Nate83SA22

hey I got a Base Model 83 "7" 12A 5spd and i took the belt off the A/C to free up a little power...since the compressor didnt work anyways but, I have nt deleted the rats nest yet and still have the stock intake and carb...etc. what would happen if I just Took the belt off the air pump? would it hurt anything and would it run worse? and by the way I live the West Palm Beach, FL so we don't have emissions down here Just sound Regulations on cars that sound like chain saws

Rx-7Doctor

iTrader: (13)

If you still have the cats on her and don't remove the cats when you remove the air pump, you will destroy the cats. Their will be no affect on the vehicles running until the cats clog then a loss of power will occur. Other thing with a single belt depending on how you rev you could get slippage on the alternator. With the removal of the A/c and air pump belt you are not freeing up anything that could be felt performance wise.

Nate83SA22

About how long will it take for the cat to clog up?

Rx-7Doctor

iTrader: (13)

That depends on how old they are and what the air/fuel mixture is on your motor. It could take many months before this happens or sooner depending on the condition of the cats and how much unburned fuel is going thru.

Nate83SA22

sooo......I should just Cut it out right?

Rx-7Doctor

iTrader: (13)

Personally I would not do anything until you have a header exhaust system to put in there. If you remove the main cat and put a straight pipe in there you will find yourself signing a noise ordinance ticket.

84RX_Se7en

Yea.. I'd say gut the cats, remove the rats nest, pull the oxygen pump and plate that off. Then you'll feel a little power difference.... maybe. With the oxygen pump still there you haven't freed up power because that pump is still there taking up space and air. Also pull the AC pump off completely and remove anything related to air conditioning. That's a lot of wasted weight and air flow.

Rx-7Doctor

iTrader: (13)

Remove the A/c, have you ever been to Florida in the Summer?

Just a note to everyone that might be reading about emissions.
According to what I have been told by smog guys. In the next 2-3 years it is on the books that there will be no more emission free States or Towns for that matter. Which means if you destroy or throw away your emission equipment you are going to have one hell of a bill to replace it.

Rogue_Wulff

Presisely why I have the rats nest still in place, but disabled, on my car. I have the AP and all items I have removed stored safely, just in case I need to reinstall them.
Hopefully, if they do impose emmission testing again around here, they will not use the same stupid "Visual" check they used before. I had 3 vehicles that would pass their appearance test, but would never have passed a sniffer test, as most or all of the stuff was disabled. I was not alone in that regard. I did it before, I can do it again. I just don't wanna have to remove the header. I'd rather just install the AP and and a high flow cat, if it comes to pass.

Rx-7Doctor

iTrader: (13)

Are you running a aftermarket carb or the stock Nikki?

Rogue_Wulff

Stock (looking) nikki.

Rx-7Doctor

iTrader: (13)

If it's a stock nikki and you have the shutter valve disconnected from the rats nest then you are losing some fuel economy.

Rogue_Wulff

How so? It is opened by vacuum, on decceleration. Otherwise, it remains open.
I have the vacuum hose going to the shutter valve plugged. I had hooked it back up for a while, but after the header install, it would flutter the valve under a light throttle cruise. It was easier to just cap the hose again, than readjust the TPS......

Rx-7Doctor

iTrader: (13)

The shutter valve does not open by vacuum on deacceleration, it closes per signal from the solenoid valve on the rats nest. By closing it shuts off fuel to the rear housing during deacceleration.

Rogue_Wulff

True, I misstated what I was trying to say, but meant the same thing. Shame on me.
With the vacuum hose capped, it no longer closes to bypass the fuel/air mixture into the rear rotor.

For those that may not know:
The purpose of bypassing the A/F mixture to the rear rotor, is to minimize misfiring on deccel. The misfiring causes higher levels of unburnt fuel to enter the exhaust. With the cats in place, this leads to a much higher temp inside the cat(s). Directing all the A/F miture into the front rotor reduces the deccel mifiring, lower the unburnt fuel entering the exhaust, and the pure air flowing thru the rear rotor gives the cat(s) more air to burn off the excess. *summarized from the book "Rotary Engine", by K. Yamamoto.

I have no cat, so the shutter valve didn't really make much difference in my case.
If I am losing a little MPG, well, I can live with 24-26 highway, 19-21 average, considering the engine has had some minor port work done.
I truly respect your knowledge doc, so don't take any offense, please. It's us older guys with years of knowledge, that keep the younger guys learning the right stuff.

84RX_Se7en

I'll trade comfort for HP any day.

Now Ohio here just removed the emissions regulations not too long ago. I think everyone would be in an uproar here if they put it back on the books. We'll see... at that point I'll figure some way to cheat the system.

Nate83SA22

What can i disconnect to stop the poping back firing noise on the down rev? I believe the noise is coming from a hose that is not connected to the cat because the cat that is on the car is the wrong one and was like that when i bought it...