here's the deal. everyone knows what a bridgeport is, there is an eyebrow added and a bridge made between the two ports. well, instead of going so extreme as a bridgeport, would it be possible to just put 2-3 small round holes where the eyebrow would be? i just thought this up one night and was wondering if it would do any good or have any significance. possibly more reliable than a bridge with faster spool than a large street?

 

Yes, but the gains are MUCH less than even the small water seal preserving bridgeport which is much less than a real racing bridgeport....

Racers tried this and many other strange ports trying to get around the streetport only ruling in E-Prod. Finally it was ruled that if the juntion of the sideseals to cornerseal or above was exposed at any time it was no longer a streetport. They pull the intake manifolds and check via the port runner w/ mirror/scope.

 

that would actually make you lose power. they wouldn't flow enough to have any significant gains, but they'd screw up the idle and off-idle drivability, THEN they'd screw up the flow in the top end from the extra turbulance.

 

How about just a smaller "eyebrow?"

-Alex

 

you could do a half-eyebrow. i usually do them at the top for a little less overlap and a little better gas milage (my friend got 21 mpg fwy with a port like this in his fc). doing the bridge on the top half only also makes it a little less touchy for tuning

-throttle pumps don't have to be so high
-not as much misfiring at very low throttle positions (by comparison anyway)
-fuel economy was already touched on
-fuel map is a little bit more linear compared to a big bridge (but still not as much as a street or stock ports)
-room to grow later...


in the port in the pic, you can't grow much more because i pulled the bottom of the port out towards the wall. i did some coloring on the other pic to help you see why. basically, the red line is...well...the red line. can't go past it.

 

Hmm, Guitarjunkie did you burnish the top of the port to harden/smooth it for the sideseal- I did that on mine and it looked like yours.

 

i always radius the closing edges.. helps the side seal and flows better.

but on the bp's, i don't pull the opening edge of the main port out very far, but since only the upper half is done on that one, i had enough room to do it with the bottom of the port.

 

Yeah, the radius just looked burnished instead of simply polished.

 

is there a difference?

the very closing of the port is a mirror finish.

 

Dave's (guitarjunkie) **** is top-notch folks, he's been at it for a while. He's also one of the people that will give away his secrets! haha. Hey, what do you mean by giving the closing edge a "radius"? Is that where you rounded it off just a little?

 

what secrets?

most of what i know i learned either in books, trial and error, or on the forums. my angle is if you want me to do your stuff, it's because of my charming personality that, and maybe you don't have a few thousand dollars in equipment...that helps too. there are guys who know a LOT more than i do, then there are guys who know jack ****... i like to think i more or less know what i'm doing, but i'm always learning. once you stop learning things, you should just quit.

but yea, the round part at the port closing edge is the radius. i did that to my last set of rotors that i'll be putting in my fd. we'll see how well they work.

 

is there a difference?

When you burnish a "burnishing needle" of harder material is rubbed over the finely polished surface and it work hardens the material, closes the grain structure and smooths it over. Lower friction surface is achieved.

For instance the back edge of a Japanese sword is burnished for a faster draw out of the scabbard.

 

oh cool...but do you need to worry about that level of friction when it only comes in contact with air?

 

I put the radius in, scissored it all the way to the end and burnished it because-

More than air was hitting it!

It was an early opening port that dropped the leading sideseal end into the port and sideseal strike was apparant on the housing and the chipped worn sideseals as it was ported by a big name shop. He said it should of had at least a radius.

I cruised it alot ~1,000rpm because of the low rpm torque and sideseal strike is worse at low rpm so I tried to minimize it.

 

Damn that's good.