Black Knight RX7 FC3S

iTrader: (7)

I just got an extra S4 engine and was wondering if it is okay to actually run the engine with the entire actuating assembly for the 5th and 6th port off. I mean take the whole thing out, and just wired up the 5th and 6th port open. Will there be an exhaust leak or anyting that will be a problem besides the no torque under 4k

Rotoracer33

I did this a while ago on my 87, because I changed to a straight pipe without the 6pi return line. This disconnected the operation of the 5th and 6th ports. So I wired them open, untill I rebuilt and streetported the engine. Then I took out the whole thing, sleeves, actuators, and blocked off the holes.. Works fine There was a significant drop on low end power. But if your running it hard, you really don't notice because you don't drop below 3000rpms a whole lot...

I say do it if anything it simplifys the engine a little.

NoDOHC

The only air source that goes to the actuators on an s4 is from the exhaust, plug that and you can remove them easily.

pfsantos

iTrader: (1)

Yes, as far as exhaust leaks are concerned you don't have to worry if you remove the actuators or auxiliary port sleeves, as long as you don't mess with the rods that the actuators turn (these have a rubber seal). But you do have to cap the little hose using a heat-proof method (where the exhaust pressure comes from) on the split-air pipe.

If you end up removing the split-air pipe running to the cat, you also have to cap the 1/2" or so nipple at the back of the LIM. This would be done if removing the Air Pump and Air Control Valve and Cat.

Black Knight RX7 FC3S

iTrader: (7)

the engine I got had the 5th port rod stuck, it doesnt move. I took out the actuator and it moves, but the rod is stuck at open all the way on the 5th port, while the 6th port is free to move about, so I just wanted to simplify it a little bit by removing the actuators and wire the 6th port open since the 5th port is stuck open all the time.

So the question now is.....does anybody know why its stuck open. I already have the engine in the car and dont really want to take it back out again

SpooledupRacing

on a well built n/a u dont notice the loss of the 6 ports.. atleast I did'nt I have a 86 n/a 5spd with 80k racing beat road race exhaust, cone intake filter, and it runs great and I noticed no loss in low end when I removed the 5th and 6th ports

Dave

Rx7TyreBurna

iTrader: (1)

Hmm, I bought my car with the sleeves removed. I thought it was quick. But then I put the sleeves back in and electronically actuated them, and it made a noticeable difference for me below 4k. If you mostly race and don't go below 4k, then there isn't really a point in having them. But, removing them doesn't increase air flow, or give more HP. It just kills torque. I remember seeing a dyno with the sleeves removed and with them in, it was approx. 10-15 trq lost. In our cars, we need more torque, I wouldn't get rid of it. Just try and make it work.

Mine was stuck a little, so I ran a very little bit of Seafoam through one of the nipples on the UIM with the sleeves opened so they would get saturated in the Seafoam. After sucking barely any, just enough so that it seemed like it would have covered everything, I let the car sit for 10 minutes. And then started the car up and moved the sleeves. It was free moving again. I am guessing that there was just gunk.

If it is the actuator rod that is stuck, just consider picking up another one. I got some from a guy on here for really cheap. I think $20 shipped for 2 of them. I think that included a new LIM too.

Anywho, keep them if you can.

pfsantos

iTrader: (1)

Black Knight: It's worth the effort to have the 6PI system working. It's worth having to remove the LIM (make sure you use new gaskets when reinstalling if they're not perfect). It could be that the rod is stuck or that the sleeve is stuck from carbon (see post from RX7tyreburna). You'll know when you remove the LIM.

Spooledupracing: Were your ports actually opening before you took the system off? Most free flow exhausts don't have enough backpressure to open them in the first place, so that may explain why you didn't notice a difference, as well as the fact that the exhaust would probably make up for the loss.

SpooledupRacing

yes they were opening... the racing beat exhaust will open the 6 ports with the air tube right on the header.. if I was to idle the car, rev it to 3k+ u could see both actuators opening..

my problem was after I pulled the manifold, and removed the rats nest and emissions they stopped openeing.. so I removed them.. Since them I have seen no loss in power.. atleast if there is a loss it is not at all feelable.. now my high end thats a different story it is way more powerfull up top

Dave

Rx7TyreBurna

iTrader: (1)

SpooledupRacing: There is no difference between having them in and having them out, if they are functional, other then a loss of low end power. What you are feeling is mostly in your head. The "butt" dyno. Take it to an actual dyno and you will see that you only lost torque low down, and gained nothing top end. Also, you shouldn't really see the actuators opening using the racing beat exhaust nipple, especially if you are just rev'ing. It takes load to make them open. So, you would need to be driving your car pretty hard and sitting in the engine bay to see them open that way. I don't advise this because it can be dangerous sitting in the engine bay while the car is accelerating hard to 60.....

More then likely OP just has some carbon locking it up. It doesn't take long to rip off the UIM, IIM, and LIM. But, only do that if the Seafoam thing doesn't work.

Look around on the forums and you will find dyno sheets proving that removing them doesn't give any extra HP, it just kills the torque, which like a civic, we are lacking a ton of.

SpooledupRacing

I have to say u are wrong.. the exhaust goes through the racing beat header nipple into the valve that pulls the actuators down.. there has to be no load... it is a s4 n/a

I could see them open and so many others have to on MY CAR...

I may have lost low end BUT because of the mods I do have there was no NOTICABLE loss on low end.. but high end it did flow much better...

the opening is alot bigger between the sleev in and nothing in.. I think u can get alittle more in when they are removed

Dave

Rx7TyreBurna

iTrader: (1)

Well, I am not going on what I think. I am going on proven dyno numbers. No gains by removing them, only losses in torque.

OP will just have to make their own decision.

SpooledupRacing

well to each their own.. I did not want to remove them however after removing all my emissions I could not get them to work so I pulled them and I am VERY happy with the decision

Rx7TyreBurna

iTrader: (1)

Indeed, what works for you might not work for me.

I have also removed all my emissions. But I chose to go the electronic actuation using an airpump and a summit racing RPM switch. I chose the summit one because it doesn't require that I buy "pills", and the RPM can quickly be set using DIP switches. Also, it was only $40.

Glad to hear it works for you though. My car is my DD. So, i am not usually above 3.8k, so I like my toque down low.

Black Knight RX7 FC3S

iTrader: (7)

So i guess its locked from carbon build up then...

Now I got another question, during start up I let the engine warm up, but it is still putting more gas into the engine untill 3-4 mins later after the engine is warmed up. During this 3-4 mins, I swear the engine had torque at low revs. But when it stop giving more gas after the 3-4 mins and its normal, at low rev it seems like there is no torque in the same rev range......
it might be in my head, or maybe not, but I did a cheap mans Gmeter
I hanged a wire from the rear view mirror and see how much it went back, during warmup it defenitly went back more then when its at normal operation.

But then again, it might be in my head.

ProChemBroTCM

I know what you are talking about. I definitely feel like there is a much bigger punch down low after I start her after sitting for a couple of hours. It could just be that most of the components have cooled, so there is less heat transferred to the incoming air making for a cooler, more dense air charge. That's my guess because my ZX2 used to behave the same way.

Rx7TyreBurna

iTrader: (1)

Hmm, well, wire trick is interesting, the only way to really tell is a dyno.

Considering that if you have all your emissions in-tact, the double throttle plate on the passenger side, or the side towards the air filter, it is closed until the car warms up and then opens. This means that you are running on just the primary throttle plate for the time being.

I know when my car used to get warmed up, my double throttle plate was staying closed. This killed high end though, not low end.

Are you running the stock air box? Or a warm air intake? Generally you will feel a slight lack in power if you are running an open filter in the engine bay. This is because once the car gets warm, you are sucking very warm air in instead of the cold air.

Hopefully you can get them unstuck and working properly. Also remember that the rotary isn't a torque beast... it is more like a Honda motor... no torque. But we have the advantage of horsepower up top, that the Honda guys don't.... haha... j/k... little Honda bashing there....

GL!

rx-7 obsessed

you should get them to work its better you get better gas millage as the motor is below 3500 where the ports should be closed it robs it of fuel if they are open. From what i have herd/experienced u also can loose some high end power to i don't see how but i can understand the ECU not being able to compensate. get them to work properly!