An End-of-build Retrospective on my Rx7 Evo GT by gmonsen

By diyauto
( 3 )

11 minute(s) of a 144 minute read


An End-of-build Retrospective on my Rx7 Evo GT

Compliments of gmonsen @


I am finally making it out to Sevenstock this year and am putting together an overview of my car that I'm probably going to put on a poster and have available as printed handouts. So, I've decided to summarize and share the things I've done to my car over the past 4 years along with the few things remaining in one thread and in an organized way. I am going to talk about why I did the things I did and something about the choices I made. These are my favorite things. Any and all comments and questions welcome. I've divided it up by exterior, interior, chassis and suspension, and motor.

The car is not quite done and I'll post the final changes as updates through till probably the end of February or so, depending on whether I decide to paint it before Deals Gap. Mainly left is some experimentation with the motor and dyno comparisons, a few small cosmetic bits and pieces, like the new emblems, some suspension tuning, and then some performance figures and weight by corner.


There are all kinds of builds and ways of modifying cars based on budget and objectives. I had a very clear idea of what I wanted based on owning another FD for years and a very clear budget. I didn't make lists of parts, but thought for a long time about what I wanted to end up with and wrote down a lot about each aspect of the car and then about how those pieces all fit together. Then I figured out how I wanted to implement each thing, whether the choice was buying a part or making something or modifying something. 

Grand Touring with a 20b-powered car

So, my car has a very stock looking interior and exterior, a naturally aspirated 350 whp 20b motor, and a moderately upgraded suspension. It looks stock despite a few external touches that are not even visible in many pictures at all. The interior looks stock, but every part is essentially custom redone leather, metal, and wool with the result being that its very comfortable and luxurious. Its fine on the track, but is the best on the highways and backroads. Imagine a very quiet interior with some quiet background tunes sitting on some serious leather cushions. Grand Touring. 


I set out to build a natural evolution of the Rx7 like the evolution of the 911 over time. I wanted the car to evolve into something a bit more exotic, more powerful, more purely rotary, while being more comfortable and having an interior like the best sports cars made. I didnt want it to jump out at people, but instead be something that they honestly mistake for a factory made car that they just never heard of before. This car could have easily been created by Mazda from parts they had readily available and by simply changing the interior material specification, fit and finish. 


The car is all about balance. Not too much horsepower, not too stiff spring rates, not too big wheels, not too many cosmetic changes, but an attempt to upgrade each major aspect of the original cars specification and performance to the same level or extent as all the others and where no one aspect of the car overwhelms any other or the chassis. The original car had remarkable balance and so should mine.


Its also about balance in terms of costs. No 20b conversion is an inexpensive undertaking and mine was no exception. So, in each separate area of the car I may not have done whatever the ultimate might have been. Had I done so, it would have doubled the cost and not really been a factory evolution at all, but obviously a very, very special one off show car. I wanted to build a car that Mazda could build today for the same time-value-adjusted-dollars as the cars cost when introduced.

Im not about giving advice, but cant help but emphasize something I just said. In every area of your car, there are aftermarket pieces that cost three or more times the average price for that piece. Take Ianetti seals at, what, $1500 whereas other very good seals are $600 or so. If you try to find and buy the best piece everywhere, your build is going to cost you a fortune. If you can make it a rule never to buy the most expensive pieces, but to try to buy at the top of the middle, you can control your ultimate costs much better. At the same time, this budget control helps ensure you dont end up with a build where one or two things are great, but there was clearly not enough money left over for some areas and they suffered.

I hope there are some things here that some of you haven't seen... 


Ill start with the few exterior modifications Ive done. The exterior of the 3rd generation Rx7 is as near 

perfect a design as possible, so I didnt want to change the lines in any way. All my efforts were simply to 

see if I could enhance it a bit through small details.

New Emblem 

I never have liked the emblems that came with the 3rd generation Rx7, though I have used the Efini emb-

lem for many years. They dont mean anything and there is no heritage or legacy symbol for Mazda or the 


like there are for Jaguars or Ferraris or Porsches. Maybe thats why the Mazda emblems are all made out 

of plastic?

The Rx7 is very much like the old Datsun/Nissan Z cars. Everybody knows what a Z is and everybody 

knows what a 7 is and so Ive commissioned a new set of emblems that are the same size and shape as 

the Efini emblems, but simply have the number 7 inside a rotor shape. These will replace the front hood 

and rear hatch emblems and all other identification.

The emblems are going to be made of three layers of metal welded with parts painted or polished and will 

be about the same size as the stock Efini emblem. Ill update the pictures here with the completed emblems 

when they are done.


Here is the final design for the emblem:


Here are the initial drawings I did for it:

This shows the 3 pieces that will make up the emblem:

And here is a version of the emblem out of polished metals:


Knight Sports Sleepy Eye Headlights

Everyone knows that the FD was not blessed with the best nighttime lighting and many upgrade it. I chose one of the best of the traditional JDM kits offered: the Knight Sports 

High Intensity Discharge (HID) sleepy eye conversion that provides much better high beams at night and looks a lot better in the up position than the stock frog eyes. The 

Knight Sports kit is very well made, installs perfectly, and works as well as factory.

Here they are from the side and above showing the lower sleepy look:

From the front they look more aggressive and the HID's are very bright:


Aluminum Grille

I have always loved the grille on the early FDs, but you cant really see it on a black car. I also have always loved the grilles on Maseratis and Ferraris where they made an 

aluminum grille surround. So, I commissioned an aluminum grille surround for my car. I really like the way it outlines and picks out the shape of the grille.

Here are a few of the grille being made:

This takes some olde-fashioned skills in metalshaping:

And of the grille installed. The fit is perfect:

As you can see, its a real piece of jewelry when its polished:

HRE 543R Wheels (17x9 and 17x10)

Generally, the most common types of wheels on FDs are variations on the 5 spoke designs and the basket-weave designs. I had several sets of 5 spoke wheels in the past and 

have basket weaves on other cars. I really spent some time thinking about what I wanted on what was to be a more luxurious iteration of the FD theme and I have always said 

the FD lacked those little detail touches or “jewelryâ€Â that so many fine cars have always had. The polished aluminum grille and valance were added as just such details and jewelry.

I thought about wheels the same way.

There were only so many manufacturers I really wanted to pick from including Fikse, HRE, and a few others. The wheels had to be made and finished in the best manner possible 

and, while other manufacturers have some good-looking wheels, few have the level of design, craftsmanship, and finish I wanted. 

I decided I wanted a busier look with more spokes. While the 5-spoke designs look more powerful and sporting, the designs with more spokes provide a lot more detail for an ex-

terior that, while gorgeous, is quite homogeneous. I looked at a number of designs and came down to the Fikse and HRE 10-spoke designs.

Here are the Fikse Aro and Mach V wheels I liked:

And here are the HRE type 543R wheels I finally selected:

I picked the HREs for several reasons. First, the curved shape of the spokes  from center to lip  is very close to the curve radius of the fenders. I believe theres a subcon-

scious link between the wheels and fender curves that you sort of subconsciously appreciate. Second, they are finished remarkably well and have the 3-piece design with the highly 

polished nuts holding the pieces together.

The HRE's are like a diamond bracelet on my girl:

I think you can see how visually harmonious the spokes are with the fender's curves:

I guess I would comment that I have always liked 17 inch wheels over 18s, because I like having more rubber to cushion the ride and for the section to provide better warning of impending breakaway. I may try some 18-inch wheels someday just to see how they look versus how they ride and whether theres any handling issues. (This is obviously one area where I went way overboard and did not follow my own advice about not buying the most expensive thing in a least in this category.)


Nice job!

Posted by Diggymart on 3/13/19 @ 9:54:43 PM