rotaryinspired

iTrader: (3)

There is a fine line on porting the primaries and low end power. Just cleaning up the runners and radiusing the closing edge of the port w/ help w/ low end. If you make it as large as you can and increase overlap you will loose low end, but it will scream up top. Dont think huge primaries are great on the street.

NoviceRotaryTech.

This weekend I was at a freinds house and able to see a N/A block, apart. I was looking at the ports and measuring some of the bridge-port area.

My question is, whats the width / most width of a bridge port?
Cause, lets say the b-port started at the edge of the rotor housing, there is only so far you can go in, befor, #1. the apex seals are in the port area, #2. the side seals are in the port area, etc... My thoughts are, there are more seals-in-port dangers than just the corner seals, as far as seals-in-port dangers go. My rough measurment is 1/8 to 1/16 of an inch wide for a b-port.
btw: Ive only seen pictures of b-ports.

Any info / comments on this?

NoviceRotaryTech.

Edit: My rough measurment is 1/8 to 1/4 of an inch wide for a b-port. ( I miss read the ruler befor.)

Aaron Cake

iTrader: (1)

I always use 3/16" as a measurement. Drill as series of holes with a 3/16" drill bit, then connect them with a small grinding stone on a dremel and finish the sides so it's a straight line...

Or just buy a template.

NoviceRotaryTech.

Thread resurrection.
This might have been asked befor but...
Can you use 2-piece apex seals with bridge ports?

btw: I have found/got the car I will do my bridge-port idea on. (see sig.)
Once I get this car/project up and going I will post a thread about the ordeal, or I might just keep posting in this thread since its about what Im going to do to it.

anewconvert

iTrader: (1)

Just to add to the discussion. I currently have a Aux BP with the pri and sec ports streetported. There is a significant bump in power at 5100 rpms when the VDI kicks in. I can feel a slight bump at 4k when the 6PI ports open, but the serious gain is at 5100-5200 when the VDI changes.

I havent dyno'd yet but at this point I think Im running on the ragged endge of the 460cc injectors ability since the ECU supposedly will only run them at 85% duty cycle. I get some bucking/hesitation at 4800-5200 rpms and then again at about 7500-8000 rpms.

In the next month Im going to dyno with a stock exhuast minus cat then go to rb header/presilencer into a single exit exhaust with a cutout where the exhaust turns toward the muffler. Im convinced there is a good amount of hp locked up in the stock intake mani, stock exhaust mani, and the injectors. As is I pull on other NA's really hard from 5500 on.


BC

rotarygod

iTrader: (1)

Forgive me if you answered this and I missed it but are you still running a stock ecu? This includes any piggyback units.

The factory ecu may be running your secondaries that high but after they kick in at around 3800 rpm or so, the primaires fall down to only 40% and hold that all the way to redline. You aren't maxing out your total injector capability as 4-460 cc injectors can supply enough fuel for your engine. They may not be capable of doing it with a stock ecu though. A standalone should really be used anyways in order to get rid of the air flow meter. I know some people say it isn't a restriction since it never opens all the way. This is false. It is one. You lose about 10% on the top end. Due to it's internal shape and the way the spring is done it is nearly impossible for airflow to open it all the way. At least in regards to the airflow ability of this engine. That doesn't mean it isn't restricted though. That's the part that's hard for many to understand.

You are correct in that there is power to be had from an intake and exhaust. The ecu should come first. The stock 6 port motors themselves actually can flow enough with very little work done to them to make 200 hp. You don't need a bridgeport to do it if it's done properly.

ArmyOfOne

iTrader: (12)

To answer the question on seals... Yes you can use Atkins apex seals on a bridgeport. Mine has 9000 street miles and numerous passes at the track with the same set. No noticeable wear and great compression.

anewconvert

iTrader: (1)

I am still running the stock ECU. Im certainly not happy with it. Im waiting for ZEAL to come out with an MS PnP then Im going to speed density. Im sure the AFM is a restriction. I have thought about sticking with the stock ECU and waiting for whomever it was to finish his Ford Hotwire MAF converter and ditching the AFM, but it doesnt change the fact that there is some hp lost to the ECU. Im even considering using their S4 MS PnP when its released, deactivating the OMP and running pre-mix until their S5 unit is finished. then again I have also kicked around the PFC. Standalones baffle me. as youmay be able to tell.

So the primaries dont come back up after they get cut back at 3800??? Dang. That sucks. That would defintely explains both the 4000 rpm hesitation and the 7000-8000 hesitation Im getting. I was under the impression that they would both ratchet up to 85% before the ECU wouldnt let them go further.

After I get the exhaust sorted out, and I have the header and pre-silencer right now, Im going to get a hold of an S5 UIM/LIM and have the extrude honed, or if the Fuji ITBs arent ridiculously priced I might go that route. I have a lot of thinking to do on the intake front though. I was actually planning on picking your brain a little when that time comes.

If it werent already done when I got the car I would probably not have bothered with the expense for an NA, but since its done already Im going to see what I can get out of it. Its the reason I purchased this car.

BC

j200pruf

iTrader: (4)

So Kim even with the butterflys closed you still get some brappyness? I am still thinking about doing this (or just do a 4 port with 2 30-40mm p-ports). But I also think that the LIM should be changed around. So that the AUX ports have their own runners. Kim definatly keep us updated.

Kim

550 secondaries installed, This thing pulls just fine despite the ghetto-*** exhaust. No dynotime yet, which sucks because I just parked her for the winter

Over the winter I just might go carb, I like a clean enginebay, hates wires so it seems like the route to go.

NoviceRotaryTech.

So I think I have certain things Im definitely going to do as far as the set-up goes.
Its an s4 n/a motor.
Im going to bridge port the auxiliaries. And street port them, mostly going up.
Ill street port the ports below the aux. going down a bit.
Ill leave the primaries alone.

The one thing Im still deciding is, if I should BP the ports below the aux. ports too.
aka: 1/2 BP
Im not sure about the mixture and tuning of the things Ill need to satisfy that size ported engine.
Like If my only plan is to upgrade secondary injectors and have a piggy back fuel controller.

anewconvert, is running stock ecu and stock injectors, is that right? And thats maxed out / your maxing them out, basicly, right?

What size injectors will I need with each BP option, if it be aux. BP or 1/2 BP?

And as far as other things go...I plan to have, presilencer and some kind of flowing muflers, and intake. Vac lines / rats nest removal. I am going to keep the aux. sleeves. And, do some kind of oil injection mod.

Ive had this car for a month now, but haven't got it running yet, mabey this weekend I will.
I had to replace some fuses under the dash. There was some yellow wires hanging under there too. They were threaded up through the dash... it was a useless mess.
The fuel tank was leaking, I got that fixed. The passenger side muffler is rusted in half. And the bottom of the oil cooler looks damaged but not that bad.

later.

NoviceRotaryTech.

Correction on seals.

I meant to say "can you use 3 piece apex seals with bridge ports?"

I realized when I woke up this morning, that "2 piece" seals are the "after market" type, and 3 piece seals are the "stock" type that come with the cars from the factory.


Correction on ports.

I realize that there are different terms/names for all the ports in the engine.

I normally refer to "primary" ports as the ports in the very middle housing.

So as far as the end housings go I will refer to the ports as; "aux." ports and the ports below them.


And once again, what size injectors does anyone recommend?
Or can I "turn the flow up" on the stock injectors with a fuel controller?

Later.

NoviceRotaryTech.

I replaced the fuel pump, and in the process I cleaned out the fuel tank.

I made sure all fluids were good and cranked the engine. It started on the second cranking.
I smoked a lot from the exhaust. It needs a new alternator and a new trailing coil though.
I shut it off and let it sit, while I checked things out. Then started it back up. It did stop smoking at that time too.

The only major problems Ive got to work out next is the clutch and brakes. It seems they won't flow any fluid. I tried bleeding them and got nothing.

And all this from a 1987 Mazda rx7 (I think the model is a GXL.) that was sitting in a junk yard for three years.

It supposedly has like 89K miles on it.

I think it need 2 new tires too.

Thats it for now.
Later.

NoviceRotaryTech.

Ok so Ive started it up for the 4th time (since I got the car.) today, it smokes a little (blue) until its warmed up.

Ive got all new clutch an brake master cylinders and a slave cylinder.

I also replaced the trailing coil and the brake booster.

I think the alternator is bad too.

I just need to bleed the systems and get 2 new tires, and it should be on the road.

I think ill run this car (as is) for a few months, then ill put it down for the bridge-port project.

fcboy89

good luck with this idea toby

NoviceRotaryTech.

So... Ive started it up a couple times in the past month to make sure everything was still good. But one of the last times I tried to start it, it wouldn't start.
Thought it was a flooding issue.

I also replaced the alternator with one from a '90 s5 rx7.
Got the brakes comfortable. Thing is I forgot to bench-bleed the master-cylinder.
Had to bleed the **** out of the system.

So yesterday I bought spark plugs, and made sure that the engine wasn't flooded by doing an extra un-flooding procedure.
I then put a small amount of 2-stroke oil in the combustion chambers to make sure that it would start. And it started.
I got it ready for the test drive, and switched two wheels from my good rx7 so it could roll.
I tried to start it again but it didn't start, so I did the un-flooding and 2-stroke procedure again. Got it started again.

Then I DROVE it. I drove it up the hill (driveway), then up the street, turned it around, stalled, but was able to kick-start it, then
drove back, stalled again at the top of the hill (driveway), got it to its original parking spot, but had to push it in there cause the
battery was worn down.

So I think it has some idle problem(s), starting/"flooding" problems and a charging/battery problem.
BTW, I also borrowed the battery from my dads Ford Ranger.

And the steering was horrible, I found out why later, (bent tie-rod end), driver side.

For now I understand / know what to do about the other problems.

The one thing I'm concerned about is the "charging / battery" problem.
The voltage gauge is reading below the 12v mark still.

Any Ideas? Comments?

Later.

anewconvert

iTrader: (1)

If you are going to tear apart the engine and bridge any of the ports at least do a half bridge. I have the 5/6 ports bridged, and frankly if I were to do it again I would at least go with a half bridge.

Reason being that the 5/6th ports and the Secondary ports (the port under the Aux ports) share a common intake runner. With a stock or streetport when the rotor covers the port the intake charge slams into the runner and a high pressure wave runs up the intake port, and charges down the other intake runner pressurizing the intake cahrge intot he other rotor. this is what the VDI on the S5 intake helps facilitate.

With a BP the port doesnt actually ever close. The bridge is wider than the rotor tip, so as the rotor shrouds the secondary port the bridge is still partially uncovered. the problem presents itself that when the rotor closes the secondary and aux ports the aux bridge is open. So now you have a high pressure wave running away from the port, but you still have air trying to enter the bridge port. Basically you screw that all up. Its not devastating. The engine still runs, but you are messing up the VDI effect, and not getting all that you can out of the engine.

If you are going to bridge you should bridge the entire secondary/aux port side at the least. This way they have the same effect on intake velocity in thier common runner. If you insist on bridging only the Aux port then I highly recommend you have a custom intake manifold built that has individual runner for the Aux ports. You would also need to have a butterfly vavle of some sort built to keep the aux ports closed under low engine speed conditions or you will lose the low end benfits of only bridging the aux ports inwhich case you might as well have gone to a half bridge.

As for the stock ECU. Im not sure that I am running it ragged yet. I have to get my header installed and see if that cures my upper rpm issues. Basically from 7k rpms on the car falls on its face. I think this is from the stock exhaust manifold being unable to flow. With a bridgeport you wont be able to, or will barely be able to, run a stock ECU. Thats the one benefit of the actuated bridgeport. I dont NEED a standalone. I do feel that the stock intake manifold and ECU are seriously holding back the cars potential however. Im just guessing, but i think there is at least 30 hp help up between the two. Likely more.


BC

NoviceRotaryTech.

About ports: This engine is an S4, no VDI.
So will the "pressure waves," if any, effect anything?

anewconvert

iTrader: (1)

Yes. How much, its hard to say.

What this all really boils down to is that the stock intake mainfold is insufficient for a bridge. Even if its just an Aux bridge it just doesnt flow well enough and it isnt tuned correctly in both length and cross section.

If you want to get the most out of a bridge port then you should build a custom intake manifold, or have one built for you. With a bridged aux port you should have the manifold built with individual runners for each aux port that are seperate from the secondary runners. If you do this you should find a way to isolate the 5/6 port runners from the plenum at low rpm so that you keep the benefits of running an aux bridge. (the good idle characteristics, quieter idle and low throttle driving.) If you dont isolate it then you might as well just run a half bridge and call it a day.

If you half bridge you can run them off a common runner and wont need to isolate the runner from the plenum at idle/low volume. You will lose low end, but gain it back up top.

In any case the S5 intake is good for anywhere from 15-25 hp (depending who you ask) over the S4 intake. If you arent going to build a custom manifold you should look into swapping them. The difference in top end is probably just going to get exaggerated by the bridge if you dont.


BC

rotarygod

iTrader: (1)

VDI is a little misunderstood. It does mean Variable Dynamic Intake but all that means is that your intake runner effective (not actual) length changes. You still have the return pulse waves on an S4 intake too. The S5 VDI valve allows the engine to see 2 different length runners depending on if the valve is open or not. Although the actual lengths never change, it's what the engine sees that counts. When the VDI valve is closed, the engine thinks you have longer runners than an S4 manifold. When the VDI is open, the engine thinks you have shorter runers than an S4 manifold. This means that you should have a broader powerband with an S5 intake and in fact you do.

I see people claim that an S4 manifold has straighter runners than the S5 so it must flow more and make more power. Yes they are shorter and straighter but the comment about making more power based on flow is wrong. There is more to power than just pure flow. The pressure waves within the manifold alter flow and have a strong effect on power. They "can" be so strong that the pressure in the port just before it closes can be up to 2 psi. It's not to say that your engine always sees this much all the time. It doesn't. For a split second it might see this before the port closes which helps force a little more air in at the very last possible moment. More air is more power.

Both of these manifolds are designed around a relatively mild intake port setup that needs to make good low to midrange power. They keep velocity high for this powerband but it hurts higher rpm use such as where a bridge or p-port would run. There's always a tradeoff. If you want a bridgeport, you need to change the manifold. It does need to flow more to get to the strong areas of the bridgeport engines. To do this you need a free flowing manifold with shorter runners. This means that low to midrange power will suffer due to velocity being slower in the manifold but it will make fantastic top end power like they are supposed to. This is the misunderstood part of porting that people argue about when they say that certain porting styles make less low end. All things being equal intake wise a bridge or p-port engine will make more power everywhere including the low end than a stock or streetport motor will. It will need to be under a higher load though. Power will probably fall off pretty quick on the top end though (not saying you still own't have more) and you won't realy be taking advantage of a brideports strongest area.

Now if you change to a shorter runner higher flowing manifold, your intake velocity slows down but your top end power really takes off. That's what a bridgeport does best and where you want it to be. With this intake design though low end will suffer and now you may not get as much low end as a stock or streetport. Many people don't quantify the total system design when saying X port makes more power here than Y port, etc... You can change the results of that argument pretty easily depending on the total system design. There's more to it than just the porting.

If you are not going to replace the ecu with a standalone (or godforbid even a carb) and are not going to change the intake manifold to something better such as a Weber style, please DO NOT do a bridgeport on a nonturbo engine. Don't bridge any of the ports. Do a streetport and enjoy it. You'll be happier you did. Forced induction changes the rules as a turbo can compensate for many different things. If you want a bridge with a turbo, you still need to follow some of the same rules as the n/a setup such as a free flowing exhaust. This means no stock T-II turbos and please dump the factory ecu anyways. No bandaid devices such as S-AFC's or other pieces of junk. Get a nice properly sized aftermarket turbo on there that spins faster and has less backpressure. That is the main enemy of a high overlap engine. Excessive backpressure not only holds power back but it also increases your risk of detonation as strange as that may sound.

A bigger port is NOT always better so don't be tempted to just go bridge because it must be better. If the rest of your setup isn't exclusively designed around it, it probably isn't and the opposite may actually be true. Be realistic on your mods and do it right the first time. I've seen people rig things up improperly using excuses such as "I plan to do it later" etc... and all that ever happens is that they hurt something that needs more work and more money. If you've got a 6 port engine and it's staying n/a, you most likely want to keep it a streetport and even then don't get carried away like too many people do.

NoviceRotaryTech.

Seems to me theres a lot of arguments/etc... on this site as far as building up N/As go.

Lets sort out a few things. Correct me if any are wrong or off. This is my opinion on these things, and I have thought up a set-up because of these.

Rotaries: "good for high end."
Bridge-ports: "also good for high end."
Reason manufacture made things like, aux / 5th & 6th ports, VDI, and primary & secondary things: "So that the high end can be open all the way, and the low end can be varied / moderate / (cant find the right word) / drivable."

So my plan is to open the high end up even more without sacrificing the low end "too much," and without going big, like a standalone.

So my setup: S4 n/a, aux-BP and SP, I'm keeping the aux. actuation. I do want a good flowing exhaust system. Mufflers with a balance of best free-flowing and best quietness as possible. (I don't want to get into that yet.)
And I do realize that better flowing intake components is good to have, like MAF, etc...
So the reason I want to only port the aux. and keep the aux. actuation is so that I can keep the low end. And the reason I want to BP & SP(besides knowing that I have a BP, and possibly that cool BP idle) is because theres more port area with a BP & SP than just a SP. More port area = more air intake / more power etc...
Even though some ppl say a good SP would suffice. I say why not add to that.

So is all that so complex to obtain?

anewconvert, It seems to me you have close to the same set-up, with aux BP and actuation. And have felt the bump in power in the high end, but have some problems with hesitation and a face plant at / near red line.
But that might be because of restrictive exhaust / MAF, not enough injector flow (bigger injectors needed) other problems etc...

So it seems to me that you don't like that set-up, you'd rather go with an 1/2 BP all because of this info about the intake manifolds and having "negative" pressure waves and intake charge. Unless you create your own manifold with separate runners etc...(I don't mean to be exact on your words, just to get the over all picture.)
Dose the "negative pressures" make that much a differance? Even at the high end, which is what were building the engine for.

It also seems to me that the S5 intake, (VDI) was built for a "saving low end" design (I'm I wrong or right on this?). And that between the S4 & S5 whats the differance at the high end? Dose one actually flow more / better? Which one?

Later.

NoviceRotaryTech.

Wrote my last post befor rotarygod's post, Sorry if missed anything, I write slow. Im reading it now.

rotarygod

iTrader: (1)

Don't worry about which flows more between the S4 and S5 manifolds. The S4 does but the S5 makes more power. It's not about total flow potential. The S5 manifold is tuned above and below the S4 manifold runners which means it should make more power above and below the S4's power peak. It's the better manifold but still wildly inappropriate for any bridgeporting.

The small bridge on the aux ports combined with the poor flow characteristics of those port runners means that you aren't really getting any more flow with them. You would do better to not use an aux bridgeport. You are not taking advantage of the bridgeporting style in any way. Stick to a streetport. If you want to do a bridge, go all the way with it and change EVERYTHING about the intake and exhaust system. That's the only way to go. Just say no to aux bridgeporting!

There are too many "but's" when it comes to saying a certain port makes more power. Yes a bridgeport (when done properly) makes more top end power. They "can" make more low end power depending on your setup and what load you are operating at. The aux ports are made to increase top end over the conventional 4 port setups because they close later. This does not mean that they necessarily make more power than a good bridgeport. Not at all. Everything is done in relation to something else but not necessarily in relation to the same thing as something else being state or compared.

anewconvert

iTrader: (1)

Im nearly certain that the high end issues are the due to the fact that I have a stock exhaust manifold still on the car. If I would ever stop being lazy I would install it, but That would also mean driving the car to an exhaust shop with an open presilencer to get the cat back cut and welded.

I would have gone with a full bridge had I known what I know now. (which is a good reason that you are asking these questions) Reason being that I will need to make, or have made, an intake manifold to take advantage of the Aux bridge, in which case I might as well have just gone ***** out and done it right the first time. I will be picking up a standalone once I get the exhaust sorted out, and that is one more reason why I should have just gone full bridge.

The way I see it, if you are going to half bridge you might as well just go full bridge. Why take on the compromises of a bridgeport and not get the most out of it. If you are going to go through the expense of building the system around then engine you might as well setup the engine to make as much power as possible.

I agree with rotarygod on the aux port. Its a compromise that is unnecessary. If you dont wnat to go ***** out and build the motor and intake/ecu/exhaust up then go with a streetport. You will be happier. Im certin that a SP 6port NA could hold tight with, if not beat me, at this point. Now if you are willing to go to the trouble of a new intake, exhaust and ecu then you might as well get all of it that you can and go AT LEAST 1/2 bridge. The aux bridge becomes pointless at that expense.


Since I already have an aux bridge (I purchased the car and engine from Rotary Resurrection as is) I am going to build up the car to handle a full bridge down the road, and once Im satisfied with the system supporting the engine I will pull the motor and have it fully bridged.


BC