Buying guide

[Mrmagpie7]

Hello I am new to all this atm I have a mx5 mk2 but really want a rx7! I love the look of them plus you never see them with is a plus! But more to the point I am looking at some but I would just want to know what to look out for etc and what are they like to own?

Many thanks

[samoht]

Hi, welcome!

FDs are awesome to drive, but tend to be somewhat high-maintenance.

The basic engine is fairly reliable, given most people do less than 10k miles a year, if you get a good engine then you won\'t wear it out for years, probably never.

However, if anything goes wrong with the fuelling, ignition, turbo wastegate, lubrication or cooling, then the engine will likely detonate and break the apex seals immediately, requiring a rebuild.  A 50 pence plastic clip or tube could break after 20 years use, and bang - you might need to find three grand for an engine rebuild.  This is true of any car to some extent, but rotaries are less forgiving.

To check the engine condition, the gold standard is a compression test.  Should be recent and should have six numbers (one for each of the three faces of the two rotors).  All six should be fairly close (total spread of less than 1.0), and numbers in the 7.0-8.0 range are good (50k+ miles life remaining).  Also check that the engine starts readily hot or cold, struggling to restart the engine when warm is a sign of low compression.


The main problem is that age, poor maintenance and badly executed modifications all massively increase the risk of failure.  If you buy a bad one, say with a badly bodged wiring loom, you will have no end of expensive trouble.  This also includes badly rebuilt engines.

So, if you buy a modified car you need to know who did the mods, ideally a reputable rotary specialist who you can talk to about the car.  It\'s generally much safer to buy a near-standard car, you need less expertise to avoid buying a dog that way - although the standard car does have some weaknesses.


Some weaknesses of the standard car are:
* Plastic AST (air separator tank) can crack and shed coolant, less commonly the plastic end-tanks on the stock radiator can do this.  [Loss of coolant can cause engine failure if you don\'t shut it off immediately].

* The intercooler is inadequate for trackdays, even at standard power on a cool day the inlet air temps will go sky-high (80+ degrees) which is dangerous.  It\'s fine on the road, but for track use you really need an FMIC or V-mount, either of which require labour-intensive work to re-arrange the whole front of the engine bay, relocating the radiator, a/c condenser, battery, and intercooler itself.  Once you have a proper intercooler and upgraded rad, you can stop worrying about temps.

* The twin-turbo system is notoriously prone to various different failure modes.  It\'s a very clever system which uses only one turbo below 4,500rpm, and then both together at higher revs, the same as Porsche used on the 959.  It\'s extremely effective when working well, because you get almost turbodiesel-like pickup from low revs, and then it gets a second wind at 4,500 and pulls linearly through to the buzzer at 7,000.  It gives a strong consistent response across a wide rev band, making it the perfect tool to adjust the car\'s line in corners.  

However, to achieve this requires two turbos, a series of flaps and valves to redirect the air, all controlled by vacuum pipes and pressure accumulators.  Most FD owners have encountered problems, often when the second turbo doesn\'t activate and power trails off early, caused by e.g. a small air leak somewhere in the control system (affectionately known as the rats\' nest).  The problems aren\'t serious (won\'t kill the engine and the car is still driveable), and can be fixed, but they can get annoying.

As a result, you will find some cars have been converted to a single turbo, which is a much simpler setup, and can offer more power, although can\'t provide such a linear response over a wide rev range.  Debate rages over the relative merits of both setups.

So, although I recommended buying a near-standard car, there are reasons to look out for a well-modified one, especially if going on trackdays or if you are going to want more power.

If the car\'s got more than the lightest of mods, it should be remapped for safety; removing the cat, or replacing it with a sports one, risks pushing the boost above what the standard ECU can fuel, leading to detonation.  Remapping requires an aftermarket ECU, usually an Apexi PFC.


General ownership:

- check the oil level every few tanks of petrol
- expect 20-25mpg if driven in a law-abiding manner, less if you\'re Lewis Hamilton
- they\'re a little noisy on long runs but more refined than an MX-5 and perfectly comfortable to sit in
- kneeroom can be tight for taller drivers; I\'m 6ft and had to fit a smaller, dished steering wheel to get kneeroom
- doors need quite a bit of width to get in and out, can be tricky in tight carparks
- boot is small and shallow, but bigger than an MX-5


My car is a bit under 300hp on the standard twin turbos, and it\'s just a joy to drive.  The steering response is amazing, grip is great, and when you go beyond the limit of the tyres, it\'s just so poised and adjustable, it really responds to the driver.  On paper, it\'s the perfect sports car - 50/50 balance, low cg, double wishbones all round, rwd, and at under 1300kgs, lighter than almost anything of comparable power levels.  And on road, and track, it really is as good as the figures promise.  Plus the engine is super-smooth at all revs, it feels like it wants you to thrash it, rather than complaining with vibration like any four-pot does.

Find a trustworthy rotary specialist, find a good FD, and drive happily ever after!