should I bridgeport or streetport?

[Polito Racing]

hey guys I'm in the process of building an engine for my s4 TII. Im a little undecided on which route to take if i should go with a large streetport or if I should go with a bridgeport. which route should I take for more and easy HP and running lots of boost. this car will be driven to regularly not my dd but it will be used every once in a while and will also be used at the track so I need something powerful but at the same time reliable and durable. I already purchased all the stuff to close the engine SCR apex seals and springs, original side seals and springs, atkins solid corner seals, original 93 corner seal springs, original O-rings and springs for the rotors, new original bearings and the original master rebuild kit you know gaskets and coolant seals and all that other crap all i need is to do the ports and close the engine so i need some advicing from you guys. once i close the block and start working on it i will start a thread to share all the fun with you guys

thanks in advance.

[85rx-7gsl-se]

What's your HP goal?

[Polito Racing]

couldnt tell you an exact number but as much as possible

[85rx-7gsl-se]

Well, if you are going balls to the walls, I'd say bridge. Advantages of Streetport IMO are better low end power, better fuel economy, and should be a little more reliable. If it was a semi-daily, I'd say street, but if its a track car/ weekend warrior, bridge that beeotch

[jtbshaw]

Sounds to me like you have prepped to do build a solid engine. I'd say go with the bridge. I drove my last bridged 13B everyday for over 2 years. Lots of upkeep (change plugs every 3-4 weeks, and change the oil often, etc...), but I had zero problems. I also had a very hot ignition system. I built it to go turbo and nitrous, but once the nitrous was on there, I never went on with the turbo. Fuel mileage was pitiful, but she was a handful on the 100 shot. 150 shot was insane!

Of course you could do a half bridge.

[Polito Racing]

as of now i dont think ill be running no nitrous just straight boost do you think that would make any difference in the life in the engine?

[jtbshaw]

Originally Posted by Polito Racing

as of now i dont think ill be running no nitrous just straight boost do you think that would make any difference in the life in the engine?

I personally don't think it should matter. Like I said, I rode mine hard for over two years (ran about a bottle on nitrous through it weekly), and never had any problems. But, there was a good bit of upkeep. I also premixed. There isn't as much power early on, as with a street port, but when the bridge comes alive, it really goes crazy. Again, you may want to consider a hlaf bridge though. Either way, if your foundation is solid, I think it will take whatever you throw at it. Just make sure you keep a watch on the timing and the plugs, and change the oil often if you go full bridge. Depending on how large of a bridge, remember you may have to address more cooling.

[classicauto]

Biggest problem is goign to be if you need emissions, or if cops in your area have a big problem with noise.

There's no point in doing a bridgeport and muffling the crap out of it or you may as well just have a nice streetport and a car that idles normally.

There's lots of sides to the argument but I've had both and currently have a streetport. The bridge was great, loved the noise and brap, but ultimately the streetport engines are more streetable. You can easily make 500whp on a streetport all while having a car that idles nearly a civily as a stock RX-7.

But no one can answer this question but you. Only you know if you can deal with the high idle, extra noise, extra gas consumption, lowered life span and added tuning nuances of the BP.

EDIT: Just noticed the point that nolimitind made. Size. You can cut a small bridge and have less of the drawbacks.....but you lose the gains at that point also. I ran a half bridge with a pretty wild eyebrow on the secondaries and after a short while I regretted not doing a full bridge. Because really, if you're doing the cuts, you want it to be as wild as it will be, so there's not a lot of point in trying to make it tame. In my mind its go big or go home because if you're introducing high overlap (which you will even with a teency weency pointless eyebrow) for high RPM power, then introduce as much as you can.

[Polito Racing]

emissions is not a problem i dont have to do those on these county and neither is noise. As of now I'm thinking on doing a little of both. thats why i oppened this thread to see if it was better to do one or the other, or if both together would work better for me because i have never owned a SP or a BP i had normally just rebuild the engines and wouldnt mess with porting it's just something new for me. but i really appreciate all the advices and the guidance and will appreciate the next ones to come.

[N.RotaryTech]

I was wondering the same question (sort of) before I rebuilt the motor in my 87 gxl.
I research all I could find on bridge porting an a little on street.
I have a mild street port in my 89 gtu.
I wanted something different.
So in the end I got something really different.
I combined the ports in each end-plate a little, aka siamese port.
I still want to do a bridge port some time, maybe on a 12a.

But your doing this with a turbo. Good luck.

[Polito Racing]

excuse my ignorance. what is a siamese port? is this a combination of street and bridge port?

[jtbshaw]

Originally Posted by Polito Racing

excuse my ignorance. what is a siamese port? is this a combination of street and bridge port?

Some of the crazy Puerto Ricans that I hang out with refer to the Siamese port as the same as the half bridge. A half-bridge is a bridge-port on the end plates and a large street port on the intermediate plate. These are fun too. I am more like classic....go big or go home. If I had my preference of a street or a bridge.....I'd go with a monster bridge all day long. Who needs full flowing water....just cut right on into that water jacket......Run that mutha all the way to 11k rpms.!!!

[N.RotaryTech]

Not sure if thats the right term, I heard it somewhere else referring to the ports Ive made.

Technically it doesn't make sense. The word Siamese means / is a breed of cat. Siamese Twins on the other hand means "any pair of twins born with bodies joined together in some way."

Anyway...

[classicauto]

A siamese port is joining the auxilary ports and secondary ports together into a giant port on an N/A iron.

[Polito Racing]

Originally Posted by classicauto

A siamese port is joining the auxilary ports and secondary ports together into a giant port on an N/A iron.

thanks