Simplified Sequential

[David Jerome]

For those who know me very well at all, they know I pretty much despise the stock sequential setup. I love it the 10 minutes of the year it performs correctly and Im sure it was probably great in 1993-1998 before people started pulling these cars apart, however, it is very rare to find them working correctly these days. Since I buy and resell fds and try to sell them as properly running cars, I almost always convert them to Non-Seq if I am doing a rebuild on the car also. This minimizes my headaches during the rebuid period and also the period after I sell the customer the car because if they have any boost issues or really issues at all it is pretty simple for me to diagnose over the phone.

Well, for whatever reason I decided to put the last car I bought back together as a proper running sequential car(shocking I know:) ) As I have been looking over the simplified sequential chart I have ran into some questions about the necessity of some of the simplified setup.

The lower vacuum nipples on the wastegate control solenoid and turbo precontrol solenoid are "T'd" into the vacuum lines for the oil injectors for the oil metering pump and ran into the plastic primary intake elbow. What is the reasoning for these lines being ran into the plastic elbow. I know it provides a slight source of vacuum, but is this really necessary? This is one area of the FD I can honestly say I could stand to do some more studying and learning. In the past I have only dealt with the Sequential setup when a customer wanted me to and that was it.

Hopefully some of the experts can chime in on this and this thread may provide some helpful information to forum members in the future.

I will attach the pic below.

[Brent]

*runs outside* Nope, Hell has not frozen over :D That is a good question David. I'll be putting a set of 99spec Twins on my VR FD soon and will be going through the entire system I'm sure. Kevin have any input on this? I'd like to learn the sequential system better as well. I have done troubleshooting over the years on a few cars that I have purchased to resale, but never really looked into what each component does and why. I understand the general concepts of each piece, but I'd like to know exactly what each component does and why. The only trouble mine has ever given me is the wastegate hose popped off once back in 2002 or something *knock on wood*. My turbo's still boost fine after 8 years of ownership, but I have an oil seal that is starting to go bad. I bet Garfinkle could prob. break it down for us wrench twisters David.

[SPICcnmFD]

I would say it's probably not necessary because mine are capped and mine runs fines, always has. I do have a Profec B but that basically just takes the place of the stock solenoids. I did leave the OI lines hooked to the elbow.

[Herblenny]

David,

I know I had also wondered about that before...

What I know is that oil metering jets are one way jets. I also know what when air is being pulled by the turbo, it will create vacuum by the intake nipple. I'm assuming the vacuum lines on the oil jets are facilitating oil injection at higher load (under boost). I've seen people run this line to LIM manifold nipple, but I think when you do that it does the opposite affect and could also distroy the oil injectors. Why?? Well, because intake manifold create higher vacuum and pressure and I don't think these oil jets are made to handle big changes in pressure and vacuum like that. I've checked over 20 jets in my life time and I have to say, about 50% of them were bad.. Either I couldn't blow thru them or it would flow both directions... As we all know these little things are there for a reason...

[David Jerome]

Would any one care to share with me why in the Simplified Sequential setup there is an extra solenoid pictured but not listed. It is below the (E) turbo control solenoid. Looks identical to the above (E) turbo control solenoid and is even labeled as such. However, the simplified setup has two pics of this solenoid and is unclear about how the lines should be ran. There are only two vacuum nipples on this solenoid and if you were to assume the two solenoids are indeed the same (E) rurbo control solenoid. It doesnt make sense as to why the simplified diagram has the red vacuum line getting T'd back in wiht the vacuum chamber and the other solenoids.

The factory non-simplified setup in no way has the (E)turbo control solenoid connecting with the vacuum chamber or going back into the UIM. Just a little confused since there is an un named solenoid on the simplified diagram.

I know there are sequential experts in her that can chime in.

Thanks
David

[Herblenny]

David,

Its a different solenoid. Its the solenoid with two nipples facing up and a filter like thing in the back (rectangular box on the back of the solenoid). It actually looks VERY similar to purge control solenoid except the purge control solenoid doesn't have the little box thing in the back of the solenoid. If you use any other solenoid you WILL have issue with your sequential system.

The diagram is correct and you have to use the correct solenoid! The "E" solenoid is the same ones as the "F", "H", "I", and "J".

[David Jerome]

Im an idiot, I figured it out. I am still going to find a way to simplify this mess even more if it kills me :)

[Herblenny]

Well, To be honest with you, you can't get any simpler than that if you are going to use stock system to control boost. If you go aftermarket boost controller, you could get rid of the Solenoid "I" and "J". And some people run their car without the purge control solenoid so you might be able to get rid of that also... But thats the simplest you'll get..

[Garfinkles Motor Works]

You will not need to put lines on the oil meter injectors and the line from the front elbow to the oil fill neck can be gone as well .Cap the nipples on the front elbow and put a small filter on the oil fill neck or cap it .I run a small filter out of the top of the oilfill cap .

[SPICcnmFD]

FWIW the simplified sequential system is just the normal sequential system minus all the the emissions solenoids and vac. lines. I thought it was some great thing to make it alot easier to work on, which it does because it's not as cluttered but when I did mine 2-3 years ago I found out that was all it is.

And like Phil said make sure you use the right solenoid they flow only certain ways even thought they look the same. But there is only 2 or 3 different kinds.

[Whizbang]

David,

I know I had also wondered about that before...

What I know is that oil metering jets are one way jets. I also know what when air is being pulled by the turbo, it will create vacuum by the intake nipple. I'm assuming the vacuum lines on the oil jets are facilitating oil injection at higher load (under boost). I've seen people run this line to LIM manifold nipple, but I think when you do that it does the opposite affect and could also distroy the oil injectors.

i would have to disagree with this partially, at least in terms of what is happening. When a volume (the intake manifold) is pressurized, the pressure WILL go in the direction of lower pressure. Which is the reason the air is moving in the first place (towards the engine). The air on the wall of the intake plenum increasingly approaches a "0" velocity.

Now, what is probably happening, is that there is pressure working against the oil jets. This is probably the reason that there is a line running to the oil jets (at least on all the FBs, and FCs i have seen). It probably is to help equalize the pressure.

If you read my thread on air and its working, you might remember this formula. M=DVA (mass flow = density x velocity x area)

Mass flow must remain constant in this situation. We shall assume that for a given density (due to pressure and heat after turbocharger), you have velocity and area as a variable. The air moving inside of the smaller lines and vacuum nipples will be moving faster to make up for the decrease area when compared to the intake manifold.

Meaning that any of that pressure in the manifold is compensated for and if anything, a pressure differential may form in favor of moving air/oil of the jet and into the intake plenum. This, coupled with the pressure of an assume good metering oil pump, will mean oil is exiting the nozzle.

Without good testing, this is the best i could reason.

[David Jerome]

I never run the lines on the OMP injectors and I always delete the purge solenoid also. I am considering making an aftermarket set of hardlines(rats nest) that would make the simplified seq a much cleaner setup underneath the manifold.

[Herblenny]

Ok.. Well, again, i have to put a disclaimer as I'm no expert..

But you have to look at the reason of oil metering and why mazda would have gone extensive length to put a "jet" and vacuum lines to a intake source.

To start, we all know as rotor spins and after apex seal passes exhaust port, it start creating vaccum (expansion of combustion area) to suck in air/fuel. If you look at the position of where oil metering jets are, its just before the primary fuel injectors and intake (I think??). By this, oil is drawn easily into the chamber by vacuum created by the engine. We also know as higher the load and engine speed more oil is needed. This was one of the reasons of why Mazda has been spending money on R&D... and why Renesis had 4 oil jets instead of 2 on 13b-rew (someone told me new one has 6!). I believe that the reason for vacuum source on the jet is to provide and control oil level flow.. As more air is being sucked in thru the intake passage, it creates higher vacuum pressure, causing higher flow of oil to be injected into the engine. By not using the vacuum source for the jets, you might not gain the benefit of increase oil flow thru the jets.. I guess you could get away by premixing.. but why pre-mix and go thru more hassle when just simple vac lines could do similar job.

bottomline, I think certain things mazda did it to save money and certain things mazda did it so it will increase the life span of the engine.. In this case, we could clearily see the reason behind the jets, location of the jets, and why mazda put it. Otherwise, why would they increase the number of jets to 4 (6) on the new engine?? That's more money for them and labor they have to pay...

[Whizbang]

Mazda is also very concerned with making the engine last. Sorta to prove a point. Plus with there being a larger rotor, there is more surface area and more nozzles who give a better spread to help reduce that wear that seems to prevail at the edges of the rotor housing.

[Herblenny]

Yeah, but I think we all want our engines to last longer.. not just mazda:) Hence some people running premix on top of working oil metering...
I was told by local dealer mazda tech that new 09 RX8 had 6 oil jets (not just the 16x).

[Whizbang]

hmm....that would be interesting, because that would required some decent chances in the the machines process...

[David Jerome]

Well, the sequential system works perfectly. Sadly this is the first time I have put one back with simplified sequential, wish I had done it years ago because it really wasnt bad at all. All the cars I put back sequentially in the past were very low mileage so I did all emissions etc. Pretty simple really, hopefully within the next 3-4 months I will get around to making a different hardline set to clear up the engine bay even more.

I think a custom setup that was paired with Charlie's coil relocation that moved the hardlines and solenoids over where the coil packs would sit from the factory would really clean things up and make replacing fuel injectors and omp lines much easier.

[afterburn27]

Glad to see you got the sequential system working David. The stock setup is really fun with a few mods. I certainly miss it and I have only driven my new setup for about 10 miles. lol

There seems to be a lot of confusion about the oil injector nipples and why they are plumbed into the primary intake elbow.

Simple answer... it was an easy place to source FILTERED air for the injectors. Under vacuum there is air being sucked into the engine through the injector nipples, and Mazda wanted to prevent dirt/dust/etc. from damaging the internals. The idea that they need vacuum to operate correctly is a MYTH. Hopefully I can explain...

First, the intake elbow is NOT a source of constant vacuum. It is atmospheric pressure. Anyone who has installed a vacuum gauge before the throttlebody on any car will know this. Under idle/light load the air in the intake elbow will be at atmospheric pressure. Under heavy load/boost there will be a VERY slight vacuum, negligible in comparison to vacuum that is seen after the throttlebody. I actually calculated the vacuum you would see under full boost and it was tiny. You would probably see slightly more vacuum if you were running a crappy air filter. But for most cases there is NO vacuum in the intake elbow. If Mazda wanted to provide a true constant source of vacuum they would have utilized a vacuum chamber.

If you take apart an oil injector you will see that it is nothing more than a banjo bolt with a check valve on top. There is nothing complicated about this check valve, it is simply there to prevent boost (and oil) from spraying back out under manifold pressure. Pics of a dissected check valve can be found here: (http://www.rx7club.com/forum/showpost.php?p=6573721&postcount=16). I have verified this with one of my old injectors as well.

When the engine is under vacuum it is “sucking” on the injectors. The check valve is open in this situation and allows filtered air to pass through the injector and enter the intake chamber. If the injector nipples were capped the engine would be placing excessive vacuum on the OMP lines and would quickly empty them. The OMP would not be in complete control of the amount of oil injected into the engine, the oil would be sucked out instead of letting the OMP “meter” the correct amount of oil.

DamonB has posted a great analogy of this process on the other forum:

An analogy of this would be you sucking soda through a straw. Imagine built into your straw was a pump that was supposed to control the amount of soda passing to your mouth as well as deciding how often to deliver a sip of soda to your mouth (this is what the OMP does. It decides when you get a sip and how big that sip is). If the pump were merely built inside the straw there are only two openings present; one in your mouth and the other in the drink. If you were to suck hard enough you could suck as much soda through the straw as you wished because you could suck it right through the pump, even if the pump were attempting to deliver a smaller amount of soda. If we inserted a tee into the straw between your mouth and the pump whenever you suck on the straw you'd merely suck air through the tee, allowing the pump to be in complete control of how much soda is delivered to your mouth no matter what you do at your end of the straw. We'd also install a one way valve in that tee so that when the pump is delivering soda to your mouth none of the soda goes out the tee, it all goes into your mouth.

When the engine is under boost the check valve is closed and the VERY small amount of vacuum applied to the injector nipples is not affecting the injector operation in any way, shape, or form. Again, the vacuum created in the intake elbow under boost is very small and would barely read on a typical vacuum gauge. When there is positive manifold pressure the OMP must overcome the boost inside the engine, which isn’t very difficult since the diameter of the injector nozzle is so small.

So, in summary the oil injectors should be provided with a source of filtered atmospheric air. It just so happens that a convenient location for this is the turbo intake. Personally, I use a pair of leftover solenoid filters. Do not cap the injector nipples, or plumb them in to a location that sees boost pressure. If you like to gamble you can just leave the injector nipples open, but be aware that there is a slim chance for some dust or other particles to enter your engine and cause damage.

Hopefully this helps a few people. :)

[Brent]

Really good information afterburn!!

[SPICcnmFD]

Well, the sequential system works perfectly. Sadly this is the first time I have put one back with simplified sequential, wish I had done it years ago because it really wasnt bad at all. All the cars I put back sequentially in the past were very low mileage so I did all emissions etc. Pretty simple really, hopefully within the next 3-4 months I will get around to making a different hardline set to clear up the engine bay even more.

I think a custom setup that was paired with Charlie's coil relocation that moved the hardlines and solenoids over where the coil packs would sit from the factory would really clean things up and make replacing fuel injectors and omp lines much easier.

It really isn't that hard of a system to figure out once you get the emissions stuff out of the way.

[Herblenny]

Afterburner.. i have to disagree with you on the whole fresh air thing..

First of all, its a one way valve... If you tried to blow air in, air does not go in. So, having filter or clean air is pointless. If it was where air is being sucked into the nipple then I could say you make sense.. But as I made a point earlier that I've seen bad oil jets that blow both directions.. which means they are bad.

Second, there was a SAE article about the 99 oil jet vs older... Let me see if I could find that info:

Apex seal lubrication has become a critical issue. In a race engine, oil supply to the rotor housing by means of injection was precisely monitored and controlled, whereas in the production unit, a larger amount is supplied, just to be on the safe side. Some of the lubricant is fed into the trochoid chamber through a metering nozzle. The previous nozzle's oil passage was 2.0 mm (0.08 in.) in diameter. Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out. When the engine accelerated rapidly, oil supply could not keep up with the speed. To prevent oil starvation, the previous system supplied a larger amount of oil to be on the safe side. In the new metering nozzle, the passage diameter has been reduced to 0.08 mm (0.003 in.), halving its volume of 0.0005 L (0.03 cu. in.). A new rubber seal is also inserted to fill a gap within the nozzle body where oil used to be sidetracked. Now, there is still some oil left within the nozzle after each suction, so that the lubrication system responds to the apex seal's requirement.

This article points out the importance of oil metering system for rotary engine... Again, Mazda would not go to an extent to change nozzle opening if they didn't think its important.. This article also talks about the oil left in the nozzle.. which the jet/nozzle is being served as a reservoir of oil. Again, the vacuum pull of the nozzle could help faciliate the oil being filled properly during higher load on the engine.

Again, the point I'm trying to make is even slight vacuum created by intake before the turbo will help facilitate the proper working of the oil metering system. And actually thinking about it, big negative pressure would be BAD for the nozzle.. Again, putting filter or no filter doesn't matter as its one way valve... Check it yourself.. And as always, I could be COMPLETELY wrong about this as I'm no engineer... but it makes sense to me:)

[afterburn27]

Afterburner.. i have to disagree with you on the whole fresh air thing..

First of all, its a one way valve... If you tried to blow air in, air does not go in. So, having filter or clean air is pointless. If it was where air is being sucked into the nipple then I could say you make sense.. But as I made a point earlier that I've seen bad oil jets that blow both directions.. which means they are bad.

Hi Phil,

You are correct that the oil injectors contain a one way check valve, but you have the operation backwards. Air is allowed IN to the intake chamber, and under boost the valve closes preventing air & oil from blowing out. Check page D-17 of the FSM if you don't believe me. :) My brand new oil injector allows air into the engine. (I bought it to replace a bad one that was clogged in both directions)

-Matt

[Herblenny]

Matt, Let me check that when I get home... I thought it only sucked in but I guess I was wrong:)

[Herblenny]

Matt,

I just looked at the service manual online.. And you are right! It does blow into the engine side.. Opps!
http://rotarycarclub.com/attachment.php?attachmentid=2657&stc=1&d=1222104901

But I still think its necessary to hook up the vac lines to the intake.. And here is the reason why..

I think the reason why mazda did this is to reduce the oil consumption when the engine does not need as much oil, ie idle. During idle, there is almost no vacuum created and air is being sucked thru the nipple of the jets.. As engine goes into load, the vacuum created by intake, blocks air going into the nipple and cause more oil to be injected into the engine. If you just put a filter there, air will still be sucked in vs. oil (but not sure what extend oil vs air will be injected into the engine). Well, that's the new theory I have.. I should have double check the flow of the jets instead of guessing:)

Also, you are right.. I also forgot that after intake ports on the iron is exposed, the oil meter jet opening is exposed at the same time. At that point, it will see pressure and hence 1 way valve must be one direction.. Sometimes I'm very stupid:)

[afterburn27]

But I still think its necessary to hook up the vac lines to the intake.. And here is the reason why..

I think the reason why mazda did this is to reduce the oil consumption when the engine does not need as much oil, ie idle.

Yes, that is exactly why Mazda allows air to flow into the engine through the oil injectors. DamonB's "straw" analogy is great for explaining this.


During idle, there is almost no vacuum created and air is being sucked thru the nipple of the jets..

Correct again.



As engine goes into load, the vacuum created by intake, blocks air going into the nipple and cause more oil to be injected into the engine. If you just put a filter there, air will still be sucked in vs. oil (but not sure what extend oil vs air will be injected into the engine).

OK, here is where your logic gets a bit fuzzy...

The slight vacuum in the intake is not blocking air from entering the engine... the check valve is. There is pressure built up in the intake chamber (boost) under load, so the check valve will be closed. Even if you were applying moderate vacuum to the nipple it would have no effect on the oil injectors.

Again, remember that the vacuum created in the turbo intake is very very small (and only present under load). You could probably argue that the stock intake setup and a crappy filter might see a few inHg of vaccum, but that's it. Vacuum is only created after the throttle plates.

The oil injectors simply need filtered ambient/atmospheric air. The turbo intake is a fantastic location to source this, but individual filters will work just as well.

[Herblenny]

Maybe my wording is bit confusing..

What I meant was that the vacuum created by the turbo, pulling the air in (which you said is min. negative pressure) is enough to stop from getting the air into the combustion chamber. But also, the negative pressure being made by the combustion chamber could be small and short so small vacuum created by the intake could stop the air from entering.. If you look at the quote I posted, the volume of oil is 0.0005L or 0.5mL. Which is pretty small volume which tells me only need small amounts of vacuum created by the air speed thru the intake might be enough to stop air entering and causing bit more oil to be injected at higher load (high air speed thru the intake).

I also agree with you that once intake port opening in the engine the pressure of the combustion chamber will be positive and then the check valve will stop the air/fuel mixture to escape thru the oil injector port. But if it was still the case of clean air, mazda could of saved ton of money by just putting a filter on as you've stated.

I think the best way to figure this out would be to put a vacuum gauge on the oil jet nipple and see what kind of negative pressure it pulls. If it doesn't pull much, then my theory should hold true.. which is at high air speed thru the intake pipe causing higher negative pressure on the hose will stop air from getting in and increase oil flow... Otherwise, oil flow is just based solely on oil metering pump pressure and the air being sucked in thru the nipple. Which could possibly be true..

[afterburn27]

Maybe my wording is bit confusing..

What I meant was that the vacuum created by the turbo, pulling the air in (which you said is min. negative pressure) is enough to stop from getting the air into the combustion chamber. But also, the negative pressure being made by the combustion chamber could be small and short so small vacuum created by the intake could stop the air from entering.. If you look at the quote I posted, the volume of oil is 0.0005L or 0.5mL. Which is pretty small volume which tells me only need small amounts of vacuum created by the air speed thru the intake might be enough to stop air entering and causing bit more oil to be injected at higher load (high air speed thru the intake).

I also agree with you that once intake port opening in the engine the pressure of the combustion chamber will be positive and then the check valve will stop the air/fuel mixture to escape thru the oil injector port. But if it was still the case of clean air, mazda could of saved ton of money by just putting a filter on as you've stated.

I think the best way to figure this out would be to put a vacuum gauge on the oil jet nipple and see what kind of negative pressure it pulls. If it doesn't pull much, then my theory should hold true.. which is at high air speed thru the intake pipe causing higher negative pressure on the hose will stop air from getting in and increase oil flow... Otherwise, oil flow is just based solely on oil metering pump pressure and the air being sucked in thru the nipple. Which could possibly be true..

I *think* I understand what you are trying to say, and I still disagree. Are you saying that even under load (boost) the injectors will be periodically sucking air into the engine?

Here's a question for you... how are the lines plumbed in the RX8? Or a N/A FC? They are routed to the intake (pre-throttle plates). There is NO vacuum present in the intake. In fact, here is an interesting diagram I stumbled upon that seems to prove my theory:

http://www.rx8club.com/attachment.php?attachmentid=100530&d=1179886044

[Herblenny]

Hmm.. Seems like you are right..

Here is the RX8 diagram..
http://rotarycarclub.com/attachment.php?attachmentid=2667&stc=1&d=1222130379

Looks like its before the TB.


Air is led from the throttle chamber to the check valve. The reason for this is to prevent the suction of a large quantity of oil by the vacuum when the vacuum of the intake manifold and combustion chamber becomes high during rapid deceleration, etc. Consequently, the amount of engine oil measured by the metering oil pump is supplied, regardless of the vacuum caused by the check valve.

I guess I was wrong:) Looks like you were right.. just to suck in air and no other purpose. The picture you linked really help me see how it works.. and I also forgot it went in one direction and somehow I was thinking it still sucked in.. I'm stupid like that sometimes..

Thanks for the picture and helping me understand:)