Hi,

Was wondering if i could take higher compression rotors from an NA 13b and put them into the 13bt block? I want to get the 4 ports from the turbo block but make it normally aspirated. I saw in one of the recent RXTuner mags a picture of a "rock crawler" that had a 13bt with no turbo attached. Any ideas?

Thanks

 

Yes, that's no problem. On the other hand, why not just start with a 6-port motor? Despite rumor and inuendo, they can be ported quite successfully and you can have your cake and eat it too (better low-end torque without sacrificing top-end power). The only times I'd suggest a 4-port are (1) if you intend to run an aftermarket manifold without provisions for the actuators, (2) you just want ultimate simplicity and/or (3) you may want to bolt on a turbo setup at some point in the future and don't want to mess with adaptors.

 

And from what I've heard, the Renesis rotors are available, sporting a 10:1 compression ratio, and they're comparable in price to other later model 13b rotors.

4port simplicity and availability of porting templates make it an ideal choice for a 13b NA port job.

Have fun

Jon

 

You'd have to pick a renesis for an auto trany car then, since the manual ones (with the higher HP) do have a six port intake.

 

Well, yes and no. They are actually the cheapest, lightest and highest compression rotors available. However, with respect to the comment on the availability of porting templates, there is a real "gotcha" with RX-8 rotors: one edge is chamfered, which alters port timing. Unless you know what you are doing -- and if you do, why would you bother with templates?! -- the port timing will not be as intended. Just something to keep in mind. The other problem with RX-8 rotors is that there are no used ones floating around on the market, so your only option is new. While they are affordable by comparrison to the others when new, they are perhaps expensive when comparred to good-used S5 rotors.

 

He was referring to using the RX-8 rotors in a 4-port TII engine; not buying a whole RENESIS block.

 

Yes you can do that

Using High comression light 89.5-91 NA rotors with TII 4 port housings is fairly common. What you end up getting is 200-250hp and tons of reliability.

Its a motor I plan on having somday.