The throw out bearing is a Tilton hydraulic bearing. This part comes with one braided line that must be cut and ends installed to form an input (from clutch master cylinder) and bleed line. The throw out bearing must then be installed onto the inside rear of the bell housing via 4 long bolts and then shimmed to be within 100 thousands to 150 thousands from the pressure plate fingers. While a bit of a hassle to setup right it should be an easy part to use and service. One of the things to watch out for, if you go this route there are two different part numbers for this throw out bearing. One is designed to be used with flat pressure plate fingers the other for slanted fingers. So ordering the correct part for your pressure plate is a must. I used the Tilton part number #61-401.

The drive shaft is the same V8R unit as the last build with the exception of being aluminum this time (vs. steel)

I decided to go with a used diff and selected the 3.23 ratio. Steve at V8R suggested this ration as being the best all round choice with the gear set in my T5 (yours may vary). I found a used diff and tore it down check the gear set and bearings etc. I then adjusted the lash vis the front nose shim and replaced seals where needed.

In the pictures you can see where the gears had not been wearing 100% correctly. The wear pattern should be even across the face of the tooth. The front shim is all that it takes to fix this. GM part numbers for these shims can be found online; however the shims are measured in metric thicknesses.






Apparently once these diff housings go through a few heat cycles the lash changes enough to cause the alignment issue I have found in my diff. While in a street car this is said to not be a problem. For this usage it is important to get it right.

Steering rack

The steering rack was a powered unit and I had to convert it over to manual (or had to de-power the rack would be more accurate). I have found the power steering rack to have a better ration for track use. While it is possible to just pull the fluid out of the rack and block the line holes. I decided to go all of the way and tear the rack down and then remove the internal fluid seals from the main rack shaft. I also installed new retainers and adjusted the rack tension before installing the threaded fluid line plugs and or my now modified (welded) line plugs.

New ball joints were then installed where needed and then new rubber ball joint boots.



Now that the front and rear mechanical components were rebuild or serviced they were installed into the front or rear sub frames and were ready to go into the painted tub. Before this was done I did under coat the bottom of the tub with a coat or two of black under coating. The fuel tank was also installed with a new fuel pump and lines before the rear sub frame was installed. (More detail to follow on this one)



Ok still a bit to do.

Fuel system

The fuel system follows the accepted path. That is a 255 ltr/hour Welbro fuel pump installed in the tank using the stock fuel tank assembly. The lines from the tank (2) run to a corvette fuel filter / pressure regulator. The stock venting system is also re-routed to the fuel filler neck. This seals the tank and allows for venting.

AN fittings (6AN) were used with braided line to run from the stock filter location to the passenger side firewall. A bulkhead fitting allows the line to pass through the firewall and converts to a braided line in the engine bay. The engine bay braided fuel line connects to the LS6 intake fuel rail which was inverted for this installation.

Suspension

I have installed the V8R tubular A arms with competition bushings, ball joints etc. This is my first use for these parts and I am VERY happy with the fit and finish. One of the key advantages of these parts (besides the weight advantage) is the adjustability. The stock castor camber bolt locations and functionality are retained. V8R has also added another caster camber bolt in each corner to allow for additional camber adjustment over the factory settings.

I have decided to install a Spec Miata (NB) suspension initially. My thinking was that I know this suspension system very well, it is cost effective, and we have setup data for most of the tracks in the area that can be used as a starting point. Now I realize that the camber, castor setting will have to be unique to this setup. However knowing from our notes that a track requires more ride height due to bumps, or that a track like more camber on one side vs. the other, or the way we previously addressed a low grip vs. a high grip surface can all be leveraged with this initial setup. Spring rates may be an issue and one that will be very easy to ascertain one we are able to do some testing.
The end links are fully adjustable Spec Miata pieces as well as the anti roll bars. All of the stock Miata components used in this suspension are new parts ordered from Mazda. It did not seem like saving a few dollars on using old ball joints would be a good investment.

Exhaust

I have installed the Enthusacar V8R exhaust kit and am very happy with the quality and fit of this system. The exhaust front section was ceramic coated to help contain the heat in the cabin and engine bay (Headers were also coated). The exhaust system just bolts up to the header flanges and has the O2 bungs already in place. It also utilizes stock hanger locations and hardware. The exhaust come with the needed band clamps and a extra hanger mount at mid car. All in all a great product that has saved me time and $. The only addition part I needed for the exhaust system was the header to exhaust flange gaskets and mounting bolts. So much easier than the last build !!!

Dash

The dash cover is retained as well as the main cross bar (the steering shaft attaches here) and the two center metal uprights. The rest of the dash assembly was removed. This process alone has removed more than 10 pounds from the dash. The ventilation system, associated harness, mounting brackets, and hoses were also removed. The stock gauge cluster will not be used on this build. In its place I have installed a racing digital dash with the associated sensors. The initial plan is to start with the following:

Oil Pressure
Oil Temp
Water Temp
RPM
Fuel level
Fuel Pressure

I was able to find a like new digital dash a fellow racer was no longer using that had all of the required wiring and sensors with the exception of the oil pressure sensor. The oil pressure sensor was sourced from the dash manufacturer.

The fuel level gauge will be a stand alone unit that is eventually mounted in the center console.

The digital dash is made by Racpac and includes programable shift lights and warning lights for temps etc.



Wiring

I have removed all of the stock Miata harness and then used just the few connectors etc that I needed to create my own (now light weight) harness. As this is a race car only the requirements for wiring are significantly less than in previous builds.

The Miata chassis electrical requirements are as follows:
Brake lights - operated via an inline brake pressure sensor in the rear
Fuel pump
Fuel sender circuit
AMD lap transponder - to be mounted under the driver front fender
Wiper motor - via the rules I must have a functioning wiper. This will have a stand alone switch in the center console

Parts of the Miata power distribution harness were removed from the stock harness wiring bundles. This allows for the stock fuse block to be mounted under the dash (vs. in the engine bay in the stock configuration) a secondary fuse block and associated relay panel is used for the GM components (FAN, Fuel, etc)

The main power line from the positive side of the battery now runs to the cut off switch mounted on the passenger rear roll cage. It then runs to the fuse panel under the passenger side dash board and then through the firewall to the starter. The stock alternator charge cable must extended and routed from the GM alternator to the under dash Miata fuse panel. The GM alternator has a circuit that is a “charge sense” circuit. Essentially the alternator receives a signal from the ECU to enable charging. I have interrupted this circuit at the ECU and run it to the other 2 posts on the master cutoff switch. Now when this switch is in the off position the battery and alternator are disconnected from the system.

The engine harness is a custom built harness for LS# transplants and has been stripped down to the bare essentials for this application.

I have created a rudimentary wiring diagram:

Tim

The "hole in the floor" was made to allow for a race seat with sliders to fit directly to the drivers floor. Once the stock seat floor humps are removed (in an effort to allow for non stock sliders and to lower the seat) the transmission tunnel to side sill space is reduced the lower in the car the seat is mounted. This is caused by the transmission tunnel angle and the now installed roll cage. Widening the driver side floor board is a solution to address this issue.

The end result looks much cleaner and has actually added strength to the drivers side floor. I made a plate with a 37 degree bend that was then welded into the floor and transmission tunnel. This was only added once the exhaust, transmission etc had been test fit to ensure there was clearance. Needless to say there was plenty of room.

The stock transmission tunnel and floor was welded on both sides (that is from the top and from under the car). I then did the OEM seam sealer treatment to all of the new joints (top and bottom) and primed and painted the drivers floor and primed and under coated the under side of the car. While this was a bit of work, it was worth doing and had to be done right in my mind.

In the pictures you will also see that the transmission (T5) does not align up to the center of the stock shift boot like the T56 did in last build. However it was a minor effort to fix this one.

The hand brake location is now used for a brake bias valve. Couple of pics may help here.


I had mentioned the digital dash and have been asked via PM how it looks.

Brakes

Braking on these cars must stand up to the abuse of numerous high speed to slow speed braking events per lap. It seems the vast majority of our new local tracks have designed slow speed corners right after all of the long high speed straights. With this in mind I went looking for a brake system that would meet my racing / performance needs. I therefore created a rudimentary list of requirements:

Must mount to the stock Miata spindle locations
Allow for a brake bias valve
Have a master cylinder that utilized the stock pedal / booster assembly
Was a vented disc solution
Cost !!! Not only for the initial purchase but also the consumables (rotors and pads)
Availability of multiple pad compounds
Serviceability of the major components
Performance, increased stopping effort without heat soak

While I did review the specifications on several big brake kits, I also talked with a few folks who had purchased the kits I reviewed. I wound up not straying too far away from the previous vendor selections and selected the new V8R big brake kit. While the consumables for this kit were by far the least expensive (Less than $50 rotors and cheap pads) the engineering that went into the kit also helped sway my decision. Simple things like a heli coil inserts in all of the hardened aluminum adaptor mounting brackets that mount the caliper to the spindles, fit and finish, quality of components etc.

So what are the components as received with this kit?

11” rotors mounted to custom hats
2 piston front and rear Wilwood calipers
Braided lines with new rear distribution block
New pads
Adapter plates (Miata spindle to Wilwood calipers)
Mounting hardware
Master Cylinder with adapter plate for Miata brake booster

Installing these components is similar to installing any brake setup. The big difference for me was that I had to also make up all of the brake lines (This car was missing some of them and also at one point had ABS) and install the brake bias valve which was also a Wilwood part. I was also installing new front spindles with tapered bearings and all new rear hubs with the bigger axles and associated bearings.

I have talked with a couple of other Miata owners who are running this setup and to date once the parts were installed they have reported a big improvement in the braking performance. I look forward to testing it out myself, for now it looks good anyway.

Hardtop

In the spirt of weight reduction why not pull a boat load of weight out of the highest part of the car? How does one do this when it comes to the hardtop. Removal of brackets, mounting hardware, seals etc that are not needed can save a bit of weight. Removal of the rear window glass and replacing it with a plastic window would also shave a pound or two....

Well having gone this far lets just go all the way !! How about a light weight hardtop with a light weight rear plastic window, with a light weight mounting solution!

Yea it is a bit "over the top"

I have been moving forward on the build. The wiring is now 95% complete. Fuel system completed. Brake lines for the rear are complete and I will be forming the front lines shortly. The cooling system is mounted and all of the sheet metal work to mate the radiator to the nose is well under way. I have also taken the time to fabricate a skid plate to protect the sump and to better direct air flow under the car.

I have also decided to add a few aero devices to the car. I have spent a significant amount of time looking at current options and have decided to go my own way here.

The front aero and under hood air flow has been an area of interest to me for quite some time now. As I have been able to create more front aero efficiency (cooling air flow and front down force). I therefore needed to balance the front to rear aero setup. My goal was to minimize drag, maximize down force adjustability and provide a new level of front to rear aero balance.

After several prototypes, numerous math exercises and much testing a new rear wing has been developed for this application. I have used an airfoil that was recommended to me by a friend with experience in this area. This air foil has been used in numerous other race series and has now been tested and sized for the appropriate balance (front to rear aero) for our car. We have made provisions for wing incidence adjustability and have also designed end plates that perform well while adding to the overall look of the car.

Here are a couple of pictures of the finished adjustable rear wing mounting uprights. These were laser cut from alloy and then anodized black.



During this long process I found that the aircraft composite industry had a distinct advantage over the typical car after market materials. The aircraft manufactures are using advanced composites. While these advanced composites require additional tooling, they produce a uniform thickness in the final product that does not shatter, is flame resistant, is repairable and is less weight than the typical comparable auto after market fiberglass product.

I have therefore made my own fender flairs and nose using these advanced aircraft composites. I look forward to additional testing and utilizing an aerodynamic advantage on the track.

Here is a picture of one of the fender parts being made.


The new fender flairs and nose are now being painted I will post more detail one I have them fitted to the car.

More to come.

Laser cut? Vacuum molding?!

I wish your shop were closer to me!! Nice!

Mark,

Your build is inspiring! I really appreciate the time you've taken to explain the "why" of the decisions you've made.

I'm now 6 days away from driving my LS1 V8R car on the track for the FIRST time. My only disappointment is that it is coming in around 2550lbs+ with driver (who could afford to dump 30 pounds himself...)

With the weight targets you've mentioned previously, how will you stay in ST2 with NASA? Throttle stop for HP? My car seems very borderline with HP/weight right now between ST1 and 2.

Any possibility you could make it to the NASA Nationals at Miller in September? If I can get my car dialed in, I plan to go out there and mix it up with the Viper/Vette boys...

Cheers,

Dean

Yes it will be a challenge to qualify for the ST2 class. DOT tires, tire width, HP, etc will all be mixed and tested for the best combo to meet the class rules with the best lap times. At least that is the theory I am working to. I am so happy for you 6 days YEA!!!!

Please let us know how it all works out, video etc would be great.

It is way to early for me to plan on a specific race date and the nationals seem like a stretch for me at this point. I would like to get it really well sorted out before I even try to compete at that level.

You never know.

Mark

I'll be running a Chasecam all day on Saturday. Let's just hope there's a couple hours of video to enjoy, instead of a few minutes...

I will absolutely provide a full report on the day.

I hear ya on wanting to get the car sorted before racing at the NASA Nationals. I'm planning to go to run Spec Miata anyway, so why not throw a second car on the trailer??

Cheers,

Dean