Im going to pull the engine out and rebuild it soon. and Im going to use a lot of brand new parts, E-Shaft is one of them.

Reason I will use Renesis E-Shaft over stock E-shaft :

- Its about 0.6 lbs lighter, better geometry, better balanced.
- Mazda does not have Stock E-shaft in stock, and god knows if they're going to make it again.

I know Renesis's e-shaft works with older engines. but Im just wondering if I drop this in, do I need to get everything else professionally balanced ?

 

You can buy used e-shafts that would work just as fine. the .6th of a pound off, I dunno how much trouble that's worth for the gain you'll get. I'd assume it would all have to be re-balanced, wouldn't hurt.

 

Honestly, Im not so sure about the current engine's internal status, if it looks beautiful. I might re-use it.

Someone has told me that if I use different rotors I have to get it balanced, but e-shaft I dont need to. Just wanna know if its true.

 

To my knowledge, the e-shaft from an RX8 should work based on balance alone, as the rotors and counterweights have the impact. If someone else can correct me if I am wrong, I'd like to know but I do believe the RX8 e-shaft will work.

 

Besides the obvious .6 lbs lighter, the 13B-MSP E-shaft is like 40% cheaper than older E-shaft.

so if its a direct bolt on (or bolt in, whatever), I really dont see the reason to re-use the old/used E-shaft.