Cat Air Pipe
05-31-09, 11:39 AM
#1
Cat Air Pipe
Car is a 1991 NA...
I'm going to be replacing my stock pre-cats/cat assembly with a cough"test pipe"cough in the next few days, and I'm wondering what- if anything- I need to do with the air feed to the main cat.
The pipe and check valve is off already, do I need to plug the feed tube from the ACV or can it just be left open?
I'm going to be replacing my stock pre-cats/cat assembly with a cough"test pipe"cough in the next few days, and I'm wondering what- if anything- I need to do with the air feed to the main cat.
The pipe and check valve is off already, do I need to plug the feed tube from the ACV or can it just be left open?
07-21-09, 12:27 AM
#3
I have a question, where do I plug the spit air pipe to ?
cuz I've been looking all over on the ACV and can't find a place to plug in, car came with Full Racing Beat Race Exhaust.
it probably has a block off plate somewhere, FSM saids there is a plastic tube that goes into somewhere on BCV, I will order that tube soon. but where does it plug into ?? Anybody has a picture of the tube plugged in ?
cuz I've been looking all over on the ACV and can't find a place to plug in, car came with Full Racing Beat Race Exhaust.
it probably has a block off plate somewhere, FSM saids there is a plastic tube that goes into somewhere on BCV, I will order that tube soon. but where does it plug into ?? Anybody has a picture of the tube plugged in ?
07-21-09, 12:31 AM
#4
do whatever you feel like with the ACV and smog pump, without a cat in place they are doing nothing except robbing power.
you don't have to do anything with the open port where the split air pipe came off of unless you're worried that a squirrel will somehow make a home in it.
you don't have to do anything with the open port where the split air pipe came off of unless you're worried that a squirrel will somehow make a home in it.
07-21-09, 01:09 AM
#5
do whatever you feel like with the ACV and smog pump, without a cat in place they are doing nothing except robbing power.
you don't have to do anything with the open port where the split air pipe came off of unless you're worried that a squirrel will somehow make a home in it.
you don't have to do anything with the open port where the split air pipe came off of unless you're worried that a squirrel will somehow make a home in it.
You can have this pipe disconnected, but make SURE you leave the check valve portion connected to the lower intake manifold. The check valve prevents air from going back into the lower intake manifold during deceleration I believe, so you either need to leave the check valve portion that connects to the side of the lower intake on, or just take that whole hose off and block it off with something really big (i believe that's a 1" opening). Since you are probably going to keep the airpump and ACV, just leave the checkvalve on so that your plug doesn't get blown off by the airpump pushing air out that opening.
Leave everything else on unless you plan on wiring your 5/6 & vdi open. Besides this your good to go.
07-21-09, 02:26 PM
#7
Clokker, you can leave the split air port open or cap it with a block off plate. As mentioned, the majority of of the air coming from the pump goes into the exhaust ports. An open split air port won't have an effect on the pressure the aux ports and VDI see when activated. The openings for it inside the ACV are tiny (1/16" & 3/16").
Got a dyno to back this claim up? I find it hard to believe that it takes 5hp (160hp * 0.03) to rotate the air pump. A fraction of that is more likely. And what would you mod it with? An electric airpump to put extra load on the alternator and make it work harder? That takes hp too. It's the same reason removing the stock clutch fan and using an e-fan doesn't really free up hp either. It's a waste of time and money to get a couple RPM switches, solenoids and an electric air pump just to make the car function like it did in stock form. And the alternative of wiring everything open would just make for a crappy street car.
Got a dyno to back this claim up? I find it hard to believe that it takes 5hp (160hp * 0.03) to rotate the air pump. A fraction of that is more likely. And what would you mod it with? An electric airpump to put extra load on the alternator and make it work harder? That takes hp too. It's the same reason removing the stock clutch fan and using an e-fan doesn't really free up hp either. It's a waste of time and money to get a couple RPM switches, solenoids and an electric air pump just to make the car function like it did in stock form. And the alternative of wiring everything open would just make for a crappy street car.
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07-21-09, 10:55 PM
#8
First off, he has an s5 n/a. If you disconnect your ACV and airpump you will not have functional 5/6th ports let alone VDI. You will be robbed OF power at grater than 5k rpm. I am a bit confused to your question. If I am right you are wondering what you need to do with the split air pipe.
You can have this pipe disconnected, but make SURE you leave the check valve portion connected to the lower intake manifold. The check valve prevents air from going back into the lower intake manifold during deceleration I believe, so you either need to leave the check valve portion that connects to the side of the lower intake on, or just take that whole hose off and block it off with something really big (i believe that's a 1" opening). Since you are probably going to keep the airpump and ACV, just leave the checkvalve on so that your plug doesn't get blown off by the airpump pushing air out that opening.
Leave everything else on unless you plan on wiring your 5/6 & vdi open. Besides this your good to go.
You can have this pipe disconnected, but make SURE you leave the check valve portion connected to the lower intake manifold. The check valve prevents air from going back into the lower intake manifold during deceleration I believe, so you either need to leave the check valve portion that connects to the side of the lower intake on, or just take that whole hose off and block it off with something really big (i believe that's a 1" opening). Since you are probably going to keep the airpump and ACV, just leave the checkvalve on so that your plug doesn't get blown off by the airpump pushing air out that opening.
Leave everything else on unless you plan on wiring your 5/6 & vdi open. Besides this your good to go.
Im trying to put a CAT back on (Magnaflow) Car came with Full RB Full exhaust. but I cant stand the smell plus I dont want to pay anybody extra to pass emission test.
I've been looking under, side, top, all over to try to find a hole to "plug the spit air pipe rubber hose" back ... but I cant find any holes
maybe im blind ...
Anybody has a picture of where the pipe suppose to connect to ?
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