GXLstylez

have been trying to figure out if i can just block it off, or if i need it,i have not noticed a difference in driving at all since getting my exhaust put on, 2.5 inch straight pipe to a muffler,
i have been searching and i cant find a straight answer.some people say to block it off and others say don't..
my car is 1986 s4 n/a
any help would be great want to fix it today

durtled

i uhh i would just get the pipe nice and short and maybe run it into ur air box or just get a silencer for it. let it chill since u have straight pipe already it should be fine. only reason it there is to make these cars pass emmisions. no cat no emissions so its just blowing air. if u remove the emissions **** on the engine u can get rid of the air pump also. and u have a straight pipe on a n/a ? how ridiculous is that. must be insanely loud

GXLstylez

the sound level actually isn't too bad,i was expecting way more noise, but for normal driving around its pretty quite until it hits the 4000 rpm range then its gets pretty freaking loud

durtled

nice mine is loud with just a dual muffler cat back

turboIIrotary

iTrader: (9)

If i remember correctly the split air pipe controls your aux ports so since you put on a straight pipe you are losing top end and it should be noticable, if you told feel anything different then they weren't working in the first place.

FC_fan

iTrader: (2)

ya, split air pipe reads exhaust pressure in the stock system so it kicks your 5th/6th ports on at around 3800rpm. but your 5ths/6ths might not have been working and even if they were, and you connected the split air pipe to the new exhaust, it probably wouldn't operate them properly due to less exhaust restriction and pressure. s4's are like this, s5's na ports are electronically controlled from the air pump or something like that. I think racing beat sells some pipe that you can hook the split air pipe to, and have it work the ports correctly.

GXLstylez

found this picture after researching more and just wondering what size of hose to use?

turboIIrotary

iTrader: (9)

That's just a normal vacuum line coming from the air pump to the ports.

HAILERS2

If you took the airpump off...........then that blue hose won't work to open the aux ports.

If you do have a airpump and connect it to the hose coming off the airpump......the aux ports will be open all the time defeating the reason of the aux ports.

If you connect it to the dump hose coming off the ACV as shown in that picture...........it still won't work right and it's not imho, it's a fact. Air gets dumped out that large hose at various rpms meaning ...........the aux ports won't operate as designed.

The only right fix is to ape what the series five non turbo cars do..........they take the air for the aux ports off the air coming from the airpump and feed it to the aux ports thru a rpm controlled solenoid (meaning they open only at a certain rpm not various rpms).

FelixIsGod29X

iTrader: (50)

Riiiiight

turboIIrotary

iTrader: (9)

It does work so you facts are wrong go ahead and try it and rev the car up you will notice the ports opening and closing.

HAILERS2

Sitting in your driveway and reving the engine over 3800 rpm triggers the Relief solenoid to open which results in air being discharged into the large dump hose that goes to the silencer in the right fender. So Yes, it works IN THE DRIVEWAY.

The control of the ACV does NOT work that way all the time when DRIVING the car. Which means the air gets dumped at other times than the 3800 rpm when sitting in the driveway.

So NO, I have the facts right and am not a bit confused on how and when the air gets dumped into that large black hose.

Just connect a single LED light to the output from the ECU to the Relief soleniod and drive the car for ten or more miles and you'll see what I mean. Anytime the LED is lit.............the air is NOT being dumped in that large discharge hose. ANYtime the LED light goes out.........air is being discharged out that large black hose......................and IT AIN'T AT 3800 RPMS, its a lower figure.

turboIIrotary

iTrader: (9)

Double post

turboIIrotary

iTrader: (9)

I'm talking about the air pump hose not the one coming from the acv, you said the ports will be open all the time but they open and close at the same time regardless if the car is moving or not.

HAILERS2

Point made. Seems to me they'd be open all the time that way.

I notice the picture he attached to his post shows the blue hose going right into the ACV discharge hose which means it's dependent on the ACV opening and shutting dependent on the signal from the Relief solenoid to the ACV. But like you say..........your talking about the blue hose going into the airpump discharge hose instead. Which is different like you just told me.

durtled

forgot about aux ports cause i don't think mine work

daviddeep

iTrader: (4)

According to an old Racing Beat catalog I have laying around from 1998 or so, they claimed at the time that if you connected the S4 split air pipe to the inlet on their cat eliminator pipe, there would still be enough backpressure to operate the auxiliary ports. Is this true or false? I have a high-flow cat left over from my old S5 NA that I'd like to put on my S4 NA at some point and am wondering if I'll have to do one of the auxiliary port work-arounds.

Hygoog

Hi guys! So my 5th/6th port will still work if I install a straight pipe and remove the split tube? I have a 1989 Rx7 GTU S5

j9fd3s

iTrader: (3)

yes. the 5/6th ports work from pressure from the air pump

Hygoog

Awesome! Thank you so much!