Alright. I intentionally waited to install my extra performance parts until I put this issue to rest. So here's the deal.

I have a 2002 Maxima SE with a 6 speed tranny. I had no modifications other than a MagnaFlow Street Series muffler. I dyno'd my car in the following conditions (in order from air intake to throttle body):

CAI: Monsterflow 3.25" filter -> PR CAI lower tubing -> MAF -> PR CAI upper tubing -> TB

WAI: Monsterflow 3.25" filter -> MAF -> PR CAI upper tubing -> TB

Stock: Stock airbox scoop -> K&N Drop-In Filter -> Stock airbox exit -> MAF -> Stock upper tubing/assembly -> TB

Each time, the car's ECU was reset by unplugging the battery for a minimum of 25 hours (24 was too questionable). The car was then started for the first time on the new setup. Parts were swapped during the 25 hour period that the battery was unplugged.

Once the car was started, it was allowed to idle for 10 minutes under no load (no A/C, radio, subs, etc). Then the car was driven under normal daily conditions for the first 100 miles. The engine was not revved over 4500 RPMs during this time. Once 100 miles had passed, the car was driven with an emphasis on performance (READ: driven like I stole it). Only after the next 100 miles was passed (200 miles total) was the car dyno'd.

The car was dyno'd at the same facility on the same dyno for all 3 different intakes. The only variables were the time of day and temperature, which the SAE adjustments fix. 3 runs per intake were done. Once the 3 runs were completed, the best run was chosen for that intake. These runs were the runs that are posted below.

There was no filter cleaning performed on any of the filters between dynos. All 3 intakes were dyno'd less than 1.5 months apart. This time was only increased by the fact that the car was disabled for almost 2 weeks at the dealer (trying to get a new clutch installed). Other than that, the intakes were back-to-back-to-back. This way, the ECU got to learn the intake, but not learn any one intake more than the other.

Then, in order to avoid miscalculations on the host computer, all 3 runs were inserted into DynoJet's RunViewer software (available at their website). The results listed below are based upon SAE corrections, with a smoothing factor that produced the highest HP/Torque numbers for all 3 runs (smoothing level of 4).

And the moment you've all been waiting for:

The Stock intake produced:
208.61 HP and 234.92 ft/lbs Torque

The CAI intake produced:
209.08 HP and 237.09 ft/lbs Torque

The WAI intake produced:
213.67 HP and 240.03 ft/lbs Torque

So the clear winner, by a decent margin, is the WAI.

And finally... I'm done with this issue. The Y-pipe, B-pipe, and Cat are now installed, so I won't be testing this issue anymore. And personally speaking, the WAI is nice, but the "butt-dyno" tells me that the CAI has the most Torque under normal driving conditions. But this is strictly debatable.

 

great job researching this in an appropriate manner, and thanks for the helpful info

 

This should be stickied in the FAQ's. VERY helpful information. Nice work (proving my preminition correct).

 

Having done some of this work myself I appreciate the time and $$$'s you spent in providing this info. I have to warn you that a total of 3 months between the first and last test is a little long for the summer/winter fuel issue.

You got a little higher TQ on stock than I did (208HP, 225 TQ). I don't know if this is due to your MagnaFlow or the "smoothing" software you referred to or simply variability in the process.

With the Injen my TQ dropped and there was lots of speculation. The only item I seriously considered was the octane/fuel issue.

Interesting data and I appreciate you taking the time to do the work and post it.

 

Thanks for the good leg work. This helped me mae up my mind. Firm Fabrications intake is now on the wish list.

 

great information - i'm sure this will help numerous people on this forum. thanks for your time and effort

 

Ghetto ram ownz!! but thanks for doing all the leg work to put an end to all of this.

 

WOW! Excellent. But you didn't say if this is the order you dynoed them in... was it stock->CAI->WAI?

If so, that should put to rest the summer/winter fuel issue. I thought "winter fuel" was supposed to rob performance... if that's true, and you did the WAI last (during the winter) then wouldn't the winter fuel make the WAI numbers be a little low?

Please let us know if that's the order you did the dynos, and thanks.

 

It's probably the MagnaFlow. I didn't use any smoothing software. I just reset the ECU each time.

All 3 were done during the winter. All 3 were done between the end of January and the beginning of March. The CAI was done on January 25th. The CAI remained installed for an additional week or so. The stock airbox was installed when the car visited the dealer. The dealer took 2 weeks to replace the clutch, as well as fix some other minor issues. They also reset the ECU, but I reset it again on February 20th (when I got it home) so that the stock setup wouldn't have an advantage over the others. On February 28th, the stock airbox was dyno'd. The Central Florida Maxima's (MaxedOut) met on March 1st. On March 2nd, the WAI was installed. The WAI was dyno'd on March 8th.

That was the order ... CAI -> Stock -> WAI

 

Great info! Thanks for posting this up.


Be sure to post this up in the moderated section of the dyno forum as well for quick and easy archival.

 

damn your torque #'s are crazy. Would like to see what kinda power your making after the y and b pipe installed.

Matt

 

TTT - Working on the FAQ entry now

 

Thanks studman. I for one very much appreciate your efforts on this intake issue. You've helped me make my mind up on what I plan on installing/buying.

 

i love my frankencar..anyone else?

this is great info, thanks for the hard work!

 

Info helped out alot I just wanted to say thanx

 

good work.

 

Great Job!!!

 

You ROCK STUDMAN!!!

Now has there been a resolution to the Y-pipe debate for the 2002-2003, or did I miss it?

 

not that I've read or heard of...

 

Thanks for takng the time and spending the money to do this and sharing your results with the .org. I, like many .org members, appreciate it.

Looking at the tourque increases in your sig it looks like both intakes give a small gain across the power band . The common thought seems to be that an intake gives even more gains when you upgrade your exhaust so these numbers would be just a minimum. I wish I had a couple hundred $$ to spend on dynos .

If the CAI has a 30-40 deg temp advatage that would cancel out the advantage that the WAI has on the dyno and probably give a power gain on top of that . I have a CAI in my basement (I currently have a hybrid intake) and I plan on installing it and doing an intake temperature comparison when the weather gets a little warmer.

 

Great work. You deserve a reward for your efforts.

 

Thanks for the good work, im guessing that the INJEN RD1940 is closer to a WAI than a CAI cause it still pulls air from under the hood. I will give more absolute numbers when i get my car fixed and re-dyno it

 

Good read.

I wonder how much better the stock intake would be when you remove all the resonators and open up the airbox? On my 4th gen, I've got all the resonators removed, K&N panel, and a hacked airbox with the stock intake snorkel funneling in cold air. I love the setup and it looks "sleepy" stock


Dave

 

Nice work on shedding some light on a hazy subject.

[nOob voice]When you say WAI do you mean something like a K&N cone filter or am i thinking of somthing different?[/nOob voice]

 

Nice numbers you got with WAI.

I am planning to dyno my car and see what I can get.

I remember Steve from FrankenCar dynoed his 2002 6-speed and got like 214 hp and 230lb with just the WAI intake.

You making way more torque, 240lb from your test. Is that extra torque comming from the muffler??

 

Basically, it was the Monster filter attached to the MAF. I used the lower pipe mounting from the CAI, just removed it from the actual tube. Then I attached the filter to the mounting. Then attached the mounting to the MAF.

It probably was from the muffler. I had the muffler removed (still have it in my garage) when I installed the Y/B/Cat because the sound was waaaaaay too loud. The muffler was a straight-through in-line design. I've notice a loss of torque when the MagnaFlow was removed. I chose to test it with the MagnaFlow because you could see the maximum amount of gains from the intakes.

For now, I'm on a cheaper Xcelsior muffler. It doesn't sound nearly as good as the MagnaFlow, but with the Y/B/Cat and the MagnaFlow, my car sounded as loud as an 18-wheeler's exhaust crossed with a motorcycle. The tone of the MagnaFlow was nice, but it drones at 1800-2300 RPMs, which is where 80 MPH in 6th gear is. So it had to be removed for now. I'm still researching mufflers for now, but haven't come to a conculsion as to which one I'll pick. I know I won't keep this cheap one, but it'll work for my 2000+ mile trip starting this Thursday.

 

how different is the Injen CAI from the Place Racing CAI that was tested? Would there be a big difference? Thanx for the researh, it is very useful, and the most objective info I have seen in a while

 

The injen intake pulls air from under the hood, while the PR CAI pulls air from the inside of the left front fender well. You also have to cut a hole in the inside of the fender well to use the PR CAI. The injen just bolts up. Im not saying one is better than the other, its all a matter of your opinion

 

With the Place Racing or Cattman CAI you need a cut a hold in your fender and that means you can kiss your warranty goodbye, with injen it take air from under the hood so there might be a a chance rain water could get in there which isn't good either, when I asked around people said to just go with the frankencar intake its the safest bet.

 

The injen is a FAKE CAI. It pulls air from the radiator
Just get the frankencar, its the cheapest, makes power. As for a REAL CAI, get the PLACE racing or cattman.

 

if you want some advice about mufflers. i can garuantee you that the cattman exhaust is quiet after around 2500 rpm. i have a cattman catback exhaust and its quiet overall. a civic's exhaust is louder than that. but for the price i paid for, i don't know if thats your price range. i haven't read or heard any quiet aftermarket exhausts YET besides cattman. it gets the loudest at 2100 rpm. but since you have a 6 spd, you won't have to worrie on the highway. for me, i go 75 mph at 2500 rpm. and its QUIET. but just wanted to give you some advice. nice work on your intakes. i like it.

 

Good intel.....

What is a WAI?

 

Warm Air Intake

 

Is it better? How does it work compared to a CAI?


neverending quest for information.....

 

Studman,

Can you put your magnaflow back on for the April meet? I really want to hear that setup and compare it with mine. My setup drones like mad at 2k/2.8k, but you get used to it. Turn the music up just a tad and it gets rid of it, and you can still easily have a conversation otherwise.

If you are totally against putting the Magnaflow back on, may I recommend a Flowmaster 40-series?? It would drone, but I think it would sound incredibly throaty and worth the drone; definatally more throaty then the magnaflow. Second option I would say, is a 60-series muffler. Or, the sweetest of them all; you could run an 80-series muffler and do a dual setup. Then finish her with some mustang/camaro style 16" slanted 3.5" chrome tips. Damn your car would look incredible What do you think?

 

Well, true cold air intakes will draw the air from the outside airstream. They would more commonly be known as Ram Air Intakes. Warm Air Intakes have the filter inside the engine bay, drawing the warmer air from that medium. Some people call the intakes with a protective box around the filter a CAI, but it's not really (at least not in my opinion).

 

Well............I thought the reason for this thread was to compare WAI to CAI! From the write up, it seems that WAI may be better.

 

I just installed a Firm Fabrications WAI. I had the Injen CAI before this and by comparing the two, I can say the WAI seems to be more responsive. I had a hesitation with the Injen around 4000 rpms. Maybe it was the long pipe, but the WAI is smoother. One thing i'm not crazy about is the loudness. OH MY GOD

I live in nyc and cops are looking for any reason to pull you over. At WOT, look out!

 

Yea, I know what you mean, at WOT my Frankencar intake Ssscccrrreeaaammmssss!!!!

 

sooooo who makes the WAI?? good job on the dynos but not enough info for me on the products..Im a newbie here obviously..so can anyone specify the intake solutions for me like where to buy..what company..etc..etc..