curious on what are the pros and cons on having the 2mm and the 3mm apex seals on a NA 13b. Im gonna get my motor re-done soon and i want to be able to make dependable HP. By the way, it's a S4.

 

WOW you are opening a can o worms here. This is a never ending debate. I have 3mm in my high boost engine. However after reading a bit it seems that this is mostly a higher friction situation and due to the machining of the seal grooves (I hear that it is impossible to get them perfect) there is lower compression. These are from respected sources on this forum so I feel I might have made a mistake. 3mm are great for fixing rotors though. I will try to find the thread.

 

2mm 2 peice unless your going for high horsepower turbo application, and need the extra security. if you want harder seals go with rotary aviation, but only use new housings with RA seals, thats what works.

 

https://www.rx7club.com/showthread.p...ow+compression
here is one of the best threads on here about this

 

http://www.performancetestedseals.com/
nice unbreakable seals but that is a whole new debate. If you are going high boost it is good to prevent destroying internals if you detonate too much. But again do some reading on them and make your own decision based on your application.

 

its a NA motor

 

IMO you should stick with 2mm regular seals then. but please run a few searches and read a little to help you decide asking the opinions of people are only going to give you some of the facts reading many opinions will help more.

 

i just wanted to kno the pros and cons of both

 

I understand but what I am saying is that it is easier to read the opinions in heated debates of the past rather than try to get everyone to discuss it again.

 

2mm seals Pros: lighter, less wear, less friction, lighter moving mass.
2mm seal cons: more likely to break on an improperly tuned vehicle, seating issues on worn out rotors.

3mm seals Pros: less likely to break on an improperly tuned vehicle, can work in worn out rotors (although requires tooling work to do so)
3mm seals Cons: increased wear to housing (depending on material they are made of), increased friction, loss of compression, loss of HP, and increase in moving mass.

 

your motor's n/a, just send it to Rotary Resurection, have him do a rebuild and a streetport and call it a day...dont worry about 3mm seals.

 

Waste of time on a non-turbo.
Hell, it's a waste of time on a turbo motor.


-Ted