datwhiterx7

I was reading up that if you delete your air pump on the s5 N/A motor that the VDI will no longer operate. Well the previous owner deleted the air pump and I'd like to fix the VDI open if possible. I know I will lose low end torque and I'm ok with that. Any help will be helpful. Thank you

Dak

You'll need to wire the 5th and 6th ports, also known as the auxiliary ports open as well. I have to go to bed. I will try to give you something more detailed on the VDI tomorrow. Till then download and look in the FSM( factory shop manual). Link should still be in the FAQ section.

wrankin

The actuator for the VDI sits down on the underside of the center of the UIM. In it's normal, low-RPM state, the actuator arm is extended. At high RPMs, the arm retracts and the rotates the internal valve 1/4 turn via a short lever.

You need to remove the actuator and fix the lever arm at the correct position (fully counter-clockwise, IIRC). You can secure it using a couple zip ties or some wire.

-bill

Dak

I don't think the actuator will come completely out without removing the UIM but that is ok. Just unbolt it and take it loose from the rod. Move the rod to the open position and zip tie it there. then bolt the actuator back into place.

As to the 5th and 6th ports remove the actuators and turn the rods to their open position and wire/zip tie them there. Use the FSM to find the location of everything. It is pretty detailed.

Aaron Cake

iTrader: (1)

No one has pointed out that with the aux ports open all the time, and the VDI set to high RPM position constantly, that the car is going to drive below 5000 RPM like a Geo Metro?

Seriously, if you do this, expect a 30% torque loss below 5000 RPM.

Dak

Is it really that bad, or only on an otherwise stock engine. I wired mine open in like '99 and never really missed having them functional. I already had a header and exhaust done before I did it though and I shift at 4 to 4.5k most of the time. As to the original poster. He said the previous owner removed the air pump and he could live with the loss of low end so I didn't make mention of it. That and I just don't remember it feeling like that much of a loss that and I wasn't stock when I did it..

Aaron Cake

iTrader: (1)

A good back to back test is to drive a car with all that stuff working. Yes, it's significant. Things like being able to use 10% less throttle, and less RPM, to get the car moving. Better idle. Increased fuel economy.

Years ago I was having this argument with someone in real life about wiring open the aux ports. He had his wired for "like forever" and said it was "fine". So I had him drive his car around the parking lot, then drive mine (functional ports). All he said was "Oh". Next meet the ports were working again.

Dak

I have wondered about it even considered making them functional at one point years ago( before the rebuild and street port). I won't really argue against keeping them but for me that ship has sailed for the most part. I removed the rods and removed the parts of the bosses that protruded into the intake path. I say most part 'cause I have a spare intact LIM if I were to change my mind but I doubt it. I'm going the other way. My end goal would be to ditch the stock intake altogether for a Pro-jay/Jay-tec style and a 4 barrel throttle body( after I go standalone of course ).

wrankin

Mister Cake is absolutely correct about the big advantages of the VDI and working 5/6 ports on a street car. It's worth the effort of making them operate correctly - it's extra power where you want it in the RPM band.

My FC is a track-only car and never really sees below 5k when driven so removing the ports and wiring the VDI open was the correct choice in my case. But the car would be pretty gutless at more "normal" cruising RPMs.

-b

fidelity101

iTrader: (11)

I hate to revive an old thread but the photos from the others are NLA due to old web hosting issues...

with removing the vacuum spring actuator

short runner mode = turn the arm fully counter clockwise
long runner mode = turn the arm fully clockwise.

is this correct?

fidelity101

iTrader: (11)

anyone?

Dak

I believe you are correct.Arm all the way down which would be Counter clockwise. Here is a picture of mine.

zh2oman

Sorry to latch on to a post, but I've been trying to get my 5th and 6th ports working for about a week now. 91 S5 N/A, I got the ports to move freely by hand, but can't seem to get them to actuate with higher rpm. First question is will these function without the car in gear and driving? Second, what is upstream of these providing the air pressure to open the actuators? I've tested them with a compressor and they function. Please spell out any acronyms please, I'm relatively new to these rotary engines.