Well that's why we have 1/4 miles tracks, but then again you're right it is never fair because it is nearly impossible to get an identical run.
As far as the Injen intake goes, I don't think it's a CAI, Injen calles it a "Race Division Intake System". Nobody said it's sucking in cold air, but nobody can attest to its performance except for those who have it - namely max_speed97.
Until somebody who has had experience with the POP and CAI has used the Injen intake, it is very hard to judge its performance. As far as we know, the temperature between the POP and CAI are not far off enough to cause their performance difference (as SLC previously stated). Then what is it? The piping? The amount of air flowing into it? Both of those things could be just as efficient if not more in the Injen system.
-Cyrus

 

Take a look at this:

This isn't just some random or lame proclamation. It's a fact, using physical evidence and common sense through some rules of Physics. I really believe Keven when he mentioned the lower resonant frequencies, and how it tunes the engine to lower RPMS, thus creating a stronger feeling of torque.

The Injen intake does the same thing as a CAI, and even if it may not exactly take in cold air, it still does the job of creating extra volume. This, combined with moving air which will prevent it from ever suffocating seems to be a good design.

My point is, I think we should just make the conclusion that the Injen intake is already on par with any short-ram cone or CAI, and that we should wait for numbers and comparisions before judging this item.

 

I still like that analogy of sucking a milk shake through a straw when trying to prove that there is more air "stored" in the tubing of any air intake. When talking about a vaccuum, even using physical evidence and common sense, I still feel that a FACT hasn't been achieved. I think that he's going somewhere with the stock box, but I think its deeped that that, perhapse the filter element. When you are talking about that stored air volume, it isn't going to go anywhere quickly with out the volume to be renewed from the filter side of the tube. Like a vacuum hose in your car, when you rev it up, you'll see it dimple with the vacuum. It creates-as you know- a negative pressure on the surface wall that will draw air up through the easiest opening-filter. So if it has to do this from 1.5m or from a 8inch tube, how do you think-unbiased-the air will equalize the quickest? Common sense will tell me that it will equalize with the shorter tube bringing the source to closer to the engine. So I think more than just common sense and a semester if applied physics is going to solve this debate. Dyno testing is unreliable when testing these types intakes, they have 2 different intentions of completeing the same task. Kind of like taking the high road and taking the low road.

 

Do you really think PRCAI has 5hp over Ingen? or vice versa?
I dont think so. Like I said in my other post, I really believe all the intakes give you similar gains, but to me, looks is important too, and since PRCAI or cattman or warpspeed cai look the best to me, thats what I like..

 

on a dyno I don't think they will, if one provides better airflow, I think its possible to yield that many HP over another intake with the proper secondary mods (y pipe/exhaust/hiflow cat...blah blah) We know that one mod will compliment another, so a CAI may only provide minimal gains on a stock car it will provide greater gains on a car with a Y pipe. It's all relative to whatelse you have on your car. I agree that looks are important, and if that spells Injen for someone, thats them and for you it has 2 letters PR.

 

How is the injen cold air? if the filter is in a HOT engine bay ?

inside=hot
Outside=cold

 

because the filter is below the engine bay if I am correct

 

Pics of Injen installed? Anyone?

 

i got it for $250...from my performace shop i go to

 

http://www.cardomain.com/member_page...200767&page=11
pic of injen intake should be here

 

So somebody was listening to me?!?

I've said that a couple of times and noone seemed to get it. I'm glad someone finally did.

 

THX

 

Since the PR CAI has long tube, that helps low end torque, but hurts top end, compared to a POP. Now, the Injen CAI has a longer tube. Is top end hurt a bit more with that intake? And low end is even better? Got to see dynos to know for sure.

Given the Maxima VQ motor, I don't think lo end really needs that much help, especially with a 5 speed. That's kinda why I went to a hybrid from PR CAI I may go back to CAI though, once I get the VI. CAI was always more linear than the Hybrid.

DW

 

No it is not worth getting over any real CAI...

 

Any "REAL" CAI? You need to clarify this, there is a flame on its way.

Lets look dwapenyi said-
The PR has a much longer tube with more bends and turns in it. I would assume that air would flow much easier and faster through the Injen since it is shorter and has less bends in it.

Nismo-No one really knows, because Dyno testing isn't fail proof. You can do other tests on an intake to read other results, but to measure power to your car its not a science. If you have a POP, keep it. Take your wife or G/F out to dinner and a show with the money you just saved.

 

Flame on its way?

CAI's are in the fender well not under the hood...

Whats so cold about air near the radiator?

 

So you think there is something real cold behind the bumper? My CAI (Injen type) takes the air from under the car just infront of the Tranny. Not in the wheel well, not from the radiator. Do you have any proof, temp wise of what your "REAL" CAI provides?

 

You think the air in the fender well is going to be hot?

 

Your avoiding the question, what is COLD behind your bumper? nothing, so what you are refering too isn't really true. Unless you are making a general comparison of a POP charger vs. a PR CAI. BTW, its not really taking air from your fender anyhow so... whats the deal with your fender question. I understand your point, there is nothing hot in the fender but there isn't anything hot from under your car. If anything this will probably allow your car to get fresher blow by air.

 

I simply stated in my first post that i dont belive the Injen intake is worth getting over more conventional CAI's such as WSP and PR. You want proof? All the documentd gains and personal experiences that have accumuliated on this board in favor of PR & WSP CAI's. Mabye you need to be showing me the proof for this new Injen intake? If you really need to discuss this more feel free to PM me...

 

Truth is that a Dyno isn't an accurate way to rate the ability of an intake. There are compensations that are made in the software, different conditions do not exist that benefit/hinder differen't intakes. All documented gains? 95% of the documentation on this board is from the butt, and don't have any physical evidence. The only post I've ever read that contains any real data is one about the intake temperatures and another on vaccuum levels on different types of intakes.

 

well IMO it seems as though the injen is a better design because first of all it is in the front of the car and not tucked up in the fender well, so naturally it should get more air unless you know how to drive your car diagonally.
secondly it is a sort of hybrid cai which gives back some of the top end loss the pr and other cai's are known for.
third, the price is not ridiculous at $225.
fourth, it is not excessively loud as to not tip off other people that your car might be fast, it will still sound good at WOT especially with a y-pipe.
and fifth, you don't have to drill any holes!

 

Hey guys...sumthing to get the debate going again here I'm skeptical about 12 to the wheels because its injen's dyno. If someone personally dynos it and gets similar results, then I'll believe it. Has anyone dynoed the frankencar for the 4th gen yet? Yes, I know dynos are biased as the hood is open and a big fan blows air into the engine bay, but its always interesting to know

 

What have you done!

 

I think its deffinatly the way to go, and the best part about it is that if you dont like the long tubing for the cold air intake you can always take the two pieces of the long tubing off and make it a ram air intake and just attach the filter. So its two intakes for the money. Yepp~

 

Wow, what a long thread!!!

I'm just about ready to have Dallas (WSP) send me the CAI extension pipes so I can make my HKS intake into a CAI just so we have some reliable CAI vs hybrid dynos and put all this crap to rest. I seem to be one of the only guys in this Org that does any real dyno testing before and after mods. Actually many of the Kansas City Maxima group does this. If I do test a HKS CAI setup, I will make sure and remove the foglight so that the fan pushes air into the opening. Or I may just setup the CAI to that all the piping and filter sits outside of the bumper and rests on top of the battery or something. Honestly, I don't see why everyone thinks the CAI is at a disadvantage on the dyno. The air in the bumper doesn't get very warm and it's not like there is some sort of void in the air surrounding the CAI at WOT on a stationary run. You guys do know that air will be replaced as fast as it's removed, right?

While I've never owned a true CAI, I did dyno my OSCAI (Poorman's CAI). My OSCAI used a K&N filter panel, all resonators removed, and a midpipe was used. With the same mods other than the intakes (HKS POP vs OSCAI), the car made the EXACT power straight to 5400rpms. EXACT!!! Both intakes made ~174-175fwhp and 192fwtq at the same rpms. There was no drop in torque in the lowend with the HKS (this was before using a midpipe on the HKS too). The real difference in power showed up after 5400rpms. While both intakes exhibited the typical "anvil dropping HP/TQ curves" after 5400rpms, the HKS didn't drop power as quickly. At some points in the graph after 5400rpms, the HKS was making 5-7fwhp over the CAI.

On the track with the OSCAI I typically ran 14.8s@93mph with my best being 14.73@93.93mph. With the HKS POP, I was getting lower 14.8s@94mph. My best was a 14.71@94.50mph. Similiar weather conditions too.

The Injen intake

The Injen intake is a very nice looking intake, but don't be fooled into thinking this is a CAI. The METAL intake piping and filter sit right behind the radiator which is typically running in the 200 degree range. As air rushes in the bumper opening, the heat off the radiator is dissipated and ultimately gets blown into the engine compartment. The hottest place in the engine compartment is right behind the radiator. The area between the radiator and engine is fairly tight plus the cast iron exhaust manifold sits there too. As the hot radiator air blows into the compartment, the hot air around the manifold is also blown around. If you think a POP lives in a hot environment, look where the Injen sits.



Dave

 

Sorry dude, that's not correct. It might sound right on paper and in theory, but actuality is where it's at. Last time I went on for a 30 minutes drive and pulled over on the side of the road, I touched the filter and the lower piping from underneath the car, and it was cold. As for the upper piping, I can actually put my hand on it for about 5 secs before it got too hot for my hand, so it's less than 200 degrees. (I do r/c racing and our motors are always @ 220 range so I know what 220 feels like on my hand) Next time I'll temp it with my temp gun and I'll let you all know.

Tifosi

 

Hmmm...my hybrid HKS is cold after a 30 minute drive, even the piping right near the TB. The placement of the Injen just isn't ideal. The piping runs between a hot battery, the block, coolant hoses, and the radiator. Then you are forced to relocate the MAF in a very hot place too.

Like I said, I'll probably be testing both setups just so everyone will shutup about this CAI vs POP/hybrid debate. It's so annoying to constantly read about it that I'm willing to waste $55 on the dyno to get the facts.


Dave

 

I did temp readings on my Injen style CAI when I first got it and compared it to POP charger temps while driving. The results were pretty identical to a POP charger it ran consitantly with the CAI. If you take the bottom splash shield off you get much cooler air.

 

I was really skeptical about the placement as well before I installed it. I had a Stillen pop charger before my Injen. According to my butt dyno(which doesn't mean much), I felt the Injen was pulling much harder from low rpms to mid rpms, more than my Stillen. But when it comes to mid to high rpms, it was pretty much the same. No, I didn't get beyond 95mph to test the top end differences. But all in all, I don't feel any loss in the top end w/ my Injen, and I got more low end pull. Keep in mind that the filter is sucking cold air at a high velocity so in a way, it is cooling the piping as well. That's just the very basic debate, Pop/HAI filter lives in a hot environment, it sucks in hot air, Injen filter lives in a cooler environment thus allows it to suck in cold air. As for the air in the piping being heated by the engine, it's really the same concern for every intake, they are all underneath the hood.

What I can do is use my temp gun to temp various locations of the engine bay to see the temperature difference. If where pop/HAI resides is only 5-8degrees lower than where my Injen sits, then I say the whole heat issue is all just a BS.

I'm supposed to go to a Maxima dyno day next weekend, I'm sure there'll be somebody there has PR CAI, HAI, pop charger. Maybe I can get some baseline numbers of different intake to compare.

Tifosi

 

If its still in your engine bay then its not really a cold air intake is it? I dont think so i might be wronge. Anyways i have the PR CAI and i love it. The drilling isnt bad at all..

 

I think there's a big misconception of what is in your engine bay, and what is actually sucking in the air. CAI should classify as to where the filter is, not where your piping is. I don't doubt PR CAI sucks in colder air than Injen, but if it's only 5-8 degrees temp different by the time your air gets to the TB, then there is no argument here, that little temp difference is very insignificant to engine performance in our case. You probably get better performance if you use higher octane gas!

Tifosi

 

I have the PR CAI and the early gains are RIDICULOUS! but i do see a difference in upper end compared to other cars with pop and hybrids...with my next maxima, i'm skeptical about drilling holes and may go for franken or injen. REally want injen now that i'm looking at this thread but want 100% proof taht its better than PR CAI and the best of both worlds giving good power in beginning and end or rpm's....

DAVE do the testing DAMMIT!

 

100% proof isn't there. What people should be asking about isn't Dyno tests, EVERYBODY knows that these tests are biased to hybrid and POP chargers. FLOWBENCH TESTING. Thats how you are going to find out which is going to let your car breath easier and faster. Take Vacuum tests at the plenum to see wich lowers the vacuum the most at WOT. a hybrid does a decent job 6-8mmhg at wot. POP charger does 7-10, meaning that it breathes easier. Also take air temp readings a digital air temp guage is about 20 bucks at Radio shack. tape the monitor to your windshield and drive around on the freeway for a few minutes and see. Seriously Dyno tests are horrible diagnostic tests for intakes.

 

You have got to be kidding me. Dynojets are excellent testing tools assuming you use the same car and machine everytime. Comparing two different Maxima's with different intakes is pointless, even on the same machine. Power differences between same models can be 5%.

If I get the CAI plumbing, I will do one run with the HKS setup for a hybrid (6 of my nine dyno runs have been with the hybrid) and then I'll do a run with the CAI attached. When I hook up the CAI tubing, I'll aim the piping and filter out of the engine bay (ie it won't be in the bumper) and in the direction of the fan so that it gets as much air blowing across it as the hybrid setup. How can this test not prove the facts?

1) both intakes will be exposed to the same air source
2) the car is under the same load (2000lb dyno drums)
3) same testing gear
4) same day
5) test within 15 minutes (to allow for cool down)
6) same machine
7) same conditions
8) same car

I'd say this reduces almost any variables between testing. I'm waiting to here back from Dallas on the piping.

One thing that strikes me as interesting is that the fastest, quickest, and most powerful non-VI Maximas (as verified on the dyno and track) were running hybrids. Now that we have the VIs and the ability to breath to 6500+rpms, I wonder if the CAI might be a better setup. That's another reason to perform the test.


Dave

 

Originally posted by Dave B


You have got to be kidding me. No I'm not kidding you
Dynojets are excellent testing tools assuming you use the same car and machine everytime. Comparing two different Maxima's with different intakes is pointless, even on the same machine. Power differences between same models can be 5%.
I agree, but you can test your car 3 times in a row and get 3 different numbers, so there is a 1-3hp +/- variance.

If I get the CAI plumbing, I will do one run with the HKS setup for a hybrid (6 of my nine dyno runs have been with the hybrid) and then I'll do a run with the CAI attached. When I hook up the CAI tubing, I'll aim the piping and filter out of the engine bay (ie it won't be in the bumper) and in the direction of the fan so that it gets as much air blowing across it as the hybrid setup. How can this test not prove the facts?

1) both intakes will be exposed to the same air source
2) the car is under the same load (2000lb dyno drums)
3) same testing gear
4) same day
5) test within 15 minutes (to allow for cool down)
6) same machine
7) same conditions
8) same car

I'd say this reduces almost any variables between testing. I'm waiting to here back from Dallas on the piping.

To prove my point, we put a CAI on a car running a pop charger and it lost 10 peak hp and 12lbs of tq. There is so much more than what we "agree" to be fact about our cars when considering open/closed loops.. What about the trims? If you want to test your car you need a control as well right? So take someone elses car and do what you are doing but in reverse. Let them drive on a CAI then switch to a Hybrid. The evidence from your second car will negate all of your findings on the first car. If the test proves positive on both cars then there is no chance of bad testing. I know you can't compare car to car dynos but look at the % of increase and/or decrease in power on PEAK power. I guess the overall arch of the power band would be nice to observe too.
Also your test conditions are all wrong. Your Hybrid Dyno's need to be with you hood closed and the fan blowing across the grill and headlight just as it would on the road, and the CAI needs to be nestled behind the foglight just as it would be on the street. If you are going to test something so it has credibility then test it as it would be used.
1 last thing.. Speed trip started off with a PRCAI with his MEVI, I wonder why he switched to a Hybrid... I know his car spends as much time on a roller as it does on the road.
One thing that strikes me as interesting is that the fastest, quickest, and most powerful non-VI Maximas (as verified on the dyno and track) were running hybrids. Now that we have the VIs and the ability to breath to 6500+rpms, I wonder if the CAI might be a better setup. That's another reason to perform the test.
Not that I am any of the above, but I did mine with a pop charger and OEM accordian and resonator.

 

Ok, I just went on a 20 minute drive on a twichy road that requires a lot lot of 2nd and 3rd gear shifting, a lot of torque required.

Here's the general setting.

Outside temp 63 degree +/- 1 degree
Altitude: sea level
I parked outside and ran up to my house to get my temp gun and these pictures were taken within a minute after I turned off the ignition
Forgot to mention Equipment used: Raytek MT2 temp gun

The hottest part of the engine was the big radiator hose @ 175 degrees
Valve cover 122 degrees
Radiator 126 degrees
Throttle body 122 degrees
Intake manifold 108 degrees

--------------------------
Injen lower piping 79 degrees
Injen upper piping 81 degrees
--------------------------
Where the pop charger or stock air box or PR upper piping would be
-Varies from 79 to 87 degrees
--------------------------

you can see all the pics here
http://litespeed-racing.com/engine-temp/

I honestly don't think the heating up of the injen piping is a big issue as people make it to be. PR piping and pop charger locations temp are very comparable to Injen, if not higher.

Tifosi

 

Okay so after reading all this stuff on the issues, I came to think that I would have to test my car somehow to show everyone what the Injen intake can do. I HAVE the injen intake and no other engine performance mod…just an intake. Here is my dollar on the issue and I am going to be honest and unbiased.

Let us assume that the engine bay temperature is 250 deg F and ambient is a comfy 75 deg F here in California.

Intakes: Injen, PR (or similar), and POP

Whenever, you have a path for air (or anything that acts like a fluid) to travel (at any rate) the air in the middle will have a higher velocity than the air on the edges (this is due to basic fluid mechanics theory). This is because there is more drag on the surface edges. This means that for a long path the fluid (air) will have a greater chance to achieve laminar flow. Increase laminar flow = increase efficiency. For those of you that still don’t understand…think of a river, the water on the edges is not moving as fast as the water in the middle. That’s why occasionally you have someone that was swept away in the river almost drowning because they thought that the water current wasn’t strong/fast enough to pull them out. Considering this on the Injen intake would mean that the air in the middle is traveling faster and would therefore have more time to achieve better laminar flow. Faster moving air will have similar characteristics of a ram air intake. As for PR intake, they do not have as long of a flow path as the Injen, but it’s still longer than a POP charger. A POP charger is the worst because the air is too turbulent. By the way, this is the biases for K&N’s air filters, they try to make the air less turbulent. Therefore, as far as airflow efficiency goes Injen would be the best, then PR, and lastly a POP charger.

Next, the temperature of the air is what everyone is talking about. The POP charger would be the worst for obvious reason. The debate comes in with the Injen and PR intake. Tifosi has a good point if we are talking about a 5-10 degrees difference in air temperature between the two then there will be little performance difference. I think that it would not really matter unless you are at the tracks going for your ¼ mile time. Then I believe that the PR would be a better choice because you will draw that initial cold air at WOT (this would be a split of a second). After that both intakes will perform the similarly because there will be a balance point between having good laminar airflow and cold air. You know what! I gave it some more thought and if your at the tracks then the fan will be on trying to cool the radiator, thus drawing in air from the outside and creating a strikingly similar environment and setup as the PR intake for the Injen intake. Therefore, all this debate is just to show that both intake (Injen and PR) are going to act the same at the tracks. However, during normal driving they would be different and I’m not going to talk about it because this is long enough and there are too many variables to consider (i.e. weather).

Whatever your needs are will determine what intake you should get. To me there will be a point when both the Injen intake and the PR intake will perform similarly. Then it is all about what looks better and cost…hmm!

Well, if you want to you can check out my setup at the link below and I'll post some more discussion about the Injen intake on the page later.I am happy with the performance and looks of my Injen intake...and that's all the matters! So as long as YOUR HAPPY with your intake, then it's all good.

 

About this never ending CAI vs POP debate, I still beleive the CAI has it's strengths, and the dyno won't show it. I don't think it's all about temperature. There's also smoothness of flow and consistency. It has been shown that with a CAI, the intake air temperature does not vary as much a with a POP.

I converted froma CAI to a Hybrid to get top end. Nothing can beat that setup where the filter is right there by the MAF . . . for top end breathing. The CAI hurt the 4th gen b/c of long tubing and the fixed manifold. With a Variable intake, that changes. Does the CAI match the POP?? No, I've seen the POP still has better top end, but only slightly better this time.

Even though I converted from CAI to pop, I like the top end, but I do miss the CAI's total predictability of engine power (linear tq curve), and low end (consisent temps?). What I don't miss about the CAI is the top end, of course, and cleaning that damn filter. It's alot more work than a POP.

I really only felt the top end loss of the CAI at the top of 3rd,4th and 5th gear, And those are extra extra legal speeds anyway. Not exactly up there as often as I'd like to be

DW