what are all these holes in my plenum

[Froggx]

My 3500 upper intake manifold arrived yesterday. I'm an utter plenum n00b so I have no idea what all these holes are for. Please enlighten me.


If there is a question mark by the item, I'm making a stab at it, not actually sure.
1)?Has a plug in it?
2)?MAP Sensor or?
3)?Map Sensor?
4)?IAT sensor?
5)?um...?
6)?EGR?
7)Throttle Body.

[Mars]

1. MAP (anyone know of a 2 bar MAP that would fit there...???)
2. Brake booster
3. Beats me,
4. PCV line
5. EVAP purge
6. EGR port
7. Hmm, got me there, not sure.

[v6h.o.]

RE: what are all these holes in my plenum

1) map sensor

2) brake booster

3) vacuum source


The second picture isnt loading up for me for some reason right now.... Hmm..
But here is what the rest of the holes are for without having to look at the plenum:
At t/b area, Top of t/b neck, Open hole -this is for the PCV hose.
on side of T/b neck round hole Purge Valve for EVAP system.
on side of T/b neck Slotted hole with bolt holes around it EGR valve

and the Big fucking hole in the middle of the plenum... well thats for the throttle body of course :P

[v6h.o.]

RE: what are all these holes in my plenum

ah mars you fag you beat me to it while i was waiting for hte pic to load.. argh.

[v6h.o.]

1. MAP (anyone know of a 2 bar MAP that would fit there...???)

Yes.. I do, 2.4L engines have been using this style of map for years now..
Did you know there is a S/C kit from GM for those engines Mars?
Search around on the .org you'll find the PN for the MAP.

[Mars]

1. MAP (anyone know of a 2 bar MAP that would fit there...???)

Yes.. I do, 2.4L engines have been using this style of map for years now..
Did you know there is a S/C kit from GM for those engines Mars?
Search around on the .org you'll find the PN for the MAP.

Yeah, umm, of course I knew that, I was just testing you, EXCELLENT work Colin.

[Froggx]

thanks for all the help!
now I have to ask more annoying questions about these holes regarding the fact that this plenum is going to see boost

1)MAP sensor, gonna need a 2 bar I know
2)brake booster, needs check valve, no?
3)vaccuum source...shouldn't need any mods, run boost gauge off that correct?
4)PCV line, block this off and vent pcv to atmosphere, correct?
5)wtf is EVAP?
6)EGR, gonna get blocked
7)Throttle body, does IAC need any kind of modifications?

maybe it would be better if this was in the boost forum now...

[Mars]

Hmm, yeah, if you get into this crap, prolly be better off in the boost forum.

Yeah, for the brake booster you will need a check valve. (I have never seen one of these before, but there's a Subird 2.0L turbo @ a local yard, and I am going to go and get all the boost stuff of it, so I can show ya when I get it...might go tommorrow.

MAP sensor depends on what your plan is wiht the ECM, you will probblay end up with the Jeff M chip, so go ahead and get a 2 bar map, yeah...

PCV, yeah sure vent it out, no biggie.

EVAP, will most likely be disabled in your ECM code,so just block it off.

IAC, well depends on the TB you use, get a stock 3400 one adapted and your all set, hell even a LS1 TB has provisions for TPS, IAC and all that stuff.

EDIT in case anyone cares :

2 bar MAP GM#09350899 (From the 2002 and up dieael turbo trucks, in case you can get under the hood of one and make a quick snag, no one wil notice.) HOLY MOTHERFUCKER they want 150$ USD for it,

[Froggx]

regarding ecm, I'm doing a self tune on the TGP code, I've already got everything needed to do the tuning, it uses 2 bar, I'll kill evap in there
for the TB I am currently going to try to use a 65mm off a mustang (it was $10 so why not try even if it fails) and try to adapt GM's IAC to that, TPS is roughly the same as GM's setup from my understanding.

[Mars]

Hey, cool, be sure to let me know how the tuning goes as I am in the same boat, I will be running a blown 3400 though. But I will be using the TGP code... in my stock ECM, for now...

[Froggx]

I've been interested in blowers for the 3400, but I have more experience with turbos so I figured I'd stay with what I know for the time being. Most tuning will be done on a dyno with a wideband as I live near a shop that has good rates on a rental by the hour basis on the dyno. I chose to swap to the 3500 plenum for likely intangible performance gains and style (having 3400 sfi showing upside-down whenever I open the fiero's trunk would be a little hard to explain to the car illiterate).

[Mars]

You have a Fiero, I dunno why, but for some odd reason, I thought you had a Cutlass Supreme.

What ECM and tranny in in the car?

[Froggx]

It's the ecm from a 91 grand prix, 7727 I think it's called, using a Getrag 5-spd, I'm using the tgp code patch for the 5-spd tranny