Review
I received the TSS brake mod a couple of days ago and got it fitted tonight. First impressions were good, it came well packaged with everything needed to install it (not including tools obviously) As with any G25/7 pedal mod great care needs to be taken when handling the stock wiring as the wires are very thin and easy to damage. The connectors pushed on and just needed a squeeze with the pliers to crimp them on tightly.
Before I go into how the pedals feel I will point out that I have come from stock G27 pedals, then G27 with nixim mod, then the AP Electrix load cell mod and now the TSS Hydro/pneumatic mod. The pedals are connected with a Bodnar cable giving 1024 steps.
The mod has adjustment of the initial hardness of the pedal by means of the black screw on the reservoir, tightening this pushes a piston inside which reduces the volume of air in the system (and thereby increases its pressure as it is a sealed system). At the hardest setting there is very little pedal travel and thus maximum pressure is reached very quickly when pressing the pedal. With the mod set at its softest there is the same amount of travel as a standard G27 pedal, it is necessary to wind the screw in slightly from here so that max pressure is reached before the pedal reaches the end of it mechanical travel otherwise it bottoms out and you still don't have 100% braking. I settled on about 25% hardness which is what was suggested in the installation guide.
At this setting the pedal feels a lot like that in a road car, it is relatively easy to press, has a decent amount of travel and reaches its maximum pressure at the end of this travel. After a few laps it is easy to gauge how hard you need to press the pedal to achieve the level of breaking you want. In terms of pedal feel at this setting it is very similar to the nixim mod, soft to begin with and only ramping up towards the very end of the pedal stroke.
Having come from the AP Electrix load cell mod I was however disappointed that the TSS mod's maximum pressure is quite low. It is too easy to max out the pedal. With the AP Electrix you have to press really hard to get maximum braking to the point that I actually had it short calibrated as I found that in race situations I wasn't always pressing it hard enough and was only achieving 80% of maximum. To me the AP Electrix really felt like a race car brake in that you could set it so you really had to give it some, a proper stomp on the pedal to get max braking. The TSS is much softer and more like family hatchback in the pedal feel.
Ideally I would like to have to press the pedal much harder to get 100% braking, with the mod as it is there are no settings that can do this. The limiting factor is the pressure sensor. I don't know what the rating on the sensor is but in my opinion it would be better with one of double the max pressure (ie if it is 50psi then it needs to be 100psi) That way the end user would have more control over the maximum pressure that can be applied to the pedal before 100% braking is reached, and if required then short calibrate it.
If you are coming from stock G27 pedals or nixim modded pedals then this is a great upgrade, the precision given by any pressure based mod is invaluable once you re learn how to brake (but this happens very quickly as pressure based pedals are very intuitive) If coming from an AP Electrix mod you may be a little underwhelmed, as I was for the aforementioned reasons. It is however a very good product and a superb piece of engineering, with a higher maximum pressure it would be perfect in my opinion. It will probably improve you're lap times and make it easier to be consistent in you're braking, as most pressure brake systems do, but if you are looking for a "race car" feel then it falls short.
