12aGod

Guys, help me on this one...my brother is a/b to let the only rx-7 mechanic in my city pull the 6-port sleeves out. The man told him around $300 parts & labor to ****** the 6-port sleeves and actuators, block the acv, the egr, and replace some omp equipment. I told him i think this is a bad idea, mainly b/c it's not possible they make that big of a top end improvement WITHIN redline, and b/c what he WILL lose is low end power. The guy told him he needed this b/c carboned up 6-ports will kill a motor, and he told him that even though his 6-port actuators move freely his 6-port sleeves might still be carboned (!!??!?!?!). Some responses to this will help me fight what is being told to him. Thanks guys.

tweaked

iTrader: (4)

It will not help top end, it will hurt it alot!! those things open to give the car top end. it's like the "v-tech" **** on Hondas. If you do anything, and I don't recomend this, wire the ports open. YOu will loose bottom end drasticly, but you wont hurt top end. how is this guy so sure they are backed up with carbon any way? the only way to know for sure is to take them off and look at them, you may as well clean them then. If you want to clean the cabon, go get some really good carb cleaner, hold open the throtel body plates and spray 1/4 of the can in there while some one crankes the moter. wait 4-5 minutes and then start it. it iwll be a pain in the ***. you will have to play with the throttle lett all the black smoke stop then repeat until you are out of carb cleaner. I do this every six months. then go and get a really good gas additive and run a full tank of mid grade or better gas though is. preferable oin the highway. tak a trip for the week end in it. while you are at it change the plugs and wires, set the timing and change the oil to Mobile 1. By the time you come back from the trip you will be running almost like new
I say again...
DON'T LET HIM DO THAT!!!!!!

Suparslinc

I agree. Removing the aux. ports on these engines is a definate no-no, but some guys will tell you otherwise. I tend to think that all that extra junk is on there for a reason, such as described by treaked. Don't remove those six port sleeves

kliftin

How do you guys figure. I removed the sleeves myself and actuators. I gained top end. Thier a post on it in 2nd gen specific. The sleeves are thier just to keep your low end and swich to high end but with them gone HOW IS IT RESTRICTING YOUR TOP END. Its freing it up. Low end loss is barely noticible as long as you have lots of bolt ons. My 89 is very streetable and reves freely to 8.5. I say do it kid.

tweaked

iTrader: (4)

the secondary ports are for top end! that is why they open after 3800 RPM. I even put the 680cc injectors from a first gen. I also plan on haveing my intake sent to Extrude hone. I am going to tell them to really go at it on the secondary runners.
The secondaries are closed at low rpm to keep velocities high at low revs. then they open to give you the extra air needed.
I would like to see a dyno backing up kliftin's claim that he got more horsies in the top. I disconnected mine for about an hour to see what happened. It was like running on one rotor. ( which I did by accident once)
Alow me to reitterrate my above statment. If you do that, you will regret it

peejay

Felix Miata did fairly extensive testing on a GSL-SE (which doesn't have as efficient an intake and has a lower max revs, 8500 vs. "higher than 8500") and made the most power with the aux port sleeves removed and the muffler removed. The "normal" and sleeves-removed dyno charts would cross at 3500 or so, with the sleeves-removed chart having a marked improvement.

tweaked

iTrader: (4)

What exactly do you mean "sleeves" Just want to be sure we are talking about the same thing.

kliftin

tweeked is thinking of something else. your right about the secondary runners giving top end but the sleeves, rod, actuator, air pump assembly is what swiches the primaries to the secondaries at who knows rpm.
OPERATION.
The rods connect the actuator to the sleeve. Under pressure from the air pump the actuator begins to twist the rod rotating the sleeve letting the secondaries open. The sleeve is cylindricle with a square cut hole in the end,side. Put two and two together.
REASON FOR DITCHING
At high horspower and rpm flow, tubulence gets created in the lower intake from passing by the rod and sleeves. By taking them out creates less tubulence only noticible to a car thats been hooked up and tuned. Good Intake, exahust. The reason for less low end is because to much air is getting in with the secondaries open all the time wich dilutes the air fuel mixture. Except on my car is barely noticible if not more low end starting at 2000rpms. Why, because I took off all my pullies. int,ex. underpullies. Some custom stuff and most importantly a s-afc wich will controll the fuel at low rpms wich isnt dyno adjusted yet. Im sure I will have alot more low end then. So to whoever says this or that kills low end , only to how your cars tuned will it effect low end. Otherwise it will raise top end with a smoother acceleration.

kliftin

You are my teacher.

Suparslinc

Alright I gotta call you on this one. . .
the reason for less low-end is NOT the mixture. Its port timing. You remove the sleeves, you changes the duration of the intake-stroke, and you lose low-end as a result.

zyounker

You really don't lose it you move it.. And buy removing the sleaves you get even more flow so you gain a little after 4500rpms...

You can also put in new sleaves that will make it flow better.. I believe rob @ pinapple racing does them.. Do a search people were just talking about that...



-Zach

Suparslinc

Once again, what people say and what they actually know are sometimes two different things. It may be true that you don't lose much low-end from removing the sleeves; I've never tried it without the sleeves so I can't really comment on that. But rotary basics 101 says that when you increase the duration of the intake cycle, you lose low-end. Allow me to elaborate from the trusty Mazdatrix website:

The shorter the port timing, the longer the gases can be compressed, the longer the explosion can be contained, and the "cleaner" the chamber will be before the next charge is sucked in. These specs give you your basic "stump-puller" engine: lots of torque at the bottom, nothing at higher revs. The later the exhaust closes and the earlier the intake opens, the more intake charge is sucked out the exhaust pipe, but the earlier it can begin being sucked in. The later the intake closes, the later the engine can begin compressing the air/fuel mixture. The earlier the exhaust opens, the sooner the remaining "explosion" is let out the exhaust pipe. The higher the engine needs to rev, the faster it needs to get the maximum charge (longer/bigger intake), the less time it has to "use" the "explosion", and the faster it needs to get rid of as much spent gases as it can (longer/bigger exhaust timing/volume). This is your basic race engine (ignoring incredible volumes of other things going on that do matter) that makes great power at 9000rpm, but won't run below 4000. Everything is a trade-off with something else. If even this overly-simplified explanation sounds complicated - IT IS!. Welcome to the world of high performance engines.

www.mazdatrix.com/r1-5.htm

zyounker

Um, yeah that is what i was saying.. You moved the power to the higher end.. But you do it at a cost to the low end.. Just like any type of porting

Wireing the 6 ports open you will lose a little top end. You wil not gain any top end doing this though.. but by removing the sleaves you generate more flow which means you can get more air.. It doesn't actually change your intake timeing compared to when the 6 ports are open. it increases the flow through them...


-Zach

kliftin

right , doesent sound like taking a frikin sleeve out is going to change timing duration. Listen listen. Take the sleeves out and gain a little up top loose a little down low. My goal is top end since that seems to be what wins races. Like I said you lose a little down low. Big deal. who cares. Whats all the huss fuss.

Suparslinc

Listen one more time. When you remove the sleeves, it opens up that whole top part of your intake. This absolutely does change the duration of the intake stroke! Whats so complicated about that? When you say things like "it doesn't lose low-end" and "its cause of the mixture" just prove that you dont' know what your talking about! I'm not saying what your doing is wrong; but since I thought you'd like to get into this discussion, I'm trying to explain why things work as best I can. You need to read up on this for sure. The whole principle of the auxilary ports is to change the intake duration. Thats what they are there for. And thats why they don't open until 3500 RPM. Removing the sleeves negates the whole system. You lose low-end, maybe you gain top end. But this is WHY things work like they do, and alot of people here seem to just dismiss that. If you don't appreciate what Mazdatrix says; then don't comment on it! I don't care if you know what your talking about or not but I'm sick of the babbling on this subject. Half-baked theories abound on this forum.

zyounker

I think he know that is what the ports do.. but buy pulling the sleaves out he is not changing the duration any from when the ports are open..

But they never close so you do loose bottom end, because it will change the duration of that..



-Zach

kliftin

Bingo. Have you ever heard of diminishing returns. Something not worth the effert because of little gain. Thier should be an oposite. Mabey diminishing gives. **** I dont know but the loss can be so little that who gives a crap just do it comes to mind. Your talking all this duration timing stuff wich of caorse is theoreticle on paper and to everyone who reads it but you make it sound like its going to f up my car and totally change its driving characteristics. Have you ever pulles the entire intake tract out and studied it, or even tried it. Yes your right about the duration if thats all you wanted to prove but all im proving is I did it and the big LOSS OF LOW END sang has got to shut up. It was easy to do myself and is better than wiring them opem. The sleeves were put thier to give more low end on a stock rx7 as well as slightly more eficiant in gas and smog. Totally not necessary or noticible in a car that has been tightly modified by me. AHHHHH YEAAAAAA.

Suparslinc

I wouldn't be posting on this subject if I didn't have any first-hand experience. Yes, I've had the intake off before. I even thought about removing the sleeves last summer before all these posts starting showing up

rxseven

What's all this talk about losing low end power? As if the rotaries have much low end power to speak of. I just wired the sleeves open last week and the low end loss was barely noticeable but performance above 2500 rpm was definately improved. My useful rpm range starts from 2500 so it worked out just fine. It did affect the idle and I had to re-adjust the rich/lean screw to make the mixture richer. All in all, well worth the time.

darius
85 GSL-SE

kliftin

thnx.

FPrep2ndGenRX7

As far as I'm concerned I have to lean toward what Superslinc is saying. I'm pretty sure all those Mazda engineers did much more work in figuring out if the auxilary ports were worth addinng to the engine. There are other factors involved like meeting emission standards of the time and making the car more drivable to the masses. Admittedly someone interested in modifying the car probably isin't going to drive it easy but the loss of lower RPM torque is still noticable. Someting else to remember is just because you make an port leading into the engine bigger doesn't mean it will flow more. If you decrease the velocity of the mixture going into the engine because of the bigger port you decrease the performance also. usually larger ports don't flow good at lower RPM, hence the lack of torque, but will usually flow better at higher RPM's. Now that nobody knows what I'm talking about I'll go.

Suparslinc

I'd like to add one thing to that; I'm not sure if its correct but heres what I was thinking the other day:
Since these engines are not forced-induction, I don't think the smoother/bigger port passage is going to make much difference. Reason being, only enough air that the motor can use is being sucked into the combustion chamber. So unless your naturally at max. volume, removing the sleeves isn't really going to change a thing if they were working properly.
I might not have any business saying that, so feel free to correct me if I'm off base here. I can take it :p

almost forgot, check out my new sig. Thats for you Kliftin!

kliftin

I remember saying that its not worth it on a nearly stock engine. Bonez race pipe and filter is considered stock to me. Not bone stock but stock.

kliftin

On a side note. I was just about to buy a crx for work end go all the way with my 7 but I got fired for nothing wich im in a lawsuit for and my 7 just got impounded yesterday in front of kregan when I was going to buy an a/f gauge for my afc.

going to try to get it out today.

Rotortuner

I friend of mine has his 6 port engine appart right now and has the sleeves pulled out for a while while he was still driving it. He said as usual that he did loose some low end and gained high end. <Normal. Any ways I think it is important for us to all recognize that when the sixth port is closed at low end we can say that port timing is ,,, well lets use the term normal. It basicaly rune like a 4 port. But at the higher rpm's the sixth ports open and at that moment is when the port timing changes. I got in on this thread late and i tried to read what had already bean written so I hope I am not to redundant. Any ways in my friends engine that is torn appart he has the sleeves pulled out. But when you pull the sleeves out at the end up in their where the end of the cylender is is like a dead end. Any ways he went and put steal epoxy and filled the hole and smoothed it. Now it feals very similar to a stock port. This should make it so that the fuel comes in much more eficiantly with the sleeves removed.
Onve again I don't want to start another big argument but I am a real big NA, Carburetor, 4 port, peripheral port, fan and I don't do that much with 6 port stuff. However I do have some friends that run a "huge" street ported 6 port with dual stock 12A nikki 4 barrell carbs. pretty interesting, I wil try and get pics of it on here sometime. Until then, peace.

CJG