So I'm doing rats nest removal among many other upgrades this winter, and I'm wondering if any particular nipple on the intake manifold is better than others. With the rats nest gone I have many to choose from. I'm looking at the one in the pic below. It sits right between the two oil injection nozzles on the inside of the manifold. The other one I'm looking at is just below the subzero start thing on the inside of the manifold. Both are just about centered in the manifold. Or am I looking into this way too much, and should I stick with one of the available nipples on the throttle body ? My gauge right now is plumbed into a fitting that I drilled and tapped on the firewall side of the manifold, but at higher boost levels the gauge flutters and bugs the crap out of me.

 

The one between your oil injectors needs a line from the firewall side of the throttle body and if I understand its purpose properly it flosw air past the fuel injector nozel to help atomize the fuel better. I'm not sure if it will show vaccume on that nipple.

I don't believe you'll get anything off the sub-zero assist niples.

For a boost guage, just 'T' off the line that goes to your MAP sensor.

 

nevermind

 

i clicked on this because i saw the word nipples and was dissapointed... but word to craiger

 

cool thanks for the info. I'd rather not "T" into any line if I don't have to. I just want a nice smooth signal going to my gauge without the flutter.

I figured if I said "nipples" I'd get somebody's input. LOL ha ha !!!

 

Well, remove the boost sensor line and connect your gauge line to the nipple the boost sensor was connected to. Then start the engine and see if your gauge is still fluttering or not.

If it is, then you might just as well reinstall the boost sensor line and tee off it.

If you remove your ACV, then make a blockoff plate for it and add one to three vacuum nipples to it as shown the jpgs attached. You have to drill for the nipples in the places noted on the jpgs and have to use a gasket on your blockoff plate. Each of those nipples shown goes either to the front primary runner or the rear primary runner.

The last jpg shows the four nipples on the back of the throttle body. Only the bottom one will show boost and vacuum. Normally it's used for activating the double throttle diaphram thru a water thermo valve. So if you don't need/use double throttle diaphram, then use the bottom nipple for the gauge.

 

would the nipple in that same location but on the opposite side of the throttle body (facing the front of the car not the firewall) work?.. the nipple thats at the very bottom like that one is.

 

honestly a "t" is your best bet the other ways you have to modify a block off plate

 

Like the decal off the hood of a turboII shows, the top front nipple is vacuum for the vacuum rack, but the other two *should *also work. Seems a long way to go for a gauge. Rear is closer.

Nobody should ever buy a ACV blockoff plate unless it has nipples on it. Boycott the ACV blockoff plate makers. They can't cut the mustard.

 

Yes

Yes a T is the best bet... but each to their own.

Yes


Oh dear god I hope i'm not turning into Ted...

 

lol thanks bro

 

Thanks HAILERS. That's what I was looking for. I've got no emissions with all block off plates. So i'll be adding a port or three to my block off plate. Thanks again.

 

Sorry to bring back a dead thread, but can anyone confirm this ?

 

The nipple in the middle is for the primary fuel injectors air bleed. Air is routed from BEFORE the throttle plates to that nipple. That nipple leads to passages that lead to the air bleeds below the primary fuel injectors.

The rotors on their intake stroke, pull air thru that nipple b/t the oil injectors and that air mixes with the fuel injected.

Almost the same thing happens with the top nipple on those two oil injectors. Air from before the throttle plates is routed to those nipples. When the rotor is on its intake stroke it pulls air thru those nipples to mix with the oil injected by the oil injectors.

Something like that.

 

Vac line for the BOV would be best at this nipple.

 

Is there a picture of the manifold that has just 3 nipples on the back side instead of 4? Is it just the same as the 4 as the lowest one is vac/boost and the two uppers are air?

 

I don't have a jpg of the three one above the other. BUT I'm sure the bottom one is vacuum on either throttle body. Idle the engine warm someday and reach back there and pull the bottom line off and feel at the metal nipple for the suction/vacuum. I'd bet money on it that the bottom nipple on both throttle bodies is vacuum. The others of course are NOT vacuum.

 

my jdm s5 t2 intake manifolds only have 3...the bottom on is vacuum.

 

I am positive that the front bottom nipple is vacuum/boost. I run my GM MAP sensor off that. I suspect that the middle nipple on the front of the UIM is not a vacuum source and in fact goes before the throttle plates based on the FSM diagrams.

I am experimenting with hooking up my primary air bleeds to the one in question (and my secondary bleeds to the top rear nipple), so once I get my motor running we'll see if I'm correct.

 

well that explains why i only show boost on my gauge. i put the tap right in the middle of the big hole of the ACV block off plate. the boost gauge i got has compression nuts