don7

how is the Peripheral Port diffrent that a bridge or street port? what is the process in doing it, also what kind of performance gains does it produce?

what does the finished product look like? pictures would be great

91_fc

i think that periphrial ports are just the location of the port. when you get it a block ported they shave off metal around the port. this changes the timing of the engine and also allows the power to be increased.

BigTone

Periphrial ports are race only ports. In a periphrial ported engine, the normal side intake ports are filled in and a massive intake port is created on the rotor housing much like the exhaust port. Periphrial ports have massive power in the upper RPM band, dont idle very well below 3000rpm and can easily spin to 10k and above.

he is quick link is a small picture
ehh link didnt work.

Digi7ech

iTrader: (1)

P Ports are insane.
There is no longer a side intake. They drill a hole in the side of the housing and it is a direct entrance.

Racing beats housings were crazy when I stopped by there at Sevenstock.

The water jacket is compromised and they fill it in with a putty stuff to seal around it. That's one of the main reasons why the P-ports don't last long.

I forget HP amounts but it's big. Also Very non streetable. Like a 1.5k idle at best.

here is RB's housings. The silver intake on the top left is it.

SpeedFreak03

holy **** that is one huge intake! I can tell why they aren't streetable...!

Joshshift

they dont fill it in with putty, its called devcon.

peejay

I'm sitting out on this one. I'll just fire up the popcorn popper and sit back and watch. Who wants extra butter?

j9fd3s

iTrader: (3)

me!

wwilliam54

they arent streetable

but you can drive em on the street

PDF

I have 4 pp's on the road, number 5 will be joining them very soon. The oldest is a 12a pp I built 2 1/2 years ago and is a daily driver. It still starts and runs as well as it did when I built it. Flat 13's in street trim.

peejay

SHHH!!! Don't tell anyone you're driving a PP on the street! Remember they idle at like 5000rpm and don't start making power until like 14,000...

PDF

...and they last for a whole 6 months before needing a rebuild

Tugboat

I've always wondered about the reason for the side intake ports. I don't know about the effect on seals, but the port size and timing are the factors determining the powerband. Model (O.S.) wankels don't use side porting and they're docile.

Thanks

peejay

Same reason Mazda went to side exhaust ports: Less port timing for similar port volume/opening area.

Downside (for intake) being that during the opening phase of the intake port, it be quite difficult for the airflow to make basically a 180 degree turn followed by a 70-90 degree turn downwards. Bridge ports help this greatly, and peripheral ports solve it completely.

Tugboat

OK, that sounds logical. Why not use both for max area?

Thanks

peejay

It's not really "max area", a race peripheral port barely has more port area than a stocker. However, the port placement is more avantageous for VE, at the expense of having far too much overlap to idle well or cruise well.

NSU used small peripheral ports on their production engines. Their solution to the idle/cruise problem was twofold: first, they used an automatic transmission (semiautomatic, actually) so the torque converter would take up the low-end slack, and second, they used a smallish (10A-sized) engine in a heavyish (FC-sized) car for the Ro80. So the engine is under fairly heavy load.

Still, that little engine made a peak of ~120hp at only 5500rpm.