Just a quick update on the MX5. The GSXR 600 throttles have been assembled and attached and are now on their way to running pretty nicely.
The physical side of the install was pretty simple, mostly a case of bolting stuff up. The only real issue I faced was the routing and length of the throttle cable, which took a few attempts to get right. After a lot of trial and error and the use of some mountain bike parts to help the cable get round some tight bends, the cable now fits fine. The ratio of throttle plate movement for a given amount of cable pull is now a little higher that it was before, making the throttles very sensitive to small pedal movements. This can currently make the car a little difficult to drive smoothly in traffic and when parking. I have a plan to move the cable mounting point on the pedal to resolve this, but it’s not an urgent modification.
On the ECU side of things, the car is tuned and running well under most conditions. Startup and idle are smooth (the car sailed through its MOT last month) as is 90% of driving whilst the car is moving. Increasing the revs off idle is still a little rough, things go lean for a split second and stumble, which again makes driving the car in traffic a little laborious. Once moving, the fuelling is smooth and wide open throttle sounds great.
There are a few things that I rushed to get the car ready for the summer which I’d like to go back and revisit. For now I’ll just enjoy the sunshine though, when autumn starts to arrive I may take it all apart again and make a few small improvements. Amongst other things I think the head would benefit from a small skim. We’ll see.