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/)
-   -   Combination Porting - Good Idea? (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/combination-porting-good-idea-32396/)

jayroc 01-23-2004 12:57 AM

So, I'm new to porting but have been doing some research on it and trying to come up with some new ideas. I want to get 175rwhp out of a 12a and am thinking of doing a halfbridge/streetport combo. Ie, streetport primaries, and bridgeport secondaries. By my calculations, it seems like this HP goal is feasable.

I've read that, ideally, you want the ports to match exactly, but I'm curious to see what kind of performance this would produce. I'm sure others have thought of this. Is it a good idea or no?

The exhaust I'm going to use is freeflowing with headers, and a custom intake with dual downdraft DRLA carbs with one carb on the primaries and one for the larger secondaries. What I also plan to do is design the throttle linkage so the second carb doesn't begin to open until maybe 3500-4k rpm and is fully open by 7-8k, but the primary carb fully opens at maybe 5k. The goal with that is to provide some good low end response and still get massive fuel delivery at top end, yet still get decent gas mileage if you stay below a certain rpm range.

Anyways, lots of problems to solve, and I'm still new to this sort of thing, but I think it'll be a sweet setup when (or IF) I get it completed. heh

What do you guys think?

BigTurbo74 01-23-2004 01:03 AM

think about how to port the exhaust ports to accomidate your goals in engine power band. i'm not very knowledgeable on carbs but if that can be done it sounds pretty cool

jayroc 01-23-2004 01:41 AM

Ah, forgot to mention the exhaust port. I planned on using the racingbeat templates for all the porting outlines, as I already have the exhaust and SP templates to use. https://www.nopistons.com/forums/pub...IR#>/smile.png

I want a low rpm peak HP/torqueband compared to a full bridge. Like peak HP around 8k or so with a decently broad powerband. Nothing too peaky, I mean.

Jeff20B 01-23-2004 03:16 AM

Welcome! I too am (still) seriously considering a half bridgeport.


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