It's difficult. 2S was introduced at the beginning because it was felt that it would be easier for people to get into the class as there were a limited range of 1S speedos. Using 2S meant that racers could pick any speedo and use it without the complexity of a receiver pack or booster when running 1S.
We put details in the BRCA Rules of which motors were zero timing and could be used to get similar speeds to 1S 13.5. That lasted about five minutes! So, with a motor timed up on 2S those cars are faster, so everyone has to run that.
It's a shame really. There's nothing you can do with a 1S/13.5 blinky set-up to complete. Like the others, I suggest you unleash a bit of timing and get the car to a speed that keeps up. To do that, set your motor timing to zero and add about 20 degrees of boost through the rev range - say 2500 to 7000 - and see how you go.
If you take the piss and boost it so it's much faster they'll probably stop you. If you get it to the same speed they should let you play.
The 2013/14 GT12 Rules will remove 2S as an option. I doubt that will reduce the take up in clubs. With the advent of a large range of 1S-comaptible speedos now available, this option is no longer required. It's a dinosaur now, but they did live for quite a time before they died out! HTH
