Tell me why I shouldn't turbo my Miata?

I thought I had set myself on just getting a VVT motor for the '90, doing I/H/E tune, maybe cams......or building a high comp, bored out one.

But after driving that 1.8 JR supercharged Miata the other day (which I suspect was in the 135-140whp range if running strong?)..........and it was punchy, but not quite what I expected. Again, it seemed to be running OK, but who knows what it was actually doing.

At my local track it doesn't take much HP for a well-driven Miata to be QUICK, but I'd also like it to be quick between the corners as well. I rode an R6 for years, it dyno'd at 109whp, approx 15-20 more than what the Miata.

But I feel like I shouldn't even bother turbo'ing the 1.6 and at least drop a 1.8 in there for boooooooost. But that adds more. I know the big deal is heat, and I'd do the FM Crossflow and stage 2 kit + oil cooler, vent the hood. It needs to be reliable for 20 minute sessions in 100+ temps.

Should I even bother with the 1.6? If I do a 1.8 it will at least have a 99-00 head on the 94-97 block, or with boost does it even matter.

Ok I'll stop rambling, thoughts?

What's your power goal?

I can give you one reason,

LS1 that is

Go ahead with the VVT motor, but leave it at stock compression ratio. If that's not enough power, then boost it.

I would NOT plan for boost now. Boosted Miatas seem to be expensive to keep together on the track and the last thing you want to do is lose track time, since it seems that this is really the only purpose this Miata serves for you.

I've owned a stock 1.8 and turbo 1.8. The turbo car is endlessly entertaining, and the extra power really allows the car to hold its own against pretty much anything else on the street or autocross. It's a no brainer - I'd add forced induction to every road-legal Miata I ever own in the future.

There is this one for sale locally...

http://www.johnfingermazda.com/Used/1991_MAZDA_MX_5_Miata_2dr_Coupe_Convertible__/Greenville_SC/LISTING-14769092/VehicleDetails.aspx

I would have turbocharged an NB, but I think that the MSM makes a better daily driver.

Swank Force One wrote: I would NOT plan for boost now. Boosted Miatas seem to be expensive to keep together on the track and the last thing you want to do is lose track time, since it seems that this is really the only purpose this Miata serves for you.

In my not so extensive experience with boosted Miatas, they tend to hold together well if they've been built right. A lot of them haven't been, including the one I owned a few years back.

BoxheadTim wrote:

Swank Force One wrote: I would NOT plan for boost now. Boosted Miatas seem to be expensive to keep together on the track and the last thing you want to do is lose track time, since it seems that this is really the only purpose this Miata serves for you.

In my not so extensive experience with boosted Miatas, they tend to hold together well if they've been built right. A lot of them haven't been, including the one I owned a few years back.

Hanging out on Miataturbo.net, seems like they're always, and i mean always breaking something. At least one of them has removed the turbo from their car in an effort to get lots of seat time without worrying about their cars.

I don't even think i'd trust my turbo Miata to hold together through some hard track time, and it's an MSM. If someone disagrees and thinks it'll hold together just fine, they're more than welcome to buy it and try for themselves.

Well, I'm not gonna talk you out of it

Keep in mind that heat is related to power output. Set your goals at 200 rwhp and you'll have a quick car (approximately double the current horsepower) that's easier to keep together on the track. If you go chasing every possible horsie, you're going to be chasing problems too. The guys at Miataturbo are often pushing the limits pretty hard.

@DaveEstey, I'd think 200-225whp would be enough to not have to give point-by's to all the V8s.

@aussiemg, really no interest in putting a V8 in the car.

@Swank Force One, I figure what I drove this week would be relatively close to a well-tuned stock comp VVT..........I wasn't impressed. I could also be jaded since the Coyote engined 'Stang is the daily drive. And yes, the Miata's sole purpose is to be a RELIABLE track bitch.

@nderwater, I'm sure it is! I'm just concerned with the reliability factor of being pounded on track . I'm willing to overbuild to keep the reliability as well.

@rotard, this one has had enough stuff done to the chassis......new hubs all around, FM framerails,butterfly, frog arms, etc etc etc.........not getting rid of it or getting another one.

I have seen approx one turbo'ed Miata that was track reliable in my six years of doing track days. I don't include mine in this equation. I'm sure it can be done but getting there will be expensive and time consuming. Especially when compared with a normally aspirated Miata that will be stone reliable and can "hold its own" with most any cars with just suspension modification.

A talented driver friend of mine repeatedly passes corvette's at VIR in a Miata prepared for spec miata classes. He has since modified the car for TT. He is now finding it easier to chase down more expensive cars with a wing for rear downforce, a rear gear change to 4.11, and a megasquirt tuned on a dyno. The MS and the associated changes, like removal of the MAF, gave him a significant jump in hp in a stock 1.8. This touch of more power has allowed him to chase down even faster cars. He may still give point-by's on straights but not often as most of the cars that are faster in a straight line know that he'll be on their a$$ in the curves. For that reason they let him by before the curvy stuff sets in and then find him in the pits for track advice after the session.

If you're looking for thrills on the street then a turbo Miata is really fun. Driving on the street doesn't dictate the need for more cooling or an exhaust manifold or turbo to manifold connection that can withstand 2000 degrees. My experience was I could drive my car on the street indefinitely but once on the track it was good for one session before it needed some maintenance whether that was turbo to manifold bolt re-tightening, inspection of the turbo oil drain hose, megasquirt tuning, tightening of the turbo to downpipe connection, cooked rubber hoses failing due to underhood heat...etc...etc.....missed session...etc...etc....

For reference I had a BEGI SSM kit running 10lbs of boost with all the needed equipment to support that. My biggest problem was underhood heat and the turbo to manifold joint. I used iconel studs with stage 8 hardware and it still came loose.

To that end, a 145-150whp n/a stripped out track day Miata should be pretty damn quick anyways. Spec Miata times and faster.

It's funny, I don't think I've ever personally lost track time due to a turbo problem.

Keith Tanner wrote: It's funny, I don't think I've ever personally lost track time due to a turbo problem.

YOU'RE A PRO! I'm just some jack ass with a wrench.

That said, if I had the resources, I'd LS1 a Miata in a heartbeat and call it the Tanner Special. My balls would swell three sizes that day on track.

z31maniac wrote: @aussiemg, really no interest in putting a V8 in the car.

You really need to ride in one, my RX5.0 is open for rides anytime there isn't snow on the ground.

I'm sure something will be at the Mitty.

My 1991 Miata was turbocharged about 3 years. It was originally built as a challenge car but I ended up taking it to work in the summer and up to NH a few times on weekends. The thing was a blast to drive and I’m guessing it made around 230hp. In the quarter it ran high 13’s with a trap speed of around 108mph with a poor launch. The rods and pistons in both the 1.6 and 1.8L are the weak point. Also you can find cheap cast iron T3 turbo manifolds on ebay for the 1.6L. Stay away from the cheap stainless stuff. It will crack in 30 different places within 1,500 miles, trust me. There is always FM if you are looking for quality.

Swank Force One wrote: To that end, a 145-150whp n/a stripped out track day Miata should be pretty damn quick anyways. Spec Miata times and faster.

I think the top Spec Miatas make about that much power... :)

I've never lost track time due to a problem with the turbo itself, but it took a while to get the brakes and cooling sorted out on the car. I'm still not sure if it will do 100F track days, but at this point I'm not sure I want to do 100F track days any more, so that's kinda moot. Then there was last April when I stripped all the teeth off third gear at Laguna Seca, which is directly attributable to the extra torque from the turbo. :)

Making it track-worthy driven hard at 200 rwhp is going to at least double the cost over the turbo kit by itself, and it also increases the consumable cost (more fuel, higher octane fuel, more brake pads, eats rear tires faster, etc). Making it track-worthy driven hard at 300 rwhp means building the motor.

Blowing past a Mustang on the straight makes it all worthwhile though. :)

PseudoSport wrote: The 1.6L has factory piston oil squirters unlike the 1.8L but the rods and pistons are the weak point.

The 1.8s have oil squirters too. AFAIK, Mazda never made an NA or an NB without them.

Xceler8x wrote:

Keith Tanner wrote: It's funny, I don't think I've ever personally lost track time due to a turbo problem.

YOU'RE A PRO! I'm just some jack ass with a wrench. That said, if I had the resources, I'd LS1 a Miata in a heartbeat and call it the Tanner Special. My balls would swell three sizes that day on track.

If your balls are swelling, that's too much pucker

So what's the difference between a jackass with a wrench who talks about Miatas all day for a living and someone who earns their pay some other way? I don't have any super-trick parts on my turbo Miata. Until recently, it was a completely standard 1.6 Voodoo II on a 120k engine. Now, it's an FM II on a MSM engine. In both cases, it was put together in my home garage with normal tools using off-the-shelf parts from FM. Seriously, I get this sort of thing all the time, and it's something I think about as my car is sitting on jackstands in the garage and I'm crawling around underneath on the cold concrete.

One of the demo cars at FM is "Igor", a salvage 1999 with a bunch of bolt-on parts. It's almost exclusively a track car these days, and runs at least twice as many laps as any other car at a typical track day as we're giving rides in multiple run groups. I've asked Brandon (who drives it more often than anyone else) and he can think of a few times where it got hot and had to be parked for a while, but that was also with our older radiator - and also with the car running double sessions. He also remembers running out of brakes, but that's a different problem

Granted, we're not necessarily out there trying to eke out the last 0.1 second. I tend to push the cars harder than anyone else here, mostly because I'm usually driving a car with my name on the title But track days are about fun, not about winning, so that seems a perfectly reasonable way to behave.

Rods on the 1.6 are the same as the 1.8 parts, BTW. No difference in strength. I don't consider the 1.6 to be a weaker platform, it just makes 10% less power because it has 10% less displacement.

In reply to codrus:

I stand corrected, didn’t know they all got them.

aussiesmg wrote:

z31maniac wrote: @aussiemg, really no interest in putting a V8 in the car.

You really need to ride in one, my RX5.0 is open for rides anytime there isn't snow on the ground. I'm sure something will be at the Mitty.

I've already got a '13 GT Mustang as my DD. I don't want another V8 car, nor do I like the sound of the LSx motors.

I've done some more reading and it seems as though a rock solid reliable, turbo Miata can be built but takes $$$$$$$

I'll have to think if I want to invest in all of it. I figured last night it would take about $6500 or so to do it properly using the FM No electronics kit as the starting point.........and that's using the 122k 1.6 in the car.

If I was going to boost, I'd really like to at least do a stock-ish rebuild on the engine. But a low mile junkyard 1.8 seems like a better idea.

I'm not sure it takes a ton of money to build a reliable turbo Miata but IME it takes a lot of care if you want to do it right. Unfortunately I don't see that sort of care taken that often by "forum eggspurts"...

Because you're a big fat scared ass Bob Costas? (I don't mean that. I'm just trying the negative motivation thing.)

I would just put the effort into getting an F20C from an S2000, they can be had for not much more than turboing a Miata.

J

I like the f20c but personally, I find that swap stupid. If you have a miata and want an f20c, sell the miata and add the money you'd spend from swapping the motor, and just buyan s2000 and have a better car.