Turbo Kits and Aux Ports
mostly harmless
Joined: Jun 2002
Posts: 3,440
Likes: 0
From: Greater Vancouver Area, BC
Originally Posted by rotarygod
The new 4 port, secondary ports do not go down very far and are in fact only slightly bigger than the 6 port engine's secondary ports. You can't go stricly off of publishd timing numbers to think they will or will not flow more. You need to see the actual size of the ports.
but still, you can't tell me that those ports look really really rediculously awesome for a little juicing from the factory, or if (hopefully) there's enough meat there, a nice porting job might make these severely awesome turbo housings.
Registered
Joined: Apr 2003
Posts: 9,134
Likes: 26
From: Houston
The intake runners for those ports are also the size of the secondary intake ports of the 6 port engine. They are about 1" or so in diameter. Have fun flowing through that! That will take some serious grind time and even then you'll need an intake manifold with a runner that is that large as well. Too much trouble. Just use the 6 port engine and set the actuators on the entire system to only open under boost. Simple yet effective.
Int'l Man of Mystery
Joined: Jan 2004
Posts: 3,651
Likes: 0
From: Central Florida
Thanks RG! I serously wanted to argue that the 6 port as still better, but the timing issue lookd pretty good.
You should think... why did Trust/Greddy make a turbo for the 4 port motor yet? Nope they started with the top-of-the-line engine....the 6PI badboy.
You should think... why did Trust/Greddy make a turbo for the 4 port motor yet? Nope they started with the top-of-the-line engine....the 6PI badboy.
Not anymore
Joined: Mar 2004
Posts: 2,423
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From: NorCal
I recently read an article regarding a 6-port rotary engine with an extended primary port and a half-bridge secondary port. Is it possible to perform such a task on the RENESIS? I don't know for sure how Judge Ito did his work, but I am curious as how the engine will behave with such a port job. Any thoughts?
Stuck in a love triangle
Joined: Aug 2003
Posts: 2,201
Likes: 3
From: Miami, FL
This is what rotarygod said about the automatic Rx8s potential for F/I earlier this year in this old post:
Is all of that stillthe major consensus or has this changed? Re Amemiya in Japan supposedly has a turbo automatic though its funny how the only informationthere is about it is on their same old page which hasntbeen updated since 2003.
Originally Posted by rotarygod
Thoughts on forced induction: Typically in the past the 4 port engines were thought to be the better choice in the forced induction arena. However the 4 port engines of the past also had greater runner area that was nearly equal to the 6 port runner area, they outflowed the 6 port engines on the flowbench, and they were simpler. All of this has changed with the new 4 port Renesis. The secondary ports are no where near as big as the older engines. The timing is not near as great. The total runner area is much less. This all adds up to an engine with less airflow. How does a turbo spool up? Airflow! If we were to add a turbo to the 4 port Renesis, it would be one with a very small exhaust housing that is designed for small gains. A lack of airflow through the engine will make it very slow to spool. A high compression ratio helps to combat this but we can't perform miracles. It would actually spool up faster if all the ports were open simultaneously by diabling the secondary shutter valves. This applies to 4 and 6 port engines. The faster we can get more air into the engine the faster we can get it out and therefore spool up the turbo. Remember that since we are relying on positive manifold pressure we just want all the area we can get so as much air gets in as fast as possible. Based on the fact that there is so much less runner and port area than the previous 4 port and 6 port engines, the new 4 port Renesis is not a good candidate for forced induction. At least not at any serious power levels.
The 4 port Renesis as well as the 6 port were designed to maximize performance in their respective power ranges. Through careful port timng, sizing, and runner lengths, Mazda has just about maximized the performance capabilities of these engine. Their tuning is insufficient though but once this engine is tuned properly, gains will be few and far between. There is always room for a little more power but gone are the days of 35hp gains from and exhaust. The 4 port engine has so much going against it in terms of pure power production that it should not even be considered a viable market for performance products. Gains would be too small to justify the product prices. Remember that a gain lower in the powerband equals less total horsepower than a gain at an engine designed to run at a higher powerband. If you have a mod that can add 10hp at 9000 rpm, it will only add about 4 or 5 at 7000 rpm. Performance gains for the 4 port engines will be much less. Sorry 4 port guys, if you are performance nuts, you bought the wrong model.
The 4 port Renesis as well as the 6 port were designed to maximize performance in their respective power ranges. Through careful port timng, sizing, and runner lengths, Mazda has just about maximized the performance capabilities of these engine. Their tuning is insufficient though but once this engine is tuned properly, gains will be few and far between. There is always room for a little more power but gone are the days of 35hp gains from and exhaust. The 4 port engine has so much going against it in terms of pure power production that it should not even be considered a viable market for performance products. Gains would be too small to justify the product prices. Remember that a gain lower in the powerband equals less total horsepower than a gain at an engine designed to run at a higher powerband. If you have a mod that can add 10hp at 9000 rpm, it will only add about 4 or 5 at 7000 rpm. Performance gains for the 4 port engines will be much less. Sorry 4 port guys, if you are performance nuts, you bought the wrong model.
Is all of that stillthe major consensus or has this changed? Re Amemiya in Japan supposedly has a turbo automatic though its funny how the only informationthere is about it is on their same old page which hasntbeen updated since 2003.
Administrator
Joined: Jul 2002
Posts: 21,958
Likes: 115
From: portland oregon
wakeech you should have come down for 7stock. you had to see that exhaust port for yourself to believe. there is soooo much more flow to be had there it is almost rediculous. and the secondary intakes could use a whole lot of smoothing/shaping. someone standding there made this comment after looking at the secondary and exhaust "it's a wonder this engen makes any power at all". not an exact measure but i could put my pinky finger through the exhaust sleeve at the bottom and nearly all of it was hidden by the port opening. where are your pics RG?
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