Can someone explain a bridgeport to me?
#4
Passing life by
#6
GrapefruitRacing?
Join Date: Apr 2003
Location: PartSource
Posts: 2,155
Likes: 0
Received 0 Likes
on
0 Posts
The material left between the 2 ports is for the corner seal to have something to pass over so it doesn't fall out thus creating a bridge for the corner seal between the 2 ports, hense the name "Bridgeport". The advantage of this is from what i know mainly to be port timing. From what i just learned from a forum member who has more knoledge then me on the subject while comparing my large SP vs his Bridgeport, is that, even a large SP starts to open ATDC while a Bridgeport can open (i think it was) 115deg. BTDC.
Now i was really tired during that conversaion but if the it's not right it should still give you a better understanding of why it's called a bridgeport and why ppl use it.
If anyone has the actuall facts of where a BP starts to open (specifying Half BP or full BP would be nice) please do so. I'm mearly trying to give an example with what i at least remember having been said.
Now i was really tired during that conversaion but if the it's not right it should still give you a better understanding of why it's called a bridgeport and why ppl use it.
If anyone has the actuall facts of where a BP starts to open (specifying Half BP or full BP would be nice) please do so. I'm mearly trying to give an example with what i at least remember having been said.
#7
Lives on the Forum
I hope you know your port timing theory...
Since you mentioned bridge porting, we'll keep the reply specifically to the intake port.
There are two ways to "open" the intake port.
Open the intake port EARLIER.
Close the intake port LATER.
Bridge ports will significantly open the intake ports EARLIER.
Opening a (Mazda) rotary engine port means the port opens up more from the "outer" edge (toward the water jacket).
BUT, if we start to open up the intake port toward the water jacket, we NEED to worry about the corner seal path.
If we just hog out the intake port without worrying about the corner seal, the corner seal (off the rotor itself) will fall inside the port!
This is where the BRIDGE port comes in - the bridge is there to help the corner seal travels over the intake port without falling in.
Thus, this is where the "bridge" in bridge port comes from.
-Ted
Since you mentioned bridge porting, we'll keep the reply specifically to the intake port.
There are two ways to "open" the intake port.
Open the intake port EARLIER.
Close the intake port LATER.
Bridge ports will significantly open the intake ports EARLIER.
Opening a (Mazda) rotary engine port means the port opens up more from the "outer" edge (toward the water jacket).
BUT, if we start to open up the intake port toward the water jacket, we NEED to worry about the corner seal path.
If we just hog out the intake port without worrying about the corner seal, the corner seal (off the rotor itself) will fall inside the port!
This is where the BRIDGE port comes in - the bridge is there to help the corner seal travels over the intake port without falling in.
Thus, this is where the "bridge" in bridge port comes from.
-Ted
Trending Topics
#8
multipersonality disorder
Join Date: Feb 2002
Location: so. cal
Posts: 5,656
Likes: 0
Received 0 Likes
on
0 Posts
here's one i did for an fd.
if you notice only the upper half is done--as opposed to my avatar. this controls the amount of overlap and tweaks the powerband.
this one is a bit more street friendly and doesn't eat quite as much gas as a longer one. still produces decent low end too. this particular one actually produced a really REALLY punchy low end...but the 9.7:1 rotors might have had something to do with that
if you notice only the upper half is done--as opposed to my avatar. this controls the amount of overlap and tweaks the powerband.
this one is a bit more street friendly and doesn't eat quite as much gas as a longer one. still produces decent low end too. this particular one actually produced a really REALLY punchy low end...but the 9.7:1 rotors might have had something to do with that
#14
is The Whoopieschnootz
Join Date: Apr 2005
Location: Asheville NC
Posts: 700
Likes: 0
Received 0 Likes
on
0 Posts
could anyone elaborate on the effects on the power band of Aux vs. Half vs. Full bridge? Which ones make more where, and which ones hurt power most/least where.
#15
Lives on the Forum
Originally Posted by kontakt
could anyone elaborate on the effects on the power band of Aux vs. Half vs. Full bridge? Which ones make more where, and which ones hurt power most/least where.
Bridge ports open the INTAKE TIMING earlier.
This increases OVERLAP.
OVERLAP is bad for low end.
OVERLAP allows exhaust gases to mix with the fresh intake charge, supressing potential power.
But, the earlier opening intake timing makes for more intake charge (+ fuel) to enter the combustion per revolution of the engine - this means more power.
At a certain RPM point, the advantage of more intake charge overcomes the bad OVERLAP down low, and the power climbs.
Half bridge port is just a COMPROMISE porting design to get the advantages of the bridge port but tame the idle and low end with the stock port primaries.
Personally, I think a bridge is a waste of time for a daily driven street vehicle.
So what if your car now makes 450hp instead of 400; you just can't use that extra 50hp anywhere unless you're street racing, which is dangerous and illegal.
All the pro BP+turbo guys are now going to jump down my throat for those statements.
-Ted
#17
multipersonality disorder
Join Date: Feb 2002
Location: so. cal
Posts: 5,656
Likes: 0
Received 0 Likes
on
0 Posts
you shouldn't have a problem with that.
obviously, you'd see the best results with an engine management system...
i haven't done any testing on it, but i'd be really interested in seeing how the motor would react to opening the ports and vdi at various rpm settings to optimise. it might end up liking it exactly where it is stock, but then again, it might not.
obviously, you'd see the best results with an engine management system...
i haven't done any testing on it, but i'd be really interested in seeing how the motor would react to opening the ports and vdi at various rpm settings to optimise. it might end up liking it exactly where it is stock, but then again, it might not.
#19
Slizzard sippin sizzurp
iTrader: (4)
Join Date: Jul 2001
Location: Cali
Posts: 645
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by GUITARJUNKIE28
come to think of it, the only people i've ever heard knock the turbo bp's are the people who have never done it.
Thread
Thread Starter
Forum
Replies
Last Post
LongDuck
1st Generation Specific (1979-1985)
12
10-07-15 08:12 PM