Plenum Spacers

[Craig Brumley]

Anyone want to offer their opinions on which plenum spacer to buy? The Blox appears to be the cheapest. Is there an advantage to the higher cost, CNC'd metal spacers?

Thanks in advance.

[cheapazz]

I'm no expert but I think its all in what you are looking for in performance. I believe some spacers give better low to mid response and others give a better mid to high gain. I went with the skunk racing 5/8 spacer, it adds a load of mid to top end power but seems to lack a bit at the lower end. It's ok though, it lets the mustang guys think there driving something fast.......till I rocket past them.

Sorry SVT!

Side note: Anyone up for driving my Chevelle in a race with my G?? HAHA

But seriously, there are lots of threads here that talk about the plenum spacer and its effects. I'm sure a moderator will throw a link to you soon.

[BrandAidDesignG35]

I got the BLOX 5/8, looks really nice, exceptional packaging, free sticker, what else could you ask for

I'll be installing soon, so I'll reply with the results, post install, oh, and it was chump change.... >$120 - egay.

[joe603]

I have motordyne, but they were the first to come out...Blox is a copy. Which is fine because the spacer is just a thick gasket made of composite plastic.

Check out the aftermarket sites in the G-Series FAQ (link in my sig)

[tollboothwilley]

I have motordyne, but they were the first to come out...Blox is a copy. Which is fine because the spacer is just a thick gasket made of composite plastic.

I went with the BLOX since it was less than half the cost. I paid $105 shipped.

I dont think it makes much difference what spacer you use, as long as its even all the way around. The BLOX is great, esp. for the price.
Modified by tollboothwilley at 10:49 PM 7/10/2008

[BrandAidDesignG35]

I finished installing the BLOX 5/8 spacer last night, wow!

It sounds very similar at lower rpm, but there is a new growl past 5K rpm... it is like a screaming eagle or something, wicked wicked sick sounds at WOT...

During the install, it became quite obvious why the spacer is helping... The manifold is quite tight on the front two cylinders.... Worth every penny

[g372go]

I'm new to the G upgrade game and am wondering if the spacers actually add power as advertised. I was at my local speed shop and when I mentioned about getting one for my G37, one of the top mechanics said that he was at an all day dyno shoot out and the conclusion relative to the spacer was that it added little or nothing relative to the cost of purchase and install, small as it is.What sayith the G performance guru's? Was I misinformed as I note that alot of members have them.Snowman

[tollboothwilley]

for the G35 it seems to add a decent amount of power especially in the upper RPMs, as for the G37 I haven't heard much about spacers

[joe603]

The intake is redesigned...I don't think there is a need for a spacer on the G37 or the 07+ G35 sedan.

[Sentientbydesign]

The newer G's have different intake designs. The 07 sedan actually seems to have a plastic/composite plenum which I would assume means lower intake temps.

I have the BLOX spacer. I didn't really notice much. Then Joe popped in and told me I needed a new lower plenum to benefit from the spacer

I think I'd rather a composite aftermarket plenum than a spacer. The plenum gets ridiculously hot and that doesn't seem good.

*EDIT*

The 5/16 spacer shows the most increase per Motordyne. As you go up in thickness, the increase decreases exponentially. So say the improvement was 15 hp for the 5/16, the 3/8 may only be 16hp...etc.

My only concern with the Blox design is that it's a little thick and may potentially reduce plenum pressure to the point of a negative effect. I don't have any proof, just theory.

Motordyne is full of when they say only the 5/16 will allow the engine cover to fit too. Check the FAQ for beaner's install. He got the cover on just fine.

[G2go]

Thanks for the good info on spacers. But this is the first time I've seen anywhere in forums where the G35 and 37's have had redesigned intake designs. Where do we get that kind of information? And, does that mean that the G35 engine will continue for a number of more years in various cars or will the G37 engine be the engine of the future? I can't see Infiniti just making a special engine for the G37 and not have some kind of economic expandability in mind for the engine. And how long will they guard the ECU codes? What about SC and Turbos for the 37 engine? If the G35 engine's intake was redesigned how did the aftermarket guys get the specs for it and not the 37 Is there a Nissan guy on the forum? Infiniti engine guy?

[Sentientbydesign]

We've actually discussed the VQ35HR and the redesigned intake in quite a few threads. I think it's become common knowledge throughout the G forums.

All you need to do is look at the engine bay and you'll see DUAL intakes with dual throttles. Pull off the engine cover and you'll see a plastic/composite plenum instead of the cast aluminum one on the earlier VQ35DE.

As for the ECU. I didn't realize the codes were kept a secret. The general concensus is that ECU reflashing is really unnecessary unless you are going Turbo/supercharger.

The G37 is still very new. Aftermarket parts makers have to find weaknesses in Nissan/Infiniti's design before they can start designing replacement parts. I don't think gathering specs on an intake are all that hard. It's a tube with a filter and scoop on one end and a drive by wire throttle on the other end with a couple or three baffles in between.

I suspect that the VQ25HR will be used for economics and the VQ37? will be used for power.

Infiniti isn't as concerned about fuel economy as some of the other brands. They supposedly will be making a small coupe with a smaller engine, but that is still in the concept phases.

The FX50 has just been released with a 5 liter V8 versus the 4.5 liter.

[joe603]

Motordyne is full of when they say only the 5/16 will allow the engine cover to fit too. Check the FAQ for beaner's install. He got the cover on just fine.

Beaner had to rig up drilled out nickels to get the 5/8's spacer to fit...to stay safe, Motordyne just advises that you can't use the engine cover.

G2go, the G37 engine uses most of the same hardware that the G35 engine has, it is just a redesign on the VQ35. The main difference is they improved on the valve train design, allowing for a higher redline (7500 vs 7000) and the stroke is increased from 81.4 to 86mm. Compression has been upped from 10.3 to 11. That's your .2 liter increase and 30hp.

[Beancooker]

Get the 5/16. I am looking at having a really hard time getting a FSTB to fit with the 5/8. I may end up pulling the spacer and getting a 5/16 to make it all fit.

[Sentientbydesign]

See if you can find one of the FSTBs that comes around front near the radiator. I know there are a few like that for the 350Z, haven't looked into it for the G yet.

[g372go]

Thanks Joe for the kind explanation. You are being nice to the NOOB here and I appreciate it. I will most likely have some other uninformed questions in the future so I appreciate your courtesy.Steve

[Sentientbydesign]

Thanks Joe for the kind explanation. You are being nice to the NOOB here and I appreciate it. I will most likely have some other uninformed questions in the future so I appreciate your courtesy.Steve

Steve,

We love helping you spend your money here in the G forums!

[Beancooker]

See if you can find one of the FSTBs that comes around front near the radiator. I know there are a few like that for the 350Z, haven't looked into it for the G yet.

Not interested in that type. It doesn't brace the towers enough. I would love one that went in a diamond from the towers to the firewall, but there isn't enough room to clear the throttle body.