Kouta

I have a S4 N/A so my 5/6 open via backpressure right?
So if i remove the smog pump and a pipe to my main cat, then after that have it be all stock, i will still be ok? because don't the air pump run to the main cat? how about if i remove the air pump and the main cat... will there still be enough backpressure or am i SOL and should leave all my crap on?

YearsOfDecay

If you look down behind the intake manifold on the left hand side you will see the air pipe for the cat.. it has a little Y on it, this is what operates your 6-ports.... so if you remove that pipe... guess what.. no -6-ports

If you take the smog pump off, and leave the cat on.. the cat will clog up...

most guys take cat off and run the ports off a solenoid valve hooked to the air pump via a bar fitting and open the solenoid with a RPM switch...

Syonyk

Well, step one is to see if you can even push them and have them move... a lot of cars are running around with them seized up.

There are a number of writeups floating around on better methods to open the 6th ports... you really might want to consider one of them. The exhaust backpressure method is sloppy at best.

-=Russ=-

patman

iTrader: (3)

if you want to remove the airpump, you have to remove the cat. if you remove the cat, there won't be a tube to the ports. If you want, you can tap a hole in the exhaust up close to the manifold, and this will open the ports just fine. there are also many other ways to do this, mainly electronically. the two good electronic way are with a RPM switch and an airpump to supply pressure to the port actuators; or with an RPM switch and a pull solenoid that replaces the actuators. there are writeups on both ways on this site, and on the other big rx7 sites. i believe the fc3spro site has a good one in the how-to section. might not be fc3spro, i always get those fc3s sites mixed up.

if you need some more advice, i and other people will be glad to help.
if you want to go electronic, i've got a good RPM switch for sale, PM me.

pat

Kouta

Yeah they open up just fine. its the circled thing right?


Also what is rusting all out? the rest of the car is fine, but that thing is shot to hell.

So if i take off my cat, and the air pump, then the best way to open 5/6 is via an electronic RPM switch?

Syonyk

Image doesn't work.

If you go with electronic triggering, you still need an air supply (unless you replace the actuators with solenoids). Kevin's way of doing this is with a modified Walmart air compressor. I'm currently working on a method that uses a low pressure air tank (read, soda bottle) and a stock WalMart air compressor. This leads to the nice side effect of having an air compressor handy for autocross/flat tires/etc, and having it actually doing something. Plus, since the actuators don't leak much, the air compressor won't be running constantly during sustained high RPM running.

-=Russ=-

Syonyk

Ok, image works now. That's the rear actuator. There's also one on the front (opposite angle, hidden by the air pump).

The rusted thing is your exhaust manifold heat shield. The exhaust manifold lives under it, and is insanely hot. It's just iron, and will proceed to rust no matter what you do - don't worry about it.

-=Russ=-

Kouta

Okay, so i have another question...
I am leaving the smog pump, but my 1st and 2nd precats are gutted, precat is still there... do i still have enough backpressure to open them? i feel a pull on the car at about 4000rpm so thats probably them... just making sure.

patman

iTrader: (3)

you probably do, but may not. it varies from car to car.

here's how to tell if they are opening:

put a fingerful of grease on the actuator rod. push it right up against the actuator syslinder part. go drive hard for about a mile or so. don't rev over 4k. after it warms up a little, do a hard 3rd gear pull up to 3500. pull over, pop the hood, see if the grease has been pushed up the shaft. if it hasnt they didnt open. get back in the car, do another pull, this time to 4k. keep going higher until the grease moves. the pull that it moves on is the RPM that they open at. you can push the grease back down and fine tune by 100 rpm intervals if you want.

if its under 4200 or so, youre fine. if its over that, you need to change something.

pat

Toxindude

another way you could test it instead of grease is to put a garbage bag twist tie around the bottom of the rod . I say this because the grease tends to melt from the heat . And yes I did this it works to and all you have to do is un twist it .

jonesfromindia

haha this was from 3 years ago. he probably got cool and got a T2