For those keeping score, the link in the last post is a copy of the Spicer test.
K&N as for Trax MAF?
- Thread starter hardcore302
- Start date
The famous Spicer test showed the K&N at ~96% (I seem to recall?) vs. 99% for the best paper. I 3% drop for increased flow. It's all about trade-off and whether you value the flow or can gain from it or not. For me with lots of performance upgrades, I'll take the slight drop in efficiency for the increase in flow. For others, this may not make sense. My UOA average silicone number for the last 40K with a K&N and now open intake is 4. It's filtering fine or "good enough". Unless you are keeping your vehicle for hundreds of thousands of miles, none of this will make f all of a difference in terms of damage from the tiny bit of extra dirt getting in.
Did you see where it says, "A filter with a 98% efficiency rating would pass roughly twice as much dust as a filter with a 99% efficiency rating, so what seems like a small difference is actually quite a large one." ?
I can only imagine how much dirt a filter with 96% efficiency is allowing through. Also, with K&N filters, their efficiency is based on the requirement that the filter has been cleaned and oiled as designed which, in my experience, most people don't do. They either bathe the filter in oil or miss a bunch of sections, etc.
Ed
I can only imagine how much dirt a filter with 96% efficiency is allowing through. Also, with K&N filters, their efficiency is based on the requirement that the filter has been cleaned and oiled as designed which, in my experience, most people don't do. They either bathe the filter in oil or miss a bunch of sections, etc.
Ed
Last edited:
I can. Four times as much dirt as a 99% filter.
If more flow is needed it makes more sense to build a modded intake with a larger filter or even two filters.
I've seen some intake kits that use a cone filter of less surface area than OEM.
Correct - so the 99% filter lets a *tiny* amount in so the 96% one lets 4x that which is still....a tiny amount. And yes, the K&N works as well as you take care of it. It's a v. simple procedure but I'd agree many users botch it. Again and again, K&N filters are a performance product and should be used as such which means most folks shouldn't use them b/c they won't be able to handle the cleaning/re-oiling. This is why the manufacturers spec cheap $15 throw-away paper filters and even with those, folks don't change them out.
Plus the fact that they work better. Win/win.
OVERKILL
$100 Site Donor 2021
If max filtering is what you want yes. If you want max flow then no. Simple.
"Max flow" is only really beneficial at WOT with ECU controlled engines ... where racer's gas pedal lives a lot.
OVERKILL
$100 Site Donor 2021
And even then, just upgrade the airbox. I'm quite sure the one for my 6.4L flows more than enough for most FI hot 4-pots, and if not, get one from Hellcat/Trackhawk or diesel.
Correct - again, some want max flow, some don't care. All good. Funny, go over to enthusiast forums/FB pages and nobody talks about the downsides of K&Ns or other high flow filters (in general of course) b/c it's all about slightly better performance at the expense of slightly less filtering. All what you are after with your vehicle.
OVERKILL
$100 Site Donor 2021
That looks like it is consuming hot engine bay air. Where was the stock airbox situated and where did it draw from in this application?
Here's my 6.4L setup, airbox seals against some ducting that draws cold air in from the front, which I've tried to capture in the pics:
Last edited:
The MK7 Golfs have a closed box that gets air from a front duct above the radiator/grill. It's a good system but has been proven to be more restrictive to flow (flow bench testing) than the open style intake I have. The issue is - your vehicle is NA, mine is turbo'd. Sure, that air is a little warmer entering the turbo (again, shown many times in testing on my platform) vs. the stock closed intake but it's leaving the turbo very hot and then being cooled by the intercooler before hitting the throttle body. I am about to have a larger intercooler installed to help out with all of this and performance in general. Folks go on an on about "hot air intakes" but the fact, intake air temp isn't the only factor here and overall flow also is critical especially on modified/tuned turbo cars. The better question is: does the increase in intake air temps outweigh the reduction in flow? Can't know without some dyno pulls and dragy times. I had modified the stock intake by removing the accordion hose and blocking off the pass thru duct on the p. side as well as opened up the d. side for more direct flow to the filter. That had shown appreciable flow increases over stock (again, flow bench tested w/data) but it just won't touch these larger open intakes. Believe me, I've done the homework including some of my own intake temp data logging etc.
OVERKILL
$100 Site Donor 2021
Right, mine feeds a 475HP 6.4L V8 that's naturally aspirated, a turbo motor is much less sensitive to air intake restrictions since it isn't relying on atmosphere, so an airbox similar to mine should be more than sufficient unless you have surpassed my HP level and then there's the 707HP Hellcat/Trackhawk airbox option (assuming they'd fit).
And yes, colder air always makes more power assuming you aren't restricting, so I can't see feeding an engine hot engine bay air, then further heating it in a turbo and then trying to shed some of that heat with an intercooler being better than a setup that flows the same but starts with colder air.
Yes, turbo motors aren't as sensitive to intake restrictions but do benefit from opening them up (whether open or close intake) which typically reduces the waste gate duty cycle on the turbo which has been shown in logging on my car/engine many times over. Several aftermarket outfits do offer closed intake systems (same as mine but with an enclosure) so a bit of the best of both worlds I suppose. Your comment regarding flow vs. air temp is correct - but only if the closed system flows the same and in my case , it does not (chart shows the air flow of the stock system at the bottom with the highest performing intake system at the top by MST - a large intake ("cone filter on a stick") with a metal shield at the filter. This argument is a near daily occurrence on other forums/FB pages for the VWs. The logging I did with an under hood temp sensor placed at the filter showed that in highway driving, I am getting effectively ambient air at the filter b/c of the flow through the engine bay. Around town, I get an increase in temps to the turbo over the stock box which clearly does provide insulation against the hot engine bay - makes sense in both counts. I've never seen dyno or 1/4 mile data that supports a significant decrease in power running an open intake. When it's boost season (fall/winter), none of this really matters anyway does it? Finally, don't forget the best thing about open intakes on turbo cars....all that whooshi whooshi pssssh psssh noise! Enjoy your truck, I'll enjoy my wagon.
Similar threads
