20 April, 2020 by Simon Descoteau
Project Synthia: 1991 Eunos Roadster – The Story So Far (Part 1)
A few months ago, I had written a brief update on what had been going on which had distracted me from writing over the past few years, and one of the key points of that was my journey back into modified Japanese cars. The car that re-started that particular hobby was this little unloved Eunos I found on Autotrader (a UK car listings website) and decided to buy as a fun little project.
It was the 24th of January 2019 when the car turned up on the back of a trailer, as the seller kindly delivered her to me from Devon and instantly I fell in love with her. I had previously owned 2 Eunos Roadsters, both 1990 models, both V-Spec British Racing Green 1.6 litre manual cars so this was my third and it didn’t take long to familiarise myself with her. The only difference between Synthia and those that preceded her was that Synthia came with ABS, a “feature” that was not ideal due to the less than efficient 30-year-old technology.
Nina, my last Roadster had been owned by me for almost 7 years when I had to, unfortunately, sell her and she was very heavily modified. I had a lot of comfort working on these cars and had a fair idea what they responded well to, so I knew Synthia wouldn’t stay stock for very long.
When I first got her, I realised that certain things would have to be done on a priority, specifically the tyres on the car were budget brands, and I had no idea when the car had been serviced or had her alignment checked. I had also planned at some point in the future to lower the car, as a standard height MX5 is quite high and does roll a bit while cornering.
I will digress just a moment here for those that may be wondering why I’ve referred to the same car in 3 different ways, and for the uninitiated I’ll take a moment to clarify. In 1989 Mazda launched their very popular MX-5 ,or Motoring eXperiment no. 5, in Japan under their prestige brand “Eunos” and thus called it the “Eunos Roadster”. In Europe where this brand does not exist, they called it the MX-5. The same car is also called a Miata by our cousins across the pond. As there are only a very small handful of cars that were sold under the Eunos brand, and again only in Japan, it has become the accepted nomenclature to refer to Japanese MX-5s as simply Eunos, rather than their model name which is Roadster. I tend to use whatever flows naturally when I am speaking about Synthia (and Prytaneia, who you are yet to meet for that matter). I will also point out that these cars are roadsters, not convertibles.
Now, while I had said that I had planned to lower the car, things escalated pretty quickly at this point. While browsing eBay I managed to find a fantastic deal on a set of 15″ Watanabe wheels which were too good to pass up on at that price. 15″ tyres are significantly cheaper for equivalent quality than 14″ tyres, and 15″ wheels also give the required space to fit the larger brakes which I knew I would want to fit in the near future. The smaller and firmer sidewall of the tyre further aides with the steering feel. The wheels themselves were gloss black, with a 7.5″ wide et8.5 model F8 rear and 6″ wide et35 model F8F front. Although the fronts were less than ideal, the package price was less than the cost of a single 7.5″ F8 so I decided to install these on the car for the time being and purchase some wider fronts at a later stage.
Strictly speaking, staggered wheels are not advised on an MX-5, but due to my previous experience of using lower offset wheels on the rear of Nina I knew that I preferred the dynamics of the car for the way I like to drive the car. Additionally, I wanted the aesthetic of a wide rear wheel with dish, without the penalty of heavier and less responsive wide front wheel so this was the best compromise and I decided to break from convention
When I had last owned an MX-5, the Toyo T1-R were the go-to tyre, so I of course decided to go with them again, with a 205/50/15 on the rears and a 195/50/15 on the front to complement the staggered widths of the wheels. The front tyres were slightly too wide for the wheel to be ideal, but would be perfect when I purchased the wider fronts. What I did not know is that in the past 5 years, Toyo had changed their tyre compound and the new compound was harder, and less suited to the light roadster. However, for my country lane drives the tyres are still significantly better than those previously on the car.
At this point, having fitted the tyres to the wheels, I realised that Watanabe wheels need the specially shaped Watanabe wheel nuts, which lead to a long wait while they were shipped (unfortunately not overnight) from Japan, but at last the wheels were fitted. This very quickly made me realise that the car was sitting far too high. A quick call to Joe at Wheels in Motion (by far the most trusted wheel alignment and suspension shop I know of in my part of the world) and I had a set of Eibach springs on order in their specified spring rate for a mild 30mm drop all around. Autolink (the number 1 source of used and new MX-5 parts) sourced a new set of standard shock absorbers for me all around, as the standard shocks were of unknown age and quality.
I chose this specific configuration as I had used this exact set up in Nina and I had been impressed with the compromise between handling and comfort. Synthia, like Nina, was to be a road car and on our less than perfect British roads, I did not want the cost or complication of adjustable coilover suspension.
The suspension finally installed, and expertly aligned by Joe to the “Fast Road” setup developed by the extremely knowledgable and well respected Tony, Synthia was finally at the correct height and ready to take to the roads. However, in doing these changes I had underestimated just how wide the rear wheels were and this lead to requiring the arches to be rolled to allow for clearance of the tyre without scrubbing issues.
This, in turn, set off another series of events, and while this post has been exceptionally fun to write, it is getting on a bit in length so I shall continue this story in a Part 2 which will no doubt follow in the near future.
I hope you have enjoyed coming on this journey with me so far as much as I have writing about it, and as always I welcome your comments and questions below.
Part 2 of the story so far is now up and you can read that here.