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Aftermarket Plenums And Aac

tets

By tets,
in Engines & Forced Induction

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tets Proficient

tets

Posted
Posted

Basically im about to install a plazmaman plenum onto my rb25. i brought the plenum second hand and had a bit of a read up before attempting this, theres a few things im unclear about and wanted to see if anyone can make things a bit clearer.

basically from what ive read if you place the aac onto the plenum you also need to plum the aac air input before the throttle body.

ive seen alot of pics of people running aftermarket plenums and on the majority of them there doesnt seem to be an aac air input welded into the cooler pipe before the throttle body. is there a way to block off the aac properly or get rid of it? is the aac required if you run for an example a q45 throttle body, was reading somewhere that theres idle adjustment screws on the throttle body for cold starts.

also when i brought the plenum the aac position was blocked off with a blocking plate with a nipple on it it also came with some other "chunk of metal" 'with the ford symbol on it which i got no idea what it does. not to sure what the previous owner done with the aac but if anyone has any ideas it would be great.

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PM-R33 Grand Master

PM-R33

Posted
Posted

I run the AAC/IAC on my Plazmaman plenum. Tried running it without it for a while but it was a pain in the ass to get to cold start and idle properly.

As for the idle adjustment screw, it is on the stock throttle body aswell. It simply holds the butterfly slightly more open. Personally I would piss off all that crap that has come with it and just put your AAC/IAC back on.

75coupe Grand Master

75coupe

Posted
Posted

wow what timing, Im just installing a RIPs plenum on my rb25, and am at the stage of plumbing in the AAC vacuum hose to in front of the throttle body...

theres not much room under a forward facing plenum once all of the AAC plumbing is under there...

ive seen the aac mounted to an aftermarket plenum with a little filter clamped onto the fitting that would normally run to the pickup before your throttle body

Are you saying youve seen just a small air filter on the aac rather than being plumb into the piping?

that would be easier but how would that work I thought it needed the air pressure before the throttle.

89CAL Grand Master

89CAL

Posted
Posted

pretty sure it just needs to be able to gather air upon closed throttle but im not sure on the issues with AFM etc

My car has the AAC set up as standard (Plumbed in before throttle body) so it works fine, not sure how well the setup with the filter works but wouldnt really cost much to try it out i guess? Just set it up with aac valve open to atmosphere

RBceffy25 Rising Star

RBceffy25

Posted
Posted
I run the AAC/IAC on my Plazmaman plenum. Tried running it without it for a while but it was a pain in the ass to get to cold start and idle properly.

As for the idle adjustment screw, it is on the stock throttle body aswell. It simply holds the butterfly slightly more open. Personally I would piss off all that crap that has come with it and just put your AAC/IAC back on.

The idle adjustment screw is on the factory AAC/IAC unit. there is also another on on the factory ecu for further adjustment.

It does not plumb in before the throttle body. It really has nothing to do with the throttle body apart from the TPS.

As far as i understand in simple terms, it all by-passes the throttle body and lets in a small amount of air to keep it from stalling while the throttle is closed and a little bit more again for cold start. The throttle adjustment screw is turned to let more or less air in to control the idle. Have a read of the 'DIY AAC clean' thread to get a bit more understanding about this or google search the workshop manual for everything you will ever need to know.

I do not own an aftermarket plenum so I don't know how valid this info is.

Cheers!

75coupe Grand Master

75coupe

Posted
Posted

well the stock AAC valve has a line plumbed in before the throttle body, so were trying to set it up to be the same as the std system... if its just extra air its letting in for idle control then it makes sense that instead of plumbing the air line in a small air filter could be used as an alternative... sounds like it would work, since its not sensing air pressure, its just letting in filtered air...

RBceffy25 Rising Star

RBceffy25

Posted
Posted
well the stock AAC valve has a line plumbed in before the throttle body, so were trying to set it up to be the same as the std system... if its just extra air its letting in for idle control then it makes sense that instead of plumbing the air line in a small air filter could be used as an alternative... sounds like it would work, since its not sensing air pressure, its just letting in filtered air...

That would be the line from the turbo intake pipe i think.

It way work but i assume you may have an issue controlling idle rpm?

any thoughts?

75coupe Grand Master

75coupe

Posted
Posted
That would be the line from the turbo intake pipe i think.

It way work but i assume you may have an issue controlling idle rpm?

any thoughts?

Well I havnt run the engine with the new setup as yet, but the last thing I have to do while waiting on an adapter for the oil & coolant lines to the turbo is to plumb the AAC value hoses... thats why this thread is timely..

so now I have the option I guess of welding in a pipe fitting into the FMIC piping or running a small air filter on the AAC valve...

RBceffy25 Rising Star

RBceffy25

Posted
Posted
Well I havnt run the engine with the new setup as yet, but the last thing I have to do while waiting on an adapter for the oil & coolant lines to the turbo is to plumb the AAC value hoses... thats why this thread is timely..

so now I have the option I guess of welding in a pipe fitting into the FMIC piping or running a small air filter on the AAC valve...

AH HA! now i understand what you mean.

Are you using the standard intake pipe?

if so, plumb it off that. If its an after market hard pipe it too should have outlets already plumbed.

Otherwise i don't think you would have a problem with the filter idea.

STATUS Grand Master

STATUS

Posted
Posted
Don't SR20s have an item with an in and out fitting attached?

I could be wrong though..

yeah they can work well...

idle control and load compensator inbuilt, hose outlet but still flange mount.

89CAL Grand Master

89CAL

Posted
Posted

How hard is your pre-throttle body intercooler pipe to take out?

Was going to say you could try the filter thing and if it doesnt work pull the cooler pipe out and just get a little 20mm (I Think is the right size) bit of pipe welded in

I can show you a photo of mine if you want? think i just bought some flexible hose and ran it from the AAC valve to the 20mm pipe

75coupe Grand Master

75coupe

Posted
Posted

yep thats what Im going to do, I'll leave it for the tuner to see what he thinks is best, when it finally gets there...

I'll leave him also with the decision of plumb back bov or atmo as well.. its all the same pipe that will need modding...

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