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Bridge port is over rated?

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Old 03-12-07, 01:46 PM
  #126  
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Originally Posted by pluto
1/2 bridge port when done properly will make more hp than the SP. It has been proven on numerous occasion. My car made approx 720rwhp with the 1/2 bridge while probably 650rwhp on SP. The only reason I think why John is arguing in this thread is the fact that some people thinks just by cutting the eyebrow for the bridge will make more hp and higher VE. This is not the case and could hurt in many cases when done poorly.
I personally don't like doing 1/2 bridge engines for customer but when I do, I go all out to what a 1/2 bridge port should be instead of trying to keep it small and driveable. I don't port it for the sound factor. It makes no sense to have different design of 1/2 bridge (more and less trail and error) when it could greatly affect VE.

Street port will affect very little in VE when ported wrong giving you more cushion for error. You won't see as much gain or losses due to porting in a street ported engine at low boost level (less than 20psi) since anytime when you enlarge the port, it will provide more flow 1/2 bridge port on the other hand will magnify the VE when ported wrong. I think this is what John was trying to point out.
was 720 as far as you have pushed your car?what turbo and how much boost?just out of curiosity
Old 03-12-07, 01:46 PM
  #127  
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Originally Posted by pluto
Yep, I recently installed a GT42 turbo in my car just to see where I am. I have the GT47 laying around that I may use when I decided for more hp using a 1/2 bridge again. My previoius 1/2 bridge broke the support for the coolant seal so I decided not to waste my time to build another 1/2 bridge at this time. Besides, my stage 3 engine seems to be making some descent hp on some of my customer's car (499rwhp@17psi and 565rwhp@22psi using a GT42), I want to play around with the SP to see where my limitation is before changing my setup again.
That's pretty well where I've been also. Seems like the sp with some tricks is still kicking some ***!
Old 03-12-07, 01:52 PM
  #128  
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Originally Posted by T04Eneedy
does that mean your fc will be going for 8's? i hope so!!!!!
Now that you have mentioned it.
Yes it does!
It should be running in a few months.
I spent the last month adding bars to the cage and stiffenning up the chassis. And yes it's going to brap brap again!
Old 03-12-07, 01:54 PM
  #129  
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Yep, that was with a T80 turbo and 29-30psi of boost using the old manifold design and IC. New setup is a bit different.

Here's a pic back in 2004



Originally Posted by T04Eneedy
was 720 as far as you have pushed your car?what turbo and how much boost?just out of curiosity
Attached Thumbnails Bridge port is over rated?-22.jpg  

Last edited by pluto; 03-12-07 at 02:01 PM.
Old 03-12-07, 02:17 PM
  #130  
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Originally Posted by crispeed
Now that you have mentioned it.
It should be running in a few months.

sign my hood
Old 03-12-07, 03:33 PM
  #131  
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Originally Posted by enzo250
You guys could keep argueing about BS all day....
I'm only argueing here with BDC since he posted both his dyno sheets and failed to prove how his half-bridge port is superior. Same person that mentioned doing nothing else other then cutting the eyebrow on the irons and assumes how his engine VE is off the roof !!!

Originally Posted by enzo250
You like using streetports so use them. It's your engine and you should run what you believe works best. Other people might believe other ports work better and they will use what they want...

Nobody should make claims that "x" port is the best...
Especially when the only "proof" they have is that "joe blow racing" uses one so it has to be the best..

It's the whole package that determines how good your setup will be in the end.
Not the port.

I'm done with this thread.
Agree....everyone is entittled to their opinion and choice regardless of application but to ignore the facts on either side is foolish.

Good luck with your own project.
I do enjoy when they run hard regardless of ports:-)

JD
Old 03-12-07, 04:12 PM
  #132  
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Wink

come on guys lets all just make up and show off some 650-1000rwhp rotary dyno sheets......
Old 03-12-07, 04:36 PM
  #133  
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BoostManic: I'm guessing this all started because of that thread on 502ss? Good times.

Here's the Bridge-Port in question:


When it's all said and done I'll give you a spin in my car and he can take you for a ride with his BNR stage-3...

Then you can tell us which one is over-rated.

Last edited by ducktape; 03-12-07 at 04:48 PM.
Old 03-12-07, 05:43 PM
  #134  
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Thats about all folks^^^^^, I've never once received any complaints about the streetability, power, power band, etc concerning my car. I wanted more, I went full bridge and it drives just like my half bridge did. I'll assume like just about everyone else here that, most have not tuned, driven, owned a bridgeported rotary. Hell, some might not even have a good driveability/street tune with theirs. I can tell you that my current turbo would not even budge if it were on a street port!
Old 03-12-07, 06:28 PM
  #135  
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Originally Posted by Slammedblk7
Thats about all folks^^^^^, I've never once received any complaints about the streetability, power, power band, etc concerning my car. I wanted more, I went full bridge and it drives just like my half bridge did. I'll assume like just about everyone else here that, most have not tuned, driven, owned a bridgeported rotary. Hell, some might not even have a good driveability/street tune with theirs. I can tell you that my current turbo would not even budge if it were on a street port!
And what turbo might that be?
Old 03-12-07, 07:06 PM
  #136  
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Originally Posted by crispeed
And what turbo might that be?
Both my old MP T70(same as PT70) and MP GT45(same as Garrett GT42R)
Old 03-12-07, 07:19 PM
  #137  
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Originally Posted by Slammedblk7
Both my old MP T70(same as PT70) and MP GT45(same as Garrett GT42R)
A streetport can't budge a MP T70 / MP GT45 huh................. and here I thought you were running a big turbo.
Old 03-12-07, 07:25 PM
  #138  
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Originally Posted by Viking War Hammer
A streetport can't budge a MP T70 / MP GT45 huh................. and here I thought you were running a big turbo.
Newp...just teeny tiny ones Anywho, done with this thread, I got some Fajitas on the grill. Numbers will speak for themselves.
Old 03-12-07, 07:45 PM
  #139  
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Originally Posted by Slammedblk7
Both my old MP T70(same as PT70) and MP GT45(same as Garrett GT42R)
Hahaha...are you kidding ?

Your GT45 has a smaller compressor inducer then your older T70 or a GT42R. Only the exhaust wheel compares to a GT42R.

Quite a few street-ported 13Bs spooling GT42s with no problem.
Old 03-12-07, 08:39 PM
  #140  
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Originally Posted by RacerXtreme7
I guess your reading and comprehension skills are lacking. I said basically street cars and even semi serious race cars will never see intake pressures greater then exhaust manifold pressures (In order to make them match, you need a extremely free flowing turbine and perfectly matched turbo combo. read: LAG MONSTER). ONLY extreme motor sports (IE: F1 of the 80's era) and purpose built RACE engines see "crossover" which is were the intake and exhaust are close or match in pressures. Most engines need some sort of responsiveness and don't run in a narrow RPM band. It's all there, go read it again, thanks for confirming what I said, but yet discounting me for stating it lol.

And the freakin purpose of my response was, I'm willing to bet of the THOUSANDS of turbo'ed engines of the owners on this forum, less then probly 5 actually get to crossover. My point was that saying you'll blow boost out the exhaust in a bridge port is just not true and **** like that being written on forums is what leads to others repeating ignorant **** like that.

~Mike...............
Mike, thats not true. The last daily driven street car I setup was equal between intake and preturbine back pressure. Car is more streetable than 90% of the forum owners cars. Not trying to bust your ***** or contribute to this ego battle, just trying to make a factual point.
Old 03-13-07, 12:41 AM
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Originally Posted by BDC
The bridge port, on the other hand, has a much higher V.E., almost double, and it does it everywhere. Down low. In the middle. Up top. They never stop. They make much more TORQUE than a street port does, so for a given level of power, they don't need as much RPM.
That's just wrong.
I've never seen proof that it does make superior low-end power, period.


-Ted
Old 03-13-07, 12:49 AM
  #142  
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Originally Posted by enzo250
You guys could keep argueing about BS all day...
I find it funny that I thought the original thread was started with an implication to STREET applications...and all this race **** for introduced into the thread.

I've asked for proof time-and-time again, and BDC likes to argue "well, it works for me so it has to be true".
What kinda proof is that?
I've proved that his low-end power is not superior.
He claims he has better boost response at the low-end - that's easy to explain with too much fuel / too little ignition advance - viola, lots of boost noises.
So does more boost equals more power?
Not necessarily...

I've never seen a dyno sheet from BDC that proves his superior low-end power, period, from any of the BP or HBP set-up's.
It's funny that the dyno sheets he posted in this thread are referenced to MPH and *not* RPM's...


-Ted
Old 03-13-07, 09:18 AM
  #143  
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Actually, assuming the dyno pull was done in 3rd. you can predict that 100mph = 8krpm and 50mph = 4krpm.......




Originally Posted by RETed
I find it funny that I thought the original thread was started with an implication to STREET applications...and all this race **** for introduced into the thread.

I've asked for proof time-and-time again, and BDC likes to argue "well, it works for me so it has to be true".
What kinda proof is that?
I've proved that his low-end power is not superior.
He claims he has better boost response at the low-end - that's easy to explain with too much fuel / too little ignition advance - viola, lots of boost noises.
So does more boost equals more power?
Not necessarily...

I've never seen a dyno sheet from BDC that proves his superior low-end power, period, from any of the BP or HBP set-up's.
It's funny that the dyno sheets he posted in this thread are referenced to MPH and *not* RPM's...


-Ted
Old 03-13-07, 11:00 AM
  #144  
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All bark and no bite.

Originally Posted by RETed
I find it funny that I thought the original thread was started with an implication to STREET applications...and all this race **** for introduced into the thread. I've asked for proof time-and-time again, and BDC likes to argue "well, it works for me so it has to be true". What kinda proof is that?
I know that I'm not arguing from that point-of-view. I think that's your attempt at a straw man, Ted. Infact, if you look at the majority of this thread as well as others, who here has actually posted dyno graphs and data logs? Me. Lots of people have argued both sides, but very few have given any real hard numbers. Who here has laid it all out in explicit detail since last August (referring to the start of my datalogs in my AI experiment)? Me. I'm arguing from the numbers and what I know is true. It's all there, ready for you or anyone else to see.

Hey, speaking of which, ya got any graphs or numbers of your own, Ted? Or, are you still arguing from the living room recliner?

Originally Posted by RETed
I've proved that his low-end power is not superior.
You did? Oh, you must be referring to that overlay you did where you not only fudged the figures (thanks, Max!) but also compared your stock turbo car to Tony Farkas' half-bridgeport car using a Schwitzer S300 w/ a slightly larger than Q-Trim exhaust wheel, saying you'd beat him in a "race to 4000rpm". Nevermind the fact that your overlay actually and unintentionally showed evidence for the power of the bridgeport. I still get a good laugh out of that.

Originally Posted by RETed
He claims he has better boost response at the low-end - that's easy to explain with too much fuel / too little ignition advance - viola, lots of boost noises.
"Lots of boost noises"? That makes no sense at all. Do you even know what you're doing? Do you even tune any cars at all or are you merely the Rx7club.com Internet thug with 23,000 posts of almost nothing worthwhile?

Try overlaying the two graphs I linked several pages back. My claim is this, and you can quote me on it instead of putting words in my mouth -- The BP turbo makes better and more aggressive boost at comparatively lower RPM than a stock/street port with equivalent equipment. It therefore produces a wider powerband.

Originally Posted by RETed
So does more boost equals more power?
Not necessarily...
In my case, it sure as heck equals a much earlier and more aggressive boost thresshold. If you look at the graphs, you'll see it plain-as-day, and it's the very same thing that every turbo BP guy I can think of says. Hey, here's a unique idea, and I know this is a stretch for you -- Get off your duff and go do your own! You just might find that us BP et al advocates are correct.

Originally Posted by RETed
I've never seen a dyno sheet from BDC that proves his superior low-end power, period, from any of the BP or HBP set-up's.
It's funny that the dyno sheets he posted in this thread are referenced to MPH and *not* RPM's...

-Ted
Oh, good grief man. It seems like so many things are either lies or conspiratorial in your accusations. Perhaps this is nothing more than a projection of the very things you're guilty of that you'd like to place on to me. Well, Ted, being in business for myself, I have nothing to gain by lying to people about what I assert. Like any other claim in the universe, it's either true or false based upon its merits. I go where the truth takes me and the truth is, to my initial surprise, these work very well.

B
Old 03-13-07, 11:02 AM
  #145  
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Originally Posted by pluto
Actually, assuming the dyno pull was done in 3rd. you can predict that 100mph = 8krpm and 50mph = 4krpm.......
Done in 3rd gear, yep.

B
Old 03-13-07, 01:01 PM
  #146  
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I wasn't going to get involved in this trainwreck but since it appears to never be going away and will likely be found in every search for bridge port, let me deposit my $0.02.

There are a thousand ways to skin a cat. With enough ingenuity you can make any port work in any application and have it look good. Street, bridge or peripheral.

The difference between a streetport and bridge port is intake opening timing. That's it. The bridge is just a feature of the landscape, there to hold up the corner seal. So the real question is, do you need more advanced opening intake port timing than can be accomplished with a conventional streetport to achieve your goals? In the case of 1000+ hp Meth drag cars, perhaps you do. I am not so sure about that when it comes to a 450hp or so street car.

There is never going to be a scientific test using all combination of turbos, engine configurations and tuning. While it may or may not be true that a 60-1 Hi-Fi (or whatever) runs best in the bridge port configuration, no one can prove it and the absense of proof to the contrary does not prove the affirmative. What we can do is look at it more logically and keep emotions and "faith" as far out of the equation as possible. I am the first guy who will tell you that when theory and reality conflict, you throw out the theory. But that does not mean that you can't explore other explanations to why the results appear to contradict the theory.

Usually when we see a bridge port motor with good low end torque, they are running it really rich and that effectively pre-spools the turbo for good anti-lag. While it is certainly not ideal (bad fuel economy and emissions), it is effective in achieving a certain goal. All's fair in love and war, right? However, we can usually get the same performance out of a streetport by tuning for it (usually by retarding the ignition timing a bit) and have better fuel economy in the process. But if you don't care about fuel economy, who is to say it is a wrong approach with the bridge port motor?

If you ask my opinion, I don't see a real reason that requires a bridge port to achieve performance goals of a street car in the mid-400s or even higher. There is plenty of port duration to fill the chambers with a streetport at those levels, so that line of argument should just be thrown out. At 15psi on a streetport with a GT35/40, we have gotten 450rwhp from a 13B-REW (Turbo and High Tech Performance magazine , Oct 2004). Not a 60-1 Hi-Fi so it doesn't count? You can believe what you want. I tend to look more at "packages". There are millions of possible setups, between motors, porting types, turbos, manifolds, fuel injections systems and tuning. Find a package that accomplishes your goals for the cost and tradeoffs you are willing to pay, then emulate it. It may be a bridge port/60-1 package or it could be a streetport/GT35 package. At the end of the day, it comes down to smiles per mile, not horsepower, torque, fuel economy, emissions or whatever. Do whatever turns you on and don't presume what turns you on will float someone elses boat.

Personally, I hate porting a small bridge because it is tedious work with an 1/8 inch bit. I also don't want the lopey idle and the (usually) bad fuel economy. If I can get similar performance with a streetport, I will go that route. In fact, I would sooner go peripheral than run a bridge port. Bridge ports were invented to get around the no-peripheral-port racing rules. Until you get *really* big (mega-bridge), it doesn't do anything better than a peripheral, and even then it is not that great and a hell of a lot more work. Just my opinion. I've driven all sorts of combos, turbo and non-turbo. My favorite was an NA PP13B with Weber 51IDA in a 1st gen, just because sometimes it's fun to be rowdy. It also got 19.5 MPG on the freeway and had the same torque at 4K as at 9K (with retarded timing). If it weren't the loudest vehicle on earth, I would daily drive it. My next favorite is a bone stock Eunos Cosmo 20B, because sometimes it's fun to be James Bond. Single turbo FDs, 3-rotor sand rails...all fun. It's impossible to drive every setup, so I'm sure there are even more great rides out there. To each his own.
Old 03-13-07, 01:04 PM
  #147  
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It's extremely simple math (as in freshman level high school or lower!) to determine rpm based on vehicle speed. All you need to know is the total drivetrain gear reduction and these numbers have been public information from day 1 of the car. If you do the math for 1st gear and find that he was at a 26000 rpm redline, you're probably using the wrong gear as a reference! 3rd or 4th are the best guesses to start with. I've never seen anyone dyno in 1st, 2nd, or 5th for the sake of getting full throttle numbers. Common sense apparently isn't so common.
Old 03-13-07, 01:08 PM
  #148  
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Originally Posted by BDC
"Lots of boost noises"? That makes no sense at all. Do you even know what you're doing?
all he means is that the way you tuned your bp's is exactly how anti-lag works.

i think that the defenders of the sp side of the argument are actually the ones thinking outside the box here. they're the ones that assert that you don't have to put up with all the hassles of the high overlap engines to get power these days. it's a pretty novel idea to think that a good sp can be as competitive as many of the bp/hbp/pp/spp combos without having to live with the drivability, mpg, noise, tuning issues of the latter.
Old 03-13-07, 01:42 PM
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The fact that you can make high power on a streetport is not in question. The fact that others with streetports have made more power than BDC's runs are also not in question. They haven't done it with that turbo though! The only thing that is relevant at all is whether or not bridgeports can make more power over the rpm range than a streetport all else being equal. That's it. The turbo used is irrelevant. The boost pressure is irrelevant. The total number achieved in relation to others is irrelevant. The only thing that matters is port for port per the same setup. If someone were to tune a bridgeport in the same way that antilag is tuned, why wouldn't they do that for a streetport too?

What does anyone have to gain from making it appear that a bridgeport makes better power if it really doesn't. Seriously, why would he go to all that trouble to skew the results in favor of something that he doesn't think works as well and then share it with others? He wouldn't. He's trying to show others what does happen and he's being faulted for that. One test result is worth more than a thousand expert opinions. How many people here that have done it have supported this? Quite a few. How many of the people who are arguing against it have actually tried it? See a correlation? If you aren't testing, you're guessing. It doesn't matter if you prefer a different setup for your application. That's irrelevant too.
Old 03-13-07, 02:25 PM
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Originally Posted by rotarygod
The fact that you can make high power on a streetport is not in question. The fact that others with streetports have made more power than BDC's runs are also not in question.
that's exactly the point of the sp side of the argument. a sp has been proven to give everything you'll ever want out of your rotary. from daily drivable twins and singles to big hp street/strip cars to all out drag cars, a sp has been a proven to support anything you can throw at it. a bp may or may not provide the benefits that it's supporters tout, but in the end it's a moot point, because a good sp can get you there as well without having to endure the cons of a more extreme port. like blake said, there are many ways to skin a cat. all us sp arguer's are saying, is that why bother with the other options when sp's have been known to make good power w/o the negatives of the more extreme ports.


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