1991rx7vert

I just finished my 13b-re swap into my 91 vert now I just need to install a down pipe...since the cosmo TT setup is similar to the fd twin turbo can I use a fd downpipe instead of the shop custom making one for me?? I was going to install the downpipe and then just cut off the flange to the DP and the existing flange to the stock exhaust and use a coupling sleeve to connect them but I don't know if the bends/ lengths are the same for both downpipes...think it will work???

TitaniumTT

Absolutely no ******* way. Similar does not equal the same. The cosmo twins have a three stud downpipe, the REW twins have a 4. The pipe itself might be able to be used, but you would need to cut off the flange and cut out a new one and weld it on

1991rx7vert

are the lengths and bends the same???

RETed

It's made for a different chassis, and you're still trying to make it fit the FC?
Good luck.


-Ted

TitaniumTT

{edited for flaming}

That being said the FD dp will fit in the FC chassis with little tweaking. As in it needs to be bent down after the firewall plane by maybe 1/2". However, you are going to spend more in fab getting it to mate with the cosmo twins which I wouldn't use anyway. They were rated @ less than the REW twins and trying to find gaskets or rebuild parts is going to be near impossible. Not to mention unless you are running them sequentially they are going to be horrible IMO. Most of the FD guys that went non-seq regret it.
So, with all of the aggrevation to make them work non-seq and you prob not liking it, the cost of doing this, the need for a new turbo when these go, why not do a stock S4/5 turbo now and upgrade later? Or just spend the money now.
I have the cosmo twins and never even thought about using them.