What type of performance advantages would this create as opposed to bridging only the secondary ports? Has anyone tried this and tested it? What would the torque look like with the primaries bridged and the 2ndaries opened with a street port.

 

I was thinking about this...

My theory (ugh) is that you could have increased smoothness at low throttle openings, because the manifold pressure (absolute) would be higher during overlap as opposed to a secondary bridge, so there'd be less exhaust dilution (due to exhaust gas pressure higher than intake manifold pressure and therefore being pushed up into the next chamber)

Just a theory though, haven't tried it.

 

I wouldn't do it. Just a personal opinion though. My reasoning is this: Ovelap will be the same regardless of whether it is primary or secondary. However the intake runners are larger on the secondary ports than the primaries and thus flow more air. Bridgeports want a less restrictive flow. You could also make a taller bridge on the secondaries than the primaries if you wanted to. I am basing this solely on flow amounts.

 

Interesting idea, I don't think it would make much more power though and it would definitly idol like a bridge port.. I think you'd get more power running a good side port and porting the exaust up a few mm's instead..

I wish I could bring the side port up about 5mm's... Damn corner seals...

 

yea, I am talking in addition to a monster street port on the 2ndary intake ports. If noone has tried it ill designate myself to be the test monkey. I dont see any loss on power or drivability so......

 

Your still going to have overlap from the primary bridge so your idol is going to be around 1300-1400 rpm and it's going to lope pretty good.. Are the cops in your area pretty cool?

 

Love the bridgy idle, and they dont harass loud cars here, you should have heard my first S4 Whoa!

 

LOL.. cool try it out and let me know how it goes...

btw.. did you get me a price on the thing I wanted..?

 

Hell, if it doesn't work out, you have half of a full bridge port ready for ya

Judging from what I've seen, the partial bridge on the secondaries is the way to go... You still get tollerable low end due to the unbridged primaries... well, if you remove the secondary plates in the TB, its practically the same thing (minus the smaller intake runners on the primaries). correct me if I'm wrong...

 

this is how i have my car setup Greg, my car is automatic so my dyno sheets would do nothing for ya but it seems to have more top end than a normal monster street port . my car is setup/designed for the auto and this is why i did it. it is hard to spool the 76 up on the transbrake with a full bridge so i tried the primary only and it works!! and the idle is ******* cool!!


MWW

 

thats just what I wanter to hear, someone that actually done it and has results! Thanks alot amigo.

 

But wont it just act like a Small bridge on the Secondrys?

 

It should make more torque highger inthe powerband but only marcus knows exactly how it will run as compared to a semi bridge on the secondaries only.

 

so are you trying to say.. bridge the primarys and huge street port the secondaires.. or vise versa? i have a n/a and its time for a port so let me know what you think would be best! thanks

 

So... having a automatic trans, low end is really important to me... However. if i was to partial bridge my secondarys, what will that do as opposed to a "street port"??? how would you advise to best port for this?? In adavance, thank you for your time and imput. Carter

 

Thats exactly what im saying..

 

? help! little thick here( between my ears) could you please explain? Thanks again, Carter

 

Ok, while we are on the subject of porting, i would like to port along the outer edge for earlier intake opening. How far can i go before the corner seal is in the danger of falling into the port? Seems like the corner seal tracks right behind the ports so you guys with extended ports, let me know how, i am thinking 2mm should be ok?

 

something i have been working on. is not in working order yet, but playing around with it. someone machined water seal groves into a 12a center housing. if you have played with this from a 12a you will know why. only 'real' obsticle (not problem) is FI bungs.

 

what i am hoping on doing is a big street port on the primarys and a bridge port on the secondaries, but since i have a 6 port would it be wise for me to convert to 4 port or keep the 6?

 

I would definetely stick with the 6 ports since they flows wery well and have god velocity.
I have built such an engine with 12A bridgeported intermidiate housing and twin small bridgeports for the outer housings. It had Hurley 2-piece race seals and fuel injection. It made 275 hp@9000rpm and it hadn't peaked yet!

 

thats good to hear.. i might do the 4 port thing just have to think about it some more.. what size injectors should i be looking at.. since its still n/a i was going to pick up a T2 fuel pump and T2 secondaries and be done with it.. you think thats enough... u did a dual bridge and im doing a street port and a bridge.. so i wonder how this will work or if anyone had lots of success with it?

 

ok put it this way.. for a T2 around 300hp do u need upgraded injectors?

 

on line worksheet at WWW.rceng.com (there ar others also) for you to do your homework..good luck, Carter

 

Okay please explain this one more time, this thread seems to have changed questions like 3 times here. Are you street porting the primaries, and bridge porting the secondaries?

Also what would happen if you just bridgeported the secondaries and left the primaries alone (to obtain better air velocity)? Wouldn't that technically help low/mid range power and torque while inproving the top end significantly???