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Old 09-29-2010, 04:56 AM   #1
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I am completely new to the miata world but have been a roadster guy from the beginning.

I own a 1998 BMW Z3 (2.8 I6) and had looked at heavily modifying it as I went along but realized that I didn't have the finances ($20k) to do it right so I decided to pick up a 'project' car I could tune. So my Zed is essentially stock and will remain to be my daily driver for the time being.

I looked into many different tuning options (240sx, rx7, e30, etc.) but several of my friends had miatas so I decided 'why not' and here we are

I'm going to go look at several miatas this week (na) and see what I can get my hands on

My ultimate power goals are 300-350 out of a built motor (1.6 or 1.8) and if I get bored with that I'll try and attempt a 1jz swap (my favorite Japanese engine).

-Eric
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Old 09-29-2010, 04:58 AM   #2
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Welcome. Stay away from the 1.6s. Go ahead and buy any year, but build a 1.8 and put it in whatever chassis you get. If it doesn't have to be pretty, go for the cheapest one available (probably '90) and add the built turbo'd 1.8 and some chassis braces. If you can find one with a crank pulley wobbling problem, that's even better.
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Old 09-29-2010, 05:06 AM   #3
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Originally Posted by curly View Post
Welcome. Stay away from the 1.6s. Go ahead and buy any year, but build a 1.8 and put it in whatever chassis you get. If it doesn't have to be pretty, go for the cheapest one available (probably '90) and add the built turbo'd 1.8 and some chassis braces. If you can find one with a crank pulley wobbling problem, that's even better.
Awesome! My friends had told me that the best chassis (lightest/most rigid) would be 1990-1993. Is that correct?

I'm trying to find one with a great body on it (i can do mechanical, i can grunt through electrical, i have NO ability with cosmetics lol) to save myself some pain in that department, in addition i found a 1990 with a perfect body and light mods for just under 2k that would be a great chassis, only problem is that it needs new belts to drive home
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Old 09-29-2010, 05:13 AM   #4
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That's a $40, 30ish minute repair for anyone with a little mechanical ability, but I for some reason suspect there's more to it than that, like the water pump bearings are squealing, not the belt.

Miatas get heavy yet more rigid the newer they are. '94-'96 are the most desirable, since you're starting with a reasonable stiff chassis, the 1.8, they're still fairly cheap, and they're OBI, which is much easier to mod in terms of engine electrics for some reason. I've got a '93 so I don't know a terribly large amount of that crap, only to push you towards the '94-'96. If you're building for 300-350hp though, go ahead and get the '90 and drop your built engine in it.
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Old 09-29-2010, 05:24 AM   #5
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When I go look at that one I'll probably ask the guy if he minds if i throw a set of belts on it and drive it before I fork over the cash to make sure he's as honest as he thinks, haha

And from what I remember how the conversation with my friend and I went, he said that even through the other years are stiffer they being to gain weight rapidly? But he assured me that the earlier years could be drastically stiffened with a full cage and some chassis sway bars
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Old 09-29-2010, 01:20 PM   #6
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You repeatedly mention weight. Are you planning to track the car on a road course? Drag race? Autocross? I ask because it will be a good bit more expensive to build a 300-350 hp car that will withstand continuous abuse for 30 minute track sessions versus only putting that power down for 10-20 seconds on a street-only car.

Yeah the 1.8 cars weigh more, but if it's just a street car then it's not the end of the world. I track mine but haven't felt compelled to strip out too much yet because it's nice having an interior in a car that's also street driven. But you can drop a lot of weight from these if you're motivated. Find the big thread on here about where to remove weight on a track car.

Also, welcome to a car that has a proper double wishbone suspension instead of strut and trailing arm garbage, and that isn't known for having the subframe self-destruct.
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Old 09-29-2010, 02:39 PM   #7
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Welcome! Get a mazdaspeed miata. More chassis bracing then youll know what to do with. I have one and on a stock blockl my last dyno session with an insanely rich tune netted me 287rwhp. i leaned it out and now im easily over 300....we'll see how long that holds up
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Old 09-29-2010, 02:53 PM   #8
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Welcome. Pics of the beamer?
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Old 09-29-2010, 03:09 PM   #9
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If you get a 90-93 car you WILL need to replace the rear end with one out of a '94-up with a 1.8. The 1.6 diff is junk.
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Old 09-29-2010, 03:23 PM   #10
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I had also been under the impression that the earlier cars (any NA) are much lighter than the NB, But honestly, the weight difference is not huge. According to Wikipedia, the difference between a base '90 and a base '98 is 200 pounds, but the NB is frankly a MUCH nicer car, with significantly better rigidity and more power, not to mention a nicer interior.

It really depends on your goal. It does sound like you've got your "nice" roadster with your Bimmer, so you may not care what the interior is like or how bad the dashboard shudders over bumps. Plus, the NA is easier to modify and the price of entry is MUCH lower.

Sounds like for the stuff you wanna do--build up a motor and possibly do a 1JZ swap--if you know what you're doing, go drive that '90. If you're going to build it or swap in a 1.8 does it really matter if there's something wrong with the motor? If you want a clean body, getting a running miata for less than 2k with a clean body is a steal.

Good luck!
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Old 09-29-2010, 07:29 PM   #11
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ScottFW - For right now I'm looking to possibly do one of two things
1. a multi-purpose car (drag, street, and eventually do some road course events) so the car would more than likely get stripped bare to shed as much weight as possible (goal of ~2000lbs wet)
2. an impressive show car that will not only look amazing but also run circles around anything else that shows up on the street

oh and i know how ANCIENT my suspension is in the car but idk, for some reason it still loves all the twisties i throw it into

LeatherFace24 - i would love to build starting with a mazaspeed but i literally can't find any for sale around here (i might not be looking in the right places either) but drive it til it breaks then upgrade!!

Chicksdigmiatas - isn't the best of my car but just a quick one i could find, i have lots more on my phone but i haven't uploaded them yet


sixshooter - how reliable is the 1.8 rear end at ~350hp? Should i get some other aftermarket rear end?

turbofan - yeah all the NB's i can find are easily double or triple the price of the NA's and for my purposes i just want a clean shell (if i get a working motor that would definitely be a plus so i can sell it to pay for a 1.8 to build)
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Old 09-30-2010, 02:04 PM   #12
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The 1.8 rear is quite robust. It is torque and not hp that will kill it and it is very difficult to make enough torque with the Miata engine to create an issue. There are 380+whp Miatas on stock 1.8 rear ends on this forum to my recollection. When you approach 400wtq you will need a Ford 8.8 IRS from a T-bird or the Getrag from a Caddy CTS. Both are common conversions for the v-8 transplant guys and kits are available. Remember that the lighter your car is the less abuse your rear diff receives...
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Old 10-01-2010, 12:37 AM   #13
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Awesome! Sounds good, so when i eventually do a 1jz swap i'll go for an even beefier rear end. I found some amazing deals on 1.8's today (~$200-$300), most need a tune up, but that's alright since I plan to build it with forged internals. Also i found a full drivetrain for a 1.8 for another $300. Are these reasonable prices for these parts? I know in the BMW world almost NOTHING is under $1000.
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Old 10-01-2010, 12:57 AM   #14
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VERY reasonable. A decent complete 1.8 engine with lowish miles would be a decent deal at $750. Add a transmission, drive shaft, and differential and you're up around $1500 if it's all in good shape. $200-$300 is very good.
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Old 10-01-2010, 01:24 AM   #15
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I made 350whp on my 1.8l miata that had a stock head and built bottom with only 20psi on a EVOIII 16G. Was the funnest car to drive too boost was always there when i wanted it even at 10% throttle i would have 10psi.
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Old 10-01-2010, 01:41 AM   #16
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curly - awesome! I'll call the guys tomorrow and see if I can go check it out and bring it home

miatamike - sounds badass, how did you manage to keep the tires from just roasting in all gears? I'm looking at going with upgraded, bigger cams as well as a built bottom end so hopefully I can make some very reliable, high power numbers
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Old 10-01-2010, 01:52 AM   #17
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Traction wasn't so bad with the tires I had the RE-11's once they where hot she held good but if you wanted them to break free they would. Its not too hard to do as long as you go the money.
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Old 10-01-2010, 02:44 AM   #18
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I imagine a good bit of that was also throttle control? How much did you end up spending on tires? My current expenses are around $350 per set of backs and close to $500 for a set of fronts (backs last around 25-30k miles if I behave myself and fronts last 45-50k miles)

this is on my Z3
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