Hi, I am currently rebuilding my engine and decided to do a street port. I was just looking around and got reminded of the half-bridge port. I am thinking about trying to do this since I have everything apart already. I have done a lot of research and know the downsides of the bp, but I wanna try doing a very small bp, like a 1/4" or smaller slit instead of a larger second port. That way there would be more meat on the bridge and b/w the water jacket so hopefully lifespan wouldn't be as bad as a larger one. The exhaust port was ported very mildly, just getting rid of the casting and trying to increase some flow. What I am wondering, is if this small half bp is gonna totally destroy spool up? I will be running a hybrid t04 compressor and housing on a s5 hotside. I don't plan on turning the boost up very high at all... keeping it under 10psi. I don't mind if lag is increased a bit, but I just don't wanna totally screw up the geometry of the turbo. I know people are running larger half bp's but with pretty big turbos, so I just am wondering how it will do with the smaller one. Any input would be greatly appreciated.



Thanks,

Aaron

i think that it will cause the turbo to spool up faster, since the motor is displacing more air thru the larger porting

Talk to BDC, he is the current online GURU of the Half-bridge. What fuel system are you gong to run?

It should actually help spool times and will produce more torque then a SP. The main thing with any type of bridge is you want the least backpressure as possible. A small t04 turbo *may* choke the engine a bit. Honestly if you only want 10 psi and a mildly biuld motor I wouldn't do the 1/2 bridge.



I have also done a good bit of research about this, since I'm planning on doing a 1/2 bridge T66 or T70 setup myself. My goals are alot different then yours though.

What you are proposing is what I call a BREEP BREEP bridge, because that is what it sounds like. If you don't open up the exhaust port you are wasting you're time. It will be slightly louder, go BREEP BREEP and make no more power. Now if you open up the exhaust ports and get a bigger hot side for that turbo, you will have a screamer. Bridge ports done correctly are very loud and will attract the police no matter where you live. Any thing you do to make a bridge quiter kills the advantage to having a bridge in the first place. As a suggestion, I would avise that even if you do do the side port, that you at least open up the exhaust ports some. There is more potential for power by opening up the exhaust side than by side porting. The turbo can force air in, but if it can't get out of the motor you aren't going anywhere. If you plan on sticking with you're turbo setup for a while just go side.

Well, I decided to just stick with the street port for now, as I think the turbo would not take advantage of the bp and I currently don't have a full standalone which would pretty much be a necessity with a bp. I was being a little modest with the exhaust ports, they are actually opened up a little, being about the size of the sleeve. I didn't want to make them any bigger than the sleeve and then have the exhuast gases have more turbulence from hitting the edge of the sleeve. Thanks for all your replies! and someday you guys will hear from me about my half bp.... someday... muahahaha.



-Aaron

You'll be hearing about mine first https://www.nopistons.com/forums/pub...DIR#>/wink.png

so you are going to have a turbo'ed n/a engine?

Read my post here:



https://www.nopistons.com/forums/index.php?...pic=17005&st=25



... as well as here:



http://www.teamfc3s.org/forum/showthread.p...&threadid=16257



B

Great post BDC.



You pretty much confirmed everything Judge Ito and I talked about as far as "streetability" and "reliability" on a 1/2 bridge turbo motor. Meaning that if the motor is purpose built(street) it shouldn't have the problems associated with a full bridge, like flooding, insanely high idle, etc...



I have also talked with Crispeed on the other forum about a turbo'd 1/2 bridge street car. He had a 2nd gen T70 1/2 bridge that made:



"515 RWHP/390 RWTQ at 20 psi on 93 octane. It was done with a T-70/ P-trim 1.0 on a TII motor. The same car made 555 RWHP/ 420 RWTQ at 25psi on 116 octane. On a 50 shot of NOS it made 615 RWHP/460 RWTQ."

Now thats ******* crazy. All that on a p-trim T70 with a 1.0 a/r hotside. Could probably make a good bit more by swapping to a bigger a/r hotside or a q-trim, I would think.



Very nice porting work by the way https://www.nopistons.com/forums/pub...DIR#>/wink.png