I've seen fd upper manifolds on fc's before but could never find anything on it really, is it a dirrect bolt up swap with the fc one and what mods are needed to run it ?

 

It is not a simple bolt on swap.
In any case, there are three ways to do it. The wrong way and the right way and the easy way. Most everyone who has done these swaps that have claimed to do it the right way by port matching are full of ****. Only Blue TII and myself (on this forum afaik) have done it correctly. It is quite involed and after reading some of their descriptions, I know they did not correctly and/or fully port match them.

The easy way is to use an adpater plate which almost makes it a bolt on swap. Not quite but as easy as it will get.

Here is a link with some info:
https://www.rx7club.com/forum/showth...=342353&page=5


To summarize:

There is absolutely NO WAY to just port match the fd uim and the fc lim without using some aluminum filler rod to add material to the manifolds in one of two ways. Anyone else tells you different did not fully port match them, I don't care what they say or hear.

1. Fill in the outside gap between the primary runners on the fd uim and use the fc gasket.
2. Fill the inside of the primary runner on the outer edge of the fc lim to shift the runner over towards the fd ports and use the fd gasket.
3. Use an adapter plate.

I believe Blue TII did the first method iirc.

The first method would have been easier but I opted for the latter since there seemed to be less ovaling of the runners where the manifolds meet.

I used an adapter plate before and did not like the angle in the plate to get the primaries to line up. However, the taller the adapter plate, the less of an angle. The adapter is certainly the easiest method but definately suffers in flow characteristics as compared to truly portmatching them. I did dyno before and after (adapter plate vs. true port matching) and there were significant gains with all else being equal.

The secondary ports are easily matched as is since they are pretty close to begin with.

 

yup, evetything rx-heven wrote is true.

 

No all of it since I did it the right way I dont think only him and BLUE TII are the only ones

 

Wow this question would have been easily answered with a click of the search button.

 

him and blue are def. not the only ones. i have one that JRX made for me by adding aluminum. i know a couple other people who has done it as well. but i have gone cosmo.

 

How beneficial is the FD upper manifold compared to the FC? In which area would you expect the gains? Does the FC throttle body mate up to the FD upper manifold?

 

i want that so bad but would prefer to buy it already mated