Hey guys...has anyone tried to install both a 5/16" or 1/2" Plenum spacer and a Crawford Plenum at the same time? Is it even possible? Im looking for the most possible things i can do to the engine that are pretty easy installs. Aka: intake (Z-tube + stillen airbox), spacer, hypergrounding kit, plenum, test pipes (Oh yea...how much power are you supposed to get from test pipes?)...etc

Are there any other mods that you guys would recommend other than exhaust, turbo, or SC? I dont want to do either of those 3. Im in love with the sound of the stock exhaust...and its going to be loud enough once i do the intake and spacer. Any help would be appreciated...

Khal

 

stacking the two won't do anything...

 

dont be expecting more than all of 10whp with all of that done.

 

i asked a while back and was told no

 

Now wait a minute guys,

I'm glad this was asked, b/c I was eventually going to ask the same exact question...

**The Spacer is there as the "Middle Man" to allow more AIR in from pushing the top plenum up, right...?

**The OEM Upper Plenum has a "tilted" front b/c it's the same used for the Z and the 350Z has the bar which they had to make the front more SQUISHED to allow for the bar, right....?

Well, if the Crawford Upper Plenum makes the front more open and the volume all around inside the Plenum more even, then WHY could you not use BOTH???

Esentially you should get better power from the spacer and even better power from the Crawford Plenum sitting on top of the Spacer........No?

Let's discuss.

 

Good point good point! Im not too smart on this topic...yet. So if anyone can give some input...it would be great.

 

I doubt that stacking an aftermarket plenum on top of an aftermarket plenum spacer will yield any additional gains. I surmise this because, if it were true . . . Two things would have already happened . . . 1) The plenum spacers being offered would be much much thicker or 2) The plenums being offered would be much much taller.

 

i wonder if anyone on the site has atleast tried it. It would be interesting to see if it would make any difference.

 

I'm pretty much too much air is not good.

 

Take a look at these two links, particularly the second:

http://www.motordyneengineering.com/dynos.asp

http://www.motordyneengineering.com/techinfo.asp

The gist of the two pages is that increasing the spacing has diminishing returns beyond 5/16" or 1/2". There's even a pretty significant performance difference between 5/16" and 1/2", as the smaller spacer adds more power throughout the entire rev range, while the 1/2" mostly adds power at the high end.

What you're suggesting seems feasible, but I seriously doubt that you'll see any gains. PM Hydrazine (Tony @ ME) and ask him directly.

 

They were fixing a specific design flaw that only applied to two cylinders due to engine hood clearence issues. Once you fix that the cylinder flow is limited an equal amount........primarily by intake valve area and cam lift [curtain area].

The standard SAE flow bench uses 25" WC as a reference, yet they are referencing 0.75 psi x 28 = 21" WC ????

Would be nice to see [flow bench data] the various heads with plenum attach to prove the flow improvement.......instead of some variable dyno assertation.

 

LOL - You're way beyond my expertise level dude...

 

Are you saying that if we all had the Crawford type plenum where the front cylinders are not *squished* down and not restricted then we would NOT need a plenum spacer at all ????

I personally think that the Crawford is just getting the plenum back to where it should have been in the first place, since the G35 does NOT need the added room for the tie bar, like the 350Z, but with COST CUTTING measures, I see that they used the plenum for both sets of cars.

Now,,,with that being said, adding a plenum spacer to the mix *SHOULD* only get you more gains. We all agree with that. Now, the question really is...with a plenum spacer in place...do we need or not need the crawford (corrected version of the Z)??

I agree with the member that said too much air will HURT more than help.

SO.......

Maybe with the Plenum Spacer, even with the OEM *Squished* front, is giving plenty of added "Air Space".....? Maybe it's all our car needs..??

Any more opinions Guys....