a big 1 its an alloy 1 on the car at the mo i have a new 1 thats a 31. and the 1 on the car is loads bigger ?the rod on the 31 was on my standered turbo witch i replaced and was ment to be runnin 12 psi ? but the rod is shorter on the 31 than the 1 on the car. it was hitin 20 psi the dropin to 14psi so i adjusted the rod on the acurator on the car and its now holdin the above it felt flat before but now feels a bit better its in for a tune in 2 weeks time but if its summin fooked id like to change kit before the tune hope this helps