[maddmatt02]

I just installed my ARM CP (bought it on sale at 117 shipped because wasn't sure when BMS was going to have their tial flanged chinese CPs in... took so long for me to get around to the install that they had them already...)

anyways stock CP fit very snugly, like you'd think it should, you knew it was going to seal. took the o ring out, put it in the ARM CP, slid it over throttle body and it just felt loose. removed and checked to make sure o ring was still where it should be and it was, so I reinstalled it and thought it was tight enough that it MIGHT not leak, but probably would. got somebody to rev the car in the driveway and I wasn't watching the gauge but probably building 2-3lbs and sprayed the connection with soapy water and of course it was leaking. driving the car I cant feel a difference so if I hadn't noticed the looser feeling connection or sprayed it I wouldn't know it was leaking. going to buy a slightly thicker o ring and that should solve it.

[Sgop335]

Good find. Honestly the stock o ring on the throttle body sits with a little slack. Nitice that? I mean the oring by itself. Not sure how well it can seal. Curious, what fat oring are you buying?

[maddmatt02]

I didn't notice that on the stock CP, maybe slipping the o ring over the TB by itself would reveal some slop but once its inside the lip of the CP it fits firm, definitely a nice tight fit with the stock CP/o-ring assembly.

found a few choices on mcmaster but going to pull my CP again to get an exact size of what I;ve got to know what to get. havent seemed to find a definite size anywhere online. some say the oil filer o ring is the same size, some say no its not, some just point out that it has different part numbers.

[Sgop335]

Originally Posted by maddmatt02

I didn't notice that on the stock CP, maybe slipping the o ring over the TB by itself would reveal some slop but once its inside the lip of the CP it fits firm, definitely a nice tight fit with the stock CP/o-ring assembly.

found a few choices on mcmaster but going to pull my CP again to get an exact size of what I;ve got to know what to get. havent seemed to find a definite size anywhere online. some say the oil filer o ring is the same size, some say no its not, some just point out that it has different part numbers.

Actually the oil filter oring has a slightly smaller id than the stock oring, which i prefer. It fits on the tb w no slack and im using with my er cp.

I have some thicker orings from mcmaster carr, same id as the oil filter oring but little thicker, put them on ebay for sale.

[maddmatt02]

thing Id be worried about with that is that if the ID is smaller and it grabs on the TB better but doesnt have a thicker cross section then it wont be fully seated in the o-ring groove and would probably still leak. I have one though so may as well give it a shot. if it doesn't work Ill get in touch with you tiago. when I have it off Im going to measure the ID of both pipes too because I think that not only is the o-ring groove larger than stock or something but the difference between the TB O.D and CP I.D. is much greater with this ARM CP.