ColinRX7

Regardless, if you're going to bring up ping-pong effect and such, you should have your hands on an FD manifold and really look at it closely.



I have both, we have different backround and opinion on the matter, I think it's a bit one sided if you've only really seen in person one of the two.





Mazda never really designed anything just to look prettier, the ports on the REW are bigger than a TII, no? they would have setup the UIM incorperating those ports and their dynamics, ping ponging, etc, it's not like for the FD they said "ahh screw it, it's turbo, so screw R+D on ping pong effect and runner dynamics this time, we will just make bigger ports and have bigger throttle plates, and a 'pretty' top half".



That's all I'm really saying here. And when you are porting a TII engine, more or less you are bringing it somewhat closer to an REW. And most guys want to go front mount anyways, why use a UIM that's setup for the TII's OEM port work and top mount design.











I haven't seen the FD LIM in person, so I won't argue with the TII LIM being restrictive. If I had an FD LIM and TII UIM, I would have constructed a way to turn the FD LIM into an FC block bolt-on.. Somehow.. perhaps that's a bit presumptuous of me, but I worked that S5 TII LIM you see in the pictures to bolt up to a 6-port block, and the porting was (to say the least) quite different.



If you want it bad enough, you can make anything happen.



Perhaps this discussion should be about how to bolt up the FD LIM to an FC block?



Then again you could just use REW secondary irons in your next rebuild to minimize fabrication..







Sorry in advance, sometimes I go on a tangent...

j9fd3s

yep, i was suprised to look in there and see its all subdivided, the 3 rotor is too

ColinRX7

The REW splits up secondary and primary ports in the "dynamic chamber" (albeit a small one) just like the TII



The primary on the REW has a barely smaller dynamic chamber in comparison to the TII primary dynamic chamber, you need to look at them both very closely, don't let the outside aesthetics fool you







Perhaps (putting trust in mazda's R+D) maybe they went with a smaller secondary dynamic chamber because of the difference in secondary throttle plate design?





Just throwing out ideas here, not wanting to argue or anything, we are all on the same team!







I don't know how many times I wish I had an R+D guy sitting next to me so I could say "why did you do this" and he would just give me the answers

j9fd3s

yeah usually there is a reason they do stuff, and its usually not obscure, but the fd twin turbo setup seems to be at odds with the lightweight theme in the rest of the car. i know people will complain about no low end tork just cause its a rotary, even if it ran 0-60 in 2 seconds

RONIN FC

Of course not. Discussions like this are positive.



The secondary ports are a little bigger on the FD, but not the primary.Looks like the primarys open about 13degrees later on the FD.Maybe to reduce some overlap. But thats another topic.

It seems to me that they compramised the dynamic chamber(s) to try to increase flow. I suppose they were relying on the sequential turbos. And I guess the weight of the car could have been a factor in wheather or not they could do without it.

75 Repu

i like the cosmo 13b intake cuz it looks pretty.. like a spider with..