SavannaRX-7

which one has more power? and reliable?

Marcel Burkett

Semi PP.

SavannaRX-7

thank you!!!!!

osdesigns

What is it mean by Semi Peripheral port? Is it a smaller port on the rotor housing? Less port timing?
Anything smaller than a regular Peripheral port, should not make more power than a full Bridge Port.
Full bridge port will give the engine broader power band, and more flow.

However, if your Semi-Peripheral-Port is done by keeping the original side ports, and adding two extra smaller ports on the rotor housing, then, It should make more power in the case of Force induction.
This is also known as the "Cross Port" in Japan.

Marcel Burkett

I think he wants to compare a semi pp and a half bp , not a full bp.

2a+RoN

and yes, i think he is speeking of the japanese known "cross port".

RX794

I'd rather go with the semi pp than a bridge.

pp13bnos

iTrader: (1)

A peripheral port motor will make more power, and is more reliable. How many people have actually owned a PP motor here? CJ

banzaitoyota

IF mine is ever shipped I will!!!!! Hopefully it comes ported this time!!!!

osdesigns

Peripheral port engine is NOT more reliable than bridge port engine, or vice versa. It all depends on how they are built.

RX794

A PP engine IS more reliable because the side seal isn't under any stress like a bridge ported motor, it's held in better with a PP, less wear.

pp13bnos

iTrader: (1)

Not to mention, with a full PP motor, you don't get a low RPM "bucking" as with alot of large bridge ported motors.

Also, you don't have to worry about water seals leaking where the bridge port is located. Who all has owned and daily driven a PP motor here besides me? CJ

Jay7 Nyc

iTrader: (3)

Who is a well known engine building to contact for a nice semi PP? Anyone on the East coast?

Rotortuner

I have owned one. Mined bucked quite a bit, but i think, if they are built right, they can be more reliable than the bridge engines.

CJG

t-von

iTrader: (8)

I though PP motors had really lumpy idles and no low end?

pp13bnos

iTrader: (1)

I was making 130ish rwhp@4,500rpms and nearly 150ftlbs of torque@4,500rpms.. Thats more than a stock 2nd gen puts down at peak power. Also, a bridge port motor still has a lumpy idle.

CJ

2a+RoN

pp13bnos, did you do your PP yourself? I was wondering how about to insert the new port sleeve so that it would be tight. What kind of material is it? aluminum? Where could I get some that would fit for making a cross port?

Thanks,
Aaron

SavannaRX-7

the reason i ask because my friend is doing a semi pp this weekend, it should be done in two weeks.

RXTASY1

Taken from Rotary Illustrated.

Bridgeports are simply a large port that uses a "bridge" to support the rotor's corner seal, thus preventing it from falling into the port and ruining the engine. Since the port goes all the way out to the trochoid surface, there is significant overlap with the exhaust port, reducing low-RPM power in favor of significant power gains in the high-RPM range (5,000+). Sometimes a bridgeport will extend slightly past the trochoid surface, requiring a notch in the rotor housing, but the water seals are not compromised. Of all the racing ports, this design is the most streetable and minimally impacts engine life.

J-ports are basically a bridgeport that extends well past the trochoid surface to the point it does compromise the water seals. The goal is more power at the cost of engine life -- a classic racing scenario.

Monster ports are like a J-port, only so large that they go well into the water jacket and require significant filling of the passages, cutting of the rotor housing, and other measures to allow it to work. As some of the coolant passages are actually filled, engine life is further compromised. Monster ports were developed to give similar characteristics to a peripheral port, where racing rules in some classes prohibited the latter.

Peripheral intake ports (not pictured above) are simply a big hole in each rotor housing (similar to the exhaust ports), with no side intake ports whatsoever. Contrary to side port designs, timing is determined by the apex seal rather than the leading edge of the rotor. This results in massive intake and exhaust overlap and subsequently very little low-RPM power, but the direct intake path permits incredible high-RPM power that typically peaks well over 9,000 RPM. A peripheral port (PP) engine can develop over 300 hp in a non-turbo application, but is not what normal people would consider "streetable" (but some do!). The water seals are not compromised, though some of the coolant passages are blocked by the intake passage (but to a lesser degree than Monster porting) -- the engine life is reduced by virtue of stress from high-power and high-RPM operation, but not so much by coolant leakage or hot spots around the intake area.

Marcel Burkett

Semi pp and half bridges ARE NOT the EXTREME versions of either , they are both "a compramise " so that a bit of everything can be had on the street , that is power , torque but to a lesser degree efficiency and reliability.
A half bridged motor used in this way (street with some strip) rarely ever fails due to cracking of the bridges , they hardly ever get to spend much time high up in the rpm range when on the street, however if the bridges are cut rediculously thin (and the builder a **** SNAKE )then wether its street or track , they WILL break eventually. Loss of low rpm torque is evident if you try climbing steep hills in the higher (wrong) gears at a slower speeds. In normal driving this is less apparent , because the motor goes through the rpm's so quickly that you are always in the "power band" if you shift when you should . I get to 9000rpm in 1st in seconds with the BIG turbo (TA51) getting well past 15psi boost ,and thats without a boost controller.
The semi pp motors dont have any bridges to crack , but if not done properly , they can leak coolant , but all thats required is taking them apart again and redoing the job. The mini pp's flow more than the small bridges of a HBP motor , hence the reason for more power .
Both versions call for larger than usual (street port) turbos , which always equals more power with less boost.
My next motor would be a semi pp , with the LIM and matching Holley ctile Tb from Pro Jay .I am however , EXTREMLY pleased with the performance and power of my Half BP thus far , If I could go back I wouldn't do it any other way .

t-von

iTrader: (8)

Ooops...when I said low-end I ment performance below 4k (daily driving cruising range).

pp13bnos

iTrader: (1)

A pp motor usually idles around 1400-2k rpms. (My efi PP motor idled around 1400, and my Carbed motores where allways around 2,000ish.) Cruising RPMs with my car where allways 3-4.5krpms due to low gearing. (.444s & .488s.) Hope this clears up some stuff. CJ

RX794

Judge Ito is the only person on the east coast I would reccomend as far as building a PP motor goes, problem is he's a one man shop, and really backed up with work.

re10

I have owned a 13b-PP, 12a-PP (very briefly ) and a 10a-PP (current motor). As someone mentioned, they are reliable but only if built right, and they are HEAPS of fun.

Lasse wankel

I have only owned one PP (in an RX-3) but i estimate i have built 10 13B PPs from 274 to 313 hp! One with a 40 mm throat idled at 1000 rpm no problem with a fine tuned Weber 51 IDA and took full load at 1500 rpm,really cool engine!