Difference between revisions of "Engine"

Revision as of 11:24, 17 November 2011

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Build Order

It looks like we can do this in a very nicely incremental fashion. We can get the 99 motor installed, do the various conversion notes below, and it will, in theory, run just fine on the 1.6 electronics. Once we know that's running, then we can do the Megasquirt conversion (and use the cam angle sensor just like a 1.6) and get that going. Once that's going then the electronics are basically all done and we can focus on the supercharging.

Finally, we can look at changing throttle bodies (since the conversion will use the 1.6 throttle body, which I believe is smaller) and see what's involved in that while we work on building the 99 motor for the supercharger.

Build Plan

• 94-97 or 99-00 Miata Block (in theory identical)
• 99 Miata Head
• Displacement?
• Pistons?
• Crank?

Do we want to try to do this ourselves or just pay Flyin Miata a metric asston for one of their absurdly expensive builds?

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.

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

• Block: 94-01 blocks are effectively identical for our purposes (piston change). Trying to find an affordable 99 full motor is becoming difficult.
• Head: Maybe just look for a 99 head and put it on a 94 full motor?
• 2002 Oil Pan: 207$ from Mazdacomp, 10-400
• 2002 Oil Pan Support Plate: Asked Bob what the support plate is -- if it's the baffle plate (10-406A), then it's 66$
• 2002 Oil Pump: 198$ from Mazdacomp
• Eagle H-beam rods: 291$ from random sketchy place
• Carillo A-beam rods: 850$ from 949
• 949 Racing Rods: 329$
• Wiseco Coated Pistons: 796$ from FM (exclusive), includes rings/wrist pins
• ACL Main Bearings: 82$ from FM
• ACL Rod Bearings: 51$ from FM
• ARP Head Studs: 117$ from 949
• FM ARP Head Studs: 167$ from FM
• ARP Main Studs (218-5401): 80-90$ around the web
• FM Head Gasket Kit: 215$ from FM
• Rebuild Gasket Set: 201$ from Mazdacomp
• 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
• Mazdacomp Engine Mounts: 35$/ea, NAY1-39-040
• Supertech valve springs/retainers/seats: 314$ from 949
• Supertech shim-under-bucket lifters: 359$ from 949 + 5.5$/shim
• FM Valvetrain Kit: $379 from FM, includes springs/retainers/seats

May make sense to get an FM head, and just do the block myself.

Bob Bundy's Build

353rwhp w/a big turbo (Dyno Plot)

• 2.0L FM Stroker
• 94 Block
• 2002+ Pan/Support Plate/Oil Pump
• 99 Head
• Ceramic coated top wiesco pistons. (now standard at FM)
• Oil Squirters Blocked off. (much less oil consumption haven't found a downside and they don't fit with the new pistons anyway now standard with FM builds)
• FM now has Inconell exhaust valves. I think these are really needed on a track car. I've burned exhaust valves twice I think related with over oiling oil control rings using squrters and after market pistons. I don't have inconel exhaust valves yet though.
• ACL race bearings
• Stock cams
• 1mm over Supertech Valves/retainers
• Port/polish

TrackDayHookey's Build

420rwhp with a Rotrex centrifugal supercharger. Build notes here.

• 94 block, 99 head.
• 1mm oversize Supertech pistons, 8.6:1, but with deck shave and head work the engine is about 9:1.
• 1mm oversize Supertech valves (both intake and exhaust) and Supertech springs (the relatively low seat force version as I don't plan on revving past ~7500).
• Rods from 949Racing.
• 1000 cc injectors.
• Integral "stage 2" intake cam - a little more lift.
• I ported the head. I might even have made it better. Valve deshrouding, clean up the bowl, match the head ports to the intake manifold.
• Custom intake manifold.
• Racing Beat Header
• 100 octane gas

Motor Mounts

The 1.8 motors use a slightly different motor mount. I'm going to have to get everything here to see what they're talking about. For now, I ordered 2 mazdacomp stiffer mounts, to use with the crazy brackets that FM makes with their 1.8 conversion kit. Prather strongly suggests upgrading to the AWR mounts. 225$, but they look much lighter and better designed as a full solution, and also much stiffer. These are all good things (except the 225$ thing).

Injection

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.

Alternator

Any weight or efficiency gains to be had with some sort of aftermarket alternator?

Links

Mazda B Engines Wikipedia Page