I have a GReddy kit & boost controller and am working with a tuner to get the most out of my 8 without popping the engine again.

It's been ported, and is using a skunk works standalone ECU that will allow us to control the secondary & tertiary ports.

Theoretically, we should be able to get more power at mid rpms by increasing the mass flow rate via tweaking when the ports open.

Has anyone actually tried this yet and/or have any substantive information to share before I charge in as the 'crash test dummy'?

Thanks.

ahh skunk works...

ahh skunk works...

'skunk works' as in 'cannot disclose the vendor' as opposed to a specific brand!

I was actually thinking of disabling the APV motor. I notice that the boost falls-off at the same time as the third runners are opened. This also coincides with a lean spike at precisely the same instant. I haven't really thought it through yet, but I am guessing that 1) the additional volume present when the third runners open is just too much for the little turbo to keep up with, and 2) that the sudden influx of air is what is causing the lean spike. There are no fuel injectors in the third set of runners.

Like I said, this is half-baked, but I do know that the lean spike, boost droop and VDI opening all occur at about 6000RPM quite consistently. I believe it is due to the opening of these runners. I want to try keeping them CLOSED.

I got mine tuned at Full Function Tech in Union City. They have a lot of experience with various ecu. You may want to give them a call. As far as port timing, the only person that I think has messed around with that is Dean (Xyntax). You may want to give him a pm, and see if he could lend some advice.

You know, I just asked about this not too long ago. Something to control when the ducts open up. Every (NA) dyno you see has a drop at each point of the variable system kicking in.

Like I said, this is half-baked, but I do know that the lean spike, boost droop and VDI opening all occur at about 6000RPM quite consistently. I believe it is due to the opening of these runners. I want to try keeping them CLOSED.

Why would it be lean? the stock pcm over fuels when they open to keep it from being a too lean point. That’s partially why the hp line drops on the dyno. You definitely don’t want to keep it closed- you want to keep it always open for a turbo

I suppose that it would be lean because you have a lot of air suddenly coming in with no fuel mixed in it. I definitely didn't see a surge in the duty cycles of the injectors when I was logging them over the last few weeks. There are no injectors in the tertiary runners. Maybe it takes an instant to reach a mixing equillibrium. You know, there could also be a dip in power due to a lean spike, not just a rich one. I'm not sure that you could see this spike with the smoothing the dyno shops do. Its pretty fast.

That being said, I think that lean spike is much less pronounced now that I am controlling the P2's like I am. I wish I could post a graph, but I'm traveling right now. It's uncanny - right at 6kRPM (or there abouts), there is a lean spike and the boost starts to fall-off at the exact same instant.

If you can fill the combustion chamber using only 2 of the ports, why would you necessarily want to have all three always open? It seems like just more volume that you are asking the turbo to pressurize without needing to.

The quantity (mass) of air that enters the engine is important for making hp, not the pressure the air is at. People port engines because it increases the flow capacity of the engine. By opening up the tertiary ports you have increased the flow capacity. If the boost falling off is due to the ports opening, then its just because the Greddy turbo can't flow enough to sustain the pressure you're aiming for. But you are better off with the increased flow and less boost pressure as a result of having them open. It means the turbo isn't working as hard and you'll have lower intake temps and even though the boost decreased, the flow itself has remained constant, or possibly even increased slightly due to less restriction.

I don't think it would be good to have them open all the time either, as that would hurt off boost response. Instead having them open at a preset pressure >0psi would be ideal.

i'll give you a warning - if the ecu goes to open the secondary ports and finds them already open, it will throw a CEL because it thinks they are stuck open

The quantity (mass) of air that enters the engine is important for making hp, not the pressure the air is at. People port engines because it increases the flow capacity of the engine. By opening up the tertiary ports you have increased the flow capacity. If the boost falling off is due to the ports opening, then its just because the Greddy turbo can't flow enough to sustain the pressure you're aiming for. But you are better off with the increased flow and less boost pressure as a result of having them open..


I agree with you. Its the mass that's important. That's why I qualified my statement with "if you can fill the combustion chambers". Porting just helps you get the air and exhaust in and out more quickly - which pressure also does (and maybe does better?). But, if the combustion chamber can be filled to capacity in the time alotted, then fill pressure seems to be the variable that determines how much air you can stuff in. It just not going to take in more unless the pressure is higher. (again, if you don't have to worry about the time available to do it) Given that you can get the air in the chamber during the time available using only the first two sets of runners, asking the turbo to also fill the othr intake runners doesn't make sense. Just my thoughts....


BTW: Am I the only one who has logged the lean spike and the boost droop occuring at exactly the same instant?

But the pressure dropped when the ports opened because the flow was increased. Pressure and flow are inversely related. A flow increase means less restriction. So the turbo isn't working as hard and won't heat the intake charge as much. Imagine trying to feed the engine through a straw. Yes the pressure would be huge, but that isn't going to give you alot of power because there isn't enough flow. By opening up those intake ports you increase the size of the straw the engine can breath through -> more flow, but less pressure.

i'll give you a warning - if the ecu goes to open the secondary ports and finds them already open, it will throw a CEL because it thinks they are stuck open

oh right- forgot for a moment. there is a cel for stuck open but not stuck shut

rk...
I don't feel like you read my post. I agree with you. What I am saying is that just because you have more passages to get air into the engine doesn't mean that the GReddy turbo can take advantage of them. You say the flow rate increased. You could speculate that its flowing faster through the turbo, but you can't say that there is any more mass flow into the the engine! Afterall there are several more feet of empty space to flow into all of a sudden. The problem is that the GReddy turbo CAN'T flow any more. If it could, it would! It would maintain the pressure when those runners open up if it were able to, right? I mean the wastegate is closed and its not ABLE to get to full boost. Its not suddenly going to a more efficient state of operation. Its incapable of maintaining boost because it can't flow any more air. If it could, it would. What else would stop it from going into full boost?

Besides, has anyone with a boosted 8 ever felt a surge in power when the intakes open? I certainly haven't. I don't think its going to buy you anything to open them or keep them open for this turbo.

rk...
Its not suddenly going to a more efficient state of operation. Its incapable of maintaining boost because it can't flow any more air. If it could, it would. What else would stop it from going into full boost?

Besides, has anyone with a boosted 8 ever felt a surge in power when the intakes open? I certainly haven't. I don't think its going to buy you anything to open them or keep them open for this turbo.

The boost controller is limiting the boost to x psi...that's what's stopping it from going to 'full boost'.

Funny you should mention a power surge when intakes open. Just today, I finally revved the engine past 7k, and WHOA! did I ever feel a surge when the tertiary intake ports opened! This didn't happen with my old setup, but now that I'm ported and have bigger injectors, maybe that's the explanation...the engine can get rid of the extra air due to better exhaust flow.

Oh well, I'll know more on Friday when I take it for my first round of dyno tuning.

I am agreeing that the Greddy turbo probably isn't flowing much if any more air as a result of those ports opening. What am I saying though is that the less restriction in the intake path reduces the work the turbo has to do. So it may be flowing the same cfm, but it is not spinning as fast to do it. This means a cooler intake charge because the turbo would be operating more efficiently. With the Greddy turbo, I don't think it will make a huge difference either way. With a larger turbo it could be significant. But hey, try it out and see what happens. This was just my opinion.

The boost controller is limiting the boost to x psi...that's what's stopping it from going to 'full boost'.



Ummm. no. We're talking about the boost drooping below the set point once you go past 6kRPM. My boost controller is at about 8psi right now. But it starts to fall at 6k and reaches about 5.5 or so at redline.

RK, your're right. We are all just speculating. Its easy enough to disconnect that motor. I'm going to try it tonight and report back.


MD

Ummm. no. We're talking about the boost drooping below the set point once you go past 6kRPM. My boost controller is at about 8psi right now. But it starts to fall at 6k and reaches about 5.5 or so at redline.


MD

Does your boost controller have an RPM offset? If so, that will fix the problem of the boost falling off at higher RPMs. The stock GReddy turbo will sustain at least 8psi up to redline...I myself have seen that as well as many others who post on this board.

Okay. I just returned from testing out my theory. I was right. Its the opening of the tertiary runners that causes the boost to fall off and gives that lean spike. I just disconnected the APV motor. It takes all of 2 seconds. I haven't bothered to type in all the data logs, but the difference is quite remarkable. With the teriary runners remaining closed, the boost is very flat, even in 1st and 2nd gears. There is not even a hint of that lean spike any more. In fact, the boost even PICKS UP towards red line! It does the opposite of falling off with RPM!!

I did all this testing with the RPM offset feature turned off - not that that feature ever made a damn bit of good for me anyway.

So, the only thing that remains to be seen is whether the mass flow rate INTO THE ENGINE (NOT INTO THE RUNNERS) is greater for the lower pressure when the runners open, or the higher pressure with them closed. Its obvious that the turbo reaches its limit on flow when the runners open, hence the boost droop. Now we just need to see if the flow is wasted by filling the volume of the runners or not.

I couldn't be sure that I felt any difference in performance either way. Its probably a 10HP type thing which doesn't feel like much on 250!! I think dyno testing is going to be the only way to know for sure which way is better. I was actually thinking of going to the dyno tomorrow. If I do, I'll test how this affects power output.

This is for sure, though. Keeping the teriary runners closed makes the boost nice and flat, even in the tough lower gears. Boost actually picks up with RPM as you approach 8kRPM. The lean spike that always accompanied the boost falling at 6kRPM is totally gone.

I am leaving mine closed for now - even just because the lean spike caused by the influx of air is gone.

good read. great job!

beers :beer:

Very interesting. Boost dropping off has been a big issue.

I've messed around with the E-01 rpm offset and I couldn't get it to go higher. Does anyone have some settings that worked for them?

I would love to be able to hold 9-10psi in the high RPM's. Now, can the stock injectors handle it, is another question.

Great results. I hope you decide to go to the dyno I'm very interested in how this effects things. I suspect as I said before that power will actually be down since there's going to be a roughly equal amount of flow, but hotter air due to more restriction. But, hopefully I'm wrong. Even if power is slightly down, this may be a good thing if we can eliminate that lean spike. If you do go to the dyno, it would also be great to see what happens with the ports forced open.

MadDog: so your holding boost to redline? if so is the power in the upper RPM's comparable to before? I was under the impression that the runners opening in the higher RPM's is what really gave us the kick in the pants? therefore if we keep the runners closed won't that hinder the high RPM power!?!?

MadDog: so your holding boost to redline? if so is the power in the upper RPM's comparable to before? I was under the impression that the runners opening in the higher RPM's is what really gave us the kick in the pants? therefore if we keep the runners closed won't that hinder the high RPM power!?!?


Acutally, boost is increasing as I approach red line. As I said, I can't really feel a difference either way. Let me ask you a question: are you boosted? If so, do really still feel a 'kick in the pants; around 6kRPM? I don't. Its hard to feel a kick in the pants with the turbo giving you a knee to the groin! :mdrmed:

Well, my experience is thus:

On the KL engine cars from Mazda (MX-6, MX-3, 626, 929, Ford Probe, etc.), the VRIS (Variable Resonance Intake System) was the cause of a lot of heartache for people when they added forced induction. Everybody wanted to keep it because it improved off-boost torque and such. Ultimately, those that just wired it open saw the best power and drivability.

When you are under boost, torque adders like that simply don't do anything but upset the flow. Now, I'd think the best situation is to have them OPEN under boost. Maybe the solenoids and motors could be hooked up to the boost sensor somehow. I'd say wire them to the VTEC output along with the temp dongle, but this would close them again after 5100 RPM.

The dyno is the only way to know for sure, though I'd want to see the intake temps as well to be certain the the turbo isn't working harder at high RPMs with the more restrictive, closed intake system.

Acutally, boost is increasing as I approach red line. As I said, I can't really feel a difference either way. Let me ask you a question: are you boosted? If so, do really still feel a 'kick in the pants; around 6kRPM? I don't. Its hard to feel a kick in the pants with the turbo giving you a knee to the grion! :mdrmed:
haha! thanks! :hands MadDog a bad of ice: and nope! not boosted yet.. weighing my options, waiting for other kits (looks to be a LOONG time), when I'm about ready to say screw waiting and pounce it seems another problem arises, but you seem to be on top of things and your research always seems exceptional! so thanks!! I'm sure I will continue to riddle you with questions from time to time!! :beerchug:

FI is all about getting a higher mass flow rate to the combustion chamber.

It is illogical to think that more power will be made with a flow restriction like keeping the tertiary ports shut.

Shutting those ports will reduce the mass of air that can get into the combustion chamber per unit time at higher RPMs. That's not speculation; it's basic physics.

You may have eliminated a lean spot, but have reduced flow. Therefore, your engine will make less power. Mo' bettuh you fix the flat spot with tuning rather than bugger your engine's breathing capacity.

^^ This is assuming that the primary ports aren't sufficient to fill the motor.
MadDog was alluding the the point that the inlet of the turbo has less flow area than the total flow area of the primary ports.
A chain is only as strong as its weakest link.
The added runners in the intake are designed to increase flow by a function of resonance.
While I agree that it cant hurt to have as much air available to the motor as possible, if the availability of that air is limited, giving it choices for a flow path is pointless.
Like some would post a GIF that reads "This thread is useless without pics!", I want one that says "This thread is useless without data!".http://www.mazdamaniac.com/portal/smiles/data1.gif
We need to know the vacuum in the inlet of the turbo and the boost pressure before the TB, after the TB and at the port (or close to it).
Along with that, we need to know the temperature at all of those points.
It pains me greatly that my car is 2500 miles and several weeks away from me at this time.
I'd build a thermocouple/vacuum probe and we would know all this tonight.:mad:

So many smart people on this board! love you guys! :kiss: :love:

^^ This is assuming that the primary ports aren't sufficient to fill the motor.
MadDog was alluding the the point that the inlet of the turbo has less flow area than the total flow area of the primary ports.
A chain is only as strong as its weakest link.
The added runners in the intake are designed to increase flow by a function of resonance.
While I agree that it cant hurt to have as much air available to the motor as possible, if the availability of that air is limited, giving it choices for a flow path is pointless.
Like some would post a GIF that reads "This thread is useless without pics!", I want one that says "This thread is useless without data!".http://www.mazdamaniac.com/portal/smiles/data1.gif
We need to know the vacuum in the inlet of the turbo and the boost pressure before the TB, after the TB and at the port (or close to it).
Along with that, we need to know the temperature at all of those points.
It pains me greatly that my car is 2500 miles and several weeks away from me at this time.
I'd build a thermocouple/vacuum probe and we would know all this tonight.:mad:

Agreed. I am going to find out more this afternoon. As luck would have it, two of the top tuners in the world are going to have a look at my 8 today.

Agreed. I am going to find out more this afternoon. As luck would have it, two of the top tuners in the world are going to have a look at my 8 today.And who would they be? If one is not Bob Norwood, then you are getting way too excited.

FI is all about getting a higher mass flow rate to the combustion chamber.

It is illogical to think that more power will be made with a flow restriction like keeping the tertiary ports shut.

Shutting those ports will reduce the mass of air that can get into the combustion chamber per unit time at higher RPMs. That's not speculation; it's basic physics.

You may have eliminated a lean spot, but have reduced flow. Therefore, your engine will make less power. Mo' bettuh you fix the flat spot with tuning rather than bugger your engine's breathing capacity.


OKAY! I HAVE A DYNO APPOINTMENT AT 3:30 PM MOUNTAIN TIME!! We won't have all the diagnostics that MM wants, but it will give us the ultimate answer, even if it doesn't tell us why!

It makes me laugh to think that this one discussion is going to make me spend $70 to answer this question! :ylsuper: But, hell.... I've done so many changes lately with the injectors and the fuel management strategy - I guess its time to see what's going on anyway.... I was hoping to lean things out a little bit before going to the dyno, but WTF. Therefore, I sacrifice my finances for the forum!

Sapph, the problem that I have is that the runners are in some sense acting like an accumulator. I just don't know, and neither does anyone else at this time, that the little turbo can supply enough air to fill all the additional volume presented to it. If the turbo were able to supply limitness flow, then the area of the intake ports would be the biggest restriction. In that case it would absolutely make sense to keep them open all the time. There are a ton of variables at work here. My totally unedu-ma-cated intuition tells me that the flow rate of the turbo is the biggest restriction right now. I say that because its unable to keep boost pressure once those runners open. If it had the flow rate available, it would try to maintain pressure. I could be totally wrong about this. Its all being pulled out of my :bootyshak . i was just happy that I was able to identify the reason for the boost drop off and the lean spike. But, honestly, no one has anything other than speculation as to the effects on power output. That's why I have the dyno appointment.

Damnit! Too late for me to get a flight to Albuquerque...

Damnit! Too late for me to get a flight to Albuquerque...


C'mon out! I'll wait for you!

I've got a bottle of Johnnie Walker Blue Label to toast with!! :rock:

I love it when people make financial sacrifices to further the 8 community. There's such love here.

How much boost will you be running on the dyno?

about 7.5 - 8 psi. Really conservative AFR though. About 10.5-11

I'm planning on just two pulls right now. One with the APV motor connected and one with it disconnected (runners closed). If it gets close to an hour's time on the dyno, I might just fork out the dough and do some tuning while I'm up there.

C'mon out! I'll wait for you!

I've got a bottle of Johnnie Walker Blue Label to toast with!! :rock:Bah! $460 for a round trip today and I can't get a return until Sunday, which is too late; I have to work on Saturday. Plus I don't think I can get to Albuquerque in time - the next flight out is at 9pm EST.

Take pics.

However, I'm planning on some free time in March once I'm moved out there to Phoenix permanently. We should book a day at the dyno.

Did you try Southwest out of BWI?

Agreed on the dyno time. I'm willing to drive to Phoenix. Maybe more 8 owners out there to hook up with. The 8 owners here are really timid. I think the RB intake is the wildest thing any other 8 owner in Albuquerque has done... we're really pushing the envelope here in New Mexico.... :boring: :boring: :boring: :boring: :boring:

Did you try Southwest out of BWI?I'd rather gouge my own eyes out with a plastic spork than fly Southwest.
Besides, I automatically get upgraded to first class on AmWest, so I am spoiled.

Agreed on the dyno time. I'm willing to drive to Phoenix. Maybe more 8 owners out there to hook up with. The 8 owners here are really timid. I think the RB intake is the wildest thing any other 8 owner in Albuquerque has done... we're really pushing the envelope here in New Mexico.... :boring: :boring: :boring: :boring: :boring:Well, so far, there are only two turbo '8s in Phoenix - mine and Mac's.
Here in DC, just about all of them are turbo now. :ylsuper:
Its really competitive around the Beltway.

EDIT - I just read your sig and realized that you and I have almost the exact same setup with the exception of the flywheel (I'm stock) and the mid-pipe (I'm not stock). Where did you install the WBO2S? I had to put mine at the back of the midpipe to keep from frying sensors every week.

Oh - HAPPY BIRTHDAY on Sunday!

This is cool, MD.

By the end of next week, we'll have some hard data. You might be right about keepin' the ports shut. We'll see!

Bah! $460 for a round trip today and I can't get a return until Sunday, which is too late; I have to work on Saturday. Plus I don't think I can get to Albuquerque in time - the next flight out is at 9pm EST.

Take pics.

However, I'm planning on some free time in March once I'm moved out there to Phoenix permanently. We should book a day at the dyno.
okay guys. I am actually posting from my phone. Im out drinking but wanted to give you early word of the dyno time. It looks like keeping the ports closed makes the power come on sooner but drop off in the higher rpm. Letting them open peaks the power later but holds it - not as much drop off. I think its better open. Ill post the sheets later. I did 233 peak running only 6 psi and afr of 11.

Okay, I'm back home now. Even a night of drinking is not going to keep me from sharing this stuff with you guys.

I'm trying to get the DynoJet software to give me a nice graph....

MM- Thanks for the B-day wishes! I can't believe you actually noticed... (sniff sniff) haha!

As far as the WB02 gage, I have it before my cat. I put it in the front flare, leading up to the cat element. Its been in there for about 8 months or so, I haven't lost one yet. I didn't even make that heat sink either....

Here it is!!!
So, let me explain.

First, I want to make it VERY clear that this set of runs represents a largely UN-TUNED MAP. I deliberately am running rich because I'm still cautious about the fuel system mods I just made. Also, I chickened-out and pulled the boost back to 6psi on the dyno. I'm running about 8 on the street. It was my first boosted dyno session and MM wasn't there to hold my hand so I was nervous. I just wanted to get this runner question answered, so like I said before, I rushed it, knowing I wasn't done tuning for my new injectors.

The first graph has the two dyno runs. Run 1 was forcing the runners closed, run 2 is with normal operation of the APV motor. It doesn't take a genious to see that the runners open is a good thing! The power definitely falls off even though the boost curve is much flatter with the runners closed. So, there is the answer! The turbo is flowing less mass with the runners closed.


The second graph has my stock NA curve for comparison. :rollingla :rollingla What a joke! Even with the richness of the boosted map, the total gains are really nice. This, my NA friends, is why you should stop wasting money on NA mods and go boosted! Sorry this one is versus speed instead of RPM. At the time I did that run, we hadn't yet found a good wire for the inductive pickup. It couldn't follow the RPM at all.

Now, the one thing that I didn't get to try that would be neat is to force them open the whole time. That motor just gets power when it needs to open or shut the runners. The polarity of the power is what determines open vs close. All you would need to do is to manually provide the power in the opening direction for less than two seconds (or you risk burning out the motor). Then, you just disconnect the motor, leaving the runners in the open position. Easy enough to do, and the service manual has everything there. I'll leave that to someone else to document. I'm not making any more trips to the dyno before I have leaned my MAP out a bit! ;) I might just try it tomorrow without going to the dyno to see if my ass can tell the difference, but I doubt it will. I am a little concerned that the additional airflow would make things too lean. But, you could just tune for it. Playing guinea pig is starting to take its toll on my nerves, though!!

BTW: any thoughts on why these curves are so rough?

you can see the VDI open at 7250 giving you back a couple of hp

you can see the VDI open at 7250 giving you back a couple of hpIts turbo. There is no VDI.

Here's a couple of ideas:
1) can the APV motor be rigged to an analog output from the e01? I know it has one, but I haven't looked at it closely yet.

2) the PCM cycles the APV when you shut down. I suppose you could try the 'always on' configuration by waiting until the PCM cycles open, then quickly removing the connector before it cycles closed! I don't know what this would do to non-boosted driving, though.

Very conclusive results. Thanks alot for providing them!

Leaving them open all the time would definitely not be good for non boosted driving. You'd loose intake velocity.

Its turbo. There is no VDI.

well he loses power from 6500 to 7250

http://www.rx8club.com/attachment.php?attachmentid=68303

the only thing that happens at 7250 is that the VDI opens to cross connect the intake tracts. so essentially at 7250 he starts to use part of the tract that he wasnt using by keeping the APV closed at 6500. unless there is some other explanation?

The VDI doesn't increase the flow to the engine. It only connects those two runners for the resonace effect. The opening of the tertiary runners does result in more mass flow rate to the engine. Hence, the power increases a little and holds steady, rather than falling off. Even though the turbo can't maintain pressure when the tertiary runners open, the flow rate is increased because, as we now know, the restriction in the system (at least at higher RPM) is the area of the intake, not the area of the turbo inlet.

The AFR curves also show the increased air flow. When the tertiary runners open, things stay on target. With them closed, the A/F goes down, indicating not enough air is entering the chamber. I re-posted that graph to only include two runs. Take a look at the new one for a little clarity on the AFR curves.

well i had to go look at the diagram again- i was connecting the wrong tracks in my previous post.

but the blue power line still does the same thing

http://www.rx8club.com/attachment.php?attachmentid=68318

drops until 7250 where it bumps up. your experiment as i understand it kept the tertiary tract closed at 6500. hence we see the power fall off. but at 7250 the VDI opens. thats exactly where we see your power bump up.

http://www.rx8club.com/attachment.php?attachmentid=13884&stc=1

so it must be having some effect?

Its turbo. There is no VDI.
Jeff are you confusing VDI with Vfad?

Scott does turn off VDI with his Interceptor. So he must have found it to make a positive improvement. My dyno graph doesn't have that spot, so Zoom may be correct in that the VDI system is causing it.

VFAD SSV APV VDI ....whatever.... ;)

;) fixed mine

rk it could be a result of keeping the runner closed at 6500. maybe if the runner opens the later VDI opening has no effect- it appears it doesnt in the other run on his chart. (well there is a small blip there but nothing like in the blue run)

I'm talking about the dip in power right around there. I've circled what I'm talking about in the dyno chart. It is there on both runs.

oh ok im talkign about the areas ive circled here.

i think the aea you have circled might be due to mad dogs injector control AFR looks like it goes a little richer there especially in the red run

Hmm, you're right. There places I circled are too early to be VDI.

ooh i just had a thought about this-

the stock maps are built with the idea that the VFAD will open at @ 5500 and WOT. so the stock maps probably add fuel at this point expecting there to be more air coming. since mad dog doesnt have total control this fuel must be added with the injectors he isnt controlling. the added fuel costs him a little hp.

with the interceptor the maps were made without ever considering added fuel for the VFAD because the T cars have all done away with the VFAD. so you dont see that dip.

Jeff are you confusing VDI with Vfad?Yes I am, absolutely.
Sorry. Brain fart.

Here's a couple of ideas:
1) can the APV motor be rigged to an analog output from the e01? I know it has one, but I haven't looked at it closely yet.

2) the PCM cycles the APV when you shut down. I suppose you could try the 'always on' configuration by waiting until the PCM cycles open, then quickly removing the connector before it cycles closed! I don't know what this would do to non-boosted driving, though.Once again, since I don't have my RX-8 in front of me, I can't contribute.
I would get an ammeter (set your VOM to current) and run it inline with the input to the APV motor. If the current is low enough, you could run it directly. Otherwise, you would need a relay/triac setup or even a low-power motor controller hooked up to the pulse output.
Its just a servo motor. I don't even know what it looks like, though.:mad:

It needs from 0.9 to 1.9 Amps ... way too much for the e-01 to supply. I was thinking about running a relay.

Wow. Almost 2 amps. That is a lot of current to pull right through the PCM.
I guess the injectors do the same.

Remember, it is bi-directional, so you need to wire it accordingly.
That is why I suggested a motor controller and an analog to PWM triac or similar.

ooh i just had a thought about this-

the stock maps are built with the idea that the VFAD will open at @ 5500 and WOT. so the stock maps probably add fuel at this point expecting there to be more air coming. since mad dog doesnt have total control this fuel must be added with the injectors he isnt controlling. the added fuel costs him a little hp.



Hey Zoom, I know this isn't the RPM you are talking about, but checkout this plot from Xyantax. This is the lean spike that I was always observing at ~6kRPM. Finally, some evidence that this is a systemic problem. No one else ever came forward to say they have seen it.

Anyway, from the looks of it, it doesn't seem like the stock fuel tables are really compensating for the opening of these ports.

http://www.deanq.com/stuff/disabled_VDI.gif

I'm talking about the dip in power right around there. I've circled what I'm talking about in the dyno chart. It is there on both runs.
I think that is where the P2 injectors come on in a NA car...you have yours cut??

There is a rich spot there and it will probably smooth out when you tune the map better

dan that rich spot rk is talking about is on mad dogs chart. rk has said he does not have that there. and mad dog the post you quoted is talkign abotu the area that RK circled- but yeah i see your lean spot

Mad...with your logging of injector pulsewidth, and injector staging...have you noticed how the P2 injector initiation is situated in regards to open/closed loop transition? Does the P2 injector initiate when the transition happens.....or at a set RPM/Load? I have noticed that the transition seems to move in response to ???? on the dyno. Probably time. Some plots have the transition at much lower levels...and go rich a lot earlier than others...yeilding lower power in the midrange....with almost the same Lamba readings after everything settles out when the APV opens. The more I think about it if the P2's come on in open loop areas...and and the Secondaries are supplying most of the closed loop areas...that you are on the right track to get the boosted areas sorted out.

Dan, yes. The injector staging varies a lot according to gear and load. Sometimes I could almost get to 7.5kRPM without the P2's coming on I was was just cruising and not really accelerating. Again, the gear you are in seems to be one of the variables. The PCM must have different tables for different gears. The P2's never come on in closed-loop operation from what I've seen. But, when they actually do come on, and their duty cycle, can vary quite a bit. The secondaries are definitely the ones that the PCM varies the most. The P1's are just always on full tilt.

When I took complete control of the P2's I had to account for the non-boosted operation of the P2's as well. I tried to err on the safe side: make them come on at the lowest RPM I had observed and give them the max duty cycle I had observed - regardless of gear or load. Seems to be working just fine so far!

The PCM must have different tables for different gears. The PCM has no way to know what gear you are in.
Instead, it extrapolates time data from the wheel speed and the RPM.
The PCM has different fueling strategies based on time at certain load levels.

The PCM has no way to know what gear you are in.
Instead, it extrapolates time data from the wheel speed and the RPM.
The PCM has different fueling strategies based on time at certain load levels.


Well, okay. While it doesn't have a 'gear sensor' it ceratinly is calculating (although indirectly) the gear by comparing wheel speed and engine speed. Its a direct and 1:1 mapping. I refer to the PCM fuel tables as 'gear sensitive' because the PCM behavior that I observe is consistent only in the same gear. The PCM isn't thinking 3rd gear, but the result is the same as if it were. And, its a useful way for me to think about it.

Scott said he believes my turbo died from short bursts of high egt's from lean spikes. These ports opening could have been the culprit! I didn't have a WB O2 at the time so who knows how much of a spike I was getting. Damn glad it didn't pop the motor!

Scott said he believes my turbo died from short bursts of high egt's from lean spikes. These ports opening could have been the culprit! I didn't have a WB O2 at the time so who knows how much of a spike I was getting. Damn glad it didn't pop the motor!As noted in tht other thread:

The shaft is blue because the turbo stopped spinning when the bearings died and it cooked with no flow.
A spinning turbo can take 2400°F without flinching.
You had oil pressure/flow problems in the turbo itself and/or surge which is why it failed.

We're seeing those same #@!$*' lean spikes.

This has forced us to take control of the injectors directly. I'm hoping to have the car back sometime early next week.

You mean that one at ~6000RPM when the tertiary runners open? Good luck tuning that one out. Its a bitch.

You mean your super-secret Skunkworks ECU wasn't taking full control of the injectors before? Interesting....

You mean your super-secret Skunkworks ECU wasn't taking full control of the injectors before? Interesting....

We tried spoofing the signals going back to the factory ECU so we could still get some use out of the factory ECU's control functions. Didn't work out.

We're controlling the injectors directly now.

Okay, I gotta say it: It sounds like you tried some kind of WB02 fooler to avoid fuel trim issues and that you are using an eManage....

Okay, I gotta say it: It sounds like you tried some kind of WB02 fooler to avoid fuel trim issues and that you are using an eManage....

Nope. No eManage, holmes.

Well?

Update please. We expended a lot of energy, and some of us $, on this question. I'd like to know what your results were.

MD

You & me both...I've been on tenterhooks for 2 weeks now.

anything?

So far, this is what I discovered on the forum and the manuals about APV actuation :
- the actuator is a DC servo motor that turns in one direction when it is supplied 12V, and the other when polarity is reversed.
- it cannot be actuated more than 3 seconds at a time - risk of burning it
- there is no mentions of mechanical stop to the system (that would stom the movement when APV is fully opened or closed) Q : are there mechanical stops?
- the system is controlled by the PCM in closed loop thanks to a (rotary?) position potentiometer feeding a 0-5V signal to the PCM.

I believe the system works in closed loop, with a DC motor controller opening and closing and determining the position with the potentiometer signal. It's basically close to the type of control you'd find for an Electronic Throttle Body (ETB), but without Pedal Position Sensors.

You cannot control it with a switch or a PWM driver. You need a proper DC motor driver with the necessary strategy. An ETB control strategy would work though with some trick for the Pedal Position Signal such a system would expect.

I have a few remaining questions about the APC actuation that I hope someone can answer :
1) Are there some mechanical stops at fully open and/or closed positions?
2) How many turns (could be a ratio of a turn too) from the APV motor to go from fully open to fully closed? This question is very important if one wishes to replace the APV DC motor by a rotary solenoid that's easier to control (any Turbo Boost Wastegate controller would do).
3) Has anyone tried to run with the APV always opened? And is there enough friction to keep the APV opened at all time without regulation?

I cannot find the answers to these questions by myself as I drive a SP 5MT version of the RX8...

Thanks for your advises and remarks,

Fabrice

^^^ I now have the replies to all my questions.

And the position feedback signal to the PCM is from a 0-2V Hall Effect sensor...

Fabrice

Has anyone successfully opened the secondary shutter on boost & spoofed the PCM? Same question for the Aux port valve.

If so, please provide all the juicy details and/or DIY.

Why can't one just unbolt the motor and turn the gear? I believe turning it counter-clockwise is the open position, but please confirm; it will be closed when you remove the motor, anyway. Then reinstall the motor but don't reconnect the harness.

Why can't one just unbolt the motor and turn the gear? I believe turning it counter-clockwise is the open position, but please confirm; it will be closed when you remove the motor, anyway. Then reinstall the motor but don't reconnect the harness.

I only want them open under boost, & also make sure that my PCM doesn' have a hissy fit. My XEDE has extra outputs, so I can wire it up to pop open the secondaries at a certain boost. There have been a few writeups in this thread, but they were all somewhat speculative. :crazy: :lol2:

any progress?

Bump.

Has anyone got a DIY on controlling the intake runner valves?

well this was a good read . A lot of buildup but no climax :(

great thread:)

I'm pretty sure Ryan, Tim and I contributed all that was going to be contributed to this thread three years ago.

but there was no real confirmation as to whether opening the aux. port earlier was worth doing or not .........
If you follow the logic that Mazda had in designing this in the first place and open it at the same g/s that they do then with a turbo you would open it at around 4000 -4500 rpm
I think it would help with the lean spike as well .