respecthewankel

Hey guys!

I brought over a mazda cosmo for a parts car and am swapping the 20B into my car. I'm getting ready to build the header before I have the motor sent off for a rebuild (full bridge, new apex seals, etc, etc) and I'm a bit perplexed. If I wanted to run a divided housing, how would I route the primaries? Or is there even any benefit to running a divided housing with a 20b? Thanks

RacerXtreme7

iTrader: (2)

hmm 3 rotors, two turbine inlets. Nope, no good. If your cheap and or lazy it'll work fine, you'll need to run a collector for the 3 runners to the turbine flange. It's not optimal, it may hurt spool up and overall power slightly, but its a 20B lol. In time it may crack, I have seen the center dividers develope cracks were a non divided manifold was used with a divided tubine. If you aren't too cheap and or lazy, just replace the turbine with a open valute (non divided) one, their only $200~350 depending were you get it from NEW.

~Mike...........

respecthewankel

I don't have the turbo I am going to use yet, I was just getting a feeler for weather or not I should use a divided housing. I went from an undivided to a divided GT4088R on my Honda and it made a huge impact in spool, but I guess if there's no effective way to divide up the exhaust pulses there's no point.

wackaloo13

iTrader: (3)

just run 3 turbos

Evil Aviator

The advantage of a divided manifold decreases as the number of cylinders or rotors increase. I don't think a divided manifold would make much difference on a 3-rotor. Besides, a divided intake manifold doesn't do much good if the turbine housing is not divided, and I am not aware of any aftermarket turbine housings partitioned into 3 chambers. I think the 3-turbo option would be pretty interesting, but probably not worth the money and effort.

RETed

How do you divide 3 into 2 nicely?


-Ted

diabolical1

iTrader: (3)

you using something with a T6 footprint? i think it's needless worry on your part. if you're running a full bridge, i really don't see major problem with spool. if anything, and if you can work around space constraints, you might try playing with primary runner lengths going into the undivided flange.

respecthewankel

I have been mildly entertaining the idea of a GT47-80, but I think I'll leave the gigantic turbo for my MKIV. Was thinking about a GT4294R, but if I don't need divided I found a T74-GTQ for quite cheap.