NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   Comparison of FD and Cosmo exhaust sleeves (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/comparison-fd-cosmo-exhaust-sleeves-58644/)

RussTypeS 04-15-2006 05:38 PM

http://russmarshall.com/d/17073-2/IMG_2299.JPG

FD on the left, Cosmo 13b on the right

j9fd3s 04-15-2006 06:22 PM

if you had the cosmo turbos in front if you you'd see that the sleeves direct the exhaust as far away from the turbo as it can.

RussTypeS 04-15-2006 07:10 PM

Yeah I wonder why they did that, it must make low end torque.



for the record the McMaster-Carr part number for the roll pins that hold the sleeves in is 92383A724

RONIN FC 04-16-2006 12:09 AM

I bet Lynn has the answer to that. Ive seen him write on air dynamics before.

Maxt 04-17-2006 07:39 PM

Its called マツダ AIPI , Mazda air injection port insert, it is designed to flush out trapped gases on the exhaust cycle via air injection , and then dilute anything thats leftover from the cylce, the purpose is to improve low speed charge ignitability, and served 3 purposes, it lowered idle speed in the cosmo with the automatic transmission to make the shift from P to D or R smoother, it made the engine idle smoother, and lowered the tailpipe readings at idle for emissions via dilution.....Maxt

rotaryinspired 04-17-2006 09:28 PM

So its for all those who want a smooth ride. I think when we bought the rotary we threw that out the window. I like my car rough and loud.

Lynn E. Hanover 04-17-2006 10:17 PM


Originally Posted by RONIN FC' post='814166' date='Apr 15 2006, 09:09 PM

I bet Lynn has the answer to that. Ive seen him write on air dynamics before.





How about a SWAG?



The open end is smaller, and matches the exhaust manifold, (Also small) so there is higher flow velocity at lower speeds. So, the small turbine comes on a bit sooner. The Cosmo is a big car and needs more power right off idle. Kind of a poor choice for a rotary (especially a 2 rotor) engine. A nice long stroke V-8 would be nice.



Lynn E. Hanover


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