SoRRoW

Has anyone here done it personally?

Right now im street porting a friends 12A,I dont think a street port will give me what I want,I want to go out and just a bridge,Has anyone here done thier B porting thier self?Did you notch the rotor housing?


Im getting so tempted to do the bridge but the notch has me worried.

680RWHP12A

is this a daily driver? remember bridgeports dont like backpressure...... with a bridge, the less backpressure you run, the more power it will make , but the LOUDER it will be..... how loud can you go???????

SoRRoW

This was a $175. car..I can wrap it around a telephone pole and walk away with out any worries,unless I can get my carb/intake and other goodies off.

Yes I know it will be loud,my car is loud now,I own 2 other cars,I know I will need a 3in exhast,

I was askin in general of the notch cut outs on the rotor housings

12abridgeport

I bridgeported my 12a, only had it running for about an hour though cause i have low compression so i have to take it apart again. I was very surprised, it was pretty queit though even with the straight through exhaust but i have a racing beat muffler, also i left the sleeves in the exhaust ports. Doing a bridgeport requires a LOT more time and grinding that a street port. To make it easier i used a drill press to drill a whole bundch of holes through out each bridgeport and than aligned them. Also a little tip is to keep the grinder at an angle and always moving.

Directfreak

iTrader: (2)

SoRRow, the only make to make REAL power from a Bridgeport is to notch the rotor housing. The problem is if you go to far and hit the waterjacket. That can be fixed too, but engine life will be limited then.

If you're really worried, then just do a Big Streetport.

A bridgeport needs a different exhaust too, and a 3" is not the way to go. You need to get the headers that don't merge until the axle, otherwise your powerband (and power levels) will suck.

Also, DON'T Remove the exhaust sleeve. All the knowledgable engine builders around here know that those sleeves are too big even stock. If you make it too big, you will lose velocity, and again - power.

Good luck and take some pictures for us along the way.

SoRRoW

I was looking into bridgeporting,big street, or a j port..

J port is out of the book to much risky work..

Bridge port was fine untill I saw the notched housings which im sure RB dont give you a template for that.

Right now I have RB street porting templates..and race port exhast..I would NEVER take out the sleaves,that will give you heating problems.

I might just go with a big street..Ill make a temp template from the RB template,I will have to watch the markings on the plates to get an idea how far to go back.

I also have a road race header and can come out in to duals intill the rear end then single over..

Right now I have it "Ÿ" off abotu 15-18 in off the header...Then single over the axel 2.5 in pipes..

I cant remember if this was low eng torque or top end set up,I will ahve to look in my RB book

WackyRotary

Right here. And a word of advice, don't use it in slow/standstill traffic long periods of time unless you want to get sick. Also, and this is no joke, ALWAYS drive it relatively hard, low rpm causes more problems with carbon seals and the apex seals will stick from build up quickly if driven like grandma under 3500rpm for long periods of time. I always stay in a gear that keeps the engine above 3500-4000 or even above a bit for long driving.

And even a better reason to drive it hard all the time!!
->it gets the same MPG no matter how you drive - 14.6mpg. NO JOKE, I check it at every fill up! It almost never devates unless you drove completely on the street or completely on the highway. Even then, the improvement is like 14.7-15.1mpg only or 14.1mpg.

Mine has turned out pretty reliable lately. Apparrent luck? ...maybe, PREMIX..everything seems to last longer with that. They REALLY REALLY do make carbon seals last MUCH longer then Racing Beat/mazdatrix claim. Ask how I know.

Yes, Rotor housings notch matched to the bridge on mine. Bridgeporting is very time consuming regardless of your porting equipment so be prepared for 2hrs for each bridge alone. The aluminum is like butter, so cut slow with that. I left a 1mm before the water jacket on mine. This is a medium size bridge compared to some. I didn't want to get to crazy with the engine I use on the road. And for highway and rural areas like were I live, its a very drivable engine.

bridgeport link

RotorMotorDriver

iTrader: (1)

Nice new sig man!! Looks damn good...Maybe Ill start messing in photoshop soon too .

~T.J.

Rx7carl

Hey in case you didnt notice, 12abridgeport is in WP (Orlando). Maybe he can hook you up with templates.

Oh and the sig is nice

SoRRoW

Hey nice web site,Yeah I know all the down sides of bridgeporting etc etc..

Heres my thing,I bought this car 3 yrs ago to race,BUT I bougth 2 RX7S in one day,Well I have 3 cars right now,I dont drive the 7 much,and im in the process to buy another 7,I dont care if my FB is gutted and bridged,I can deal with the fuel consumption,Im runnign a 600 dbl pumper and dont get much right now.

Im scared of the notching,Other than that im scared of the speedign tickets I will be getting..lol

SoRRoW

The dam fonts came out blurry and im nto that good on photoshop,

it still took me like 2 hrs to do ..lol

And why wont it stay on my sig unless I click the box to show it?

SoRRoW

I hope he responds..dam I didnt even notice..

Thanks..

Im still scared on the notching on the housing part..

fatboy7

Ah.... c'mon, don't wimp out man, go for the gusto

680RWHP12A

an easy way to cut the rotor hsg. is to lay the rotor hsg. on the side hsg. , using a permanant marker draw a line on the rotor hsg. following the bridge you made in the side hsg. cut the rotor hsg at a 45 degree angle to get the best flow... using a flashlight look in the intake runner with the rotor hsg. in place... there should be a smooth 45 degree angle all the way in the motor for the best power...

SoRRoW

Do you know if you get this as a template also with the RB BP templates?

rotarygod

iTrader: (1)

Are you going to use stock apex seals? If you are then the small triangle piece will fall into the bridge if you notch it. If you are using one piece seals then disregard this.

SoRRoW

I was looking into the Atkins 1 peice,

I want to stay with steel seals though,

DOES the notch have to be there?

peejay

The relieved rotor housing doesn't HAVE to be there.

You can't have both sides of the rotor housing relieved if you have stock 2-piece (or 3-piece if '86-up) apex seals. The corner piece acts as the final 1mm or so of the sealing surface, and if it's relieved where the corner piece is, it can fall into the port. Bad things ensue. Traditionally when stock seals are used, only the front and rear ports get relieved, the center ones stay unrelieved, and the rear apex seals are flipped around so the corner piece is against the center housing.

The Hurley style seals would work with all four ports relieved, however general consensus is that they suck - they eat housings, they don't last very long, and the long piece breaks easily due to being too short and thus being inadequately supported as it sweeps over the exhaust port.

WackyRotary

You should go with carbon seals! You'd be surpised how long carbon apex seals can/will last if your experience with them are anything like mine. They are softer then steel obviously, but if kept lube'd with 2cycle pre-mix, they seem to last and last. I think the key is having near flawless housings so they don't get abrased from imperfections in the housings. I have just under 25,000miles on my carbon seals. Hows that for advertisement for Racing Beat!? I drive it hard all the time, no problem. I have had a failure 6000miles ago unrelated to the seals though. A stationary gear failure. Took out the rear rotor too, but no other damage. Got another rear rotor from Mike-128.

So my opinion on carbon seals is they are great as long as you keep the revs up, they don't seal well below 3000rpm, but part of that will be contrubuted to having the overlap of a bridgeport.

Rota_Motor

umm a small bridge that doesnt extend past the edge of the rotor housing wont need the housing to be notched.

around here with most of my friends, a bridge is only to the edge of the rotor housing, past the rotor housing like these are counts as a J-port, but onlt up to the water seals, past the water seals becomes a monster port.

dont waste your time tho, and go for a nice big bridge.J-port, you know you wanna, like other said, cut the bridge sio its angled back towards the intake, have heard anything 30-45 degree angle, and then notch the housings to match the port you cut...

oh then twin system, probably 2-21/4 inch to the diff then into a single 3 inch muffler, loud but best powwer from what I hear...

peejay

That's odd. The reason a J-Bridge is *called* a J-bridge is because it extends into the water jacket, hence "J"-Bridge.

Directfreak

iTrader: (2)

Yep. A "J" goes into the waterjacket which is then sealed off. - Usually Devcon or something similar. This is why J-bridges usually fail from a water seal going bad.
Maybe they call them differently down under?

Rotortuner

How is the startability? I just blew my PP engine and im going to be rebuilding it and i want to go with the carbon seals but im kinda afrain about the startability due to their bad sealing at low rpm. Also how do they do over REALLY BIG ports? has any one had trouble with them breaking in the middle?

CJG

SoRRoW

Ok so I guess step 1.

Get the template,
Check to see how far the bridge go towards the water seal.

If I have to notch it,where to notch it.

I wonder instead of notching on BOTH sides of the housing,BUT ONLY on the center plates side,with the seals flipped so that the triangle/apex seal is AWY from the notch will still produce nice HP gain,OR will it just be shitty.

Cause notching it CLOSER to the center plate,would help the intake MORE then notching it TOWARDS the end plates..


Im sory to confuse you guys,you probally wont understand unless you ave seen the inside of the engine.

I still want to see a nice pic of the notch on the housing,cause im not sure if I have to leave a lip on the cutting side before the seal or what.

REVHED

If you're going to run the stock apex seals you want to flip the seal around on the rear rotor and notch the housings on the secondary (end plate) side... not the intermediate plate. Well that's how it's usually done anyway.