Hi All,

I have spent a lot of time searching the forums but haven't found any answer to my question. I have a 2006 G35x which obviously does NOT have the rev-up engine. I was looking at improvements to the intake manifold. It seems the 2 main options are (please let me know if I have missed anything!!)

1) Motordyne Copper Iso Thermal plenum spacer (I live in Canada hence going for the copper option) This seems to be what most people are using for non Rev-Up applications. Cost is $341.78
https://motordyneengineering.com/pro...plenum-spacer/
2) Kinetix Racing V+ Plenum for $259.99.
http://www.kinetixracing.com/kinetix...5g3503-07.aspx


I haven't seen anything comparing the two and from what I can read the Kinetix plenum does the same thing as the Motordyne but is cheaper and since it is made out of plastic has fewer heat sink issues. Am I missing anything here. All input greatly appreciated.

Hugh

 

Yes, you're missing the cheapest option: the Blox 5/16 spacer.
I haven't had any problems with my plastic Blox spacer and I daily my G in Maine winters. Just make sure you're careful with installation torque values, if you just tighten it as much as it can go you risk cracking the plastic spacer hence the negative reviews on amazon.

IMO heat sink issues with spacers are either minuscule or invented by tuning companies to sell their overpriced "engineered" spacers. If it raises the intake plenum by 5/16 inch and seals perfectly it's doing its job, you could make a spacer with a CNC router and a 5/16 thick wood board.

 

POP goes the weasel!

 

There's no doubt a plastic part is less durable than a metal one, if you over torque the screws it will crack around the bolt holes, and the guy in that review should have thought twice before installing a warped spacer that sounds like it was exposed to a nuclear meltdown in a past life. I

All I can say is my plastic spacer has held up fine for years and years on my NA car despite being aggressively driven daily in conditions ranging from -10 F to 100 F.
It's your money to spend, if the extra $250 for peace of mind is worth it to you then go for it.

 

If I remember correctly the V+ plenum is already raised higher than the OEM plenum, in which case you may not even need the spacer. I would have to research it again though.

 

The V plenum is composite material. The cork gasket can be an issue if you remove the plenum often because you're supposed to use gray gasket maker to help seal it. A rep at Kinetix told me that it's not possible to seal the plenum without the cork gasket, so if it's damaged, you gotta cut a replacement piece or send the plenum to Kinetix for a new gasket. He said he knows of no one that's sealed it without the cork gasket, thus all end up with a vacuum leak.
Recently, I pulled mine for the 5th time, very carefully. Gasket is still in tact, barely. Not an easy thing to do as the gasket maker doesn't want to oblige. I didn't replace the gasket maker this time, I just slapped it back on the way it came off and no vacuum leaks. I believe one can do away with the cork gasket and use only gray gasket maker (permatex) but one must use the gasket maker correctly. The bolts need to be tightened just enough to see the gasket maker squish out the sides a bit, let it cure for an hour and then torque to specs. I think most fail to read the gasket maker's instructions. The V plenum's instructions are a little sketchy as well regarding this.
The V plenum is lighter and stays cooler. It adds volume like a spacer does but the biggie imo is that there's a ****-ton of composite material around the "neck", or that section of the plenum that is post throttle body. I've removed a lot of material in this area, matching it to a ported 75mm throttle body adapter plate (NWP). This "neck" area is the biggest restriction and to be able to open it up so much makes the V plenum my #1 choice, at least for a naturally aspirated plenum.

 

So then so far 1 vote for the v+ plenum over the spacer

Hugh

 

-1 for the Kinetix, it's too ugly for my taste. Any slight gains it might produce over the spacer will never be felt from the butt dyno.

 

Too ugly? Perhaps. Everyone's different. The V suits my engine bay just fine.
To the rest of the referenced post above...

 

Different looking bay for once!

 

Thanks. Like it or not, it is different.

 

TL;DR
All products offer the similar performance, with Motordyne you get the most long term durability, Kinetix you get unique looks, and with plastic spacers you get low price. Pick based on your values.

 

Yes, for sure BUT you can greatly and easily enlarge the neck on the V plenum to match a 3" throttle body. Can't do that with the stock plenum, at least not easily. The Kinetix is the more fragile choice though, so if you're a brute, stay away. (It's been opened up even more since this photo. Had to take it off to replace cam sensors.)


Then you can enlarge the area from the neck and into the plenum, removing more of the pressure drop caused by the radical bend in the neck, out of the equation.



While you're at it, Mrev2 you're lower collector...



...get an isothermal spacer which may reduce temps but more importantly, it fits better than the o.e. gasket which overlapped each of the runners a bit...



and before you slap it all back together, remove the casting from the lower collectors runners. Takes 10 minutes. Why not.

 

I just want to know what all you did to clean up the engine bay and what can be taken out that is not necessary to get it looking that clean? Looking good! I'm fairly new g35 owner and new to this forum. Tons of great info here!

 

Here's a link to my thread; https://www.infinitiscene.com/thread...e-mods.230572/
Much of what I did is on my thread. Most is regarding wire tucking. Deleting the washer fluid res., useless heater hoses, idler pulley & bracket, oil filter heater, brake booster and pass. side fuel hard lines are not addressed.