So the theory is, if you insulate your intake from the engine's heat, the incoming air will be cooler & denser, and give you more power. I used Thermwell/Frost King 1/8" thick vinyl foam, foil backed, self-adhesive pipe wrap, available at Home Depot (search for SKU # 402585).


You just wrap the stuff around the tube and squeeze and shape it along the way. i also cut out around the bracket and nozzle that sticks out. Looks kinda ghetto but hopefully it works?!?!

On a side note, the last picture shows the stock air filters from my and my friend's G35's. The filter on top is mine at 3900 miles, the bottom one is a friend's, at ~12k miles. Wow, my filter is already so dirty ! I replaced it w/ a K&N.

slap some of that sheit on your intake manifold too, im guessing, maybe 10hp to the wheels?

If you are moving, and suking air, you will never know a difference.

It is really only useful if you are stuck in traffic and the heatsoak starts to build up.
If you are cruising, and moving air, there is virtually no measurable difference in the air
temp at the throttle plate.

I too agree this insulating the intake stuff is getting a little out of hand. It's their car though.

I've tested my G35's intake temp via my OBDII scanner. At idle, the air intake temp rises ~5 to 8 degrees over ambient while sitting at a stop light in 60 degree weather. Once rolling, the intake air is within 0 to 2 degrees of ambient. This is with the stock intake and Z-pipe. If that's not a valid test, I don't know what is IMO, wrapping plastic intake pipes is a waste of time and money.

haha, very interesting. Reminds me of nasa space suits...
I guess everything can't be functional, and pretty at the same time

P Diddy,

An observation... the picture of the dirty air filter elements may show them upside down in relationship how they were mounted in their respective air cases. IMO the vast majority of the air flow comes into the aircase from the main air duct. The heaver dirt sweeps across the face of the filter element and collects on the right hand of the enclosure. (Thanks for the filter pictures Jeff.)

Based on these dirt patterns and other observations, I have an unproven theory that very little air may be supplied to the power duct when the hood is closed. Therefore I went in a different direction. If you'll check out the pictures you'll be able to see my intake system mods to increase cooler air flow to the engine. They've worked well for me.

While some opinions will differ, I believe insulating the air intake system is a good idea. Alagolfer and I, along with GSedan35 ran a series of tests that were summarized in this thread --- https://g35driver.com/forums/engine-drivetrain-forced-induction/34658-air-intake-system-test-results.html.

Right now I'm back to testing the stock insulated aircase and K&N drop-in filter for a second time. Why? Because some continue to say CAI's cause a loss of low end power. If so, I haven't noticed it yet on my G. What I have noticed is the ECM's AIT Sensor (air intake) temps are slightly higher and there's seems to be a loss of some power from around 4k rpm to redline. Hopefully some G-Tech Comp Pro runs will support this dyno-butt observation. If not, I'll have a trick CAI for sale.

the stillen lends itself very nicely to actually sealing the edges to the body to prevent sucking in hot engine air - it is an obvious thing to do.

I became curious on this myself, and did some temp testing.
No doubt when you are stuck in traffic you will get some heat soak, but as soon as you start moving and/or bringing up the revs so that it is sucking enough air. The air temp drops very rapidly. Sealing the edge of the stillen box to prevent sucking engine compartment air I think you'll find better results than insulation.

Hello Brother. I have this problem with my g35. I understand why its there. But do you think the under front Panel Under the whole front of the engine and cooling system is a good idea when it come to heat soak. I know if I install headers the heat problem under the hood is only going to be worst. IM thinking that In stop and go traffic this could cause some problems.
Plus I hate the fact that this plastic shield needs to be pulled off every time. Just to do an oil change. Ya IM just an old guy too. Help me figure this out. Dennis

Dave O...
After taking the filter pics awhile ago I keep looking at the so-called Power Duct and trying to figure out how in the heck it sucks in much additional air vs. the center duct. I don't think it really does--maybe 5% even flows via the Power Duct--who knows? I like the mods that you made and I'm thinking of another near that area which is directed by the grill in that area.

this is worthless if you are using a plastic intake tube like the Z-tube, etc... BUT if you are like me and running an aluminum (metal) intake tube, it might yield slightly different results...

More than anything else, I wish I would have coated/wrapped my headers before I installed them

All you guys obsessed with cold air should just get this intake:
http://www.01designsystem.com/diis.html

Who says we're obsessed? $15 worth of thermotec is not obsessive. Maybe just a little old school, or not as blingy as a heat soaked chrome intake pipe, but it is effective in reducing the heat transfer to air going into the plenum.

To each their own.

I wrapped mine, I admit it.

What other wraps are there out there guys?

Depends on your style, personally I prefer Trojans over Lifestyles....