91 na air pump removal
 

so, i just read on a post of emissions removal, and something of it troubled me...about 6 months ago i took teh air pump off my s5 na because while driving somehow i managed to snap the bracket (on the front of the motor) in half so belts were spinning and the air pump was literally just sitting there. so i took it out and plugged the line. i have a n1 apexi exhaust, rb header and aero highflow car for my exhaust...now what i read was taht taking the pump off can clog your cat = that would suck and that taking the pump of a s4 doesnt do anything but off an s5 will not open 5th and 6th ports? so basically for the last 6 months i have been cloggin my cat, and losing out on some hp? and making my motor work harder than it should be..can some one clear this up for me. i actually have my car chillin at my parents house while i replace the oil cooler lines and ps lines, so now would be a good time to slap that air pump back on . thanks!

No.. you pretty much nailed it. :) Yeah, put it back on if you have cats and want more power.

Or, you can do a search for "electronic vdi" and see how to electronically actuate your 5/6 ports and VDI. Then you could remove your cats and live without your air pump.

But the easy solution is put the air pump back on.

dont the 5th and 6th ports only acuate at high rpm? ill check out the electronic vdi for the eff of it. i dont want to remove cats its my daily driver and here if you get caught without cats 2400 dollar ticket. and my car already....is...LOOOUUUD. you can here me 2 miles away ive heard :P thanks for the reply ^^

If high RPM is 5000ish to you, then yes...

VDI is where a lot of your power is made as well..

If you have to keep your cats, you have to keep your air pump.

pssh that aint high :P thanks micaheli

ok so went to work on the car today and new update :P the line that goes to the cat WAS drilled out and welded in the new exhaust. HOWEVER the shop that did it welded the line in after the cat...so i need to get it cut and drilled in the new cat. may be a dumb question but popped in my head today, to get the pressure to open the 5th/6th ports does it need to be in cats or just exhaust in general. im gonna do it anyway cuz i dont want to pay for a new cat down teh road, but im always thinkin :P

ive got my air pump and all other emissions removed. I've had no trouble with my 5th and 6th ports. If anything removing the air pump has allowed the engine to create more power since it can produce more output. (air in = air out)

except that the 5th and 6th ports are acuated by the air pump at 3800 rpms.....unless you have an alternative method of opening those ports.

You've got a TII though! No aux ports!

Winner! "Most misleading info packed into one post"

lol thats a good one.

O.K. Once again to clarify...

- all factory 86-91 NA's have the 6PI system (6 port induction), turbo's do not
- 86-88 use exhaust back pressure from the split air pipe on the cat
- 89-91 use air pump pressure controlled via a solenoid
- 6PI system activates around 3800RPM
- VDI is only on 89-91 NA's and is a system where the intake runner length is changed after around 5700-5800 RPM's
- VDI does not use Air Pump pressure

I'd get an Air pump bracket quickly and put the air pump back on. Sure, I don't like the space it takes up, but overall in your case you want it on.

right i posted another post, that hasnt been replied to other than by me :P i gota bracket to put on, however the bolt that goes to the adjuster arm thing, the part that connects to the block, cant find a bolt that fits it, my question was, is it a bolt that threads in i cant see threads, but i cant get my head down there either lol, or do i need a bolt and throw a nut on the end of it. thanks santos appreciate the comment

my 88' n/a has had the cat removed, and i just bought an 86 n/a parts car with the same style exhaust system...both no cat's. now i was told the thin pipe running almost to the Y-pipe controlled my 5th and 6th ports. now would my 2 dynomax oval style mufflers be giving me enough back pressure to even open them?? im curious

Meximan: checked the FSM, if it's the bolt that has a bracket for the OMP, yes the right bolt should find some threads there (looks like it bolts to the water pump. Keep in mind I have an S4 myself.

Jarome: I have the same cat-back system with cat and the rest of the system is stock. My ports aren't opening. Test it yourself. Put some grease on the rods, go for a drive, and see if the rods moved. Search under "actuators" - I've seen great posts on this and electric actuation.

Actually it does use air pump pressure by way of the ACV.

I think the air pump only delivers extra air to the cat during warm up.
Electric pumps can be wired up to do that, the aux ports & the VDI.
Vette's have been using electric air pumps for years.

http://208.62.166.66:82/guest/Shop_M...pump-setup.gif

i think that was it. heres a picture of what im talkin about, this is a turbo motor though. but same bracket close to the same spot. im gonna work on it tommaro so tryin to figure it out tonite lol.

Sureshot: I stand corrected. :)

Meximan: Yes, the bracket is in a similar place, only the adjustment channel/slot is on the air pump side.