Not much of an upgrade. SOHC + 3 valves per cylinder = FAIL. It's 2.2 L but in N/A form makes less horsepower than a stock 1.8 Miata, though a bit more torque. I couldn't even guess how much more the block weighs. The GT used a tiny schidt-kicker pea-shooter of a turbo and only made 145 hp and 190 tq. By the way that 145 hp peaked at 4300 rpm LOL. Total weaksauce, nothing I'd want in a Miata. You're better off just turbo'ing the motor that's already in the Miata and saving yourself a bunch of time and money.

If you're going to bother swapping in a bigger Mazda 4-cyl, the one that makes some sense is a 2.0L FE3-DOHC swap. Those were used in the 95-03 Kia Sportage and are cheap and fit pretty well once you cut a few inches out of the oil pan and fab up some mounts. It's DOHC and 4 valves per cylinder with big forged rods, well-supported main bearings, piston oil squirters, etc. IOW, it's turbo-friendly and the stock internals are proven to stand up to some decent power. There's a guy with a nice build thread on miataturbo.net.

Cool stuff Rueben. Never let the quarter mile monkeys drag you down. Everybody knows a real car has to be able to turn. <img src="/forums/images/graemlins/wink.gif" alt="" />

How much are you looking to pay? I have no idea what open diffs go for, but I can keep my eye out. For axles and driveshaft check out www.partsgroup.com. Not the absolute cheapest but not rip-off prices either. They are good to deal with and have a steady stream of inventory.

There's a Torsen on craigslist in raleigh for 300 which is a good price, though it doesn't come with driveshaft or axles. Any reason you want to run the RX-7 LSD? Just because you already have it? I'd think the Torsen would be better for tight turny stuff like most Miatas see, though I haven't driven a clutch-type diff in a Miata.

I don't suppose your RX-7 LSD has a 3.909 ring & pinion with it that you don't need? If so, lemme know. <img src="/forums/images/graemlins/wink.gif" alt="" />

I reckon my Kia Sportage would do about 75 fph and an elapsed time of August 3, 2011.

But at least it makes it over the speed humps at Maccas <img src="/forums/images/graemlins/lol.gif" alt="" />

Scott,

I did read that torsens work great unless you unload one wheel a lot and then they don't work. Both clutch-type and torsen work well, but in different ways. Torsen is probably better in the rain. Although the clutch-type can be adjusted. The down side being the clutch plates will wear over time. However, the main reason is cost. RX-7 option is a lot cheaper, even compared to the very good priced torsen on craigslist. I've got 3 teenage kids and so everything I do is low budget, which is fine. I enjoy the challenge <img src="/forums/images/graemlins/lol.gif" alt="" />

I don't know what the gear ratio is in the RX-7 diff. It's been sitting in my garage for 2 years <img src="/forums/images/graemlins/lol.gif" alt="" /> I don't plan on keeping the R&P or the pinion housing. I'm just keeping the LSD, carrier housing and stub shafts. I'll have a look at the gear ratio and let you know.

I'd like to get an open diff, drive shafts and prop shaft for ~$200 (about $120 at the pull-a-part, but they never have Miatas). Let me know if you come across someone with any of those parts. I'll take any and all.

<img src="/forums/images/graemlins/cheers.gif" alt="" />

<img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> All good fun. Hey, I bet your Jag would get some oohs and aahs at the drag strip <img src="/forums/images/graemlins/kewl.gif" alt="" />

Yea...it would make a bunch of noise, roast the tires for a bit then hook up but I'd be rustling through the Moss-box trying to grab gears as the Honda v-tech flies right by me. <img src="/forums/images/graemlins/lol.gif" alt="" /> Now some smooth country tarmac is where the E-types like to run. I don't know about the Miatas but the E-types stay neutral through turns, meaning they don't over-stear or under-stear. I've flipped it through a few corners way too fast and all she does is slide sideways.....like a skateboard. <img src="/forums/images/graemlins/lol.gif" alt="" />

Sounds like a good time <img src="/forums/images/graemlins/kewl.gif" alt="" /> We should go to the strip together sometime and compete for slowest car status. My new-to-me Focus is not blindingly fast, though I suspect it will turn the corner at the end of the track quite well too.

I'm about to turbo my Miata, and one of the items sitting in my basement is a full 3" exhaust. In the rear of the car it gets routed up under the subframe brace, near where the stub/halfshaft flange is. Some people who have made 3" exhausts have had clearance issues with that flange and have gone to the later 96-up single piece halfshafts for clearance (no flange to hit stuff). My fabricator says I "should" have room with the way he built it, so hopefully I won't have to mess with it, but on the off chance I do end up having to switch to the one-piece shafts I can give you my '94 ones.

There ought to be people on the forums with open diffs sitting around. I can post a WTB ad on your behalf if you like. If you have any local Spec Miata racers check with them too as it's not unheard of for them to accumulate parts cars. <img src="/forums/images/graemlins/lol.gif" alt="" />

BTW when you get around to looking at that RX-7 diff, a 3.909 should have 43 teeth on the ring gear and 11 on the pinion. <img src="/forums/images/graemlins/wink.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" />

Drivetrain swap stuff confuses the crap out of me, frankly. I have a few links saved so I don't have to use my brain remembering any of it. You've probably already seen these but I'll post them just in case.
http://www.solomiata.com/Drivetrain.html
http://www.solomiata.com/RingandPinion.html
http://miataturbo.wikidot.com/differential
http://mazdatrix.com/g5.htm

sounds fun Reu, I've been there once. I like the 4 lane drap strip, not too many of those around the east coast, might be the only one. They have events there like "Pinks all out" and a couple other that I cant recall. My VR4 wont be ready for atelast a month or so, but a buddy of mine took his VR4 out there that had 30 less HP and edged into high 11's, So if I can get a good launch, I hope I can get high 11's too. I saw some amazing cars and trucks when I was there last time, even a GMC Sierra Diesel that was getting 13's, crazy strong. Its fun for sure, keep me posted next time you head out there and vice versa