Oh I think it would be very easy. Building the slide throttles/extra airbox/actuator/runners is the part I dont want.
Id rather a bit more simple.

Does anyone know if anyone has actually done the side port primary, PP secondary yet?

I did read a thread on the UK rotary forum of a guy who was doing just that, but the thread just stopped.

I am tempted to try this, one because it makes the manifold WAY easier and two, because Im curious!!

Obviously though, if someone has tried it and it made less power than a stocko...I would reconsider.

 

Do it other way around. Peripheral port used all the time and side port actuated in high rpms. Mazda did build such engine and though we don´t know absolute power numbers, volumetric efficiency curve was very good and high in whole rev range.

Using side port as primary won´t give you smooth idle nor torque of peripheral port in low-end and midrange, and running both would hinder airspeed with poor consequences in driveability and again - torque.

Make PP rather tame in size and timing, for strong low-end and midrange and additional port area and duration of side port will take care of top end.

 

Due to the way the throttle body is designed, I dont think I could. The throttle pull operates the primary shaft which in turn (through the adjustable linkage) opens the secondaries.

I am not after a smooth idle, if this thing dosent brap its head off, I will idle it off the PPs!!!

Also as far as the low end stuff goes, it will be interesting, because you must remember that the throttle is mechanical on the secondaries, not rpm activated. So the PP would be open if I put my foot down, regardless of RPM.

Where the staged thing comes into it would be when driving light throttle around the street, running off a primary bridgeport only.

Does anyone have any suggestions for the timing?

I was thinking of positioning the PP to open equally before and equally close after the primary BP. But I wont know this till I speak to Xtreme to see what the timing of the primary BP is.

Does that sound resonable, or should it be something else? Also for ease, I was looking at keeping the PP round on the housing surface. Obviously this would make the port open and close slower though. Is that bad?

The port timing would be something like this pic, this is for visual only not actual. You can see the red would be the opening closing of the PP and the green would be the BP.


Does 40mm PP sleeve (with 45mm runners) plus a BP primary sound like enough port area?

 

Also I have just realised that BP only on the primary ports, would allow me to run a 2 piece seal if i wanted to.

The plan was to try this setup on my old housings, which arent perfect and then if all is good, buy some new housings, port them and buy ceramics. Being street driven, I imagine the 2 piece would be better.

 

Vtec controller?

 

To you mean to actuate the slide throttle?

If I was to do this, the LINK G4 Extreme is capable of that with one of its many aux outputs.

 

I think my mind is made up on purchasing the LINK G4 Extreme for this job. It seems to do everything I need and more.

I will be looking at running 3 X 550 primaries and 3 x 1000cc in the standoff position on the secodaries.

The LINK can not only stage the injection, but allows you to allocate how much % of fuel you want from primaries vs secodaries. This is handy for me because I would like the standoff injectors to do most of the work at WOT.

Also anyone out there have any suggestion as to the PP size/timing questions?

 

I love that you guys in AUS will use other ECu's than microtech and Haltech. I've been a vipec distributor here in the US for 2 years. Haven't sold a single one yet. Guess I'll just get one for my FD.

 

That picture looks familiar
Round ports act like square ports with less timing, also, looking at your lines, that's going to be one small bp, why not make it roughly the same timing as the p-port? Intake closing also looks a bit early, like 65-70 deg ABDC? As for intake port timing, There are some handy SAE papers floating around about that. What I basically did is determine intake closing timing by looking at what sort of RPM range I want my power to be at, then determine port area, and the width of the port and how I want to make the runner, which automatically defines intake opening timing. I think early intake opening timing is a 'nasty' bi-product of a large peripheral port that closes at a normal point that you just have to live with.

 

Hey John, yes all credit to you for that pic!! It was just too easy to use it for a visual.(hope you dont mind).
The BP is just a visual too, so people could understand what Im talking about. The BP is being done by Xtreme Rotaries and is done with a CNC. I will be hand finishing the port but it will be whatever they do.
So Im not sure whether to design my PP around that BP timing or, just out it wherever a 40 odd mm PP would be.
Having peak power a little less than normal wouldnt hurt. Im guessing somewhere around 8500-9k?

 

Yes, it sure is handy. On my computer I can manually enter a port timing, and the rotor will automatically move to that position. Really handy for sketching in different port designs quickly. I can not help but think that a side port + bridge port + peripheral port will peak a little bit higher than that, even if you keep port timings conservative. There's just soo much port area, you'll probably need to get those RPM's up to get some velocity in there. Have you contacted judge ito on this yet? I can image he knows a thing or 2 about this.

 

No I havent had any input from Judge yet. I have posted on nopistons tho.
Still waiting to see what Xtreme thinks about it.
Maybe it would be better to even loose the BP on the primary and just an extend?
The primaries are pretty small on the 20B.

 

Well LINK G4 Extreme is on the way.
Injectors and D585 coils are also ordered.
I see much beer required in the near future for re-wiring my engine bay!!!

 

D585 are the gm Yukon coils right? That's what im currently running on my 20b. I upgraded from the Ls1's. I'm not sure if their an improvement yet since I have some electrical issues to sort out.

 

Yes, thats right. However these are not made by Yukon, these are made by a different company, same specs though, so hopefully same performance.
With the built in ignitor, the LINK should run these directly.

 

So Ive been thinking of the electronic RPM activated secondary throttle setup.

Does anyone know what type of motor would be suited to this application?

I was thinking something off a fly-by-wire car or something similar maybe, if anyone has any ideas Im all ears.

 

Older setups like on the 787B use regular 12V DC motors with potentio type sensors for feedback. Modern setups use stepper motors, and if you want to get real fancy you'll want a PID controlled servo motor.

But if I were you I would look at what the ecu can run. The link ecu can use the rx-8 e-throttle setup right? Can't you get one of those rx-8 throttle actuators, hook it up to the secondary throttle shaft and tune it in the software so that is does what you want? I can imagine there can be some sort of tuning map for it?

 

John, sounds likely. I believe the LINK has some PWM 12V and 12V outputs.

If I was to do it, I would drive the car off the PP, and have these open up the primary ports (as secondaries) when it suited in the RPM range.

So Id imagine that I only need the LINK to open or close it, (switched 12V?), I dont think it would require anything in between.

 

Fyi I know there mot made by Yukon. Here in the states a Yukon is an suv built by general motors that these coils are designed for. They are also found on the Cadillac Escalade.

 

On your electronic secondaries, you can also go witj a vacuum actuated butterfly valve setup.

 

The 70's called, they want your idea back
Seriously, if you have a fully programmable PWM output onboard you should try to use it. Works much better, PP's don't have a lot of vacuum, and vacuum don't offer a lot of adjustability. Most RC servo's can use a PWM signal, and probably some automotive actuators can too. Maybe give LINK a ring to see if they know anything suitable?

 

i'm not 100% sure, but i think they are miata headlight motors with a pulley on them. there are actually a TON of stock mazda parts on the 787B. the wiper is just a rear FC wiper, it uses a gsl-se radiator cap, etc etc

 

That's good thinkin! I like using stock parts whenever I can.

 

why reinvent the wheel? or the wiper arm? or the radiator cap? or the taillights?

 

I was actually looking at RC motors. They make HD ones which will be great to act against the butterfly springs.

Also they rotate at .15s for 60deg. So they wont be too slow!!

A little link on the arm to adjust that to the 76deg I need and thats it! Too easy.......hmmm.

Anyways, Xtreme didnt really have any input as to the timing of the PP. He hasnt tried anything silly like this before, so understandably probably doesnt want to guess at it.

But Im happy to try!

So lets say I go with the PP sleeve with a 40mm round opening at the housing face. Does anyone have suggestions as to where the centre hole would be, for a given timing?

John Im sure you could work this one out!! Keep in mind I will also have the primary ports open.

I also worked out the amount of area in the runners. The two for each rotor come to around 89cm2.
A 60mm throttle is 89cm2.