Parts list and suppliers

Drivetrains, ECUs, brakes, lights, radiator, instruments, etc
Midlana1
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Parts list and suppliers

Postby Midlana1 » 24 Dec 2008, 09:49

Suspension, steering, and brakes:
Miata parts are used throughout. The best situation is to find a 94-97 car, which allows "one-stop shopping" for:

Steering rack and (if you want) the steering shaft
Hubs/Spindles/Uprights
Brake calipers and discs
Emergency brake lever, cables, brackets
Wheels and tires (or not, read on for details)
Fuel filler and tank vent assembly

If you can't find the above generation of Miata, use the following guidelines. Alternatives are discussed for each:

Steering rack
Any year. Note that the rack is not shortened as it is when used in a Locost. I am told (not confirmed) that the 99+ racks are "better" because of their mounting. That may be but I've never seen one. Either can be used but if the mounts are different the brackets have to be modified.

Spindles/uprights/hub
90-97. Later 99-05 uprights cannot be substituted unless suspension pickup points are redesigned (in other words, are unusable.)

Brake calipers and discs
The rear calipers have the emergency brake brackets built in so the emergency brake lever and cables are used, too. (This limits the use of aftermarket rear calipers.)

The following information is from the http://www.flyinmiata.com website, along with information from Keith Tanner, author of, "How to build a cheap sports car":

Mazda put three different sizes of brakes on the Miata. All the 1990-93 models shared 9.3" fronts and 9.1" rears. 1994-00 models used 10" fronts and 9.9" rears. In 2001 the larger "Sport brakes" were introduced. These brakes became standard in 2003, with 11" discs in front. A 2001-02 model with 16" wheels from the factory has Sport brakes, otherwise they're the smaller size. Note that pads and rotors are not interchangeable between the different types of brakes.

Summed up:

90-93: 9.3" front, 9.1" rear
94-00: 10" front, 9.9" rear
01-02: 11" front optional
03+: 11" front

Depending upon the expected power, 94+ discs are more desirable than earlier brakes for their 15% greater surface area and fade resistance. If you're building a cruiser instead of a racer, any of the discs will be fine. Early calipers can work with the larger disks but require 94-05 mounting brackets. Regardless, even the early small Miata brakes work fine on hard-core Miata race cars. Our car will be 1000 pounds lighter, so no matter what brakes you use they'll be fine. Oh, and don't forget the cheap simple solution of running cooling air to the front brakes; this can make an enormous difference with very little cost or weight. I highly recommend going this route first instead of the weight and expense of huge discs and calipers.

A great supplier I've dealt with for Miata parts is Panic Motorsports, http://www.panicmotorsports.com/. Great prices, easy to deal with, quick shipping, and he doesn't even know I said that. No kickbacks here, just a very satisfied customer.

Suspension arms
Custom, though this is trivial since you are welding the chassis together!

Drivetrain
The drivetrain must fit the following space, with a couple caveats:

Width: 45"
Height: 24"
Depth: 20"

Caveats:
Width is absolute max including engine mounts off the sides. Less is better.

Height is flexible; it depends how high you're willing to allow the valve cover and intake to extend above the horizontal tubes around the engine's "shoulder line."

Depth, fore/aft. 20" as measured from the backside of the head to the firewall. My engine has the intake on the forward side of the head and the exhaust on the rear, extending under a lateral cross tube. If your engine is reversed, with the intake on the rear, that tube can't be used. Also, chassis tubing is negotiable around the transaxle, where it is understood that a portion of the transaxle will extend rearward which houses the differential. This section is not part of the 20" depth - within reason.

Drivetrain choice is such a huge field there's a thread for that alone,
http://www.midlana.com/forum/viewtopic.php?f=4&t=3.

Nosecone and fenders
I got both of these from http://www.kineticvehicles.com/noses.html#catfish. The "catfish" nose is a critical component to Midlana and is sole-source. He also supplies the fenders which, at the back, are two-piece so they can be adjusted for different tire width.

Radiator
Overall width: 22", Overall height: 19", 3" thick.

I got mine from Summit Racing, part # GRI-1-28182-X, http://store.summitracing.com/partdetail.asp?autofilter=1&part=GRI%2D1%2D28182%2DX&N=700+0&autoview=sku. This is a double-pass radiator, meaning water crosses its face twice, but isn't required. Note that the lower hose connection will likely need to be relocated depending how close it ends up to the steering rack. Also, the radiator cap must be removed due to height restrictions. It won't be known for sure until the first car is built.

Brake/Clutch pedal assembly
Tilton:
72-605, http://www.tiltonracing.com/content.php?page=list2&id=13&m=b

Wilwood:
340-4828, http://www.wilwood.com/Products/005-PedalAssemblies/003-RSMP/rsmtmc/index.asp

The pedal ratio affects how much pedal effort/travel is needed. The lower ratio is a shorter assembly which gives much-needed space for the fluid reservoirs. The Wilwood 5.1 assembly says it has a 10" swing while the Tilton assemblies have nearly the same height for both, around 11.5" which is strange; it may be a typo. I got mine here http://www.summitracing.com.

Shocks
QA1 double-adjustables, DDR7855, http://qa1.thomasnet.com/item/proma-star-reg-single-and-double-adjustable-shoc-2/proma-star-reg-single-and-double-adjustable-shocks/ddr7855p?&seo=110&plpver=1001. Best price was found at http://autofabcart.net/qa1shocks.aspx. Hold off on buying these until I confirm these are the correct length; it's possible that the slightly shorter DDR5855 unit will work just as well.

Tires
Doesn't matter except for outside diameter (OD). Fronts should be 23.5" OD and rears 25" OD. It's okay to use slightly different sizes but the further from these targets you go the further off the suspension geometry gets. Doesn't matter what size the tires are, only the OD*. For basic sizes, 15", 16", or 17" are fine. 14" are impossible to find and 13" won't have the correct ODs. For the street I'm going with 17" just because there's a much wider selection. Yes they weigh and cost more.

[* Actually that's not quite true. If you put on racing slicks that are, say, 2" smaller OD that the above numbers, that's okay, if you leave the resulting lower ride height as-is. However, many people think since they have adjustable shocks they can just crank the ride height back up to restore the original ground clearance. No - it changes the designed suspension geometry, placing the tires on different points on the camber curves.]

Wheels
They must have a 4 x 100mm bolt pattern, dictated by the Miata hub. Depending upon widths the fronts should have roughly 44mm offset and the rears 35mm. Size is dictated by tire choice above. I haven't bought tires yet but plan to go with 17", roughly 195mm at the front and 255mm at the rear. If you search you can find fairly wide wheels; I'm using 7" fronts and 9" rears. The trick is to search for Nissan 240SX wheels which have the same bolt pattern. Turns out the drifter guys use the wide sizes. For street driving be careful buying super-light racing wheels. Some of them are seriously light, to the point where they aren't even strong enough to hit potholes, which equals bent wheels.

Steering
While the steering rack is Miata, the shaft and steering wheel are up to you. For safety reasons it's good to try and incorporate a collapsable column, which the Miata column is. I strongly suggest a quick-release hub which makes it easy to get in and out, plus far easier to service the dash panel without it in the way. Also, having the wheel removable is a small step toward theft protection, though walking around with a steering wheel looks a little funny. However, since there will be a lockable storage area under the "hood" it makes a good place to hide it.

Seats
Again, a hugely subjective choice, ranging from used Miata seats, to Corbeau, Cobra and other name-brands, to aluminum Kirkey or Ultra-Shield seats. I used the latter, http://www.ultrashieldrace.com/prod.php?id=2. I got tired of paying $600+ for one seat and, sooner or later the car will get rained on. I didn't want the thick foam padding sucking up two gallons of water and me having to sit in it. The aluminum seats come with covers so they can easily be removed for cleaning or replacement due to the sun beating on them.With a thin snap-on cover I won't have to sit in a seat holding half a gallon of rain water in its thick upolstery. Also consider some of the cheap Chinese seats coming out; though I know nothing about them it's hard to ignore their very low prices.

That said, they aren't very comfortable for long distance due to the thin padding. I plan to place some special foam under the cover in appropriate places it they aren't. Oh, and do not buy bare seats, fiberglass or aluminum. Body sweat gets trapped between you and the seat and the vibration will rub your back raw.

Seatbelts
Buy these last because if you plan on doing any organized racing, they'll be checked to confirm they aren't more than two-years old. Doesn't matter if they spent that time sitting in a box! I don't like this rule at all but really don't care since I'm not doing SCCA or NASA events. Slightly more expensive FIA-approved belts are supposed to be good for five years which seems like a better deal.

Gas tank
Due to the shape only a homebuilt or custom-size tank will work (or a small-capacity off-the-shelf unit.) Details are in the book and you'll need both the Miata vent valve and filler neck pipe. Both include one-way valves that prevent fuel spills if the car ends up on its head.

Axles
The axles serve as a "bridge" from the Mazda upright to the drivetrain of choice, using an outer CV from the Mazda Miata and an inner CV from your transmission's manufacturer. This typically requires custom axle assemblies from a place like The Drive Shaft Shop, http://www.driveshaftshop.com/, or Gater Racing Axles, http://www.gatorracingaxles.com/.

On perk of using Miata uprights is that a common Miata swap is to install a V8 which resulted in broken axles until the aftermarket created stronger custom assemblies. All you have to tell them is that you want a Miata outer CV, Brand X inner CV, with an axle length of Y.

For my Honda K24A1 I used 19.9" axles. If you use a different drivetrain then the needed lengths will be different, and maybe even different from side to side. Check carefully because once they're made, you're stuck with them!!!

Custom axle assemblies can be expensive, around $400 minimum for OEM power level axles, increasing from there the more power you want to run through them. An axle set for 450hp is currently about $800. However, you are getting all new parts and the price includes the custom length axles.

Some builders express dismay at the price but what's the alternative? I could have dictated one specific drivetrain in order to use OEM axles but then I'd never hear the end of it, builders saying they can't get/find/afford whatever drivetrain I specify. No, drivetrain selection is left up to the builders.

Even for stock power levels, $300-400 is a lot, but not terrible (though I admit I hate it when someone tells me something's not expensive - it's not their money that they're deciding is so easy to spend!) Anyhow, stop going to Starbucks, take a lunch to work for a couple months, cancel the cable TV, and the axles are free. Oh, and if you're thinking of welding the axles, that's not a safe thing to do.

Lighting
All electrically-related parts info has been moved to the Electrical sub-menu, http://www.midlana.com/forum/viewforum.php?f=8

schultzy_86
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Joined: 23 Dec 2008, 17:29

Re: Parts list and suppliers

Postby schultzy_86 » 25 Dec 2008, 16:32

Just a quick comment on the radiator... A dual (or more) pass radiator will be more efficient (such as the one you describe) than a single pass due to the increased coolant flow rate in the individual tubes (up to 40% efficiency increase in some cases from memory) - the more passes the higher the flow rate which increases the heat transfer coefficient between the coolant and tubes. This has the adverse effect of increasing the pressure drop however, so a compromise must obviously be made. Multi-pass also ensures that more of the surface area of the radiator is used.
Last edited by schultzy_86 on 27 Dec 2008, 15:36, edited 1 time in total.

Midlana1
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Re: Parts list and suppliers

Postby Midlana1 » 26 Dec 2008, 11:51

Good point, post corrected!

isaac
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Re: Parts list and suppliers

Postby isaac » 03 Jan 2009, 18:49

you should also mention under steering that seeing as midlana's being designed with a lockbox up front then thats an ideal place to store the removable steering wheel.
just make sure its not obvious its being stored in the car or the box is too easy to get into... ;)

Midlana1
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Re: Parts list and suppliers

Postby Midlana1 » 03 Jan 2009, 18:55

Added, thanks!

ekim952522000
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Re: Parts list and suppliers

Postby ekim952522000 » 03 Jan 2009, 19:17

In regards to the seat belts even for SCCA in you spend the extra little bit for FIA belts they are ok to use for 5 years.

Midlana1
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Re: Parts list and suppliers

Postby Midlana1 » 03 Jan 2009, 19:53

Sigh, I learn something new everyday.

jerelw
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Re: Parts list and suppliers

Postby jerelw » 19 Feb 2009, 09:35

Re: the steering rack. If you look in the techical information section at FlyinMiata, they have instructions on how to depower a Miata steering rack.

Poboy
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Re: Parts list and suppliers

Postby Poboy » 12 Feb 2010, 13:38

Is there a list of the parts that had/will have to be custom made?

Midlana1
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Re: Parts list and suppliers

Postby Midlana1 » 12 Feb 2010, 14:08

Midlana is designed so that no machining is necessary; you won't need any lathe or mill-work, though a drill-press is a big help. I'm assuming you'll handle the cutting, drilling, and welding.


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