Bridge port is over rated?
03-09-07 | 06:48 PM
#51
IRS Champion
Joined: Aug 2001
Posts: 2,038
Likes: 1
From: NY
Originally Posted by 13B-RX3
When was the last time your tach dropped below 4500 RPM during a 1/4 mile pass?
You bring up very good points...
IF your building a drag car you will want to run it where it makes it's max power/tq and keep it there.
Makes no sense to build something that makes max power at "x" rpm but they drag race it and spend most of your time at "y" rpm..
03-09-07 | 09:50 PM
#52
Rotary Enthusiast
Joined: Feb 2001
Posts: 867
Likes: 0
From: Union, NJ
Originally Posted by BDC
Attached is my dyno sheet from March 30, 2000. Linked below is the dyno sheet from Dec 30, 2006. Same turbo (Turbonetics 60-1 HIFI). Street port in 2000 vs. a half-bridgeport in 2006 as well as going from a chilled air-to-water intercooler to a stock top-mounted intercooler. I invite everybody to thoroughly compare the two and critique them.
-your original street-ported (SAE-corrected) dyno of 424rwh and 327rwt @16-17psi vs
your most recent (STD-corrected) dyno of 438rwh and 361rwt @ 24psi w/ Methanol injection ???
Where do you you see an improvement with that BP ??
Should we ignore the ~8psi difference in boost ??
Originally Posted by BDC
http://bdc.cyberosity.com/v/Tuning/D...geViewsIndex=1
John,
I haven't done anything special with the BP and I've never claimed that I did. I just experimented with it a few years ago and found that it worked on a turbo app, despite my predilection for street ports. I still don't understand all of the science behind it, but it nonetheless still works. I just make a couple small cuts and let it do its thing. Zoom, zoom.
There were a few logs that went to 7500-8000rpm, but admittedly not alot. They were all on the street and only one on the dyno. The runs on the dyno were my fault. I screwed up in going to the session with overconfidence of the tune, not recognizing the lack of high RPM street tuning I'd done by way of not removing fuel way up top once I was ramping alcohol up. But, I suppose you'll wrench that out of context, make up an excuse about that, project that on to me, then argue against it as you've done I don't know how many times already, right? Give me a break, man.
Horsepower?! What's the big fricken deal about a single horsepower figure? Whatever happened to torque, powerband, peak power, etc. etc.? Are you willingly choosing to ignore the torque figures on my car, not to mention the overall powerband, given the turbo that was used on that setup? Nevermind the fact the bridgeported motor was easily able to out-pace that 60-1 HIFI compressor without breaking a sweat. Nevermind the fact a bridgeport's potential power band, given having enough compressor up front, doesn't drop off at your typical 6000-7000rpm range like you and your buddies' street ports. Nevermind the fact that the boost thresshold is dramatically more aggressive and poised earlier in the powerband. Nah, none of that stuff matters. Don't confuse you with the facts, right? What the heck do you think happens when you crank the VE way up in a motor anyways, John?
Think outside the damn box already.
B
John,
I haven't done anything special with the BP and I've never claimed that I did. I just experimented with it a few years ago and found that it worked on a turbo app, despite my predilection for street ports. I still don't understand all of the science behind it, but it nonetheless still works. I just make a couple small cuts and let it do its thing. Zoom, zoom.
There were a few logs that went to 7500-8000rpm, but admittedly not alot. They were all on the street and only one on the dyno. The runs on the dyno were my fault. I screwed up in going to the session with overconfidence of the tune, not recognizing the lack of high RPM street tuning I'd done by way of not removing fuel way up top once I was ramping alcohol up. But, I suppose you'll wrench that out of context, make up an excuse about that, project that on to me, then argue against it as you've done I don't know how many times already, right? Give me a break, man.
Horsepower?! What's the big fricken deal about a single horsepower figure? Whatever happened to torque, powerband, peak power, etc. etc.? Are you willingly choosing to ignore the torque figures on my car, not to mention the overall powerband, given the turbo that was used on that setup? Nevermind the fact the bridgeported motor was easily able to out-pace that 60-1 HIFI compressor without breaking a sweat. Nevermind the fact a bridgeport's potential power band, given having enough compressor up front, doesn't drop off at your typical 6000-7000rpm range like you and your buddies' street ports. Nevermind the fact that the boost thresshold is dramatically more aggressive and poised earlier in the powerband. Nah, none of that stuff matters. Don't confuse you with the facts, right? What the heck do you think happens when you crank the VE way up in a motor anyways, John?
Think outside the damn box already.
B
I just finished telling you I made more torque then you on stock ports and stock non-seq turbos !!!
The 60-1 turbo was the most popular turbo to be used on the 13B's and 400+rwh and ~350rwt was the normal @ ~1 bar.
FYI: my stock port peaked @ 7200rpm !!! do you think my street-port drops off below 7krpm????
Like you said: " I still don't understand all of the science behind it, but it nonetheless still works. I just make a couple small cuts and let it do its thing"
Wow ! can't believe you actually made that statement....I figured you atleast had a clue.
Give me one example of one of your motors where it outperformed a SP under same conditions.
For most street applications making 400, 500 or even 600rwh B-Porting is over rated for sure. But if you enjoy that "brap-brap" sound and shitty fuel efficiency then be my guest.
03-10-07 | 12:21 AM
#53
Needs more Displacement.
Joined: Jun 2005
Posts: 1,329
Likes: 0
From: Louisville, Ky
I'd like to apologize about this thread. I'm the one that originally said that bridge porting was over rated on a LOCAL forum and Boostmaniac had to create this thread in an effort to prove me wrong.
Nothing against you BDC but those numbers don't impress me at 24psi. And I don't care that I don't have experience building them or what not. I'm the customer, what I know doesn't matter. It's about the numbers to me. If I can have a SP that makes those numbers, gives me a smoother ride and less fuel consumption I think I'm going with a SP.
/thatisall
Nothing against you BDC but those numbers don't impress me at 24psi. And I don't care that I don't have experience building them or what not. I'm the customer, what I know doesn't matter. It's about the numbers to me. If I can have a SP that makes those numbers, gives me a smoother ride and less fuel consumption I think I'm going with a SP.
/thatisall
03-10-07 | 01:00 AM
#54
Lives on the Forum
Joined: Feb 2001
Posts: 26,664
Likes: 19
From: n
Originally Posted by BDC
Attached is my dyno sheet from March 30, 2000. Linked below is the dyno sheet from Dec 30, 2006. Same turbo (Turbonetics 60-1 HIFI). Street port in 2000 vs. a half-bridgeport in 2006 as well as going from a chilled air-to-water intercooler to a stock top-mounted intercooler. I invite everybody to thoroughly compare the two and critique them.
I'd like to see RPM-dependent runs, so I can compare them with almost everyone else's dyno runs.
-Ted
03-10-07 | 01:36 AM
#55
moon ******
Joined: May 2005
Posts: 1,308
Likes: 0
From: Jacksonville, Florida
I wonder how many people in here are rotary guys who like turbos vs turbo guys who like rotaries.... given we're talking turbos here.
For NA, well duh a BP is going to beat a SP, and a PP is going to beat a BP.
With turbos, everyone seems to forget what they actually do. They pump air, and are more efficient at certain flow rates than others, and at certain pressures than others. The bigger your ports (and the higher the rpms with those ports... assuming they're timed for higher rpms) the less of a restriction you have, and your pressure ratio goes down. For people who say they "make boost", thats like saying drowning "makes your skin moist".
For some turbos, you would want some back pressure, and thus you would not want to port it. For others, you would benefit from a heavy porting. In other cases you simply have to port to be able to make power with a big turbo at all, and might be trading off being in its efficiency range to simply have the capability to spool it up!
tl;dr match the porting to the turbo and the application. Saying is a BP better than/less than "port x" out of any sort of context is like saying oranges roll down hills better than apples do.
If you have a HUMONGOUS turbo or it's efficient at low pressures, by all means bridge port it. If it's on the street and you don't need to, why spend the money and kill longevity? The turbo is there to do the work!
For NA, well duh a BP is going to beat a SP, and a PP is going to beat a BP.
With turbos, everyone seems to forget what they actually do. They pump air, and are more efficient at certain flow rates than others, and at certain pressures than others. The bigger your ports (and the higher the rpms with those ports... assuming they're timed for higher rpms) the less of a restriction you have, and your pressure ratio goes down. For people who say they "make boost", thats like saying drowning "makes your skin moist".
For some turbos, you would want some back pressure, and thus you would not want to port it. For others, you would benefit from a heavy porting. In other cases you simply have to port to be able to make power with a big turbo at all, and might be trading off being in its efficiency range to simply have the capability to spool it up!
tl;dr match the porting to the turbo and the application. Saying is a BP better than/less than "port x" out of any sort of context is like saying oranges roll down hills better than apples do.
If you have a HUMONGOUS turbo or it's efficient at low pressures, by all means bridge port it. If it's on the street and you don't need to, why spend the money and kill longevity? The turbo is there to do the work!
03-10-07 | 09:39 AM
#56
Originally Posted by enzo250
Not sure if im reading your statement correctly here.
But what i got from it was you said exhaust pressure will never be lower then intake.
Your dead wrong.
You even mentioned F1 from the 80's turbo era.
They had intake pressure almost twice what there exhaust pressure was.
I guess you don't have any experience with high hp /or big turbo'ed engines...
But what i got from it was you said exhaust pressure will never be lower then intake.
Your dead wrong.
You even mentioned F1 from the 80's turbo era.
They had intake pressure almost twice what there exhaust pressure was.
I guess you don't have any experience with high hp /or big turbo'ed engines...
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...............
03-10-07 | 10:49 AM
#57
Originally Posted by idsigloo
Nothing against you BDC but those numbers don't impress me at 24psi.
03-10-07 | 10:56 AM
#58
'Tuna'
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
Originally Posted by rotarygod
Actually if you look at his compressor map you can see that at 24 psi, that turbo is WAY out of it's efficiency range. A properly sized turbo at 24 psi would have made tons more power than that. Don't judge power by how much boost is run. That's a big mistake that many people make. Boost pressure is irrelevant without knowing efficiency and total airflow at that efficiency. That's why questions like "how much boost can I run" should never be answered without far more information. They can't be.
Or better yet how about a direct comparison between the two different porting styles on the very said setup. That will truly show the differences.
03-10-07 | 10:56 AM
#59
Originally Posted by RETed
You got any of those dyno sheets with RPM on the X-axis?
I'd like to see RPM-dependent runs, so I can compare them with almost everyone else's dyno runs.
-Ted
I'd like to see RPM-dependent runs, so I can compare them with almost everyone else's dyno runs.
-Ted
03-10-07 | 11:02 AM
#60
Originally Posted by crispeed
Or better yet how about a direct comparison between the two different porting styles on the very said setup. That will truly show the differences.
03-10-07 | 11:36 AM
#61
Lives on the Forum
Joined: Feb 2001
Posts: 26,664
Likes: 19
From: n
Originally Posted by rotarygod
As long as your comparison is only with those running 60-1 HiFi turbos. If not, they are irrelevant as just a turbo can change everything. No one would compare porting gains between engines if one used a stock TII turbo at 14 psi and the other one ran a T66 at that pressure. The turbos need to be the same for it to prove anything. How many other dyno runs do you have on file that use a 60-1 HiFi? That would be a good comparison.
I'm not the idiot who makes such dubious claims...
Then when I do post a graph comparing the two set-up's, my findings are called bullshit?
-Ted
03-10-07 | 12:40 PM
#62
Well for one Ted, see you like to compare all of our BP set ups to your stock turbo claims. Anything Anything below 4k RPM I dont care about. Exactly what Rotarygod is saying. We saw the gains from going from street to bp with no other mods besides to rough bp cuts.
03-10-07 | 02:07 PM
#64
Originally Posted by RETed
Well all this bragging about how superior the BP is all over the damn RPM band without conceding the problem with low-end power...why should we be restricted to identical turbos?
I'm not the idiot who makes such dubious claims...
Then when I do post a graph comparing the two set-up's, my findings are called bullshit?
-Ted
I'm not the idiot who makes such dubious claims...
Then when I do post a graph comparing the two set-up's, my findings are called bullshit?
-Ted
03-10-07 | 05:25 PM
#66
Originally Posted by joeylyrech
The Siguel crew its running semmi pp with bridgeported secondaries
. At least it would eliminate all the "what port is better" threads.
But seriously guys, there is some great info in here, thanks for sharing!
03-10-07 | 05:57 PM
#67
this thread says so much and nothing all at the same time. the pros get to slap hands and show impressive proof of their respective arguments out of context, then tell the amateurs/small-scale guys to shut up and listen.
me? well, i'm one of the small-scale guys and while i truly respect the talents of all our resident pros, i've resigned myself to believe nothing more than what i can prove for myself in my own experiences - past and future. there will never be agreement or resolution on this, and that's cool, too, as long as everyone realizes arguing is wasted energy. there's still a lot for us all to learn.
me? well, i'm one of the small-scale guys and while i truly respect the talents of all our resident pros, i've resigned myself to believe nothing more than what i can prove for myself in my own experiences - past and future. there will never be agreement or resolution on this, and that's cool, too, as long as everyone realizes arguing is wasted energy. there's still a lot for us all to learn.
03-10-07 | 09:20 PM
#68
Lives on the Forum
Joined: Feb 2001
Posts: 26,664
Likes: 19
From: n
Originally Posted by Slammedblk7
Well for one Ted, see you like to compare all of our BP set ups to your stock turbo claims. Anything Anything below 4k RPM I dont care about.
It has nothing to do with the claims that the BP is superior ALL across the RPM band...
-Ted
03-10-07 | 10:33 PM
#70
Old [Sch|F]ool
Joined: May 2001
Posts: 12,635
Likes: 464
From: Cleveland, Ohio, USA
Originally Posted by classicauto
Really, I can't see port size/shape (bridge vs. street) making a gigantic difference in power because the air is being crammed into the engine. It won't care if there's a brow to go through or not because its got a giant turbo at the other end mashing it into the engine.
Unless you're above sea level, of course.
VE is VE no matter if the manifold pressure is 14.7psia or 30psia or 45psia or 12psia (driving up in the mountains
)I love these nerdfights.
I was driving behind a "monster port" (ahem) RX-4 and was really shocked. It drove around as smooth as a stockport, just a very mild brap at idle. So mild you hardly noticed it. (When he pulled into the parking lot at the meet, I almost didn't think it was even ported) I didn't notice anyone's heads rattling around so it must have been driving smoothly enough, too. I've seen stock cars with less drivability. EFI is a *wonderful* thing if it can tame something like that.
Didn't get to ride in it, though. Maybe later this year.
03-10-07 | 11:09 PM
#71
Originally Posted by diabolical1
this thread says so much and nothing all at the same time. the pros get to slap hands and show impressive proof of their respective arguments out of context, then tell the amateurs/small-scale guys to shut up and listen.
me? well, i'm one of the small-scale guys and while i truly respect the talents of all our resident pros, i've resigned myself to believe nothing more than what i can prove for myself in my own experiences - past and future. there will never be agreement or resolution on this, and that's cool, too, as long as everyone realizes arguing is wasted energy. there's still a lot for us all to learn.
me? well, i'm one of the small-scale guys and while i truly respect the talents of all our resident pros, i've resigned myself to believe nothing more than what i can prove for myself in my own experiences - past and future. there will never be agreement or resolution on this, and that's cool, too, as long as everyone realizes arguing is wasted energy. there's still a lot for us all to learn.
I have always been under the impression that a bridge-port was a serious upgrade over a street-port. Now I'm a bit more skeptical--but not less likely to actually create a BP-engine... I guess the grass is always greener on the other side. F**k streetports, lol.
03-11-07 | 12:06 AM
#72
spoon!
Joined: Sep 2002
Posts: 1,208
Likes: 49
From: Dousman, WI
Hell, **** sideports in general. I, personally, have gotten so utterly sick of grinding on irons that I'm just going peripheral on the next build because I can use the milling machine for so much more of it.
Oh yeah, and it should move more air than a streetport, but that's just a minor thing...
I, personally, have gotten so utterly sick of grinding on irons that I'm just going peripheral on the next build because I can use the milling machine for so much more of it.Oh yeah, and it should move more air than a streetport, but that's just a minor thing...
03-11-07 | 06:34 AM
#73
'Tuna'
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
Originally Posted by rotarygod
I would love to see a comparison with the only thing being changed being the porting style and nothing else. Same intake, exhaust, turbo, intercooler, boost pressure, etc. If the engine makes more low to midrange power with one porting style over the other, you've got your answer. I actually suspect that a bridge (on a turbo motor) would make more power earlier than a street port but top end may not be any greater with the same turbo setup. It all goes back to the system needing to be optimized for the porting style. Use a different intake manifold and turbo to match up with it better and top end would probably start to walk away but with the low end suffering. Of course then people would conclude that a bridge does kill low end when it's the total system that altered power curve rather than just the ports themselves. There are many things that effect the powerband. To get a true comparison, everything needs to be identical except the ports. That's the only valid way to make a comparison and get any true conclusions out of it. I hope someone does this.
Only difference between both was porting. When I find the old dyno sheet I'll post it.
03-11-07 | 11:57 AM
#75
Banned. I got OWNED!!!
Joined: Aug 2002
Posts: 4,666
Likes: 1
From: chatsworth,Ca.
Originally Posted by rotariesrule
have you streetport guys forgotten about: time=power. more time allows more air/fuel which means bigger bang (power). with or without turbo.
1 vote for bp if its tuned properly
and the turbo has gotta be sized right!!