The holes are chamfered on the rotor side.The first 3mm into the housing(rotor side) is larger than the rest of the hole.

Maybe i looked a bit serious,but i was actually kidding when i said j-bridge ..

Overlap and flow will be less,the timing however will be the same as a j-bridge.More driveability and durability.
Intake duration is aprox 340 degrees.

Thanks for the input.I`ll keep you guys updated!

Karis

 

340 DEGREE intake duration? That's almost the entire rotation of the rotor!

 

34 degrees maybe?

 

Ya i think thats about right. 340 degress of the SHAFT rotation. Duration is usualy maeasured with respect to the shaft and not the rotor.

CJG

 

DOH!

 

just curios, with a single row "cheesport" do you have to cut reliefs in the rotor housing like you would on a bridge? I have a set of radical streetported plates that I was thinking of doinf this cheesport thing to.

 

340 degrees of shaft duration is how much rotation of the rotor?

 

340:3?
around 113*

 

it cant be that easy, lol. for soem reason i think there must be some mroe mathematical equations involved to figure it out

 

nope
3 turns of the E-shaft to one turn of a rotor

 

i am going to ****-port my motor. i guess you can imagine what that looks like.

 

I must have my maths wrong, becuase I worked out a stock port at around 300° and a bridge at around 430°

 

Zenjoe : No,you dont have to cut the rotor housing.The holes end before the rotor housing.

This is how i measured my intake duration :I made a mark when the intake opens.turned the eccentric shaft untill it closes again.So,out of the 360deg rotation,the intake stays open 340 degrees.

Stock port timing : Intake opens :32 ATDC,closes 40 ABDC.

32+40 = 74deg(you will never make 100hp with that timing,its just impossible)If it stays open that short,then you will probably make 35hp or something.

32+40+180=252deg intake duration.You have to ad 180 degrees eccentric rotation,because its ATDC & ABDC(seperated by 180deg).

Example : 1800 8v VW engines have a duration of aprox 245 deg stock.The aftermarket cams range from 268,276,288,296,300 deg duration.

Hope this helps ?
karis

 

Except it is not 180° between TDC and BDC, its 270°, which is why the rotary has a 1080° Otto cycle.

So you stock port is not 252° but 342

The best primer on this is http://personal.riverusers.com/~yawpower/dectech.html

But you MUST have the picture open

http://personal.riverusers.com/~yawpower/rotcyc.html

Bill

 

How much hp are you gonna have if you get a bridge port done or a jbridge on a 12a and a 13b. Also are these only done for racing or are they streatable?

 

j bridge is not really streetable, the bridgeport well... some people to run bridges on the street but they are more so used for racing applications. but they do sound cool as heel stopped at the traffic lights

 

It depends on alot of stuff.A bridge can be sortoff driveable,if your running efi.A j-bridge is pushing it,seeing that its almost the same as peripheral.(which is not driveable at all)

bridge gives good gains, 260-280hp,if all the right goodies are used,even more for a j-bridge which is about 300hp

read the following web pages,it will answer all your questions
http://www.mazdarotary.net/porting.htm

 

NSU's came with Pports from the factory ... peripheral ports can be driveable ... its all down to design and what the goal is ... most Pports are for maximum power so they are not really streetable

Mike

 

Yip,your right !Some peripherals can be driveable(if the size is 30mm).The best bet for street is streetport.If you dont care about fuel consumption,a bridge will work great.

All depends what your looking for.

 

This is my favorite port

 

i delivered pizzas driving a peripheral port

 

are you serious? wouldent that be a total waste on gas? how big was the PP?

 

Woo-wooo...so not everybody just support Turbo?
PP...their fun to drive...!

 

what size holes did you drill the plates? I am definitely going to do this style of port, (reliability with the bridgy sound, yea!) also, how big did you go on the exhaust port?

I basically want a motor that builds power up to around 8 to 9K rpm, I have a 48 IDA weber and a custom designed exhaust. I am in the process of building a new intake manifold to bring the powerband down a little bit (long runners, similar to that of aircraft P-P engines that peak their power at 6k rpm)

any help would be much appreciated.

 

I just can't help but say how paradox that sounds. 1. You deliever pizza, hence, your not going to be too rich a person I presume. 2. You have enough money for building a P-port. 3. You have enough money to pay for gas driving around delieverying pizza.

I hope your pizza deliever business is oriented to people who pay extra money to get their pizza's REALLY fast->since you drive a P-Port engine!? You'd have to, to pay for the gas!

My bridgeport got ON AVERAGE 14.6mpg(hwy/street) If it was only street like in the delievery busness, I can imagine something more like 10mpg or so.