BDC

Disagree all you'd like, but it most definitely was. Fred is right on the money.

http://www.turbocharged.com/catalog/compmaps/fig9.html
After checking that out, take into account it's not one of the larger T-Series front covers -- it's a typical TO4B front cover w/ a 2.75" inlet and 2" outlet. It's not a full 60-1; it's a 60-1 HIFI, of the small-shaft T4 variation. Do the math; it all lines up just fine.

60-1's or 60-1 HIFI's? If it's a HIFI, then show us.

"Should have"... How do you know? What's your reasoning? And how do you know I'll encounter the same issue?

Contra la corriente...

What's wrong with it?

Keep talkin', John...

B

BDC

The S5 IC's actually have a higher pressure drop than the S4's. The S4 is a better core to use. Check out the article on Autospeed when they compared a bunch of stock cores.

So it's my "fault" that I am (was) stuck with what I've got to test a bridgeport out until I can put a different unit it? Well, forgive me your excellency, for not going out of my way to impress you. Heaven forbid some of us think outside the box for a change and experiment with something using what we've got on hand. How was I supposed to know the 60-1 HIFI was too small of a turbo for a half-bridgeport? I can't read the future. Can you? What a joke.

By the way, thanks for mentioning my turbo as a "bad example" for a bridgeport. It truly is in the grand scheme of things, even with the smaller bridgeport cuts I'd made on the irons. You've just unwittingly substantiated my bridgeport over streetport claims about that turbo not only being peaky on an HBP but also how a BP can all the sudden throttle the VE of the motor into the stratosphere and therefore outpace and out-demand even that kind of turbo up high.

B

joeylyrech

iTrader: (11)

BDC how much you charge for bridgeporting just the secondaries i cannot find the dam template that my brother send me from PR a couple of month ago.I been looking around forums and i cannot find a decent template.I want to do my irons with out cutting the rotor housings but every vendor offer that version of the template,PM a price if you can thanks

BDC

In my opinion, this comes from a few things: First, this is a smaller community when you compare it to others. It's a bit more niche-ish. With that in mind, I think the drive and demand for innovation and to try new things is considerly less energetic than in other communities that have many more people. I get slammed on the alcohol deal and on the bridgeport deal, yet I know with hours and hours of what my own senses convince me of that they work. I think there's also the element you get in smaller groups with the whole "top dog" thing. Some guy who has experience wrongly so yet somehow has a way of compelling others into what's the right thing to do, and if they say "you can't do this", then many others will implicitly listen w/o questioning it. I see it all the time here on this forum with folks. Just because some guy w/ a flashy car and forum signature made power doesn't mean that he's got the answer to everything. He may know how to do some things, sure, but it doesn't mean he can't be challenged still on the merits of his claims.

Like I said earlier in response to John, people need to start thinking outside the damn box and not be afraid to try things. I was so against doing BP's, fully "convinced" that they wouldn't work on a turbo setup, yet fast-forward 4 years later and here I am on a several-page long thread defending them vigorously. Funny how that works when you replace pride and stubbordness with humility, huh?

I've been working on doing partial BP's for street use for about 4 years now, some of which on my own car. I really and truly believe they can work, even though they do present issues that make it a bit more radical than a street port (noise, very low RPM fuel mileage, stress of needing to build the fuel system and cooling systems correctly, etc.). As far as powerband however, I think it's pretty indisputable that they can well outperform a street port or a stock port all over the place. Even all the fanciness and flare aside, the fact that it raises the VE well over it would be w/ a street port, that in and of itself ought to suggest their potential.

BDC

Something I've been meaning to post over. The following was written by Heretic on the NoPistons.com forum as this thread was started over there as well (albeit without all the drama -- big surprise!). I think what he wrote nails this subject's coffin shut:

"Torque is force. Pounds of force per foot of leverage = lb-ft, for example.

Power is using that force over time. James Watt (the steam engine guy) decided that a horse could lift 550 pounds one foot in one second. So, lifting 550lb per foot per second = one "horsepower". Convert linear motion to radial motion, divide by 550, carry the two, it equals that at one RPM, 5252lb-ft of torque is one horsepower. Or, at 5252rpm, 1lb-ft of torque is one horsepower.

The SI unit of power is the watt. Old James has a monopoly in the power buisness.

Notice, that the power is interdependent on torque and the speed at which it makes the torque. 5252lb-ft at 1rpm is the same power as 1lb-ft at 5252rpm. So, if we want more power, we can increase the torque or increase the RPM at which the torque happens

Torque is created by burning air and fuel. We get more torque by burning more air and fuel: larger engine, making it easier to get air and fuel into the same size engine (volumetric efficiency), forced induction, artificial air (nitrous oxide). More difficult, we make the existing air and fuel work harder for a bigger push: higher compression ratio, better thermal efficiency, optimal ignition timing.

Volumetric efficiency is the big one. An engine's V.E. curve is almost directly linked to its torque curve.

You're yawning, because this is all basic stuff that even magazines like Import Tuner and Sport Compact Car have covered in their tech articles. Don't worry, there's a point, and the point is:

A street port makes more power by taking the existing V.E. (torque) curve and while it does get a little larger, it gets mostly shifted to a higher RPM. The power increase is mainly due to the increase in RPM.

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.

The V.E. comes from the port open time. The peakiness comes from the port closing time, which has a large effect on intake reversion at lower RPM, when the air's velocity (inertia) is relatively low. Street ports mostly make their power from extending the closing time later, which is where they get their low end power hurt. You could make a bridge port peaky like that, too, but it's not due to the overlap, it's due to the late closing.


The stomping was to kill the fallacy that low RPM engines make "torque" but high RPM engines make "power". The truth is, a lot of modifications that increase power also increase torque. The misconception stems from the fact that low RPM engines are necessarily low power engines for a given level of torque. Torque is what shoves you back in the seat, so a low RPM engine will feel a lot faster than it is, just like a high RPM engine will feel boring to drive because it never really seems to shove you back in the seat very hard. Cover ground quickly, though."

http://www.nopistons.com/forums/inde...dpost&p=862440

B

rotarygod

iTrader: (1)

I do need to point out that high overlap turbocharged engines (bridgeports and peripheral ports) do have a history not only with the average engine building Joe but also with Mazda and their efforts as well. Remember Mazda puts more research time, money, and effort into the rotary than anyone has and they definitely know what to use and when.

In 1984 Mazda raced their first turbo bridgeported 13B in a March 84G chassis. The car wasn't designed for this power level but the failing wasn't in the engine design. It worked. That engine produced 500 bhp at 8000 rpm and 326 ft lbs of torque at 7500 rpm. It had a 7.5:1 compression ratio and used Bosch K-Jetronic mechanical fuel injection. It even had BOTH air/water and air/air intercooling. I know those power numbers don't seem that impressive today, but remember, we are talking about 23 years ago with none of the fancy electronics we have today.

As we all know Racing Beat ran both a 2nd gen and 3rd gen at Bonneville and set land speed records. These attempts weren't merely done by Racing Beat alone. Mazda themselves had a very large part in them. The 2nd gen had a 2 rotor twin turbo bridgeport engine as well that was very similar to the March 84G engine from 2 years earlier. This car set a land speed record that was only just recently broken in it's class.

The 3rd gen used a 3 rotor triple turbo peripheral port engine to again set a land speed record. This car wasn't even going as fast as it could as the condition of the salt was very bad that year from early rains. That car had far more in it.

Many people consider Racing Beat conservative yet they currently have a 3 rotor peripheral port turbo engine for sale. They've built a couple of these.

The whole point is that a high overlap engine can work quite well with turbocharging. If Mazda's racing efforts with forced inducted rotaries involved high overlap engines rather than relatively low overlap engines such as stock or streetport setups, that should tell you something about their potential right there. They obviously work quite well. That's some pretty solid evidence right there and they've known it for over 20 years!

680RWHP12A

enough said!

Boostn7

Yes, but we are talking about the fastest, right?
Now I ask you. What is fastest rotary in the world using ?

Full race car, not a street car, right?
So you tell me those top PR cars will race same motor weekend after weekend 'till they break ? Don't think so.
When I said "refreshed" it simply means they get throughly inspected before another weekend of racing. That is the only way to know how long parts last when under that immense stress and go rounds when needed without failing.

I agree. Everyone is entitled to their opinion and choice.
But there's quite a few here that have regrets for getting their plates Half-bridge ported since they did not performed as expected or maybe they expected too much from them.
Makes no sense to half bridge-port a motor, run a stock top mount intercooler and never rev past 7.5krpm!!!

Again, the fastest rotary DOES RUN STREET-PORTS !
But if you choose to run a PP and 50+ psi of boost choice is yours and should be respected.
For street applications street port is all most people will need !!!
With all the half-bridge motors on the forum there hasn't been any that stood out in a performance perspective to say -"wow, I want one"

JD

Boostn7

Thanks for the info and link.
The PR cars have a proven combination....mainly with reliability.

Some more on street ports....

Dee's Reactive Racing best time was a 7.49 @ 179mph
Mike Lowe also ran a best of 7.815 @ 173.03
Abel's best run ever was a 6.794 @ 209.95 mph on street ported 20B. He ran numerous 204mph passes.

JD

Boostn7

No one said they would not work.
Keep in mind they were turbochaging PP motors back then already since it performend the best port in NA form.
Those cars have gone from full PP to BP and now to Semi-pp, overlap is an obvious reason.

Ok, at least we agree on one thing :-)

JD

Boostn7

I assume you're using a crazy rotary correction factor when looking at the compressor map.....another one that needs a 100lb/min turbo to make 500hp !

If your bottleneck is that stock intercooler then it will continue with bigger turbo.

Just showing that even at lower boost where the intercooler is not much of a restriction the numbers are NOT spectacular for your exotic porting.

JD

crispeed

Steidel Racing also is full PP using an E&J throttlebody.

Boostn7

Sorry, you and your source are wrong. 89-91 turbo used same exact core with larger diameter inlet.

Wait a minute.....you're the one who posted both of your dynos and asked for anyone to compare and critique them !!!
see below
Since VE is directly related to torque, does that mean that my stock port motor which made more torque is running at higher VE then your HB motor at less boost?

enzo250

You guys could keep argueing about BS all day...

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.

joeylyrech

iTrader: (11)

crispeed thats correct STEDIEL ITS running PERIFERAL PORT setup.

blitzboy

Just a quick reply as I have owned both specs extended Street port and now Half bridge.
On my street Port I made 450rwhp on 1.3BAR and now with the half bridge I spooling up to full boost 600rpm quicker with a shed load more torque mid range, it will be going on the dyno next month, at 1 BAR it feels like I am making the same power as I did at 1.3 BAR.
Personally I noticed straight away pulling out of corners is much much quicker on the half bridge. For me the half BP is more streetable as I have a lot less lag

crispeed

So are a couple of people up in your area!
I know Enzo is very familar with one of them!

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.

zinx

iTrader: (3)

I agree with you here, the quicker spool alone makes it a more streetable car.



Steve, what were your thoughts on my 1/2 bridge? good, bad, indifferent? It won't hurt my feelings one way or the other.

pluto

PM sent

crispeed

Now who was it that awaked the sleeping dragon!

Just like old times.
I see all the old, new and soon to be retired veterans in this thread.
I remember me and Steve having this very conversation about sp vs bp about 5yrs ago at a race in Texas.

pluto

and I recently went back with a SP.... go figure?!?!

crispeed

Well I have not done a BP turbo in a while but with the recent batch of turbos available it's not going to be long!
For me the turbo was the limiting factor at higher output levels.

T04Eneedy

does that mean your fc will be going for 8's? i hope so!!!!!

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.