Finally finished nyt's front secondaries today. I also bridgeported them and matched both the BP cuts and the port outlets to the already done rear ports. Link to the folder of all pictures:



http://bdc.cyberosity.com/pictures/RobertMosher



Here's a few pictures:



http://bdc.cyberosity.com/pictures/R...Secondary1.Jpg



http://bdc.cyberosity.com/pictures/R...Secondary2.Jpg



http://bdc.cyberosity.com/pictures/R...Secondary4.Jpg



http://bdc.cyberosity.com/pictures/R...Secondary5.Jpg



http://bdc.cyberosity.com/pictures/R...Secondary3.Jpg



B

very nice brian. i cant wait to see the car running

I love thoes backlit pics. Really shows the port well.



Your ports look killer man! Great work!

NICE JOB https://www.nopistons.com/forums/pub...1047683894.gif

Thank you.



You and me both -> First time to do a half-BP on a 13BREW motor. I'm interested to see its torque and horsepower curves.



B

Come on chicken. Ok, just go out 2mm more. Next time try angling your port at about 30 degrees through the plate. You can also try leaving some material on the backside of the bridge so that the bridge port actually catches more air. If you look from the intake manifold side it looks like a flap hanging out. leaving this extra material also makes the bridge stronger, so you don't have to worry about it breaking out. That's alot nicer finishing work than what is in my motor. Of course I'm not doing it for anyone else but me anyway.

Thank you. Glad to hear that from someone in Japan who is around this all the time with the best of them. https://www.nopistons.com/forums/pub...IR#>/smile.png



B

Chicken? Nah, it's not about being scared; it's about applying certain theory and ideology to this stuff. I very well could have angled the port outlets on the secondaries to be at a considerably more obtuse angle but I chose not to. The port opening timing has been extended but not a great deal. Considering the use of the vehicle (still being comfortably street driven), I felt this as well as leaving the primary port outlets small comparably speaking was a good compromise for gaining benefits of the bridgeport style of intake port along with retaining a fair level of streetability and low-end torque. You guys in Japan may have more experience with that, but over here in the states there's not many folks who run turbocharged, half-bridgeported or full-bridgeported 13B's on the street.



On the bridgeport cut comments, I left 9/64" of bridge iron in the shape of a wedge instead of that of a rectangle (which is difficult to see). I don't believe there will be a strength issue with this thickness and shape. I've seen bridgeports done with substantially thinner iron bridges left over after hogging everything out that still withstood boost up to about 26psi on a fairly large turbocharger (Turbonetics T70).



As far as scooping more air in, I also ramped the underside of the port tunnel behind the bridgeport cut just for that very reason you eluded to -> make the bridgeport cut less turbulent and more efficient at 'scooping' air in. You're right on that, by the way. The way some people do BP cuts is by going down and leaving a port that's exactly 90 degrees adjacent to the port tunnel just below it and I feel that that doesn't make much sense.



The finish of the port outlet and tunnel is left somewhat rough on purpose (as you can see in the pictures). Having a slight boundary layer in the intake ports has been proven to better distribute and mix and air/fuel mixture as well as produce higher power, everything else remaining constant.



Thanks for the vote of confidence. https://www.nopistons.com/forums/pub...IR#>/smile.png



B

Correction, I meant to say port closing timing on the secondary port outlet; not port opening timing. I kept that almost the same minus matching the nitride facing to the cast iron port.



B

Actually the I was not refering to port closing, I was referring to cutting the bridge port down through the plate towards the port inlet at a slight angle. Your bridge iron is actually thicker than most I've seen. I just added that by leaving it thicker and shaping it you can benefit. It also seems to me that most bridge's I have seen are cut at a 90 to the runner and it doesn't seem right.



Basically I just put the info out there for everyone. I can't stand when people don't share info. I run across this alot in Japan.



The chicken comment was all in fun. Whenever I port something I always have someone calling me a chicken(Dragon and a couple of others not on the forum).



As a side note, all these people that say the secondary bridge is not going to drive as nice, you are way wrong. My car actually made more low to midrange torque with the bridge than with the side. The only reason I don't have one now is because they are to damn loud for the cops and my neighbors.

Ok. I must've misread part of your post, then.



On the bridgeport 90 degree cut, I absolutely agree with you in the gut feeling you've got in how it does seem wrong. With regard to fluid mechanics, it's most definitely wrong. https://www.nopistons.com/forums/pub...IR#>/smile.png I suppose the best way to do it would be to use a press to cut the bridgeport cut itself at an angle, similar to that of the port outlet. This is why I taper and wedge the underside of the iron (just below the water jacket o-ring land) prior to the bridgeport cut to help make it 'catch more air' as you suggested in your prior post.



I figured you were playing around with the chicken comment. I do stuff like that here w/ my friends all the time. https://www.nopistons.com/forums/pub...IR#>/bigok.gif



You know, alot of those naysayer types are the guys that have never done it and have no reason or technical knowledge to back-up what they say. I've run into it so many times myself with all sorts of things:



- "that air to water intercooler won't work. it's not streetable."

- "that turbo combination is too large and won't work for drag or make power."

- "you can't make a bridgeport streetable w/ a turbo".



Baloney! https://www.nopistons.com/forums/pub...1047683651.gif



B

I actually use a hand drill to the same effect.



What turbo is going on this setup and what is the target?

I'm not sure what turbo Rob's going to be using. I think he's got a TO4S derivative at the moment but I told him it'd be too peaky up high and run out of steam.



Power goal? Good question...



B

B: next time you come up you can use my Drill press

Thanks, amigo.



I really need to buy one. I've been eyeballing one on Harbour Freight but I'm not sure if it's too cheap or not. Got any suggestions on a good one I can save my pennies up for?



B

The Harbor frieght unit is decent. You can pop out the cheap chineese bearings in the drill head and replace them with some decent ones, Scalliwag has done it.



PS did you ask scalliwag about the press pieces for me?

I haven't talked to Mike since you and I talked last night. He had to go to bed early; he's one of those types that has an 8 to 5 day job. :p :p



B

Igy;s talking about cutting it like this.. and not like the second drawing.. The second drawing is the way you will see most bridge ports cut even though that way sucks and won't produce the power that could be had if the port was cut the right way..



LOL.. this was a really quick pic...

Absolutely agreed and good illustration even if it was a 5 minute job. https://www.nopistons.com/forums/pub...IR#>/smile.png The picture illustrates well how the cut itself needs to be drilled and made initially.



B

yeah my 7:5 job interferes with my Rotary endevors



Good point made on that sketch IGGY

https://www.nopistons.com/forums/pub...1047683894.gif Dragon and Iggy have alot of experance, can lean alot from them

ya...and they're funny as hell in person too.. https://www.nopistons.com/forums/pub...O_DIR#>/11.gif

Can't wait to see my BP plates Chris https://www.nopistons.com/forums/pub...#>/biggrin.png Better yet I can't wait till it is all in and tuned!

Thanks Chris. I was to lazy to go through the hassle, and I figured BDC knew what I was saying anyway.

Tell him you want your port bigger than mine. Who is doing the exhaust port?

Ok gopher!!

IGGY got any pic's of you BP? I need as big as I can get to spool the t-88!

Are you guys in the military stationed over there in Japan?



B

Igy and Dragon aren't stationed here. I am https://www.nopistons.com/forums/pub..._DIR#>/sad.png They both used to be though...

That's Mr. Van Diesel to you!

That's Mr. Van Diesel starring as "The Gopher" in the critically acclaimed action thriller "The Shop"!!!!!!

lmfao!!!!



I'm not an rx-7 driver, but I pretend to be on in real life https://www.nopistons.com/forums/pub...IR#>/boink.gif

I get to port those when I get over there.. He's already got a small port on them, but I'm going to open them up a cm or so.. https://www.nopistons.com/forums/pub...DIR#>/cool.png

lol.. the Gopher... The Gophers main job is to Gopher parts, Gopher food, Gopher give me a 10mm.... he's moving up in the world however and now has his very own sub Gopher getting **** for him... My new personal nickname for the taxi is squire by the way.. I thought tool bitch sounded a little harsh... https://www.nopistons.com/forums/pub...#>/biggrin.png

No worrys, your bridge port will be kicking that T-88 in the ass...