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How to Build an FD RX-7 PT1 – Overview/Chassis Selection

FORWARD:  Since one of the main themes of this site is to discuss how to properly build cars of all types, I thought I would take some time to discuss my tuning philosophy on my FD RX-7.  In this series of articles, I will go through each aspect of the build and talk about how I came to my conclusions.  But, as this is not a recipe for everyone, I will also discuss what factors may lead someone down a different path, and some benefits and drawbacks of each.

The most obvious place to start this discussion is the chassis selection.  To do this, we must first decide if the car is to remain stock, medium level modification, or full-on race car.  Then, we would have to understand the different trim levels and differences between years so we can achieve the final vision in the most efficient way possible.  I’ll then discuss how these factors influenced the purchasing of my own FD as a case study.

[A small note before we get started:  I’m not going to discuss ways in which to maximize, or even keep, resale value.  We are discussing building the car for YOU and what YOU want out of the car.  I think the days of flipping FDs for a couple thousand bucks are over.  And the market is too volatile to definitively say what the best path would be to ‘make money’ on an FD will be in the coming years (outside of getting the highest trim level, keeping it completely stock, and not driving it…. but who wants to do that??).  Full disclosure, I do not think these cars are wildly amazing cars out of the box.  I am the type that would need to modify any model FD…. this includes the Spirit R.  I personally do not feel the premium that those models demand is justified.  Hopefully I haven’t alienated any and all potential readers with that statement.  I don’t intend to change anyone’s mind who feels the Spirit R deserves the admiration it gets.  But I hope you’ll hear me out and read through my ramblings to at least understand that viewpoint a little better.  On that bombshell, let’s begin.]

One main point I’d like to get across about choosing an FD chassis is, these cars are like Lego sets.  Things from later model years fit on earlier model years, and visa-versa.  And unless you are talking about steering parts, break booster, ABS, pedals, and interior parts; even a lot of the RHD stuff will fit LHD (heck, there’s even some interior swap-ability to LHD-RHD).  That means, if you are taking the car down to bare shell for your build….it really doesn’t matter which year/trim you go with.  The only real question would be if you want a RHD or LHD, and/or a sun roof or not (but even those can be changed with enough money).  The other end of the spectrum would be if you are looking to keep it stock.  Well then, yes, model year and trim will matter.  It’s that middle area of the scale which can get muddy.  Now, as I alluded to a couple sentences ago, with enough money, we can basically make any chassis into whatever version you want… but we are looking at how we can most efficiently achieve our goal.  So, with that in mind, the closer we get to the ‘keep it stock’ end of the spectrum, the more vigilant we need to be about the model year/trim level aspect of the search.  Let’s dive into the quirks and features offered in the different model years/trim levels.

First and foremost, in chassis selection, should be the differences in model years.  In general, the FD can be broken up into three categories:  Series 6 (Zenki) – ’92 to ‘95, Series 7 (Chuki) – ’96 to ‘98, and Series 8 (Kouki) – ’99 to ‘01. [No, these terms are not restricted to discussing S-Chassis cars]  In actuality, the FD can be further broken down into 6 total ‘versions’ (these versions cover the entire JDM lineup, however it should be noted that the change from version 1 to version 2 also coincide with changes form the USDM ’93 cars to the ’94-’95 cars):  Version 1 was produced from December 1991 to October 1992 (USDM Model year ’93); Version 2 was from August 1993 to September 1994 (USDM Model years ’94 and ’95); Version 3 was March 1995 to July 1995; Version 4 was from January 1996 to October 1997; Version 5 was January 1999; and finally the Version 6 was produced from September 2000 to March 2002.  For the most part, the changes throughout these series/versions are easy to find using a quick google search, so I’m not going to go into the nitty gritty of the differences between each (I will post a few links at the end which I believe are good foundational resources how the chassis evolved over the years).   I would like to take some time to talk about some of the lesser-known changes between model years.

[Asside:  I’d be remised if I didn’t also mention Canadian spec cars or European spec cars as well.  Full disclosure, I do not know as much about them, so I won’t risk misinforming on them.  But we can assume that the J-Spec ‘version’ breakdown will also apply to the other markets.  If I remember correctly, the Canadian car trim levels were very similar to USDM (base, touring, R), but they got some extra color options the states didn’t get.  For example, you could have a CYM Base model in Canada, while those were only available in ’93 R1 trim in the states.  On a related note, I do know that the Euro-spec car trim levels were a bit simpler than even the North American options, but with all the different requirements from country to country (things like headlight washers, rear fog lights, rear bumpers for license plates, etc), I will defer you to the google machine for more detailed breakdowns of FDs in those markets]

The first of the items I’d like to bring attention to, that doesn’t really show up in the brochures or on spec sheet breakdowns, is something I consider one of the most undiscussed differences between the versions:  the gas tank.  This might sound odd, but it was simply something Mazda upgraded throughout the run, which I think was for the better.  The Version 1 cars were seen to suffer from fuel starvation during (I believe) hard left had corners.  So, for the Version 2 cars, the tanks got some upgraded baffling.  Then, the baffling was further upgraded for the Version 4 cars.  [Coincidentally, if you go to Mazda to buy a brand-new gas tank, this ’96 issued tank is the only one available.  So, in a no expense spared-type build, this aspect isn’t as important to consider…and obviously if a fuel cell is planned, this is something that does not need to be considered at all]  There was also a change in the drain plug somewhere in there as well, but I don’t really consider that a notable change, though a drain does make things better from a maintenance standpoint, so it is something that could be considered.  Another feature/change that is less well known (but I believe a little more widely known than the gas tank evolution) has to do with the rear diff/subframe bracing.  Again, an issue that was noted in the Version 1 cars was wheel hop, so starting on the Version 2 cars, the rear subframe got some additional bracing.  I say this is slightly more widely known, because if you were to look into getting some aftermarket under car bracing, like Mazdaspeed or AutoEXE, you would have noticed that the bracing is only available to Version 2 and up cars.  This is because those braces utilized holes in the subframe from the additional support added by Mazda [This is something, again, that could be dealt with easily by swapping to a later model subframe or welding to the early model subframe.  Additionally, and very very recently, an enthusiast ran company in the US, JP3 Motorsports, has come up with a bolt in solution that would accommodate the extra bracing to the ’93 subframe.  No welding required.  So, this is far less of a concern today as it was even back when I began to write this article]  The last talking point here, and by far the most well known of the ‘hidden’ differences between versions, would be the sway bar stiffness.  The Version 1 cars had a very beefy rear sway bar, which was changed out for a softer one in starting in the Version 2 cars.  General consensus is, this was due to complaints from the American market wanting a more compliant/more predictable experience.  [In addition to this being the most well-known difference, this would also be what I consider the lowest on the priority list.   Upgraded sway bars are readily available and easy to swap out.  It’s really only pertinent if you preferred the softer rear bar.]  Again, this section didn’t dive into some of the more well know differences like turbo/y-pipe upgrades, intake, interior plastics/gauge clusters, or exterior upgrades.  These upgrades are easily learned more about with some google work or by following some of the links below.

Next, the question would be which trim level to go with.  As I alluded to earlier, Mazda really did it right with the FD.  The engine package, outside of an additional oil cooler, will be the same from base to the highest level (the only differences coming with model year).  This means you really can’t go wrong here, and the further you go towards extreme modification, it truly doesn’t matter because you’re going to change out all the things that differentiate it from, say, a ’93 base model to a ‘93 R1.  Creature comforts was the name of the game in differentiating the trims.  Mazda gave the option for a low frills base model; the luxury/creature comfort model; and the enthusiast model.  This can be seen throughout the production run, with further models sprinkled in throughout the lineup which would slot in between those 3 overall generalizations…. And as we’ve discussed previously, you’d be able to change anything out you really wanted to (with enough of a budget for the more sought-after parts).  So what’s the point of this section?  Well, I guess if I had to give advice on trim level selection, I would simply say:  If there’s a particular feature (exterior option, color, interior option, etc.) that is only available on one or two trim levels, and that car is within your budget to purchase…. go with that one.  Even if you end up paying a slight premium for that chassis over one that doesn’t have that feature, you’ll probably end up better off financially (due to the exorbitant prices FD parts are fetching), and you won’t be out the time and effort to find the part, and install it.  Also, for example, the Bose Wave system on virtually all of the cars it came on has failed over time…. so maybe that’s one feature that you would be aware of and want to avoid.

[Aside #2:  Let’s just throw out any and all factory optioned suspension as a reason to choose one trim level over another (outside of a Mazdaspeed catalog coil over upgrade).  Let’s face it, even if you had the means and desired to purchase a Spirit R…. you’re probably still swapping the ‘sport’ Bilstein shocks out for coilovers, so I see absolutely no reason to look at factory suspension as a reason to prefer one trim level over another.]

There is one other recommendation I’d like to put forth, that doesn’t really have to do with trim/MY, but this does kind of align with the trim level.  As we know, a large number of FDs have already been modified, so you’re going to want to purchase a car that has some of the major features already in place.  Here, I’m talking more along the lines of the turbo setup, A/C, cruise, emissions parts (if that applies where you live).  Let’s say you are planning a twin turbo build, but the car you are looking at already has a single turbo conversion (and for argument’s sake, we’ll say the owner does not have any of the TT parts still).  Well, to revert the car back to twins, it’s going to take a very large financial and mechanical commitment to get that system back up and running properly.  There is A LOT that goes into that TT system, and aside from the cost of the parts, the system itself can often be difficult to diagnose and get working properly even for the more knowledgeable FD crowd.  You also need to know all the parts associated with it, including all the solenoids, and vacuum chambers, etc.  Oh yeah, and your engine harness has probably been cut up and simplified for the single conversion, so that’s another cost.  You could argue, you’ll sell the single kit to recoup some money… but if that kit isn’t one of the more respected kits in the community, and it’s closer to an eBay level kit, you won’t come anywhere near the cost of reinstating the twins.  So, if you want your car to have twins, then buy one that still has twins; if you want a single car, then buying one with a good single turbo kit is a good way to go.  A/C is another thing that can really cost a lot if bought second hand.  I’m just going to go ahead and recommend to buy one with A/C.  Even if you think you don’t want it now, you’re probably going to want it later on in life.  You can always take it off, then if you wan it back, you have the parts to do so.  I’d also say that a car with the exterior features you want will also make the build more efficient.  If you know you want a ’99 spec front end, for example, finding one with one already fitted (provided it’s done correctly) will really make things easier.  Both from an effort standpoint and financial one.

Now let’s put this knowledge together, and show how all this factors into the purchase of an FD.  We’ll use how I came upon my FD as an example.  One thing I’ll note before diving into this:  RHD FD was immediately ruled out for me.  The main reason being, they just were not legal at the time.  Another reason being, I wanted to track the car.  I felt the years of driving LHD cars, and the muscle memory formed during that time, would mean I would be far less comfortable pushing a RHD car to its limits than I would be a LHD car (and after now owning a RHD car, I can confirm this to be the case).  So, something to consider first and foremost.  Anyhow, I knew wanted a black car with no sunroof (non-sunroof cars leave more headroom, and for taller drivers this is important if you are going to need to wear a helmet at any time).  While this doesn’t rule out a Touring/PEP/PEG package, those trim levels are more difficult to find without a sunroof.  Plus, I didn’t want the Bose system, as it takes up too much space in the already limited hatch (I need room for hockey equipment).  So, ultimately, we are down to looking at just 2 trim levels:  Base, R1/2.  The next big key points for me were the upgraded gas tank and sub frame of the ’94-’95 cars.  The upgraded interior plastics were a consideration, but ultimately not a deal breaker if I would have found the right ’93 car, but since we’ve ruled those cars out via other means, all the better (I also prefer the look of the simpler gauges in the ’94-’95 cars over the more crowded ’93 versions).  Now we have funneled the search down to a ’94-’95 Base or R2.  There was one wrench thrown into my ‘ideal FD’ in that, I wanted dual oil coolers, but also wanted cruise control.  Well, this didn’t really happen from the factory.  Base cars had cruise, but not dual oil coolers.  R2s had dual coolers, but not cruise.   So, I conceded to leave my search open to both trim levels, and either add a second oil cooler to a base, or just live without cruise to an R2.  But the car would have to check a couple more boxes to be considered.  My ideal FD would have many old-period correct parts strapped to it, and three of those parts were:  Knightsports twin turbos, intake, and downpipe.  This meant my search needed to filter out any single turbo converted cars.  I also require A/C, so the car would at the very least, still need to have all of the A/C components with it.  So, my search was limited to a ’94-’95 Brilliant Black, non-sunroof, Base or R2, which retained the twin turbos and A/C.

Well then, we are almost 5 pages into this ranting…. so it must be pretty difficult to choose an FD chassis to start with, huh?  I actually hope this long-winded discussion has actually shown the opposite.  When you take resale value and trim level clout out of the equation, it really boils down to a couple simple things:  RHD vs LHD, color, twins vs single, and creature comforts like A/C.   The best advice I could give is:  buy the best RUNNIN and DRIVING example of the car you can afford.  Unless you a VERY mechanically inclined and/or have a super strong knowledge of the rotary engine, you will probably end up spending twice as much to get a ‘project car’ up and running than you will on the initial purchase price of a running car.  This advice has been around forever and holds true to more than just FDs, but it’s advice that people too often (including myself) do not pay attention to.    I don’t think I’ve covered EVERYthing to consider when choosing a car for your build here, but I hope I was able to give a bit more insight into some of the less talked about aspects of the choice.  I’ll conclude with a bit of a hat-tip to Mazda.  The FD is one of the only cars I can think of where you can get just as much engine performance out of the base level car as you can from the top of the range.  Meaning, you almost can’t go wrong with any FD you pick up.

 

*EDIT*  I had mentioned I would add some links for some other information on the model differences, and forgot to do that….so here they are.  Again, these are not all encompassing resources, but they are a good jumping off point.  For more thorough deep dives into things that wouldn’t necessarily be in the brochures, the RX7Club is probably the best first stop:

 

Good Overview of JDM Trims, but also includes USDM Trims at the end

Another Overview of JDM Trims and Production Dates/Numbers

USDM Overview

Goober Goalie

Just an old guy who's into rotaries and all things 90s Japanese. Been involved in the rotary community for over 20 years now, and have dabbled in other platforms over that timeframe as well. I'm so old, I took a modified FC RX-7 to see the original FnF in theaters. I'm looking forward to sharing my experiences and learning some new things from this community.