Keisuke T.

I have a 91 convertible automatic. Obviously it needs all the help it can get to accelerate. I plan on removing the air pump because I want to lose the 10 lbs or so especially being in the front plus I like the added space. I understand on 89+ models the air pump opens the secondary intake ports. What is the best modification to accomplish this without the air pump? Thanks in advance, and yes I have my mind set on losing the stupid air pump.

beefhole

iTrader: (29)

You're better off leaving the stupid air pump. That 10 lbs won't do **** seeing as your car is a convertible AND automatic. I don't see why you even need the space there. Weight loss starts with the PS and AC removal if anything.

Keisuke T.

I want to keep the AC and PS, but I have no use for the AP besides opening the ports. I am definitely not expecting a measurable performance gain but I have a personal problem with the air pump and if someone actually knows a way to lose it please share. Does wiring the ports open make you lose low end torque? How is the powerband affected? Thank you.

beefhole

iTrader: (29)

Just like you said it will affect low end torque and your powerband. Really I don't understand why you want it gone.

shiftnmadkwik

you want it gone too beefhole, dont lie.

you have a few options, either just wire (not electrically) the ports to stay open, as beefhole said but you are losing low end power. think of it as sucking through a drinking straw, and then trying to suck water through a garden hose, its just hard to get going with all that volume. if all your other mods are designed for high rpm and if thats where you do alot of your driving then you might be happy.

you can also use electric actuators and an rpm switch to make them open at a specific rpm.. there are alot of posts about this, do a search for more info.

andrew lohaus

no no no you dont need an rpm switch the ecu already sends signals at the appropriate rpms for both the vdi and aux ports. i dont know why people think you need an rpm switch.

whats beefhole anyways?

NZConvertible

If you remove the air pump you'll lose the operation of both the 6PI and VDI systems. This will make the car considerably slower. If wire the auxiliary ports and VDI open you'll lose a bunch of bottom end, something an automatic NA doesn't exactly have much of in the first place.

All this for a weight reduction of well under half a percent of the car's weight, which you will not notice no matter what you believe. Anything you add to compensate for the loss of the air pump will just add weight back on and probably won't work as well.

This is a really dumb idea. You need to get over whatever your problem is with the air pump.

SureShot

To remove the air pump:

Without pressure in the split air pipe, tha cat will clog, so remove the cat & install a presilencer.

Without the air pump belt the alternator belt alone will not pull the mechanical fan, so either install a dual belt alternator pully or loose the fan & install an electric fan.

To work the aux ports & VDI, install an electric air pump powered by a relay that closes on the aux port signal.

Keisuke T.

Thanks guys I think I will keep the air pump.

beefhole

iTrader: (29)

It's obvious by now.

shiftnmadkwik

maybe because you dont want them to open at the rime the ecu is telling them to open. maybe he wants them open at 12rpms i dont know.. a rpm switch is just a handy idea and useful! why do people put vtec controllers in hondas when the ecu sends the appropriate signal/? n/m.

and it should be quite clear by now what a beefhole is.

btw nice system sureshot..where did you source that pump from.

SureShot

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