ESC and motor combo seem slow.

[BeachBuggyPhil]

I bought a B4 and it came with a Novak GTB and a 5.5t.
It didn't have reverse on so I found a manual online and activated it.
Could it be slower with reverse on? Could it be the cap has had it as its about 5 yrs old? The motor seemed ok in my Mardave, I had to dial it WAY back to drive it. Do Esc's lose there oomph as they get old?
I'm going to try the motor on my Tekin to check it again but just after some advice.
Thanks