Just curious, with the SP, BP, and PP.. how much harder or more worse is it when you go up in porting levels in terms of daily driving? I know SP is perfectly fine, but once you hit BP or PP.. how bad is it, and how so?

 

SOYCH NOOB!!!!

 

Just compare the BP to a piston engine with a much larger cam. Poor idle, poor fuel economy, etc..

A PP would be a piston engine with a god awful cam in it. Meaning it would have a real choppy idle and you would have to turn the idle way up to keep it from dying. The fuel economy for the most part would go way down.
Not you best choice to use for a daily driver.

 

shove it

 

I figured that much about the PP, but in terms of bridgeport.. is it something people have been able to live with? I'm sure it kills your mpg incredibly but, is the power difference between the SP and BP worth it for what you lose in mpg and constant harsh idle?

 

I wouldn't worry so much about MPG as I would actual drivability. Yeah there's people who have done it but I don't think it's recommended. I think a 1/2 Bridge is about as big as I would go for DD and that's still pushing it. The problem is the powerband shifts into the upper range so street driving is sacrificed quite a bit. Below 3k RPMs it'll buck and bog basically while trying to cruise. Not to mention, the bigger the port, the louder it gets

 

I see. Well, street port it is. Thanks Firebird.

 

No problem. I'd seatch into a Judge ITO streetport, still streetable but with a little more aggressive power band and the sexy brap of a bridge LOL

 

hahaha really? I've have to look into that, thanks for the advice!

 

I like '74 spec for a daily driver.

 

I agree with a BP & PP being off limits for street useage normally.

However a Piston engine with a wild cam will idle rough,but smooth out just above idle.Now with a Rotary the reversion makes it allmost no fun to drive at light(small)throttle.The more load you put on a heavilly ported Rotary at lower rpm,the smoother it will be,or select a lower gear,and get the RPM up.It bucks severely when the piston engine just lacks in torque.

Karis

 

lack of low end torque will kill you....thats why you add forced induction

 

I used to run a 12A with a 1/2 bridge on the street and it was fine. I just learned to keep my foot into it a little bit. Yes it did buck a fair bit under the 3K rpm range but it also did that on the highway at cruising speeds. It seemed to like WOT more than anything. I know have a 13B peripheral port on the street and i have it idling at 1100 rpm and seems to work pretty well. That engine has no power below 4K rpm but once it hits 4K its like a turbo that just spooled. haha. The 13B-PP bucks as well doesn't like cruising again likes the WOT.

If your worried about fuel economy than RX7's arnt for you. haha. Who buys sports cars and then are concerned how many mpg your going to get. Its kinda like a drag racer concerned about tires.

 

what size diameter intake ports on your peripheral port blown7? and did u optimize the exhaust system for peripheral use yet?

does the pp kick and buck less than the bridgeport? never drove a pp.

 

I actually stated, if you read correctly, that I did NOT care about fuel economy. I just wanted to know the views on these two portings for daily driving. I think im gonna talk to Jeff20B about that 74' spec.

 

Cbz, yes i did read your post those comments were ment as a broad statment. As i can see you like to drive your car and that is why most of us bought our cars.

Drivefast7, yes i have a dual 2" exhaust system on the car now. I have yet to tune the weber as that will be done this winter. The port size is 44mm with a D shape port inside. Going to be installing a turbo II transmission, flywheel, and clutch since i kinda broke some things last race of the year.

 

I see. sorry for the misunderstanding, and yes of course I do love to drive my car. I honestly couldn't be more happy without my FB

 

I use a half bridge for six months of the year during autocross season. By late summer I'm tired of driving it because it is so much drama. The idle is loud, normal driving is loud, and it hates light throttle. When the cold weather arrives I install a standard port engine and I love it. I'm sure come spring I'll be dying to put the bridge back in.

 

Don't do a BP or PP unless you are using it off the street.