Q45 K&N cone filter install

[Sopdadope]

The general conscensus here is that the K&N filters are BAD, BAD, BAD!

However, I had a K&N drop-in panel filter installed in my '91 Q45 for nearly four years. Worked like a charm and did so without a hitch. Never had any MAF sensor problems I'd been warned about.

At every other oil change interval, I'd pop out the filter for a wash and re-oil. I'm certain any MAF sensor problems were caused by excessive oiling.

So, with the good track record of the K&N filters, I had one installed on the parts car. For the test, I used a universal filter with a 3" I.D. There's a few different styles to choose from: you could either use the long, narrow type cone or the shorter, wide cone with a metal cap. Because of clearance issues with the longer, skinny cone, I chose the stubbier cone for this install.

First thing I did was use an air-nibbler to cut off the plastic flange that secures the MAF housing to the air-box. I ground down any excess plastic.

The filter comes with a 3" rubber mount "tube" to so I just slid it over the MAF housing and then tightened the hose clamp and WALLAH! I have a cone filter for only $40.

First impression: the filter did absolutely nothing during an around-town trek....BUT at WOT there was a definite seat of the pants improvement.

Just to make sure there was an actual improvement, I had the mechanic himself drive the car around the block. As soon as he pounded the pedal he asked, "hey...did you clean out the intake goodies...? It feels like there's more top-end power..."

Keep in mind this install was done on a car with an untouched intake tract and plenum. Lots of carb cleaner and shop rags are in store!

Summary: Definitely a good mod for the money. I'm obsessive about squeezing out every ounce of power from my cars so this is definitely a worthwhile 'mod.'

PROS:

1. Cheap- $40 for the filter and $10 for the reclean and recharge kit. In essence, this filter can be reused for years with proper maintenance.2. Super-easy. It was easier for me to install this cone filter than it was to replace the drop-in filter.3. Slight seat-of-the-pants improvement. I don't have the test equipment to prove it, BUT my BUTT-METER's pretty accurate. 4. Awesome sound. The Q definitely has the bark to match it's bite. If you thought the 4.5 sounded bad, try hearing it with a K&N cone filter.

CONS:

1. I can't think of any really other than the finding the right cone filter to fit.

Pics will be posted soon.

[maxnix]

First impression: the filter did absolutely nothing during an around-town trek....BUT at WOT there was a definite seat of the pants improvement.

It feels like there's more top-end power..."

Interesting, but all subjective. Before and after data would be much more convincing. There is little doubt that less rigorous filtering will allow some short term performance improvement at the cost of long term wear and consequent degradation of clearances.

Feeeelings.

[sultan]

my problem with the cone was ingesting hot underhood air, which is why i no longer use it. i was thinking of running a pipe through the metal under the airbox and putting the cone filter down there.

[Sopdadope]

I agree with you entirely about not having scientific proof or 'hard evidence.' No if I had a dyno, that'd be different.

Also, I ran a K&N drop-in in my '91 at 90k on the odo and was still using it when I sold it with nearly 190k. Frequent oil changes with high-quality oils and diligent maintenance basically nullified any supposed ill-effects of the K&N.

When I took it in to the dealer for some work, the tech complimented me on having the "smoothest running 1st gen Q" and cleanest engine, I might add. And this is an engine that saw WOT at least seven or eight times a day, everyday of the week for nearly six years. Degradation in clearance? I didn't notice 'em.

[Sopdadope]

my problem with the cone was ingesting hot underhood air, which is why i no longer use it. i was thinking of running a pipe through the metal under the airbox and putting the cone filter down there.

I've already addressed that problem. I purchased some thin industrial aluminum sheeting from a body repair shop but I'm sure Home Depot would carry the same thing.

I used the MAF Housing a cut-out stencil and the mounted this before sliding on the cone filter. Basically I used this sheet as a shield, drawing in cooler air through that little air-horn that drew in under-bumper air to the stock air box. Easy stuff. Hopefully I'll pics before the day is out but then again, the weather's great outside.

[AZhitman]

Please do, Sope.

I need to free up some underhood space for my remote dual oil filters (so i can change my own damn oil).

I've got a dyno day scheduled in May... Hmmmmm. Perhaps a "scientific" study is in order (WITH the hood closed).

[maxnix]

I think timing several runs in opposite directions at the same atmospheric conditions and engine temperature would have been helpful.

Even dynamometers readings are relative, not absolute.

Wear won't show for at least tens of thousands of miles, hopefully. Oil analysis would have been good with a baseline before and additional readings every 10K or 15K miles.

[Q45tech]

You don't need a dyno...........you have one on the car........the MAF voltage tells you every thing you need to know about air density and air flow.

A simple low cost [$40] manometer installed after the MAF will display the vacuum across the MAF and anything in front of it.......a zero to 10" W.C. should be fine on a Q or J or I/G20/35.

Less vacuum means more flow and more flow will raise the MAF voltage.

The norminal 1.0 volts at idle goes to a maximum of 5.0 volts in an exponental curve.........4.447 volts is the highest I've ever seen on a Q at 6500 rpm.

OBDII translates the voltage to grams per second and is read this way...........255 grams per second is around 325 HP and idle is 5-8 grams per second [8-10 HP consummed in idling [overcoming friction and accessory losses]]

"The complete intake system can be evaluated on the flowbench to indicate the level of power that the system will produce. The airflow at a test pressure of 25 inches of water multiplied by 0.272 will estimate the Horsepower that the components can make. (When a test pressure of 10 inches of water is used, the formula becomes the flowbench reading multiplied by 0.43). This number may shift slightly if the engine is not matched with the components or if the engine is extremely efficient. This estimated power versus air flow number has been a reliable indicator of predicted performance for well over a decade."http://www.superflow.com/suppo...t.htm

http://www.nissaninfiniticlub....19671

This might scare you about the inaccuracies of using a K&N directly coupled to a MAF.........note the metal horn and shape of plastic deflector in stock air box.http://www.ecutek.co.uk/tuning/induction/

[Sopdadope]

I think timing several runs in opposite directions at the same atmospheric conditions and engine temperature would have been helpful.

No disrespect to you guys but I think trying to time runs in the same atmospheric conditions is just ludicrous, especially since K&N isn't cutting out any checks for me.

Even then, results would be somewhat misleading, it's impossible to test and count on all the millions of variables beyond our control being the same.

One doesn't need a myriad of test equipment to prove that a brand-new K&N cone filter breathes better than a stock filter used for x length of time.

If anything, I'd stick with a K&N filter for economic reasons: I'd expect the K&N filter life to exceed my ownership of the vehicle so no need to shell out $10-$15 a pop for a stock filter.

[Dave 88 LSC]

I have a lot of 5.0 Ford experience, and from what I have seen and tried, panel style flat K&N filter is the best way to go for a street car. Cone filter will only benefit you at high Rpm, most city driving is in 1000-3500rpm range. Stock inlet pipe is designed for most torque at usefull rpm range. So going with cone filter and a mandrel bent inlet pipe with raise the tourqe curve to higher rev range.I know Q45 motors are breathers and love high rpm, but they are not too strong on the low end. More flow at intake and exhaust will yield more HP at higher rpm.

[Jeff Williams]

Yeah, but the growl from the cone filter is pretty impressive.

I was thinking of building a cold-air box for my Q out of fiberboard (The stuff used in residential HVAC construction).

I have seen some pics of one built by Rick Masta. If he reads this post, he might offer some info on his.

I have the flat K & N filter in my 2000 I30t, because I don'w want it to sound too loud.

I have used K&N for 20 years on all the race cars I have built, and run. The performance is small, but in racing, every 100th of a second can be worth thousands.

It also looks cool, when you open the hood.

[Q45tech]

If you look at the fenderside lower section of the Q air box, below where filter sits you will see it's flat..........a 2" hole could be cut allowing a supplemental flex hose to go from the lower box to [thru] the rubber flip into the protected fender well and or down to a rubber plug covering a round hole in metal [where actice lines would have gone], etc ,etc,.

This extra air path and extra diameter can flow about 25% more [shorter path length] reducing the restriction of the tuned convoluted section in front by close to 50% without much extra noise!

The above with a stock new oem filter can reduce the vacuum differential as read in front of MAF [test hole in top of air box] by almost half at 6500 rpm and 10-15% at 4,000 rpm.Good for a HP maybe 2 without much expense and safe from water incursion..........and all the air still gets filtered by oem design............no disruptions in air turbulence so the MAF still reads correctly unlike the K&N cone mod. AND no hot air to reduce power or cause unstable idle in summer.

[AZhitman]

If you look at the fenderside lower section of the Q air box, below where filter sits you will see it's flat..a 2" hole could be cut allowing a supplemental flex hose to go from the lower box to [thru] the rubber flip into the protected fender well and or down to a rubber plug covering a round hole in metal [where actice lines would have gone], etc ,etc,.

Dennis - Once through the rubber flap, where to then?

Where is the opening for the ActSus lines?

[Jeff Williams]

Greg, Every time I start thinking about doing something to my Q, I see you mention it in one of these forums.

I see your mention of the remote oil filters. I did this on the Dash cars, and decided, the last time I scratched the heck out of my arm while changing the oil, that my Q would be a perfect recipient of this treatment. I even mentioned the modification to my friend Jim, who is a Nissan certified mechanic, last Friday.

Have you already purchased the proper filter kit?

I was looking at the kit in Summit Racing, but was unsure of the threads.

Any insight would be appreciated.:help

[AZhitman]

Sure thing - The Summit G4985 will fit, as well as allow you to use the "jumbo-sized" Ford-style filters.

There's another kit by PermaCool that has all threaded lines, for a few bux more.

Since the cone isn't really an option for me in Phoenix, I'm considering relocating the battery. I NEED SOME DAMN ROOM UNDER THE HOOD!!!!

[EWT]

Sure thing - The Summit G4985 will fit, as well as allow you to use the "jumbo-sized" Ford-style filters.

There's another kit by PermaCool that has all threaded lines, for a few bux more.

Since the cone isn't really an option for me in Phoenix, I'm considering relocating the battery. I NEED SOME DAMN ROOM UNDER THE HOOD!!!!

Your battery will thank you. One of the few things GM did right on the POS Aurora I used to own was to put the battery under the rear seat. Mine still had the original 7 year old battery in it when I sold it, which isn't uncommon. Underhood heat is hard on batteries.

[Jeff Williams]

I just got an email from Rick. He is having trouble logging into the site, and asked me to post this pic of his home-made cold air box.

You ca nemail him at: [email protected]