Intake Plenum or Spacer

jumbosrule

jumbosrule

Fully FX Invested
Premium
Car
2003 FX35T
Name
Brad
Wondering if anybody has anything to say about replacing the intake plenum with something bigger, or just going with a spacer to increase the volume? Anybody ever try both of these on the FX for comparison?

I do NOT plan to get headers, but have the Stillen CAI and Exhaust kits.
 
The spacer will give you the similar gains with any plenum if you plan on stay NA.
 
Intake manifold upgrade

I plan to go to a TT eventually, but was looking at an intake manifold upgrade that will benefit me immediately as well as after the TT install. I've looked at Spacers like the Motordyne, or intake plenums like Kinetix (2 options).

Just wondering if it's any value added or if the stock manifold is enough for the TT demands.

Anybody out there have a strong opinion about spacers or larger volume intake manifolds with NO boost? Of course, there will be boost eventually. Oh yes. There will be boost.:glasses:
 
Kinetix SSV will cause you to lose power when NA and won't give you any significant gains when TT. You should stay away the other Kinetix upper plenum since it's plastic and can crack easily under NA or TT. These would be my choices (sorted by $) if I'd go TT:

$ MD 1/2" spacer
$$ MD MREV2 + 1/2" spacer
$$$ Cosworth Plenum (replaces upper & lower)

The gains will increase as the money you spent will increase. How much I don't know honestly and I don't think spending $1000+ on Cosworth is worth it but Rookie can chime in I guess.. I believe he had Cosworth or some of his close friends have it.
 
I have the motordyne mrev2 with the 5/16 spacer, both were put on at the same time and I noticed a difference. I emailed motordyne and what they recommended for me was the 5/16" spacer with the mrev2. If I remember correctly, 5/16" spacer was a little more even powerband, with more on the lower rpm than the 1/2".

I do have a crappy memory so you might want to email them and see what they tell you.
 
HYME said:
I have the motordyne mrev2 with the 5/16 spacer, both were put on at the same time and I noticed a difference. I emailed motordyne and what they recommended for me was the 5/16" spacer with the mrev2. If I remember correctly, 5/16" spacer was a little more even powerband, with more on the lower rpm than the 1/2".

I do have a crappy memory so you might want to email them and see what they tell you.
Click to expand...

Those are all right & known for NA. He's going to go turbo soon so the additional (although may not be that significant) space provided by 1/2" spacer would be fine for him. He's going to get +100 torque anyways.. Low end vs high end torque becomes an irrelevant question at that point. :smile:
 
Done deal

Thanks for the discussion. I pulled the trigger on the Motordyne 5/16 Spacer. Once I go FI, I may upgrade the whole plenum or go to a larger spacer. :glasses:
 
Thought I'd put up a couple shots of the finished install. Took about an hour and I used a nut driver to get everything snug, then a torque wrench in the recommended pattern to finish it up. I left the original plenum gasket in place. Reset the ECU and then drove it around a bit to feel the change. I noticed a more open, free acceleration on the lower end and the engine sound has changed in tone a bit. I like it.
View attachment 163867
View attachment 163868
 
Stupid question but can you not recover the plenum? That looks hideous without any sort of chrome/polishing/painting.
 
tdawg183 said:
Stupid question but can you not recover the plenum? That looks hideous without any sort of chrome/polishing/painting.
Click to expand...

if you clean it it just looks like metal lol
did you think that the FX came with a polished/painted plenum?
that's the stock one...you can paint or powdercoat or polish it...

mine looks the same...completely stock lol
the 5/16 motordyne is awesome....felt a little on the low-mid rpms and added a tiny bit extra sound in the front of the vehicle...

spacer.jpg

and that's after I cleaned it up a little bit...

I am thinking of doing what fxlr8 did with the VHT wrinkle plus....check that out if oyu are complaining about how the stock plenum looks.
///4742
 
This thread has been quiet for a while, but I just happen to be planning to paint my plenum this week - so it's a timely resurrection.

Yes, I could put the original cover on there, but to be honest, I really don't want to. Plan is to completely disassemble the intake from the filter all the way to lower plenum. I'll pull off the filter, wash it and get the plenum painted first so they will dry while I'm doing the rest of this stuff:

- Clean out entire intake interior surfaces
- Clean, dry & re-oil filter
- Clean throttle body & MAF
- Clean & paint plenum
- Swap out red hump couplers & clamps for black
- Rotate MAF 90 degrees down (hide connector)

Going to buy the paint & sensor cleaners after work today. Hope to do the work tomorrow or the next day. Already have the black silicone couplers & new T-clamps.

Since I've had the plenum spacer, I've enjoyed the FX a lot more. It definitely is one of the best bang for the buck mods, besides an Cold Air intake upgrade. I actually raced another FX with a half inch spacer and I pulled ahead of him from 40-80, but then he started passing me as we approached top speed. Of course, this was before some other mods. Now I'm pretty sure I could take him.

Thing is, top speed isn't real important to me in the FX. The VQ engine spends a lot more time between 1500 and 3500 rpms than it does at higher rmps. For my reasoning, the 5/16" is the way to go, unless you plan Forced Induction. If you are dropping the cake on a turbo kit, you might as well get an aftermarket plenum for FI that doesn't need the spacer. As far as I know, the best one out there is the Cosworth:

http://www.z1auto.com/prodmore.asp?model=350z&cat=intake&prodid=2842

The only other spacer out there I would have liked to have tried - only because I don't know anybody on the scene with it - the Altered Atmosphere angled plenum spacer. The logic behind the engineering makes good sense to me, though I haven't seen dyno numbers to prove it's any better than the flat spacers everybody uses. It's the most unique design of all the spacers.

http://www.z1auto.com/prodmore.asp?model=350z&cat=intake&prodid=1796

Oh yeah - and here's a current picture of my engine bay. I took a wire brush to the plenum and have had a few more mods done since the photos in this thread.

EB-elec002.jpg
 
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Got it all finished last night and into this morning. Here's the painted plenum. Looks like it's the same color as the spacer.

IMG_0852.jpg


IMG_0854.jpg

Looks a lot better. Doesn't seem like that should have taken four hours, but it did...

Since this really is beyond the spacer, I'm moving this to my engine bay thread:

///4862
 
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Hey guys I'm looking into the plenum spacer which one do you guys recommend the 5/16 or 1/2 in one. Iso thermal copper one Also what do they mean by lanyard. Thanks
 
where can I get that straight pipe on your intake? Does it fit with the Stillen CAI set up?

Thanks.
 
By the looks of his last pic he has the intake running to the stillen box. You just need a coupler and some 3 inch hose clamps. The intake tubes are cheap on ebay also.
 
I use a Spectre aluminum pipe with Stillen CIA too. I got the pipe from AutoZone for $29.95.
 
Thank you gents. I saw this on e-bay not sure if this is his set up: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300643465269&category=38634&_trksid=p5197.c0.m619

la-fx35 - do you have a part number for the Spectre from AutoZone? What about the small protuding tube that connects to a rubber tube on the OEM and Z-tube set up? Does this aluminum tube has a provision for it?

Thanks again.

---------- Post added at 11:59 PM ---------- Previous post was at 11:41 PM ----------
Bklynjohn718 said:
I have the 5/16 thermal installed. I have read that the 1/2 is too much space. Try using the search bar for more info.

One on ebay for a reasonable price. http://www.ebay.com/itm/MOTORDYNE-5...Parts_Accessories&vxp=mtr&hash=item23185ccd19
Click to expand...

+1 on the price. I got mine for a higher price :mad.:.

Mike, since you are in NY, go for the Copper Iso thermal spacer. I have the 5/16 copper iso thermal. It is ideal for colder regions. I read somewhere that 5/16 is said to give more added boost on the low to mid range rpms while the 1/2 is more on the higher rpms. Since NY driving has more stop and go, I think the 5/16 is ideal. My 2 cents
 
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