ok i have a s5 block with a s4 ecu.
that being said, i once, in a dumber existance, removed my 5/6 port sleeves rods and actuators. i no longer have the parts.

i also have no air pump, rats nest, or cats.

so;
1) can i use a s4 lim on a s5 block with s5 upper intake?
and if so
2)which would be easier to reinstall make operable s4 or s5?

i am planning on installing a high flow cat so i may make enough backpressure to run s4's thats whay im asking.

 

if its already removed, and has run fine, just leave it be

 

see im thinking ill get not only better torque, but less air means less gas needed on my safc so better fuel mialage.

 

1- yes
2= if you have an S4 LIM, go with s4 ports. depending on how you actuate them, well the S5 vacuum rack and actuators are better for exhaust options. But electronic actuation would be the best. Since with the S5 stock system yo MUST keep the air pump to operate the VDI and 6PI.

 

man i did the electronic activation thing and I did not find it reliable over time. I would rig up an s4 smog pump to activate it. and if you've got the money get the pineapple racing auxilary port sleeves. I had good luck with mine.

 

so just to confirm if i go s4 5/6 ports on my s5 engine with the s5 middle and upper intakes i can use the stock air pump to activate them without needing the rats nest/ vac rack and everything will bolt up?

 

S4 and S5 port sleeves are the same.

No.

I would stick with the S5 LIM. You will have to drill and gring a spot for a new hole on the S5 UIM if you were to use the S4 LIM. There is no need to do this unless you are swapping the s5 intake manis onto a s4 block and want to keep emmisions. Otherwise in both cases, use the S5 LIM.

To use the S4 lim you will also have to change the lim to engine gasket. reason being because the emisions ports on a s5 block are in the middle and on the end plates but the ones on the end plates are not used and covered by the gasket. So you could either cut holes for those ports or get a new gasket from mazdatrix.

If you don't open up those ports, you will not be able to use the S5 ACV correctly.
Notice I said S5 ACV. That ACV has a nipple for ports with air pressure from the air pump.

You can wire up 2 rpm switches and reuse 2 3 way solenoids and the wiring, the EGR and FPR to activate them.
https://www.rx7club.com/ne-rx-7-forum-30/any-one-ne-area-know-how-do-s5-vdi-manifold-swap-665432/page3/

 

I wouldn't expect to save any fuel from doing this. Opening and closing the sleeves changes the port area and timing, which changes how efficiently the chambers are filled. More efficient chamber filling means more airflow (and hence more torque), not less. The S-AFC has nothing to do with this either.

 

With the ports open you are loosing intake velocity so the chambers are not filling as quickly as if the ports were closed. As we all know, we gain power down low from keeping them closed.

 

Rota man that write up is showing you still using the rats nest. i do not have that system installed. can i do this with out that?

 

You've just said basically the same as what I did...

 

^ hm.

I kept the vacuum rack because the owner wanted to keep emmisions.

you can remove the vacuum rack but that means you loose a spot to mount the solenoids and you loose the mounting location for the PCV which you SHOULD keep. You could modifiy the vac rack and keep only what is needed but cutting the rest off. Keep the solid tubing that is used for the AUX and VDI actuation so you don't have rubber lines running from one side of the engine to the other. Also keep the large tubing which should have 4 nipples for the oil injectors.

the vacuum rack I wouldn't call a rats nest when you eliminate a lot of the vacuum lines and only keep what you need.

I just now noticed you have no air pump or cats. So in the case , I would still keep what you need off the vac rack and just block off the ACV. You COULD, if there is enough pressure, operate both vdi and aux with exhaust pressure. When wanting power from the engine though, pressure in the exhaust is what we try to minimize. You may have to go electronic such as air pumps.

I was actually going to use a small1/4 gallon air tank with a mini air compressor and a 3 way solenoid that could hold pressure without leaking it that would pressurize the tank to 10psi or so that way the ports would operate quickly without any electrical load or pumps overheating if at high rpms long enough. My lumbar pumps overheat and shut down after 5 minutes of running in ambiant air temp. That is probubly reduced when in the hot engine bay and constantly used over and over again without being able to cool down. With that said, I have not had any issues with my 2 lumbar pumps to speak of.