OK - just free mods but I think it helped cause I definitely feel a little kick in the pants. Pics to come this weekend.

1st mod was the airbox*. I replaced the air filter when I just purchased my car about a month or so ago and I noticed all kinds of crap in the airbox. Leaves, sand, dirt, feathers, and other random organic material. That just made me sick (thank you ocd) and I had to remove the assembly to completely to clean it. When I removed it I noticed that the airbox is actually 3 peices, the hood duct that you can see going to the front grill, the actual airbox where the MAF plugs into, and a separate balloon looking peice that bolts to the fender but fits to the airbox via another vent type hole just like the grill duct peice. I pulled it out which was a pain, dumped all the leaves and crap out of it, and decided to just keep it out because it did absolutely nothing except maybe muffle the intake sound to tame the engine noise. This now gives the airbox 2 holes to source air from and to my reasoning this would allow more airflow. To those that think I'm loosing a RAM AIR effect from the front duct I can dispell that reasoning because there is no way the grill ducting seals enough to allow for any type of pressure to build in the box.

With this mod the engine intake noise is only slightly higher but it also sounds good - while not being annoying. Seriously adding only a tenth of a decible.

- why didn't I just buy an INJEN intake? - For starters I don't like oiled air filters. Say what you will, but I will never use and oiled air filter again. On my silverado it came with an AirRaid filer setup when I bought it and it allways required premium 91 fuel because of a detonation problem and it had a hard start problem. I thought because it probably had a programmer on it making these problems more apparent. My first oil change and air filter cleaning everything goes well, I didn't over oil the filter and I let it dry out in the AZ desert heat all day before driving. Well the detonation problem got worse and the hard start turned into a really hard start problem. I diagnosed everything from fuel pressure - timing - manifold leaks - all sorts of stuff with no avail. I finally put in 100 oct racing fuel and it still detonated with the temps outside at 60* F I knew something was wrong. So my last resort before taking it to a shop for diagnosing was to clean the MAF. I took it out and it was dirty as all H - E - double toothpicks. Cleaned it thoroughly and reinstalled it and now - all problems disappeared!

I will only ever use Amsoil Dry filter technology from here on out for performance.

2nd mod is the Throttle Body Coolant Bypass** - I noticed this super easy mod when I was changing the engine belts. The throttle body has 2 coolant lines connected to it from the top and the bottom. These line allow coolant to run through the throttly body and back into the main cooling system. The purpose of this line is to heat the TB plate and surrounding area to prevent icing of the throttle plate and having the throttle stick open when not desired. Unfortunately this line also heats the incoming air which makes it less dense and thus makes less power. I acheived the bypass with an approx. 8" - 10" of 5/16" coolant hose and routed it around the TB instead of through it. This connects the 2 ends and gets the TB out of the coolong system. I reused the factory coolant hose clamps to retain the factory look.

With this mod I did not notice anything until I drove it for a while. I honestly thought I lost power initially but after 2 days of driving I really notice it now. The engine is more responsive, has more torque in the lower end, and is generally more fun to drive I doubt it gave much hp in the higher rpm range but I could be wrong.

I wish I had some sort of Dyno or Gtech to document any changes, sadly I only have the trusty BUTT Dyno software which can only be taken with a grain of salt.

These are free except the coolant hose, which was $1 per foot at autozone, the guy forgot to write down the sku number so when I bought all the other stuff he just threw it in there and said happy holidays - so technically I did get it for free.

Keep and eye out in the coming months as I attempt to manufacture my first performance poduct. I will attempt to produce a bolt in performance air box that will utilize the stock ducting from the front grill and also a new duct that will pull from the bottom of the car that will utilize an oversize amsoil dry air filter and a removable plexiglass top to help with air filer replacement. This will completely replace the stock airbox and intake hose. It will still fit under the engine covers and look almost factory. I have no idea on pricing but I hope for it to be competative with the INJEN unit but be far more appealing cosmetically and make more power. I'm at a time in my life where my bank account can support my knowledge of performance and manufacturing to compliment my and others vehicles. If it is not cost effective then it will only be available in limited runs.

Also keep an eye out for phenolic intake manifold spacers. these are commonly used to isolate engine heat from the aluminum intake manifold as to provide a cooled, more dense air charge. These have been proven in other applications to reduce underhood heat and increase in hp/tq by approx 5-7hp and 5-7tq. This is accomplished two fold - heat removal and lengthening of the intake runner.

Disclamers -* Perform this mod at your own risk**Perform this mod at your own risk as this mod could cause you TB to freeze and cause serious damage to you, your engine, and others around you. I am in no way responsible for any damages that occur as a consequense of the mod.

Thanks and Happy Holidays!

Ken

Here are some pics.....

Remove the engine cover

Then remove the Grill duct

The upper hose connects to the empty barb with the red box around it

The bottom hose goes to the empty barb in this picture

The line should follow behind the TB as shown in green here

Here is the airbox extra inlet to allow more flow

I forgot to get a pick of the actual part I removed, but here's a pic from the FSM - I think this illustrates it better anyway

These mods have seriously woken up the car. The more I drive it, the more fun it is. Definitely worth the 30-45min it takes to do this.

The plus side it that it is easily reversed if you need to take the car in for service. So far no check engine lights are on and I've run 3 tanks of gas through it so far.

I'm guessing the coolant mod is applicable to the first gen models?

Cute holiday bow btw.

What can I say....I'm festive - lol

Yeah, the coolant bypass can be done on almost any vehicle. I remember alot of programmers in the past have a basic tune, then a tune which includes a TB bypass kit and a cooler temp thermostat. I looked into the lower thermostat for the second gen VK and there are actually 2 thermostats, one for the cylinder heads and one for the engine block. I've found the main thermostat in the lower temp range but the rear secondary thermostat I haven't been able to find.

I've done the TB bypass on all of my vehicles, 300zx, that chevy truck in the picture, toyota camry, and does it do anything??? Well my experience is that with the hot summers our here in AZ and running the AC that almost any car will have detonation problems. When I do the bypass the detonation is reduced to almost none so it does do something, but actual hp and tq - i can't say but it should let your ecu run more timing which as long as you arent detonating is qalways good for power.

One would think that there's already a thermostat in that line somewhere that stops flow to that TB hose once warm. In any case, I'll give it a look over at the next oil change and see about it.

ttt

Double E wrote:One would think that there's already a thermostat in that line somewhere that stops flow to that TB hose once warm. In any case, I'll give it a look over at the next oil change and see about it.

I've never seen a thermostat that controls the coolant flow/ temps going to the TB. Did you see this somewhere?

J

Who is supposedly going to make an intake spacer for our cars? An aftermarket company or you?I would like to see what some mild radical cams would do for the 4.5L engine.

J

I'll have them made by a machine shop but i'm not sure it'll work because of the injectors...we'll see. I don't even have the uprev yet

So you remove part #6 right?

New2Import wrote:So you remove part #6 right?

Yup, that's right. Technically you could cut the bottom off of it to block out the hot underhood temps.

I just made a small heat shield from thin sheetmetal and attatched it to the airbox to block out the hot underhood temps. If one were so inclined they could even attatch their own custom made ducting to reach down to the front of the car to draw in fresh cool air like the stock ducts do up front.

Can anyone tell me how to view pictures for these guides?

TLDR; don't try these mods at home, or anywhere else for that matter.

Not sure what the OP is trying to achieve by leaving out important details like how coolant goes everywhere if you don't drain the radiator or crimp the hoses when you attempt the TB bypass, or how there are three bolts in the airbox resonator, but only one is accessible without specialized tools unless you remove the front wheel well and bumper entirely.

It seems like the OP just fantasized about doing these things and then wrote a guide that is likely to cause people to waste a lot of time and make a huge mess for no reason.

Don't get me wrong, I'm grateful for the time people put into making guides where they have genuinely done what they say, but this thread is worse than useless and anyone trying to do what is mentioned is likely to end up with coolant everywhere or disassembling their air intake only to have to reassemble it exactly how it was before.

Don't bother with the airbox mod, it's fake, Nissan have made it incredibly difficult to delete the resonator.

If you're going to do the TB mod, watch some videos on YouTube for ways to avoid spraying coolant all over your engine bay.