Engine
Contents
Solo Rules
Engine block must be the same make as the car (Mazda), with some technicalities about cross-make stuff (we could use a ford probe motor since it's the same thing as the 323). Aside from that, everything's virtually unrestricted.
Rev Limit
I was originally going to go with 7500 rpms, since that's a super safe stock limit. However, lots of people seem to be revving to 7800-8000 and above on stock internals and not exploding stuff much (Fuji Racing has been revving to 9k on stock internals and only finally blew up a motor). I figure on the overbuild internals I'm throwing in there, 8000 should be more than safe. Unfortunately that doesn't really help us on gear ratios.
1.8 Conversion Notes/Parts
Flyin Miata makes a 1.8 conversion kit for 194$ that looks like it will make our lives a little easier. They have a good writeup of the conversion process as well.
Make sure to use a 94-97 alternator. The 99 alternator doesn't have an internal regulator and will totally hose the NA electrical system.
In theory, we can just swap the 1.6 thermostat housing over to the 1.8 motor to maintain the working electrics. Also move the 1.6 FPR over to the 1.8 fuel rail end so that it turns into a return system. Here's a good Miata.net post about it as well.
Parts Research
I've stored some Other Builds for reference.
- Block/Head: Used 99 motor - Bought
- Rebuild Gasket Set: 201$ from Mazdacomp - Bought
- Mazdacomp Engine Mounts: 35$/ea, NAY1-39-040 - Bought
Block
- 2002 Oil Pan: 207$ from Mazdacomp, 10-400 - Bought
- 2002 Oil Pan Support Plate: 66$ from Mazdacomp, 10-406A - Bought
- 2002 Oil Pump: 198$ from Mazdacomp - Bought
- Eagle H-beam rods: 291$ from random sketchy place
- Carillo A-beam rods: 850$ from 949
- 949 Racing Rods: 329$ - Bought
- Wiseco Coated Pistons: 796$ from FM (exclusive), includes rings/wrist pins - Bought
- ACL Main Bearings: 82$ from FM - Bought
- ACL Rod Bearings: 51$ from FM - Bought
- ARP Head Studs: 117$ from 949 - Bought
- FM ARP Head Studs: 167$ from FM
- ARP Main Studs (218-5401): 91$ from 949 - Bought
Head
- Inconel Exhaust Valves: 33$/ea (264$/8), 1mm oversize
- Intake Valves: 22$/ea (176$/8), 1mm oversize
- Supertech Valves: 18$/ea (288$/16), 1mm oversize - Bought
- Supertech valve springs/retainers/seats: 314$ from 949 - Bought
- Supertech shim-under-bucket lifters: 359$ from 949 + 5.5$/shim
- FM Valvetrain Kit: $379 from FM, includes springs/retainers/seats
Head Gasket
For the first build I'm using the 01+ head gasket, which has a slightly blocked front coolant passage to spread coolant more evenly through the engine. If I end up doing the coolant reroute, we should switch the head gasket to the 94-00 gasket with the proper spread.
Intake Manifold
Stock 99 manifold for now... Need to figure out exactly how we're gonna do the supercharger setup... Ideally cold side...
Options:
- BEGi 99-05 - Only for big power/boost, 539$
- Flyin Miata Old Ubercharger Manifolds - Could be interesting to hack up for a new custom install - 250$
Fuel
Solo Rules
16.1.D.3 allows basically everything. Open fuel lines, pump, filter, pressure regulator. Cool can allowed (up to 1 gallon).
Injectors
What injectors will we need? 1000cc or can we get away with less? I got 392whp on the Alltrac with 880cc injectors without coming too close to maxing out.
Fuel Pressure Regulator
The KLiata has an adjustable FPR on it. May be easier to steal that and fit it back with a normal stock FPR if I don't supercharge it.
Fuel Pump
I have a Walbro 255HP and Miata install kit sitting on the shelf to go in whenever.
Fuel Filter
How heavy is the stock unit? Are aftermarket units lighter?
Induction
Pre-Supercharger
Presumably a simple cone filter of some sort. Need to wait to see how the supercharger attaches before deciding this.
Supercharger
I currently own a Lysholm 1600AX that I was going to use on the KLiata. It was about 2200$, plus 300$ for the snout. It has a maximum pressure ratio of 2.2:1, which is probably below what we're going to be running. The compressor map looks like it's going to fall off pretty quickly above 2:1 anyway, though, so I'm still not sure it's a great idea to even try...
I'm interested in the Whipple W100AX, which came out in Sept 2011. Blueprints are available for mocking up a test unit. The unit is 2150$ (had to call and ask) and the direct drive snout option is 140$ (Drive snout options). It flows more than enough for us, and has a pressure ratio up to 3:1 (30psi). Our target will probably end up in the 20psi range, and it's an incredibly efficient supercharger, so I should probably get it...
The Eaton TVS 1320 could also be a viable option, but it doesn't like quite as much pressure ratio. They're harder to get a hold of. Harrop sells a generic 1320 kit for 2500$ AUD (~2530$ USD). The full specs PDF is here and it has a bunch of drive snout options and BPV mounting methods.
We're going to be flowing ~650-700 CFM of air, for reference.
Intercooler
Air to Air
The primary contender right now is to do a half-width radiator, and then a same-size intercooler with two top exits in the other slot. This gives us about 13"x13" of space to work with. Could probably get a custom one built to specs by Bell Intercoolers for not too much.
I emailed Bell with some basic questions and asking for a quote on my proposed design. Waiting to hear back.
Examples
Air to Water
Laminova
Laminova makes neat little cylindrical cores that make for nice compact and efficient intercoolers. I've heard some rumors that they're not as efficient as they claim. Look for more data?
Ignition
Spark Plugs
Starting with NGK R5671A-7 (heat range 7, no-resistor race plugs), which FM recommends for high boost applications. We'll go from there.
Coil
Doing the standard COP conversion using 1ZZ coils. More info here.
Alternator
We need to use a 94-97 alternator on the 99 block with the 1.6 body. The 99 alternator will blow out the electrical system because it has no voltage regulator built in.
- Stock 94-97 alternator: 10 lbs
- Pegasus Mini Alternator: 6 lbs, 280$, requires fab
- More Tiny Alternators: Down to 5.68 lbs, pricing unknown
Don Nimi suggests looking at the Suzuki Spring/Pontiac Firefly alternators.
Clutch/PP
Bought the Spec Stage 3+ (SZ453F) kit.
Flywheel
- Stock 1.6: 17.6 lbs
- Stock 1.8: 19.0 lbs
- Flyin Miata - 295$, 10.3 lbs
- Spec SZ81A - 381$, 9.5 lbs
- Fidanza - 355$, 8.0 lbs
JSC has a good overview of all the options as well.
Bought the Fidanza 8 lb flywheel.
Motor Mounts
- FM 1.8 conversion mounts + mazdacomp stiff mounts: 6.38 lbs total
- AWR mounts: 6.28 lbs total, 225$
Prather strongly suggests upgrading to the AWR mounts. I emailed AWR and they say that those (94-00) mounts work fine with a 99 motor in a 93 chassis. They seem to weigh basically identical to the stuff I have in hand, though, so I think I'll start with what I'm holding and if I need stiffer I'll go from there.
Header
Emilio says to just use the Racing Beat 99 Header -- I don't need a custom header at these power levels. 410$ from 949. Bought one of these for now. It's a 4-1 with 1.7" primaries and a 2.375" outlet. We'll see if it makes the power we need. The 420rwhp guy is still using one, so it's probably fine. Superchargers are weird...
Called Prather Racing about a custom header, they forwarded me to his son, Jesse Prather, 785-249-0284. He makes a couple different headers, but for wide powerband he doesn't suggest his biggest one. His is a 4-1, 1.75" primaries, 2.5" collector, and it makes a bunch of power over the RB header in NA applications. He doesn't know if it will help a lot on S/C applications. 900$ for the header. Not too bad at all, really. If the RB can't make the power I need, can get this for stage 2.
Performance Coatings in Tacoma has been suggested by a couple people and is 165$ to coat a 4-cyl long tube header.
Exhaust
Doug wants about 1500$ for a custom 3" exhaust. Don't know how much for 2.5".
I emailed Emilio (949) about what to do for an exhaust with the RB header and he says: I'd suggest custom 2.5" or 2.75". Gonna be insanely loud. big resonator and a really big muffler out back.
Prather Racing suggests doing a 3".
Emailed FM to see what they suggest or if it's easy to adapt one of their turbo exhausts to be quiet enough supercharged.
Cooling System
Radiator
Currently stock, but the radiator is brand new (replaced Nov 2011). Radiator core is approx 26"x13". The full area for the radiator in the front is ~27.5"x17".
- Stock 1.8 Rad: 4.5 lbs dry, 1500 cc capacity = 3.2 lbs of water = 7.7 lbs total
Look for half-width radiators to fit an intercooler next to it. People suggest civic radiators.
1992-2000 Civic half-size radiators (like this one) seem to be what we're looking for. Need to measure the full area of the rad support area in the bay and mock it up to make sure we can fit everything appropriately.
The Koyo R1570 looks perfect. Need to make sure to get a Koyo radiator cap with it. Full unit seems to be 14.5x18", leaving 13" for the intercooler.
Re-Route
There's a cooling system re-route that moves the thermostat to the rear of the motor. We could potentially use this to our advantage to move to a half-width radiator.
BEGI has a kit as well, which is cheaper and I like their tstat design better as well.
Radiator Fan
The stock one is actually plastic. The A/C one that looks basically identical is 2.75 lbs, so not as big a deal as I thought. Probably get a slimline fan if/when changing radiators.
Thermostat
Currently Stock. Stock or go lower for autocross? Part of the engine and therefore unrestricted.
Heater
Looks like we need to keep the heater fully intact.
Solo Rules
16.1.A. All Stock, Street Touring, and Street Prepared category modifications are authorized. Except as noted by these rules and the referenced rules, vehicles must be as originally delivered including all road-going components such as lights, wipers, interior, heater, etc.
Water Pump
Stock. Any benefit and/or possibility of going electric?