Ok guys it's not far away for me to pull the dummy block 20b out of the RX4s engine bay and get it built.



Before I hand it to my engine builder I'll have to decide whether to run a X-Treme Rotaries stud kit or not.

At over $600 Aus for the kit and over $400 Aus to machine the block it's not cheap. :shock:

Plans for the engine...
Gt42/45 turbo 10PSI boost 15 max, 3mm mazda apex seals, RX7 exhaust port sleeves and standard porting maybe a little tidy up. Car to be used for the odd cruise but mainly for events like Powercruise, Easternats, club days, and the odd hillclimb and drag meet.

Just interested in you guys opinions and experiences.

Cheers

 

I am at the same point...stud kit from mazdatrix is $600

I am running a 4508r with a 12psi spring and the occasional 25psi pull.

I have heard mixed opinions

 

I have a mate thats got his cosmo 13b studded but unless the engine breaks it's hard to say whether its worth it.

 

$1000 AU is cheaper than a new motor :p

think of it as insurance..

and if u decide u want bigger power later then there's no need to pull/rebuild/re-machine the motor either..

in the short run it seems more expensive.. but it will be cheaper in the long run

 

I did a huge amount of R&D on this very subject before making a decision. The short answer comes down to power. The more you are seeking, the greater the requirement for studding the engine as well as gaping and balancing the rotors. If you ask enough people who have had 20BT failures, the general reasons are (in order) seals - go unbreakable - not cheap, but worth it (see my post), twisting gapes - from dowel failures, and oil starvation - from asking for too much revs without upgrading the oil galleries.

My 'personal' opinion is this: If I can safe guard my engine with quality build methods and parts, then I will. Even combined, they are much cheaper than a rebuild.

If you want more info, visit my FC 20BT build thread at https://www.rx7club.com/20b-forum-95/stewie-says-its-boy-i-say-its-fc-20b-were-both-right-though-%3D-854859/
I'm documenting everything I can in the name of helping the next guy out =)

Cheers!

 

Unless you've got money to burn, I don't see any reason for them at the level you're shooting for.

Awesome car. Good luck wrapping it up.

 

Thanks for the input guys. Still haven't quite made up my mind but the engine will be coming out soon regardless.