Vq35 Plenum Spacers For V35/g35/350z

[chad bob]

It is a good idea, but to install a spacer, you need a second gasket anyway.

So you might as well buy one (from Nissan or wherever) and take it in to be used as the template.

For Water and Laser cutting a template will not be good enough, they need a CAD drawing for the machine to read. It's all very techie, not simply an old dude with a plasma cutter, the resulting component is accurate to less than a tenth of a millimeter ( I've made a few intake manifold flanges using this method with good results).

As far as a new gasket is concerned, I would just use high temp gasket silicone, it's not the PROFESSIONAL method but the number of times I've used RTV silicone on intake manifold gaskets I'll stand by that statement 100%

[scathing]

Just a though, could make 6mm, 10mm, 12mm or even 20 - 25mm spacers to experiment

The guys in the US already have experimented.

They've found that the 5/16" is the best size. Any smaller and the front two runners still don't get enough air, too much bigger and you'll get clearance issues with the strut brace/bonnet (on 350Zs anyway).

If you're planning on going to a strut brace that relocates from the factory position (like APS' to clear their Tall Boy plenum) then you could go bigger. I'm not sure if there's much benefit on a NA car though.

[iamhe77]

The guys in the US already have experimented.

They've found that the 5/16" is the best size. Any smaller and the front two runners still don't get enough air, too much bigger and you'll get clearance issues with the strut brace/bonnet (on 350Zs anyway).

If you're planning on going to a strut brace that relocates from the factory position (like APS' to clear their Tall Boy plenum) then you could go bigger. I'm not sure if there's much benefit on a NA car though.

No problem with a 17mm spacer on a V35 in regards to the bonnet. My mate made himself one with no clearance issues. Couldn't go much bigger though.

Dunno about the strut brace as he doesn't have one.

If the whole idea is to get more air in, how could a larger one not be of greater benefit to a thinner spacer?

With 5/16" being just under 8mm and 5/8" being just under 16mm there is a fair difference in the volume allowed in the plenum.

Dunno if/how it changed his economy or what difference it made as I haven't been in his car enough... but he tells me that it changed the note of the engine slightly and has given it a bit more torque.

[scathing]

If the whole idea is to get more air in, how could a larger one not be of greater benefit to a thinner spacer?

With 5/16" being just under 8mm and 5/8" being just under 16mm there is a fair difference in the volume allowed in the plenum.

The plenum only needs to be as big as required to not be a restriction at full noise. At a certain point the size increase becomes irrelevant from an induction perspective. Actually, if the volume becomes too large then the speed of the airflow drops and you could see a performance drop as a result.

People still make 5/8" spacers so there must be a gain. I'm wondering if going to a 1" spacer would make a massive difference over a 5/8" one, assuming it fits.

Still, if someone's willing to test it I'm always willing to read about it.

[666-GTR]

I got 1/2 thermal from motordyne loss a bit low range but it pulls hard right to red line now I put a Y pipe and vq exhaust sys at the same time so hard to tell how much the spacer has given me

[V35_Paul]

Yeah having the exhaust would make it soft in the low end. But your mid and high end should have a good gain.

[lankanrascal1]

Hey guys,

I've done a bit of research and I'm still kind of stuck. Motordyne or skunk? Any thoughts?

[Nightcrawler]

From all the extensive reading I have done on the US G35 forums I have decided that I will will buy a Kinetix cover, and am going to pull off my lower collector and sand it back to a mirror finish (the $US450 MREV2 seems to be a mirror polished oem collector anyhow). Even on the 206kw engines this apparently gives a good result. It makes sense, as the casting on the lower collector where air flows is very roughly cast and looks like crap (especially when 50,000km old and covered in carbon).

When I eventually get around to this I will do a direct before and after dyno on the same dyno to compare.

Also, the Kinetix cover holds much less heat than its oem metal counterpart (so allows cooler inlet temps).

And while I have it all apart I am going to do the throttle body coolant mod, which stops hot coolant water running through the t/b .... and also leads to cooler inlet temps. since I live in Adelaide where is does not get below zero I don't need the heater t/b to avoid freezing.

[V35_Paul]

Yeah good idea.

I did look into the Kinetix cover aswell but that was after i got the spacer and now wishing i waited and got the Kinetix cover insted.

Really keen for your before and after dyno tests

[ka86]

From all the extensive reading I have done on the US G35 forums I have decided that I will will buy a Kinetix cover, and am going to pull off my lower collector and sand it back to a mirror finish (the $US450 MREV2 seems to be a mirror polished oem collector anyhow). Even on the 206kw engines this apparently gives a good result. It makes sense, as the casting on the lower collector where air flows is very roughly cast and looks like crap (especially when 50,000km old and covered in carbon).

When I eventually get around to this I will do a direct before and after dyno on the same dyno to compare.

Also, the Kinetix cover holds much less heat than its oem metal counterpart (so allows cooler inlet temps).

And while I have it all apart I am going to do the throttle body coolant mod, which stops hot coolant water running through the t/b .... and also leads to cooler inlet temps. since I live in Adelaide where is does not get below zero I don't need the heater t/b to avoid freezing.

Sorry for using one of these however I wanted to ask how you went with your mods in particular the coolant mod.

You guys probably hear it a bazillion times but I have been going through numerous threads on the internets to suss out which way to go. Either Plenum upgrade or Spacer.

The Plenum upgrade (i.e APS) seems to be the go for top end power which would better suit F/I. The spacers seems to give good mid range power though some say they feel a difference all the way to the red line.

I'm still deciding which way to go but wanted to hear some feedback in general from those who have installed theirs since this thread was made. Whichever way I go, I plan to hopefully do a Dyno Run as well. Not expecting a huge gain as such however it will be beneficial to others.

Only mod I have atm is a Fujitsubo exhaust atm.

[fcruz3r]

If you have a spacer then you should get 170kw at the wheels thats what i got.

read this

http://www.skylinesaustralia.com/forums/Sk...20&start=20

skunk 2 spacers are double the thickness of the 5/16 motordyne, so you should be getting a higher top end hp reading. I think the 5/16 was developed for more low/mid range responsiveness.

I'll be getting the motordyne and a z-tube in about a week and once I get the harness for my f-con I'll take it in for a tune.