No-Pistons-TT

ok so i have my air pump off while im installing some stuff on my fd what would happen if i just didnt put it back on. i still have the cat on but i dont see the differience if i were to just get a mid pipe and the air pump would still be gone???

any help would be great thanks...

hotrodrx7

If you don't have a cat, you won't need the air pump. The exhaust smell gets pretty strong without a cat but if you don't have emissions checking you don't need it. You may need an ECU upgrade with a straight mid-pipe.

wstrohm

If the air pump isn't there to add air to the cat, the cat won't have enough O2 to burn off the unburned HCs. There will be no effect on the engine's running per se. If you don't care about emissions, neither the cat nor the air pump is useful.

---- Bill

TwinTurbo93

Many of us already did it,it would aslo be good to remove all the crapp associated with the air pump, put the block-off plates and clean up the engine bay.

You will need a short belt for the water pump (295K5, best size for thight fit) after you take of the AP.

Even w/the stock center cat you'll be ok w/o the air pump, just cap the air pipe on the cat, I rane it like that for about 2 years and it was just fine.

DaleClark

iTrader: (55)

If you're running the stock ECU, the car will idle rough and have bad throttle response without the air pump. The stock ECU is tuned to think the O2 sensor's input is skewed due to the extra air pump air. Without that air, it compensates the wrong way, and you end up with a rough idle and a stumble at on/off throttle. I accidentally blew my air pump fuse not too long ago, and it drove me NUTS how the car ran.

Not sure about no air pump and a chipped ECU. I know aftermarket ECU's like the PowerFC and Haltech won't have a problem at all.

There is some debate that running the main cat with no air pump can cause problems to the main cat - the cat runs cooler than it should, and eventually could clog or break down. There's not a lot of consensus on that one, though, or hard evidence. It's your call.

Dale

No-Pistons-TT

thanks alot guys i plan on going with a power fc soon so i guess ill just wait till then and leave it in for the meantime

Aeka GSR

iTrader: (4)

wont removing it cause a check engine light? The previous owner of my 7 removed the plumbing from the pump but it is still there. It is verry annoying sounding. I would like to toss mine out as well. I'll be getting a powerFC soon but would like to do something about it in the meantime.

quicksilver_rx7

just take it off. It's not gonna hurt anything to remove it. It shoudn't cause the CEL to come on, but it may actually store a code in the ECU without the CEL comming on. Still, that's not gonna affect driveability, just idle.

rx7what

iTrader: (6)

the AP should not effect the idle or the way the engine runs. the ap only sends air to the main cat in your mid pipe so it never really goes through the engine just half the exhaust. I removed mine very shortly after buying my car and never had a problem. I didnt even notice a differance. except all the extra room under the hood. Then i went single and was glad I had already removed it.

Sgtblue

iTrader: (16)

^Just to stir the pot a bit...
Other than gaining some space in the engine bay, why remove it? The increase in HP is almost non-existent, and I don't think they go bad very often. Plus, you'll have to spend the money and effort on a block-off plate set as well as a mid-pipe or metallic cat. Not to mention the above mentioned nasty exhaust smell with a mid-pipe and goofy idle without a PFC. IMHO, it's not worth it for a relatively stock, street driven car.

ShogunOfHarlem

iTrader: (1)

The previous owner of my FD diconnected the pipe from the cat and capped it off but the air pump is still in the engine bay. should I remove it? There is not much I can do with it as the cat is welded closed along with the tube that was originally going into it. If so where do you get the block off plates to remove it

No-Pistons-TT

the hp gain is about 20hp. Take to the guys at rx7.com about all that. im just worried if my stock ecu can handle any more. I have intake and exhaust but exhaust without a cat. As for the block-off plate kit im to worried about spending 62$.

ShogunOfHarlem

iTrader: (1)

Are these the block off plates I would need to remove the air pump? If so which of them would I need to use?

http://www.rx7store.net/index.asp?Pa...ROD&ProdID=272

ScreaminREW

$62! I just cut the flange off the airpump pipe & filled it with Liquid Metal ($2). It's held up thru 4~5 races running a 12-10-12 boost pattern, so no worries. It's not too difficult to feather the throttle during idle, it doesn't fluctuate with the stock ECU.

Don't forget, you need a new (shorter) serpantine belt once the AP is removed. This can be done cheaply or with a pulley kit.

Trash the pre-cat & main-cat if you can. They weight like 85lbs. together!

Btw, the exhaust smells great

No-Pistons-TT

whatever one would fit

No-Pistons-TT

i guess i could just adjust my idle posotion to???

kerry chandler

Anybody knows the part no. for the shorter belt to use when removing the air pump?

No-Pistons-TT

im just going to go to a parts source and try out a few different belts

Sgtblue

iTrader: (16)

Mmmm. As I understand it, the air pump has very low parasitic drag to begin with and free wheels after ~2800 rpm. If you want to remove it to gain space and clean-up the engine bay, that's one thing. But I'm not seeing 20 hp by that alone. I think you misunderstood RX7store.
LOL, if your worried about spending $62 for a block-off plate set, you might want to reconsider removing the pump...or even your choice of car.

wstrohm

"The stock ECU is tuned to think the O2 sensor's input is skewed due to the extra air pump air."

I don't see how that is possible. The exhaust pressure ahead of the catalytic converter must be higher than the pressure in and after the converter, or else exhaust would not flow through it. Since the pressure at the O2 sensor is higher than the pressure in the cat, the O2 in the injected air cannot flow backwards from the cat up to the O2 sensor.

---- Bill

No-Pistons-TT

sorry i said that wrong i ment to say im not worried about spending the cash for the block off piece set. also i dont see how 20 hp is not possiable?????

rynberg

Wrong. Get out your FSM and read it....

There is no way in hell removing the air pump nets you 20 hp. Give me a fricking break. Above 3200 rpm, the electronic clutch is disengaged and the pulley is just free-wheeling. If you think eliminating a free-wheeling pulley gives you 20 hp, then I've got a bridge to sell you.

Sgtblue

iTrader: (16)

I told him that too. But your much more articulate.
If removing the AP got 20 hp, they would have all been recycled into beer cans by now.

afterburn27

iTrader: (5)

The ACV also directs air from the airpump to the exhaust ports, so the O2 sensor does indeed "see" extra oxygen from the airpump.

wstrohm

Afterburn27,

Thank you for the explanation. After looking at page F-115 & subsq. in my FWM, I now see why I own a Miata, and my wife owns the RX-7. That diagram is completely over my head. It doesn't show the O2 sensor, but I guess the air pump pressure must exceed the exhaust pressure at that check valve for the port air, so there really is O2 being inserted into the exhaust port.

Jeez, I thought the vacuum hoses were complicated! Does anyone actually understand all these control valves, etc? Looks like the Space Shuttle.

---- Bill