What if...

I have a question that has been bothering me for quite some time and finally decided to ask someone in the know. In Jay Lamm's book, "Miata MX-5 Guide", he states that an aluminum block for the Miata engine was never considered because it would have been too costly. Is this an accurate statement?

If I'm not mistaken, Honda has been using aluminum blocks for the Civic for a considerable length of time. If Honda could do it, why couldn't Mazda?

What type of weight savings might have been achieved if aluminum had been used for the engine block?

Thanks for any insight you might have.

Robert, Allentown, PA USA

Partially correct. Mazda had no aluminium-block engine in production when the Miata was under development, and the budget didn't allow for an all-new engine. It had to be done out of the parts box.

As for Honda doing an aluminium engine and Mazda not, Honda is Honda, Mazda is Mazda. Car companies - even Japanese ones - have philosophies, personalities and biases. As well as different engineering budgets. Mazda kept the Wankel Rotary under continual development from the early 1960s, so that absorbed a certain amount of manpower and resources (physical as well as financial). Honda had no such 'sideline'. Additionally, Honda's available engineering facilities, staffing and program budgets have been and larger than Mazda's by a couple of orders of magnitude since the mid- to late-1970s. News flash, they still are and by even more.

However, back in the days when they weren't (late 1960s, early 1970s), Honda's technological base was coming directly from motorcycles where aluminium engines were more common than in passenger cars. Going even farther back to the early- to mid-1960s, Mazda used to use all-aluminum engines in the entire passenger car and light commercial range: the Carol 360, Carol 600, Familia 800, Familia 1000, Porter Cab and Bongo. The company encountered technical problems which equated to high warranty costs Mazda decided it didn't want to wear. Out went the alloy, in came nodular cast iron.

As a sort of example, why is Bill Gates' house bigger than mine? Sure, he's got deeper pockets, but he also he may like obscenely large houses while I don't.

Weight savings on the bare block could be likely to have been in the 20 to 35kg range, though the basic configuration of the engine as well as the technology involved in manufacturing the block (e.g. sand- or high-pressure die-cast) would have had an impact on that figure.

But inasmuch as an aluminium block was never available as an option (and therefore never under consideration), the situation is like that of a Miata wagon; perhaps an interesting 'what if', but not much more than that.

bwob

Cost of a European adventure

I am going to move to Italy soon, and I am thinking about taking my 1990 Miata with me. They told me that in order to import a car to Italy, it has to meet the European specifications, otherwise I would have to make "costly modifications". My car was made in Japan, for the US market. Do you know if it meets the European specifications, or what needs to be modified, if anything?

George, Michigan/US

I don't know who 'they' were, but I'd suspect the reference points 'they' had were American cars. I don't think the mods a Miata is likely to have to deal with are especially costly. Especially vis-a-vis the cost of a new (or good condition used) car.

The single biggest problems with a Miata are likely to be lighting and perhaps seat belts. You'll need to add a rear fog lamp (Mazda came up with an inelegant solution for this for EC-bound NAs which is easily sourced in Europe and can be added with similar ease to a US-spec car) as well as add a side repeater flasher, immobilize the side marker lamps, fit an amber lens to the rear one, add EC compliant parking lamps (replacing the front turn signal clusters and I think, though I am not certain, rear lamp units will work, though you may have to wire them yourself - I don't think the US car had the same harness as EC cars) as well as headlamps. A kilometre speedometer (along with gear to match in the transmission) is also a good idea.

US emissions are tougher than EC ones, so the hardware and software should be fine. If your tires are already E-marked (an upper case 'E' in a circle, usually with a number adjacent) they should be fine.

While the lenses for Miata front turn signal/parking lamps may also have an E-mark, the reflector unit may not be compliant, which is why it's a good idea to fit the EC-legal lamp units.

I sure hope that is of some assistance.

bwob

Finding the Miata's 'sweet spot' for tires

What is the best size tires for my '93 Miata?

Fred Cawthon, Saratoga/NY/USA

Fred, there are a bunch of variables at work here, with your budget perhaps a prime point of consideration. If you intend to keep your original 14-inch wheels, 185/60 14s are the logical choice. The size makes them (normally) cheaper than either of the more common alternatives, 195/60 14 or 195/55 14. This size also ensure that you'll have no speedometer gearing problems.

The negative side of the ledger is pretty short, with the general lack of really high-performance rubber a potential difficulty in the eyes of some people. What was a moderately performance-oriented tire size when the Miata first appeared in 1989 (that is a 185/60 14), is now found more commonly on small economy cars, with economy or low rolling resistance tires more prevalent to those dimensions than high performance tires. You might find a slightly better selection of performance-oriented rubber in 195/55 14 than the OE size. This tire size is also going to keep the gearing (overall and speedometer) closer to the OE fitting than 195/60 14s will.

Of course if the lack of high-performance tires is not a factor for you, the OE 185/60 14s are the most economical way to go.

If budget isn't that much of a factor and you are contemplating a wheel change (and going to 15 or 16 inch at the same time), the options are more varied. While 16s can look real, real good in NA Series Miatas, in most cases they are past the point of diminishing returns. With stock (or near stock) suspension and the engine at or near the OE level of tune, 195/50 15s are an excellent balance - sort of a 'sweet spot' for NAs. The size is also my own pick for the ideal size on any 1990 - 1997 Miata in my garage. About the best price/performance balance for my uses.

There are plenty of high performance tire models available in this size with prices which are reasonable. Additionally, 15s are still reasonably lightweight. There's a noticeable increase in weight when you go from 195/50 15s to 205/45 16, thanks to a carcass that's wider (remember the weight of the steel belts - in this regard Kevlar-belted tires can offer a benefit or two) and with more rubber in the compound. Because of the car's relatively light weight, it can be very sensitive to additional unsprung mass (such as the wheel/tire combination). So if the utmost in wheel/tire performance is important to you, you should try to find a set of lightweight wheels with a design you like.

So if you want to stay with the original 14 inch wheels and aren't concerned about a big selection of high performance tires, stay with 185/60 14s. If you want to go larger with new wheels and tires, 195/50 15 is the go in my book.

bwob

It's called the AFTERmarket for a reason, part XXIV

when will the I.L. tail light conversion for the M1 be out if it will be?

mike, holland pa usa

I don't know, but I have a sneaking suspicion the people at IL Motorsport do.

bwob

Ask the Man Who Owns One

No question, just a comment. (I'm the guy who asked you about trading my Integra Type R for a Miata with the suspension package two years ago.) Tila's question in the March Ask Bob! is an easy one. After two years of owning a Miata it is obvious there is no better alternative for three times the price. The longer you own one the more you appreciate the simplicity and (relatively) light weight. Boredom is NEVER a problem - I learn something about vehicle dynamics each month I drive it. Thanks again for the excellent advice.

Terry, Sarasota, Florida

Not much to add to that.

bwob

And best of all, no balloon payment!

How much is it monthly for a 1990 Miata?

Maria, San Fransicso CA

Depends on the price, condition and mileage of the particular 1990 Miata, term of the loan, amount of down payment and your credit rating. However I charge $2630 a month on a 48 month plan. Other banks or lending organizations may charge less or more. Though I wouldn't count on it.

bwob

No, we didn't make this one up

my dad owns a '96 Miata and he is going to put a bigger turbo on it. will the smaller turbo work on a s-10 4.3L v-6 engine. i didn't know if u would know..he said u got a turbo on one of ur trucks. so i fugured u might know....thanx

dustin, Cedar Rapids, iowa

Ask your father. I don't do trucks.

bwob

They're longnecks anyway. Big 'uns

I am probably not the first person to notice that a case of beer fits perfectly into the well on the bottom of the Miata's trunk and that the spare tire holds it there securely. Is this a happy accident or an amazing feat of engineering?

Mike DeMonte, Philadelphia, PA USA

Not a factor, since beer in Japan isn't sold by the case and liquor stores all deliver.

bwob

It doesn't smell that bad. At least not from here

Sudden onset of gas fumes in a 91 Miata. Nothing wet (that I can see) under the hood.
Throttle area looks dry. Hoses and connects appear OK.

rick, tucson, AZ

I don't notice any fuel smell from where I'm sitting. I bet it's something in the fuel system. Maybe somebody else who can get to the car or has a much more sensitive sniffer than I should have at the car. If you can get it a little closer - say, Fiji - I'll take another whiff if you'd like.

bwob

Huh? A 'four-wheel-drive' Miata? In 1987?

I was reading the Mazda Miata Performance Handbook and noticed the picture of yourself standing next to the clay model of the P729, in what is clearly an outdoor shot. It struck me, other than "very carefully", exactly how DO you move a clay model? I'm assuming it didn't stay outdoors all the time?

canyoncat, Valencia, CA

Well, you sure as don't just put your hands on the decklid and push. Especially if it's hot...

No, the bucks we did the clays on had steerable front wheels, actuated by a long T-handle you'd put under the nose and slide onto a connector with two pins. Then you'd pull and steer the car with the handle while four assistants pushed the tires to roll them. Sort of a four-wheel-drive Miata.

If the weather were cool (and not-too dry as well as not-too damp), we'd leave clays in the viewing courtyard for a few hours. If the sun were out, they'd go out for a viewing/presentation and get rolled inside - or at least in the shade - ASAP. We didn't want them to create the wrong impression to management and think all we could do were blobmobiles!

bwob

Only one modification required

I have a 95 Mazda Miata and I am looking to put the gored turbo kit on it. However, the turbo kit is made to fit the 1.6 litre and i have a 1.8 litre. What kind of modifications would have to be done to this kit to make it fit my car? Thank you

Eric Sitterle, Cincinnati, Ohio USA

It's a pretty straightforward mod; replacement of your car's 1.8 litre BP engine with a 1.6 litre B6. The kit will be just fine then. It'll bolt straight in with no further modifications required.

bwob

Bwob,
Who is Skippy Oyster and what ever happened to him?

William, Santa Clarita, CA USA

He's a former insurance salesman from Upper Montclair, New Jersey. The last I heard he had been killed in a painless cycling accident with Louis Rukeyser last Octvember. Trustworthy sources (e.g. The Weekly World News) have mentioned he was brought back to life by a vanguard of friendly Xist aliens from planet Klystro under the instructions of J.R. "Bob" Dobbs.

Not a question but a comment. Since you hear so much from the power-whiners I wanted you to hear from one of the many people who appreciate the original design intent. Those who want S2000 power should buy an S2000 or get FI. The Miata is perfect as it is. The insurance is cheap too! My only complaint is that American's are wimps and seem to demand all the power accessories and cushy interiors, thus adding weight. Therefore, Mazda does not offer a truly base Miata with L/S. Anyway, keep up the good work and don't let the power hungry morons get to you.

I don't.

Well, usually.

bwob