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a different kind of bridge and build

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Old 12-09-13, 06:05 PM
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NY a different kind of bridge and build

so i'm building my new motor now and ported, before anyone decides to start posting, WTF is that or talk any kind of BS, if your going to say something bad, abck it up with hard documented facts,

ok now with that being said this is my current setup i'm still working on and should be finished within a 2-3 months just in time for spring.

My setup is a S5 NA 6 port engine with a modern swiss cheese style bridge port, Lightened rotors and Lightened front and rear counter weights and eshaft rebalanced at 12K rpm, 54mm dual throttle bodies also fuel injected on racing beat ported manifold, intake ports ported, exhaust ports ported, rb true dual header to a y collector and 3inch exhaust, 2mm carbon apex seals with race springs, race bearings for rotors and stationary gears, 9lb turbo flywheel, those are mainly it for the engine specs.

here are some pictures, i will put up more pictures are progress goes on






NO bashing posts please
Old 12-09-13, 06:26 PM
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Wow very interesting! What did you use to create the port?

I'm hoping this thread will include a dyno run to see what kind of power and torque curve it produces?
Old 12-09-13, 06:29 PM
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it was ported by dave at KDR/Speed1, i will put up a dyno and video come spring time once the motor and car is done with numbers as well.
Old 12-09-13, 06:46 PM
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interesting, but i really just wanna hate... you said get the shaft balanced for 12k? you know you balance the rotors counter weights and shaft as an assembly right? also i dont see ceramic seals on your list for your 12k redline. also peri-ports don't even need a 12k redline.

as for the ports... your results will speak for themselves. i can't say i would encourage this idea if it was brought to my attention.. but you've already come to far NOT to get results
that being said, get er dun !
Old 12-09-13, 06:51 PM
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interesting, but i really just wanna hate... you said get the shaft balanced for 12k? you know you balance the rotors counter weights and shaft as an assembly right? also i dont see ceramic seals on your list for your 12k redline. also peri-ports don't even need a 12k redline.

as for the ports... your results will speak for themselves. i can't say i would encourage this idea if it was brought to my attention.. but you've already come to far NOT to get results
that being said, get er dun !
Old 12-09-13, 06:56 PM
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the shaft rotors and counterweights are balanced together currently at Chip motorsports, its balanced at 12K, it doesnt mean i will rev to 12K, if i make peak power at 9500-10K i will be very happy already, as for ceramic seals i though about them but its also $300 each on racing beats site as compared to the 1 piece 2mm carbon seals for $50 each, my Hp goals are to far a stretch for my setup as i am looking for 230-250whp range with the lightened rotors and higher revving with 54mm dual throttle bodies.
Old 12-09-13, 07:01 PM
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I couldn't really see the extent of your porting for the exhaust but I would personally port it much more for an NA application. I'm not hating at all lets see how it all goes
Old 12-09-13, 07:33 PM
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What you're doing is like doing a half or 3/4 eyebrow. The drivability is the same but you don't get as much power.

Actually, what you're doing is worse, since airflow through many small holes is much worse than airflow through one hole of the same area.

You can do what you want, but I discovered power gains, with no downsides, by not screwing around and just opening the eyebrow up to the full height of the port. I think my first bridge 6 port engine made about 160-170hp, same as a stockport with the same intake manifold and exhaust system. Then when I had it apart to fix a coolant seal issue I opened up the bridges and saw power gains everywhere (peak roughly 190-200hp) with the same drivability.

I'm on 230hp with the 4 port engine and Holley manifold. Limited mainly by RPM and my exhaust system, which is rather quiet. Still excellent drivability and decent fuel economy and good torque everywhere from about 2000rpm up.
Old 12-09-13, 07:42 PM
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quietness wont be much of an issue i am using this car for autox and track days and maybe a meet once in a blue as i'm on my bike most of the time and daily subaru for work, but my setup as a whole i hope to net 230whp microtech is my ecu i have currently also
Old 12-09-13, 08:06 PM
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Originally Posted by peejay
What you're doing is like doing a half or 3/4 eyebrow. The drivability is the same but you don't get as much power.

Actually, what you're doing is worse, since airflow through many small holes is much worse than airflow through one hole of the same area.

You can do what you want, but I discovered power gains, with no downsides, by not screwing around and just opening the eyebrow up to the full height of the port. I think my first bridge 6 port engine made about 160-170hp, same as a stockport with the same intake manifold and exhaust system. Then when I had it apart to fix a coolant seal issue I opened up the bridges and saw power gains everywhere (peak roughly 190-200hp) with the same drivability.

I'm on 230hp with the 4 port engine and Holley manifold. Limited mainly by RPM and my exhaust system, which is rather quiet. Still excellent drivability and decent fuel economy and good torque everywhere from about 2000rpm up.
has anyone done 230+ on a N/a 6 port? i'm kbnow there are full bridges out there over that, but are any of them 6 ports?
Old 12-09-13, 08:37 PM
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Why would you want to drive a Subaru when you have a bridge ported RX-7 at your disposal?

I have two cars (well, four technically) and the RX-7 is my go-to for everything unless I have to haul something big or there's salt on the ground.

(disclaimer: I did drive a Subaru to/at/from the Rallycross National Championship this year... good thing I did too, as the trans in the RX-7 exploded at the next regional I attended. That would have been a looooong 1000 mile trip home if it happened in Oklahoma. I wouldn't have had room to take a spare trans with me like I did in 2012)
Old 12-09-13, 08:47 PM
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i drive a subaru for my daily driver to work, being its new york city alot of people cant park, signal and taxis like to dip in and out in heavy traffic and it has heat and ac for when girls want to go to the beach, and nyc roads are pothole central , my rx7 has no ac no heat proper depowered rack, not something i wanna drive everyday anymore, with 80% humidity every summer after a long days work sitting in 10mph traffic jams for hours long.
Old 12-15-13, 10:14 PM
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I made 225 on a Holley N/A 6 port Bridge, back in 2004
Old 12-22-13, 11:20 PM
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We use to do cheese ports about 20+ years ago , and they were kind of a fad . but I'm glad to see someone bringing it back ,good luck on your project and it will be cool to see some hp #'s
Old 12-23-13, 12:29 AM
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these cheese ports are at angle to direct air compared to the ones i seen from 20 years ago and i only seem to find the ones that only have 3 drilled holes, i have many holes and angled as well, ill keep this updated as soon as i get my rotors back from Chip Motorsports
Old 12-23-13, 12:30 AM
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just doing a little test fittin with the dual 54mm throttle body

a different kind of bridge and build-forumrunner_20131223_012929.jpg
Old 12-27-13, 07:55 AM
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Carbon seals would aide very well in this instance. Sure ceramic are better but on a "budget" you will be plenty okay with the high rpm of those carbons.

Originally Posted by peejay
What you're doing is like doing a half or 3/4 eyebrow. The drivability is the same but you don't get as much power.

Actually, what you're doing is worse, since airflow through many small holes is much worse than airflow through one hole of the same area.

You can do what you want, but I discovered power gains, with no downsides, by not screwing around and just opening the eyebrow up to the full height of the port. I think my first bridge 6 port engine made about 160-170hp, same as a stockport with the same intake manifold and exhaust system. Then when I had it apart to fix a coolant seal issue I opened up the bridges and saw power gains everywhere (peak roughly 190-200hp) with the same drivability.

I'm on 230hp with the 4 port engine and Holley manifold. Limited mainly by RPM and my exhaust system, which is rather quiet. Still excellent drivability and decent fuel economy and good torque everywhere from about 2000rpm up.
However wouldn't it make great response/torque? You are increasing the velocity of air by forcing such a large volume through those small ports.

I'm curious to see how this performs, should be fun at the very minimum.
Old 12-28-13, 08:45 AM
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Originally Posted by fidelity101
However wouldn't it make great response/torque? You are increasing the velocity of air by forcing such a large volume through those small ports.
It's not going to want to go through them, so no large volume will be going through them. To make air move, you have to trick it into *wanting* to move...

I'm all but convinced that until you get into large J-port style ports where you have a MASSIVE cut into the rotor housing, the majority of the purpose of the eyebrow is during the time the main port window is closed - it gives somewhere for the slug in the runner to go without having to stop, and it opens up the "window of opportunity" for exhaust vacuum to pull air/fuel in. Which is why bridge ports tend to have much broader powerbands than street ports with their smaller overlap period.

That assumes that you have a free flowing exhaust to begin with, of course. If the exhaust is so choked/poorly tuned that the vacuum portion of the exhaust pressure cycle is not very lo, or doesn't happen during the overlap period, then you won't see much scavenging. And any time the exhaust pressure is higher than manifold pressure during the overlap period, you're losing power compared to a street port with the same exhaust system. Brap brap brap.
Old 12-28-13, 09:18 PM
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Interesting ..... Over here people that do that sort of porting call it a Drill port. Drill a few holes throw it back together, They end up with Shity gas milage, Same power, More noise and the Best thing of all you get the **** factor ! but that's NZ in itself.

Your's is more of a TearDrop Port to me, Hope it work's out well for you.
Old 12-28-13, 09:35 PM
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yeah my ports are more tear drop shaped and angled as well to direct the air, i'll see how well it works out in spring when the car is all back together and tuned
Old 12-31-13, 08:42 AM
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if one of those rear counterweights is for an S4 I'll buy it off you.
Old 12-31-13, 08:49 AM
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sorry none of those are s4, its a 12a and a s5
Old 04-04-14, 10:46 PM
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What ever happened to this build?
Old 04-04-14, 11:24 PM
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NY

its still going i actually have the motor almost done, just waiting on a few parts i'll upload some pics in a little bit after tomorrow
Old 04-06-14, 12:40 AM
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Cheese port eh?

What is the point of a cheese port?

Is it a one step further modification, but one step under a bridge?

Kind of like a mild cam upgrade type of deal?


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