A better Auxilary Air Regulator

[FastWoman]

I installed mine yesterday.  It didn't give me much of a high idle with the engine cold, but neither did either of my OEM ones.  I think it has to do with errors in my idle mix with my engine cold, since I've modified the resistance of the CTS circuit.  When I start my engine, I'm running at about 1100 rpm, eventually dropping to about 900 rpm (where I like it).  I know the AAR is working right, because when I pinch the air hose with a pair of pliers (cold engine), the idle drops quite a bit.  As the engine warms up, there's little or no difference in idle when I pinch the hose.  Anyway, if the thing operates more consistently, I should have a more consistent idle, which is really what I was after.  So I'm happy with it.  In truth, 1100 rpm is plenty fast an idle for my cold engine.  It runs strongly at that speed, with no hiccups -- even in the dead of winter.

[Chickenman]

Just an update on this AAR valve. A couple of people seem to be having problems with the idle not being high enough. Even with the adjustment sent to maximum. There is a relatively  easy way to correct this.

 

Just an FYI for adjusting to maximum airflow ( for those who may not have this valve yet ) . Remove the 4 Phillips head screws holding on the cover. Now remove the cover. You will see a sliding composite piece that covers the inlet hole. It moves via pressure from a Bimetallic spring. At room temperature you will see a " Crescent "  shaped opening that allows air to bypass the Throttle plate during cold start.

 

You can adjust the amount of this opening with the 8mm lock-nut. This will increase idle speed when the engine is cold. Chip the " locking epoxy " with a small screwdriver. It comes off fairly easily. Now remove the nut and have look just to see how things work. You will see that the threaded stud protruding from the AAR housing has a slotted hole and that by moving the stud back and forth in the slot, this adjusts the inner stop. The inner stop rests against the middle of the Bi-Metallic arm. This is important to understand as you will see later.

 

This is how you make the adjustment. Put the nut and washer back on, but leave it loose. With a small screwdriver push the nut and stud away from the inlet hose housing. At the same time rotate the slider clockwise so that more of the inlet hole is exposed. Now tighten the lock nut with your 8mm nut driver. If everything is correct you should see that you have a larger " Crescent " air hole exposed. Note: For some strange reason, you have to move the composite slider before you move the adjustment stud and tighten it.  Check things a couple of times to make sure that you have the maximum size air hole exposed, and reinstall on car.

 

If you STILL don't have a high enough idle speed you can make a further adjustment, but it is rather permanent. BTW... if you have to make this Mod you may want to check out the rest of your EFI idle system, as the allowable adjustment should be MORE than sufficient airflow. Note: Engines with big Camshafts may benefit from this following Mod.

 

Here's the Mod. Take the cover off again and have a look at the slider. At room temperature you will see a Crescent shaped hole, but you will see that the slider will rotate further clockwise exposing an even larger air flow area. This slot becomes exposed at lower temperatures and the Bimetallic strip bends more, turning the slider even more clockwise. Remember that the limiting stud rests against the middle of the Bi-Mettalic strip. So you get more airflow at cold temperatures which the engine needs.

 

But we need more airflow at ambient temp. So take a small Jewelers file and file away some of the material from the slider to make the initial " Crescent " opening bigger. You can fine tune the airflow this way. The slider is made out of a type of composite material that files fairly easily. Don't take too much off. Try small amounts at a time.

 

Hope this helps

 

Edit: See my post below. Filing the slider is a Major mod and should not be required if everything is set-up right... and the Planets are all in alignment... and your car likes you. Vintage cars can be enigma's...

Edited August 15, 2015 by Chickenman

[Chickenman]

After adjusting the 22660-45P00 to get maximum airflow I get 1,900 RPM at Cold start-up ( 70F ambient right now ) tapering to 1,500 RPM after about a minute and then settling at 1,000 RPM. I have a big cam in the car and set the idle stop screw on my TB to maintain 1,000 RPM warm. Edit: I did not have to file any amount off the slider.

 

My car is really snarky when cold,(  due to the big cam ) so I am quite pleased with this. I don't know why Rob's car idled so low with this particular AAR valve.. Adjusting them beyond the factory setting really allows a large amount of air to bypass the Throttle Butterfly.

 

Only thing I can think of is the importance of rotating the slider before you move the stud and cinch it. On mine, if you moved the stud and didn't rotate the slider the opening didn't change much. Move the slider and then move the adjusting stud and you got a LOT more opening... weird 

Edited August 15, 2015 by Chickenman

[Chickenman]

One other thing to note. Federal ( 48 State  and Canada ) and California cars have different distributors in 1975 and 1976. Federal versions have two pickup coils in the Dizzy. One pickup coil is used only during warm-up and advances the ignition timing by 6 degrees ( Phase angle ) when the engine is cold.  More ignition advance will raise idle speed.

 

California models and all models 1977 and later, only  have one pickup coil . Those models may not see as much idle RPM rise as on my car... ( 1976 Fed model Dizzy ). As always....YMMV

Edited August 15, 2015 by Chickenman

[Gary L]

I just took off my original air regulator from my 76 and when I put it in the refrigerator for a little while it opens and then when I hook it to 12 volts it closes such that I can't see any daylight through it. However, I can still blow a little air though it with little effort. Would that be enough to cause a vacuum leak? Also, since this is strictly a fair weather summer car, would it matter if I just got rid of it? 

 

Thanks

Gary

[rossiz]

i don't believe the unit is designed to be completely air-tight when closed - it's just a sliding plate with no rubber seals. but if it's closing all the way you should be fine. i don't believe hthe aar creates a vacuum leak, it just allows extra throttle air past, kind of like having your foot on the gas pedal a little bit for starting.

[Zed Head]

As described, it just lets air past the throttle blade.  As long as it closes to the same spot consistently it doesn't matter much unless idle speed can't be controlled with the idle screw.

 

Are you trying to solve a problem?  Even in warm weather, the extra minute of high idle speed is convenient.  The concept works, that's why it has stuck around so long and Chickenman has a modern part to do what the old parts did.

[Gary L]

I'm just cleaning things up and checking on things like electrical connectors, etc. I saw this post and thought I check on my AAR.  As I mentioned, it's a fair weather car only, but\ when I do start it I don;t get the momentary RPM surge so I thought I'd see if it even moves, and as I noted, it seems to move OK. Actually, It does stumble for a little bit when I first start it before it smooths out. Gary

[Chickenman]

I think most of these cars stumble a bit when they first start. Seems to be a common problem. The advantage of the newer design is that it is readily available, serviceable and relatively cheap. Many of the old AAR valves have failed and are hard to find or expensive.

 

My car always seemed to run rich when it first started. After a short while it would clear up. Increasing the amount of air bypassed by the new style AAR valve finally gave me a proper fast idle, and cleared up " some " ( not all ) of the initial start up richness.

 

Edit: I'll be glad when I get the Haltech installed. Slowly gathering parts.

Edited August 23, 2015 by Chickenman

[2377kN]

I finally got around to addressing my lack of a faster idle at start, which has been the case since I acquired the car.

After reading through this thread I removed my AAR to see what’s what.  At about 70 degrees there was barely a sliver of a crescent shape to let air through.  Hooked it up to a battery to see what happens, and nothing.  No change in the shape of the crescent.

Put it back in the car and ordered the 300ZX AAR part number 22660-45P00 from Courtesy at a cost of 100.66.  Price has gone up.

Put the new one in the car and upon startup my car now idles around 1200rpm. Success!

P.S. my car is an April ’75 build date 280z California Emissions car.

[LorenB667]

Part number has been superseded to 22660-30P10