I guess there is some contraversy over bigger apex seals, but I dont see the problem, if the seals are bigger, they can withstand more, allowing for more boost, resulting in greater power. Am I right, or wrong?

 

um.. more seal = more surface contact
surface contact = more friction/drag
friction/drag = more heat
more heat = needs more cooling

ALso, there is more drag, so it takes more power to turn over the rotors.. well if you're upping the boost then i guess taht's not a problem.

Look the Mazda engineers spent a SHITLOAD of time researching the perfect inbetween size. 2-3mm is good enough for wahtever you need IMO.

 

From what I have read, 3mm boost buy you a little mistake in tuning. but at a cost, 3mm seals increase parasitic drag of the seal to housing.

 

From Pineapple:
First of all, 2mm seals are perfectly fine for extremely high boost levels. Many people sucessfully run 20+ psi on stock 2mm seals with no reported problems. However, 3mm seals are much more durable and not all of us have (1) great tuning skills and (2) the financial resources to shrug off a small tuning mistake that requires a full rebuild. One hard ping and a 2mm seal will likely break. 3mm seals generally take much more tuning abuse (multiple, hard pings), which is often enough margin to back off and save the motor. Also, we use a special 2-piece 3mm seal that, when it does fail, tends not to cause subsequent damage to rotors and housings. While getting the rotors machined out for 3mm seals and purchasing the seals themselves costs a bit more, it does not begin to compare to that of a second rebuild. For this reason, we recommend 3mm seals to customers who plan to exceed stock power levels and/or go with aftermarket fuel injection systems. Again, it's not mandatory if you have advanced tuning skills or are willing to risk a second rebuild, but 3mm seals are relatively cheap insurance.

 

https://www.rx7club.com/forum/showth...threadid=88920

mike

 

3mm seals also do not seal as well against the rotor housing.

 

Wrong.&nbsp Have you ever seen the relation of the rotor and apex seals on the rotor housing especially at "TDC"?&nbsp The apex seals are at a very "bad" angle, and even with an extremely thick apex seal (10mm), you'd get only a fraction of the apex seal edge beval against the rotor housing.&nbsp

Also, there is no "protection" of the apex seal against damaging detonation.&nbsp Due to the dynamics of the combustion chamber, the force of the detonation is actually "funneled" against the apex seal, which is one of the big reason the rotary engine tolerates very little detonation.&nbsp A piston engine with either blow head gaskets (relatively "easy" job to replace and fix) or the damaging force needs to blow by the piston land before it hits the piston rings.&nbsp Piston tolerances are TIGHT, and rings can be really far down the piston skirt - all of which help to protect the rings against blow-out from detonation.


-Ted