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The great GReddy-style plenum How-to of 2007!

By Kym.

I think I'm going to be the first one to actually post pics on how to install these eBay plenums. Enough talk already! Pending everyone's comments, I'll create this as a thread in the tutorial/how-to section. :)

To clear up all the BS circulating on these forums about them being no good etc. I bought this thing off eBay a few months ago, for science, oh and to clean up the engine bay and see the actual driveability difference between the two.

* Plenum cost $380

* Throttle-body adapter $90

* Brass nipples $30

* Fuel/Heater Host $50

* Silicon Bends/Pieces $80

Still not done yet. I need to get one bit made up first. It's for the AAC valve air-feed. Usually comes off the intake side before the butterfly. Maybe another $50 making this bit.

About $680 all up.

I took the time to replace all the engine belts, install some HID's and re-mounting my intercooler in the process, so I took my time.

Tools you'll need?

A good 1/2" Drive socket set.

A good 1/4" drive socket set.

Vice grips, pliers, insulation tape, wire brush, soldering iron, some hookup wire, loads of screwdrivers. Hacksaw, side cutters, a bench vice helps,

If i've missed anything out, or you can see anything else that I have forgotten to mention, let me know so we can make this a valuable resource.

Well, Here goes.....

Loosen and remove the throttle body, top crossover pipe and other various pipes. Easy stuff.

PlenumInstall%20001.JPG

Yeah, I took the front bar off too to remove the headlights. You'll see why later. Yes, my front radiator support is pretty hacked up eh?

PlenumInstall%20002.JPG

Remove these pipes below, and your washer bottle.

PlenumInstall%20003.JPG

Under the stock plenum, there is quite a few brackets that hold on coolant lines you'll need to remove.

PlenumInstall%20004.JPG

See the bolts below;

PlenumInstall%20005.JPG

Remove the top coolant bleed-valve bracket.

PlenumInstall%20006.JPG

Put the stock throttle-body onto the new plenum, for science.

PlenumInstall%20007.JPG

Remove the AAC valve from the rear of the stock plenum

PlenumInstall%20008.JPG

Oh, it looks like this btw.

PlenumInstall%20009.JPG

After you've removed the top collector assembly, (see how many bolts in the pic below), YES they are a pain in the ass to get to, no it's not impossible.

PlenumInstall%20010.JPG

Test fit the stocker fuel rail to the new plenum. Under each injector you'll find a rubber O-ring. Don't lose them!

PlenumInstall%20011.JPG

Yep, looks good.

PlenumInstall%20012.JPG

Stick some rags in the top pipes, so you don't drop shit in there. Remove the bottom stock plenum, pretty simple, the bolts are easy to find.

PlenumInstall%20013.JPG

Test-fit the new plenum, I put a rag so I don't drop shit in there again.

PlenumInstall%20014.JPG

NOW, let's get to the cool stuff.

We're going to block this pipe off. Watch.

PlenumInstall%20015.JPG

Snip this line, pliers will do.

PlenumInstall%20016.JPG

Stick an appropriate-sized bolt in it, and clamp it shut.

PlenumInstall%20017.JPG

Stuff to buy:

Threaded Brass nipples. I bought

3x 6mm for small vacuum hose.

2x bigger size (to suit brake booster and cam cover breather)

1x HUGE one for underneath. You'll see later.

3 Meters of 3/8 Fuel line

1 Meter of heater hose.

Gasket-making stuff. You'll see why later.

PlenumInstall%20018.JPG

Mmmm, nipples. (Don't try and lick them gents, they taste like shit)

PlenumInstall%20019.JPG

Big nipple below, oh, and unbolt the coolant lines from the stocker to the new one as per the next few pics. Same with AAC valve. Not rocket science.

PlenumInstall%20020.JPG

This is how you hook up the coolant solenoid and lines.

PlenumInstall%20021.JPG

Don't forget to put some gasket-making stuff on here for a good seal.

PlenumInstall%20022.JPG

The nipples go here. K.

PlenumInstall%20023.JPG

I put some gasket-goo-making stuff on this seal too. Call me silly, but it makes sense.

PlenumInstall%20024.JPG

Pull out the injectors from the fuel rail. Like this. A vice and big flat screwdriver helps.

PlenumInstall%20025.JPG

Take them ALL Out. You'll see why in a sec.

PlenumInstall%20026.JPG

CUT, saw. The top fuel feed off. You don't need it, and it looks ugly.

PlenumInstall%20027.JPG

Then cut off the supports that hold that top fuel feed on.

PlenumInstall%20028.JPG

I used a small set of files to get rid of the crap inside, so nothing can fall off and end up in the injectors later.

PlenumInstall%20029.JPG

Remove the fuel pressure regulator like below, and spin it round.

PlenumInstall%20030.JPG

Check (if you live in usa): Kroger Weekly Ad, or Myer catalogue.
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Now, remember that bit of fuel line you cut off before, let's re-use it smile.gif Remove the bracket from it like below.

PlenumInstall%20031.JPG

Cut, cut cut!

PlenumInstall%20032.JPG

Strap it to some fuel line we bought earlier. You only need a bit. And clamp it down.

PlenumInstall%20033.JPG

Remember this below? It's the turbo water line that went into the back of the stocker plenum! (yes, we gotta hook it up!)

PlenumInstall%20034.JPG

Use our bit of fuel line, and some ingenuity, and extend the water line to the nipple below. You'll see what I mean. It's hiding.

PlenumInstall%20035.JPG

Back to the plenum, Plumb the heater hose to the bottom, and cable-tie it to keep it neat.

PlenumInstall%20036.JPG

Replace the gasket to the head. Like below. Notice our newly patched hose at the back left there? :)

PlenumInstall%20037.JPG

Slide the plenum on, like so.

PlenumInstall%20038.JPG

Looks pretty huh?

PlenumInstall%20039.JPG

WIRING and beyond!

Cut these two loom connectors off, ONE AT A TIME. We're going to extend them out a bit.

PlenumInstall%20040.JPG

Using some hookup wire, and a soldering iron, extend the wire by about this much. But not too much, you don't want it hanging in the way later on.

PlenumInstall%20041.JPG

And tape them both up again. Like below.

PlenumInstall%20042.JPG

Bolt the plenum in now, you'll need about 5 new shorter bolts for a few of them. You can't re-use the stockers. They're too long.

PlenumInstall%20043.JPG

Looking DOWN the top of the plenum, there's the water line solenoid you'll need to connect to the plug again. It's hard to get to.

PlenumInstall%20044.JPG

Yeah, its the blue one.

PlenumInstall%20045.JPG

Stick the O-rings in the holes, like so.

PlenumInstall%20046.JPG

Bolt the injector rail back in. THERE ARE LITTLE NYLON SPACERS UNDER THE BOLTS. Don't lose them!

PlenumInstall%20047.JPG

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The top cam breather pipe goes into the big nipple at the rear of the plenum. Add fuel lines to the rear (pictured below) This comes from the fuel filter. It's the feed-line.

PlenumInstall%20048.JPG

See how we spun the fuel pressure reg around? There was a reason for that. So it didn't hit the injector!

PlenumInstall%20049.JPG

Clip on the FRONT fuel line, which is actually the return line.

PlenumInstall%20050.JPG

Put the brake booster on the back to the nipple. You'll need to cut the hose and make it a bit shorter to fit.

PlenumInstall%20051.JPG

Put the injector wiring harness back on, and put the main loom back over. Don't worry, you can't screw it up.

PlenumInstall%20052.JPG

This is how i did the throttle-body, using stock cable!

PlenumInstall%20053.JPG

A few more pics coming soon of the finished product.

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The finished piping.

The plenum along the side;

Plenum2%20001.JPG

This is the AAC valve air input.

Plenum2%20002.JPG

Don't forget to plug in all the wires again.

Plenum2%20003.JPG

I welded a piece of galvanised tube to the side of the pipe for the AAC air input (without this your car won't start, FYI) and plumbed it into the pipe just before the TB.

Plenum2%20004.JPG

Closer-up of the welded piece of tubing onto the side.

Plenum2%20005.JPG

Underneath the whole thing.

Plenum2%20006.JPG

Nice stealth location for the BOV too I reckon.

Plenum2%20007.JPG

The finished deal.

Plenum2%20008.JPG

End summary. Horsepower gain? haha NO. Throttle response gain, +40% pedal feel. Very nice. Noticable lag/reversion decrease.

Thanks for reading!

  • Like 1
  heslo said:
Nice writeup mate, how did you find the quality of the eBay item?

Not too bad, the water galleries all line up, everything was decent. Let me just say I think i got "one of the good" ebay plenums (judging from previous pics people have posted)

  [Michael] said:
nice work kym, be interested to see what difference it makes

I'm not aiming for hp, but for throttle-response mainly. I think it'll make quite a bit of difference :)

  Adriano said:
Excellent work mate, i would just be a bit weary abou that throttle cable, from my experience they have to line up well to work properly.

Noted :) I guess my first drive will tell the story.

I copied most of the hookup layout from my gf's car. She has a genuine GReddy plenum on hers, always good to have them side-by-side for comparison.

Stay tuned for more soon...

Excellent work, and the efforts at making a pictorial are commendable. Many thanks, because my own fit-up is currently being planned. The fuel rail mod looks good too.

I will be interested to see the on-road results.

Did you de-dag the plenum inlet, or the runners? What about facing the mounting flange? And any cleanup work on the injector mounts to get a good seal?

yea i had a bloody horrible one arrive in the mail! was lucky enough to be able to refund it in the mail and receive another one (all postage paid). This one is a bit better. This post will come in handy when the time comes to install it on my car (currently undergoing engine conversion).

Keep the updates coming!

I dont know how much extra throttle response your going to get. But in terms of power, what i have noticed is that you lost a noticeable bit of down low power and torque. Obviously the shorter runners are to blame, however it does open up the top end. But they do neaten up the whole engine bay and make more room for changing plugs and less piping running everywhere.

Very good guide mate. Excellent bunch of photos showing all the bits that need to be done.

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