has anyone ran any #'s on the diffenence in HP by switching the upper and lower intakes off the Fd and installing the Cosmo intakes and Tb . I just got one in and the Cosmo ports are HUGE. Im sure several people have made this switch , but I cant find any post .

Thanks in advance

Va

 

This sounds promising... bump

 

To use it with the full effect, the runners on the FD engine would need porting down, to match up.

 

Yes and no... the cosmo 13B manifold ports are slightly larger because the intake ports on the irons are taller and slightly wider. the same as doing a port job, except that the manifold ports are in essence "port matched" meaning the size of the ports on the manifold are matched to the size of the ports on the irons.....


you MAY see an increase in power or not..... but there are other things to consider for bolting on such as; the distance of the stud holes, amount of nipples for vacuum lines(emissions, check valves etc...) and runner length(longer= more torque, less response; short=more horsepower at high-rpms, more response)

 

There's a discussion about the FD vs Cosmo manifold and engine porting in this thread:
https://www.rx7club.com/showthread.p...t=cosmo+intake
RX-7 Owners Club - Swapping in a Cosmo motor (2 rotor)

 

I have a post at the end of that thread trying to get some answers but there were none. *sigh*