rotarycrazy

iTrader: (8)

Ok here is my question how streetable is full bridgeported engine vs half bridge.
What cind of engine life can I expect from bridge motor. Becouse I am picking up a 1980 SA with 12A in it that need a rebuiltits not blown it just leeks oil and its bin siting for 3+ years. Once I get it I will bridgeport it and then put S5 turbo with ported wastegate on top of that. So if anybody could help me out with this simple dilema I would gratly appreciate it. And what cind of power would I be looking at with this set up.

Thanks a lot for any help.

Mindaugas

theNeanderthol

iTrader: (1)

I think you would be looking at a non streetable, but plenty powerful motor. You can probably get a good 250 - 270 maybe 280 hp from a bridgeport without the turbo. But you will have a shorter engine life 50,000 miles I'd guess, and a cool sounding, but rough idle, about 2000-3000 rpms. Id's say go with a streetport and turbocharge that. Plenty of power and longer life with better streetability. A well tuned well setup rotary can take A LOT of boost.

trochoid

iTrader: (6)

I can set the idle on my 1/2bp-1/2sp at 800 rpms. Sounds more like a bp at 1k though. You should be able to get a full bp to idle around 1500, maybe a little less.

steve84GS TII

A full bridge is not as sutible for turbocharging.
The more porting you do,the more RPMs are needed to utilize that port volume.Typically,carbon apex seals are needed to safely travel into those higher RPM's,(8000-9000)...and turbocharging with carbon apex seals isnt a good idea.They arent nearly as robust as steel seals,but their light weight is ideal for high RPMs.Ceramic seals can satisfy both requirments,but are much more expensive.

Turbo engines typically specialize in making midrange and factory redline highend power(7000-8000).Thats why most turbo guys are running stock or streetports.The factory steel apex seals are safe up to 8000RPMs and are much more resilient to detonation than carbon seals.

If you do a half bridge with steel seals, then turbo the engine,youll retain more lowend and midrange grunt,but still breathe very well on the topend.Youll just be limited to about 8000RPM's.For the most reliability,Id stick with streetporting if your final goal is forced induction.Youll be able to keep the strong 3MM steel apex seals and you wont have to worry about the water seal failures that are common to bridgeported engines.

rotarycrazy

iTrader: (8)

One thing for sure I need this thing to be drivable and have about 300hp becouse it will be driven everyday until I get a different car. You think I would hit 300hp with a streetport and if so how big do I need to go?

PaulFitzwarryne

I go along with Steve's excellent advice.

Streetported turbo will get you 300hp flywheel.

It will be just streetable in light traffic. Noisey and lumpy. Engine life will be around 50,000 mile if rebuild done with care. Clutch wear may be a problem in a daily driver, so check out what is available and match it to a good flywheel. Expect fuel consumption to be around12mpg, probably less if you have a heavy foot. Might be difficult to get it past the authorities in many states.

LokiRx7.1

iTrader: (1)

Speaking of engine life and not to go off topic, but I've got a J-bridge and its still alive and strong at almost 100,000 (thats how much mileage I've accumulated since the rebuild and port job) someone told me my engine would be thrashed a long time ago. I bought the car cherry at 42,000 Then I totally rebuilt the motor, ported it, and threw it together I dont drive the car daily but every so often I take it out and run the **** out of it. Maybe I'm lucky? I'm a new member but I've been reading these forums for years now

BlastinSideways12A

Streetable 300 HP setup? TII engine with a slightly larger than stock turbo. A 12a will take more reliability mods to hold up to 300HP worth of boost. This is coming from someone who is building a boosted 12a and has a TII engine.

Cruspeed-RX-7

I can tell you with the 1/2 bridge then winter sux my 1/2 bridge has a horrible time in the winter...besides that streetability isn't a problem and I have had a few minor things like fuel pump issues and getting a good tune on it was a bitch

rotary emotions

Don't forget that the "bridge" in a bp engine isn't the strongest point of such a setup. It tends to break in turbo configurations.
Other then that, a good tuned BP shouldn't idle all that rough once warmed up. A lot depends on how far you extend port timing (opening/closing of the ports, can be compared with valve timing by the camshaft in a piston engine)
Even PP can be streetable, but not with huge port runners of course. And one thing to be aware of: a lot depends on what is considered streetable

WackyRotary

I have run a bridgeport 12a. Seriously, don't do it. Streetport+ turbo. The bridgeport had no torque at all. Its actually pretty slow unless you rev it way the hell up-its a narrow useful powerband, and its loud as heck if you use the power it has. And, driving it slow doesn't seem to give good milage due to all the overlap. Turbo, you have a broad powerband-ablity to keep noise levels in check. No need for fragle carbon seals.

rotarycrazy

iTrader: (8)

Cool. I just needed to know before I stuck my money into the motor and then regret it. For the reliability I will do quite a bit right now the motor has everything stiped off of it. It has the carb alternator and the distributor and that is all. A/P, A/C rats nest all that is gone.

My plans for the motor is to geti t rebuilt with the good port job all new rotor seals, Light flywheel street/strip clutch GSL-SE rear diff and some stronger axels there a shop near my house that will do it for about 200 per side, 2gen ignition set up biger fuel pump all the necesery gouges, bigger antisway bars with poly bushings and lowering spring with good shocks stuff like that.

Other question how stong is the transmision in SA I know that the one in there has bin rebuilt about 1000 miles ago the guy showed my the bill for it. Only reason I am asking that is becouse it has 15/8 wheels all the way around he has 195/40/15 tires on there but they will hold a 225 tires so my question is how long is it going to be untill I brake something related to the drivetrain.

FIBREMAZ

Save your money and get a PP. You will get sick of the bridgie in a few months. I drive an EFI 13bPP sa22c on the street

steve84GS TII

If your deadset on forced induction,then yea a streetport is all you need.400+HP isnt an issue even with stock ports.Thing is,porting doesnt play nearly as much role when your forcefully cramming air down the engine's throat.
Its just a matter of balancing boost pressure with port volume/timing.You can continue to make power with stock ports by simply increasing boost pressure...to a point,because the more you compress,the hotter the intake air becomes.Then you have to cool it back down.You intercooling needs go up as boost pressure goes up.
Boost is a measure of resistance placed on the air going into the intake system.The resistance is the closed intake ports.The amount of air that actually makes it into the engine for the intake cycle is determined by the boost pressure AND the port's timing/volume.More boost isnt always better.You can relieve the restriction by porting and make the same power,with less boost pressure/intake heating.....but then,its also to a point.If you port too much,then you start to suffer from bad lowend and intake dillution,ect...the stuff that big port N/A guys have to deal with.
If guys can make 8 second and faster 13B's that only use a streetport,I cant see why anyone would want/need bigger porting....except for a cool idle and a more ON/OFF powerband.

kenn_chan

I am with steve on this one, the only good thing about a 1/2 bridge on the street is the "brap brap brap pshshsh, brap brap pshsh" that scares the **** out of non rotary owners other than that a mild street port will get you your HP and last a lot longer (plus better mileage)

Kenn