Hi, I have been suspecting a power loss on my 1990 GX because of my 6 ports lately.

The 6 ports are operated by the Air Pump NOT back pressure from the split-air Right?

So I checked them out and found that the rod was retracted all the way and I had to pull UP to make the rod move. This is wrong isn't it? Shouldn't the rod retract as the ports are opening?? It wasn't easy to move but it didn't give me too much trouble. The funny part is, once I got the cam to touch the stopper and let go, the rod would retract itself back...

What could cause this?

BTW, this test was done with the car NOT running, if it makes a difference...

Thanks in advance,
-Mike

 

Nope, sounds like they are working actually On the newer 2nd gens the actuators where opposite of the older ones. On my 86 the actuator rod retracts under pressure, but on yours as pressure builds the rod will slide out. It goes back in if you pull on it because its spring loaded. I guess the grease on the shaft of the actuator shaft test wouldnt work since they move out, but there must be some way to test them.. you could always disconnect them and see if there is a noticeable difference, there ought to be... Otherwise, just make sure the shafts for the valves, not actuators, rotate pretty freely. You ought to be able to open them with your finger by pulling up on that little cam, all the way to the stop.


~Jesse

 

they better be working since I was barly catching up on sun....

like my avatar LOL

 

hehe, Scott, I'm sure you would woop me with your RB exhaust now...

Skibum, I actually thought about disconnecting them too, so I tried it and It didn't seem to make much of a diff. Like how much should I notice it? Night and Day??

Thanks,
Mike

PS I like my Avatar too

 

I'm pretty sure that those newer ones snap on and off, instead of gradually like my 86, so you ought to feel a burst of power at 3500 when they open.. if not, make sure they're not stuck, make sure to check both! If you don't feel a difference, maybe try timing getting on the highway and see if you can get going faster with them connected than disconnected... You really ought to notice them though...



~Jesse

 

one way to test'em is to put grease on the actuator rods,get out and get on it,and see if they moved.hmmm.actually..i guess that might only work 86-88..not sure

 

First a disclaimer....never worked on a newer than 87rxx. But the ports still work from pressure. Can you not get a piece of vaccum line about three feet long and hook it the the supply port for the actuators and blow into it like the dickens and see the ports retract, move, whatever? Use low pressure air and you should be able to see them move. Remember my disclaimer. That method works on 86-88.

 

I don't feel my ports open until about 5000 rpms (1990 GXL).

 

Actually what you feel is the VDI system... Variable Dynamic Effect Intake system is the long form... don't ask me why they took out the "E" for effect. It was on all 1989 through '91 Non-Turbo RX-7's... What it does is: As the rpms climb higher, at 5500 or so, the Dynamic chamber begins to create pressure waves forcing more air through the intake tracts and thus causing the combustion chambers to have a higher air to fuel ratio which in turn causes mo' power for us rotor heads... That's the quick explanation ;o)Your six ports will open between 3500 and 3800. And it won't be quite as noticeable.

Thanks,
-Mike

 

VDI, Really, I had no idea. I will have to check to see if my ports open at 3500. Is this system related to the intake ports and how they are machined? Do you have any other info on this?

 

Yes the VDI does have to do with the way the intake system is machined the most noticeable thing on your engine will be the 4 tube like tracts comming from the Dynamic Chamber on the drivers side. Whereas the '86 through '88 6port 13B's will just have a plain solid Dynamic Chamber.