for all of you that now or have already modified an n/a. eg... tb mod, ported manifold.... and everything else possible .. or something like that
did you all stick with 2mm apex seals? or is it wiser to go with 3mm? i know the 3mm's can take alot more punishment then the 2's ... but anyone have any feed back on this? thanks

 

I always thought that the 3mm were used on turbos so they can run high boost levels. I dont know of any improvements on an n/a though.

 

Stick with 2MM seals. There is no real advantage in going to 3MM seals.

 

Usually 3mm are used on a N/A b/c the rotor clearance for the apex seals is not to spec. When this is the case they can make the 3mm fit by widening the apex groove since the 2mm will not fit properly.

 

lol--stick with the 2mm--lol--lol--lol

 

Hehe, yea just stay with the 2mm. Usually, 3mm seals are used as a kind of "band-aid" to help fill the gap left by worn rotor housings. Theoretically, 3mm seals may be able to handle slightly more detonation than 2mm, but nothing really worthwhile. I believe most of the top Japanese tuners use 2mm seals in their race engines.

 

Whoah... can o' worms!
Here's the lowdown.
OK- 3mm seals ARE stronger, no argument, anyone that says otherwise probably drives a Honda, or a Mustang.
-3mm seals WILL still break after repeated detonation, but can take many more pings than a 2mm seal, so if you are tuned a little too lean, the 3mm seals will make your engine last a little longer before it goes. It also protacts against accidental fuel loss or any other temporary even that leads to a bad ping.
-If you are not planning on ever experiencing a bad ping (VERY optimistic for anyone with a nicely modified turbo or NA) 2mm seals are fine... But if you would rather not spend the 100 bucks for the 3mm seals (if your engine is already apart), and buy a new engine down the road instead when you get a bad ping, go ahead! It's just extra insurance- but NOT a magic bullet!!!
-3mm seals result in about 5% or less compression loss, but after about 5000 miles or so, that disappears.
-3mm seals seal better at high RPM's becuase of higher rotating mass, the centifugal force presses them harder agains the housing.
-3mm seals are commonly used as seals in rotors that have had their apex seal grooves deformed or worn too much top hold a 2mm.
-2mm seals are lighter, have less rotating mass, and are therefore used in racing engines, which are also rebuilt regularly, are not worried about blowing a seal, and the builders usually have access to very precise fuel tuning methods. In racing engines, every gram of internal rotating mass counts.

To say that 2mm seals must be better because they are used in racing engines is like saying that the carbon apex seals must be the best, since they are used ONLY in racing engines.... but they wear out VERY quickly. Not practical for a street machine that needs to take a beating and reliably keep going without rebuilding monthly.

I know I just used it in the argument, but I don't fully understand how some people can say that 3mm seals increase rotating mass, since the same amount of metal is being machined out of the rotor that is being added by the larger seals!!

Anyways. That's both sides, hope that clears up some misconceptions.

 

Hey watch it budy.

 

Pineapple racing's website suggests 2mm for most applications. They suggest 3mm for those tuning an after-market ecu for optimum power as an added safety net against detonation.

 

I've heard 3mm is only used as a band-aid to use bad rotors or housings or something.