Lowering intake temperatures is always a huge part of producing more power and doing it safely. One of the more important components in lowering the intake charge, are intake manifold spacers and throttle body spacers.
These intake spacers have been around for a long time, and aid in lowering the temperature of the incoming air. Today, I’ll be showing you how to install a intake manifold spacer in a 3.5 liter Nissan VQ35DE engine.
There are quite a few vendors that manufacture this product, Stillen, Motordyne, Skunk2 and many many more choices for you to choose from. Regardless of which company you decide to spend your hard earned cash with, the install procedure is the same.
If you want a no-hassle component that will not compromise drivability then it’s hard to beat these spacers, which can also be called risers or plenum spacers. Unfortunately most customers do not know how to install a VQ35 intake spacer, but that’s where we come in.
The unit we are installing today is a BLOX intake manifold spacer, part number BXIM-40200, which measures 5/8” in thickness. We have seen gains upwards of 4 wheel horsepower that can be realized just by bolting this part onto your VQ35 engine on our own 448X Dynojet dyno. Most customers report a gas mileage increase upwards of 2-3 mpg using this spacer, and most kits come with all the hardware and bolts you need for install.
Before we get started on our How To Install a VQ35 Intake Spacer Guide, you will want to disconnect the negative terminal on your 350Z or G35. Always operate safely around your vehicle, and for this install make sure your engine bay is clear of any debris as you will be working with the intake plenum removed.
Remove the plastic engine cover by undoing the 10mm bolts and nuts that secure the Nissan or Infiniti cover to your engine. Next you will need to remove your strut tower bar if you have one, if not unplug your MAF sensor next.
Now with the intake snorkel and MAF removed, you can unplug your throttle body and begin to undo the hex bolts that hold the throttle body to your intake manifold.
Loosen the top hex bolts and then move your way down to the bottom hex bolts that must be loosened.
Loosen these hex bolts and then remove them to clear the throttle body, make sure you undo the throttle body connector from your engine harness.
Now you’ve got those clear, it’s time to disconnect the hoses that lead to the plenum.
Using a set of pliers, loosen the tension clamps and slide off the hoses before you start removing the top half of your VQ35 intake plenum.
Once you have these hoses detached, move onto to the intake manifold bolts which must be removed.
There are six long bolts that make up the inner portion of your VQ35DE intake manifold, remove these longer bolts and then start removing the smaller outer ones. These are 10mm bolts and do not need to be saved, as you will be replacing them with new hardware.
There are two brackets you must undo so that the top half of your plenum can be removed. These brackets hold in your igntion coil engine harness, and are also secured by way of a 10mm bolt.
Continue your way around the manifold removing the outer bolts until you are ready to pull it off. There are bolts and then there are two nuts, we’ll get to these nuts and the studs they tighten later on in the article.
Shown above is the bolt and nut combination, if you have all the outer bolts removed, you can now pull off the top half of your plenum.
Pull up carefully to avoid damaging the intake manifold gasket, and make sure you have your engine bay clear. Because the top half of your intake plenum is removed, the engine is open to elements or things falling into the motor. Don’t let this happen to you.
Depending on your mileage and how much abuse your VQ35 has put out, you may have this oil pooling issue that’s extremely common in this engine.
Get your intake spacer out and all the hardware and prepare for installation by cleaning the intake plenum. Use brake cleaner if you don’t have acetone, but acetone is best for this cleaning job.
Depending on the thickness of the plenum you are installing, you may or may not need to remove the studs we talked about earlier. If you are using a thin spacer, you can get away with backing out the studs just a tad so that the plenum 10mm nuts have enough thread to grab.
Apply hi-temp sealant or liquid gasket maker to the intake plenum, applying a thin layer on the top and bottom halves of the spacer. We prefer Hondabond for it’s ability to withstand high temperatures and not break down.
The next part of our How To Install a VQ35 Intake Spacer, you will be removing any excess gasket maker from the top of the spacer. Leave a thin layer and make sure you do not have any clumping bits or large unseated sections of gasket maker. With your thin layer achieved and gasket maker cleaned up, use a rag and acetone to clean the inside lip of your lower intake manifold and the spacer.
You are cleaning this section to prevent any gasket from hardening and entering your engine. When installing your plenum, make sure to clear the oil cap gasket carefully.
Now install the top half of your intake manifold back onto the engine. Because the studs have been removed from the lower section, you may need to lift and shift the gasket or spacer around, as to not cross-thread the bolts.
Now use the bolts provided to correctly secure the VQ35 intake plenum, do not tighten but snug them in place before torquing the intake manifold to specification.
Tighten the bolts in the proper sequence to complete your installation of a VQ35DE intake manifold spacer. Make sure to check back for our VQ35DE Intake Shootout, where we dyno and review / compare intake systems, intake spacers and test them to see which one puts down the most power!
That does it for our How To Install a VQ35 Intake Spacer DIY article, if you have any questions or comments please feel free to leave them below!