I really don't know anything about those things but i was told that putting after-market intake will reduce the life of the engine because the stock engine must work with stock motor parts. Please comment.. and maybe someone can explain what does the after-market intake do for the engine. thanks.

 

Who told you that? An intake will help your engine breathe better, actually reducing air RESTRICTION. Along with an exhaust, the engine is able to consume and expell more air(A good thing) easier. This 1. makes noticiably more power, 2. the ability to really "open" the car up on the road and 3. if driven normal on the freeway will actually increase gas milage due the engine processing the air more proficiently. I have a Stillen intake and I highly recommend them. It was perhaps the most noticable mod I've done. Plus, the sound produced by the Stillen Intake is more throaty than most american V-8s. Oh yeah, the intake has a million mile warranty on it. Just take it off, clean it and put back on every 50K. Your gonna spend money on replacing air filters anyways, you might as well buy an intake that will increase power, enjoyability, and never need to be replaced. have fun,
Gramdacious

 

That's basically what I was told before and what i told that guy..But he said that everything has to be proportional in order for engine to function properly, and air flow has to be proportional to the fuel injection. And also the stock air system is probably more expensive, so why doesn't nissan use the high flow intakes if they give better performance.

 

He's right in a sense that if you tweak the fuel injection(I.E. an ECU upgrade) you will maximize the intake's performance. But even without touching the ECU, the intake makes a noticable difference and is safe. Also, maximas have a variable valve timing system(similar to VTEC without the need to service VTEC every 15K), which means that the engine senses more air being rammed into the mainfold and thus increases the amount of gas injected. If your engine is consuming more air like an intake will do; about 33% more air, the ECU will recognize this and inject more gas. Have you noticed that at about 3000 RPM the car pulls more? That is because the ECU is pushing more gas into the cylinders becauase it is programmed from nissan to do that. Upgrade your ECU and your car will rev faster and be quicker off the line. As far as why nissan doesn't use high flow intakes, they are louder, and not every mom and pop wants a race car type sound. They actually did use a "higher" flowing intake and exhuast sytem on the 2000 Max. The engine in the 2000 max and the '99 max (like mine) is the EXACT same yet, Nissan claims 227 Hp on the 2K as opposed to 190 Hp on the '95-'99. How did they achieve 37 more horspower from the same engine? Nissan claims a "higher flowing" intake and exhaust system.... exactly what we are talking about.

 

Thank alot, this information really helps me

 

No problem. I used to sell Nissans for three years and I've owned two generations of maximas. I strived to learn all about them from service techs working at my dealerships and found that they are one of the most potent all around sedans ever made. Let me know if you have any other questions on any topics relating to the maxima, technical or not. good luck and have fun modifying.
Gramdacious

 

I don't think this is true...who told you that?

Quote:

Have you noticed that at about 3000 RPM the car pulls more? That is because the ECU is pushing more gas into the cylinders becauase it is programmed from nissan to do that.

I don't think this is true either -- the car pulls better
around 3000 RPMs because that how the engine's power band
goes...

anyone else?
FLO_BOY

 

What's not true? The fact that Maximas have VVT? Because they do. I'm not sure how the Maxima's specific VVT works, but the basic idea is to give higher lift and duration at higher rpm to better facilitate intake. The car's computer and intake system will always respond with the programmed optimal fuel injected depending on temperature and airflow. The cooler the charge and the higher the volume, the more fuel that will be injected.

I think that person's post is misleading as its not just more fuel being fed to the engine, but the actuation of the VVT which allows the engine to pull more air. At which time, the ECU allows the injectors to spray more fuel.

As for "pulling harder at 3000 rpm", most 4 and 6 cylinder engines will see a marked power gain at these rpms. Get ahold of a dyno sheet for smaller engined cars and you will see. Smaller engines will generally have fairly low torque at low rpms nd rise rapidly around 3k and then peak somewhere around 5k to 5.5k and then drop off rapidly after 6k where peak hp is generally calculated.

 

Power band obviously has something to do with it yes, but the VVT really kicks in at around 3000 RPM. this can be altered. The alteration has nothing to do with the power band, it has to do with kicking the VVT in before 3000 RPM. If you were get an ECU upgrade combined with a lightweight flywheel(5 speed only), the power band would be completely changed off the line. I did over-simplify the part when I said more gas is being injected, VVT is actively controlling other parts as well, but for the most part this is true. Anyways, my main point of chatting was to relay that fact that an intake will not harm your vehicle. nuff said
gramdacious

 

true.

lates...
FLO_BOY

 

in a sense it will hurt your car.. flooring it every time u get the chance is not good for the car..

 

On the part about the air being proportional to the fuel. You have to keep in mind that the manufacturers purposely restrict the intake in order to keep the car quiet. Oh yeah, and VE's have variable intake.

 

Let me check what forum we are in. Yup, 4th generation forum. 4th generations' VQ engines do NOT have VVT! The surge you feel at 3000rpm has everything to do with the way the intake manifold was designed. If the 4th gen's VQ had VVT, why does it fall on it's face after 5000 rpm? As for intake cleaning, every 50k? I'd hate to see how much dirt would have accumulated by then. Most people would clean it every 10-15k.

 

The 4th Gen Mxaima does not have variable anything. Also, the engines in the 99 and the 2000 are not the EXACT same.

 

Not true, they have variable wind shield wiper speeds

 

Not all of them do...

A GXE or SE without the C&C package will not have variable intermittent wipers.

 

i thought it was the Cold weather package not the C&C..

 

well darn it mine are variable, why can't you 4th gens have it too?

(sorry.. bad typing)

 

What?

 

Intake cams Ben.

92-94 Se came with varible intake cam timing(not lift)
2002 3.5 maximas saw the re-introduction of varible cams timing(again not lift) now it's infinitly varible though.

In JAPAN, Nissan does have some type of varible cam LIFT tech. It's called NEO or something. Varible cam lift tech is nothing new now. Porsche/Honda/Nissan and others have it

 

I know...I just had no idea what his sentence was supposed to mean.

 

The air box is designed to keep the car quiet,

Your ECU is constantly updating your injectors for optimal fuel ratios

The car pulls hard at around 3000 because thats when the first cam kicks in, the second I believe is around 4,500.

I took off the pipe connected to my intake resinator and ran a 3inch pipe down under my car that curves forward into a four inch opening. Under the car is where you get a ton of air, and the front of the car is totally blocked by the radiator. I was hoping the 4inch opening facing forward under the car, connected to the 3inch pipe, connected to the stock 2inch opening on the intake snorkel would create a venturi effect speeding and compressing the air. Also with the stock intake snorkel still inplace this gives the intake two sources, so if one is clogged by water the other will take over(think about sucking up water through a straw with a hole in it.) This along with my Y-pipe has really made me stand up and take note of the max. Just as the max starts to pull harder at around 3500 and you can feel this, I feel this same change again at 5,000 rpm to redline. This mod has also kept my intake manifold very cool to the touch (which surprised me more than anything) in 50-60 degree weather after heavy racing and street driving.

 

You mean up to 3000 rpm, the maxima is only running on one per bank?

 

I am guessing that this is where mechanical advantage is provided most from the design of the cam profile. I read this in another thread.

 

sorry man, I left out a word due to typing too quickly. The VE just has variable everything.. I was jokingly referring to the windshield wipers up above.

 

When do the 3rd and 4th cams kick in?

 

As I said before I believe it has to do with the particular cam profile and the mechanical advantage it provides at different RPM's. As far as the third and fourth, we have dual over head cam engines.

This information was provided from an outside source in refference to the VQ30 engine.

 

The VQ30DE only has one cam profile. What is this "outside source" that is feeding you BS?

 

Believe it or not, I believe it was on this web sight, I listed it as an outside source to let people know that I am not the one to answer specific questions about cams. It made sense to me at the time as the car does seem to really pull from those RPM's.

Thanks for clearing it up. Do you know why the car just wakes up at around 3,500, for future refference?

 

It wakes up because that is the RPM range where the cams and intake manifold work best.