I am looking for info on a half bridge port for my engine. I have the ability to do it myself, but I am not able to find any info or pics of what it is exactly anywhere. I have just gotten the RX-7 performance handbook by Mike Ancas which talks about this process briefly and the benifits of it over a full bridge port (powerband between 4k-8.5k instead of 6k-9.5k). If anyone knows where I can get templates or at least pics of a half bridge port, please let me know.

p.s. I also searched for this on the forum and internet, so don't freak on me if I missed it somewhere

 

Also, I just had a bunionoscopy on my left foot, and the right one is in 2 weeks, which means I can't drive for the next 5 WEEKS, so I will probably have other tec questions like this so I can plan my engine rebuild for this summer.

 

Here's a few pics of my half bridge port on TII end housings. Hope this helps a bit.

- Cooper Lacy

http://alex.yovanovich.home.comcast..../DCP_0417.html

http://alex.yovanovich.home.comcast..../DCP_0419.html

http://alex.yovanovich.home.comcast..../DCP_0420.html

 

I'm pretty sure Judge Ito over at nopistons.com has some really nice templates for you.

 

thanks for the help!

 

Heres what i have been working on. Its much more refined now, but this is the most recent picture i have.

It's based off the racingbeat bridgeport templet.



-Jacob

 

Here's mine. Done by BDC.
http://bdc.cyberosity.com/pictures/BruceBoulan/

 

half bridge template.

http://mazdatrix.com/toolport.htm

you want this one. less hassle and no cutting into the rotor housing.

http://mazdatrix.com/getprice.asp?partnum=49-22201

this guy knows his stuff. not sure if you can get templates from him or not. has got very nice results from his ports.

http://www.nopistons.com/forums/inde...opic=35390&hl=

 

Quick question. Are the intake half bridges really any different than a street port on a 4 port + the extra little slit? It looks like it wouldn't be any worse for passiing emissions because unless it's larger than the street on the main port, it doesn't make any progress towards the exhaust port. I'm assuming the reason bridge ports are usually race only is the exhaust port causes an overlap?

 

It is worse for emmissions, not as bad as a full bridge, but still worse than a mild port or no port at all

Other than the eyebrow, there isnt much of a difference between the a half/full bridge and a mild - extended port

Along with the overlap you get driviablity problems in the lower rpm ranges. Ive read that an engine can buck/surge under 2k with some load with a halfbridge, and even higher than that with a full bridge.

There is alot of information about these types of ports and others, i sugesst browsing the rotary performance sections for answers to questions like this

-Jacob