I can see spending money on headers and pipes. At least you get a much better sound. My friends new acr w/ belen. headers and pipes make the car sound totally differant(much,much better).Even w/a 50hp diff. its still going to be a drivers race !
K&N air filter info for Gen IV.
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SilveRT8
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No CEL, no issues and the K&N filter fits tight and well in the stock box.
Before putting the filter in, I removed it from the bag and let it dry in the sun for a few hours, so there was no issues about oily filters deposits on the mass air flow sensor.
Well, Mark, if KN had furnished me any new data.......it has been 3-4 biz days so far.
Safe and correct to say, and per KN, the KN filter # you cite, (and we distribute from Snake Oyl,) is NOT yet rated by K+N to handle a 2008-09 G4 motor. Any issue would be at REDLINE.....
KN has only furnished me 2003-06 data since my post, but this particular filter wont fit that intake! {if it DID it would work G3 OK pr KN}
My further concern is one customer above states the SnakeOyl filter 'fits loose'...why ?? Not a good thing.
PS I can get these by th case and sell em for $49, but Im not ready to do that yet...
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If there is, it would be less than 7 ! How could you prove it? But the TONE IS DEEPER......like a larger diameter musical organ pipe inlet
FLL-B/W-GTS
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Installed K&N Air Filter in 08 Coupe today,fits perfect in the stock box/tight,sounds good and no check engine light.
viperfuntime
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Same here in 2009. Fit was tight seems like it revs more quickly.
From the K&N website, just do the math:
Use the formula below to compute the minimum size filter required for your particular application. The usable portion of the filter is called the EFFECTIVE FILTERING AREA which is determined by multiplying the diameter of the filter times Pi (3.1416) times the height of the air filter in inches, then subtracting .75-inch. We subtract .75-inch to compensate for the rubber seals on each end of the element and the filter material near them since very little air flows through this area.
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Example: A 350 CID Chevy engine with a horsepower peak at 5,500 rpm.
A = effective filtering area
CID = cubic inch displacement
RPM = revolutions per minute at maximum power
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Aftermarket Filter Users NOTE......there is a new discussion of the 08-09 Mopar Venom Controller which has just disclosed this tidbit. A key SRT Engineer just posted in the GRAILKEEPER thread for VCA members the following comment, in part:
".....First, the addition of an aftermarket air filter element can and generally does adversely effect the operation of the MAF sensors. Any change to how the air enters the clean air duct upstream of the MAF sensors can change the airflow measurement. A change in the construction of the filter element will change its characteristics. In any of our testing, the production air filter element has almost no restriction at production airflow (we worked ******* this!) so save your money and prevent other issues by not changing the filter element......................"
Note: This was speaking of Gen IV 08-09, WITH the MoPar Venom PCM. VCA members please go there to GRAILKEEPER THREAD and read the ENTIRE discussion for context but this tidbit remains topical here.....
http://forums.viperclub.org/grail-trail/625903-why-venom-control-runing-10-4-afr.html
JonB
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SilveRT8
Enthusiast
I just did the math for this to see the true requierment of the '08 Viper.
At 512 CID with peak power at 6100 RPM we need 150 sq.in. of filter area.
Since I have both the Stock and K&N filter on hand, I measured the EFFECTIVE FILTERING AREA of each one. Here are the results :
STOCK FILTER is 13.6" x 7.8" x 1.6" high = 170 sq.in.
K&N FILTER is 13" x 7.2" x .75" high = 70 sq.in.
When you see both filters side by side, it's very clear that the Stock filter is at least double the height of the slim K&N filter. So even if the K&N would flow better than the Stock one, it just does not have the cubes to compete.
As a last test, I measured the area of each pleat of the filters as if to unfold them flat. The Stock one has 1000 sq.in. of filtering material vs 529 for the K&N.
So for me, as per the SRT Engineers' advice, the Stock filter goes back in the car to stay.
SilveRT8
Enthusiast
Yes, but they dont make a specific one for the 08/09 Viper.
We just use model 33-2284 wich is specified for the Mazda RX8, that happens to fit our box opening.
viperfuntime
Enthusiast
Stocker goes back in the car for me too after reading this. Thanks...
VIPER GTSR 91
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This all sounds good but the reason I started the thread was seeing a post here where a Gen 4 ACR owner got a 7 HP gain on the dyno with a before and after run with only the K&N filter VS stock. I bought one and will see if it fits tight otherwise toss it, but several owners here really like it with no problems.
Cop Magnet
Enthusiast
Duct tape will make anything fit.
As far as not working well due to some calculations, let the real world be the judge. It's not like it's going to blow the car up or anything. If it doesn't flow as well, the dyno numbers would be down and they are apparently not.
As far as not working well due to some calculations, let the real world be the judge. It's not like it's going to blow the car up or anything. If it doesn't flow as well, the dyno numbers would be down and they are apparently not.
Playing devil's advocate here but the engineers wrote "the production air filter element has almost no restriction at production airflow" which implies there's some restriction and probably for a reason. I'm assuming that reason is due to the strict emissions targets they had to achieve and not necessarily performance-related. I assume the extra 5-7HP wasn't worth the emissions aggravations. I don't know how anyone can feel a 5-7hp difference on a 600HP motor (maybe on a 70hp Smart Car) unless it shows up in better 1/4 times. 
FLL-B/W-GTS
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Ok,as I stated before ,I have the K&N in my 08 Coupe.It did seem to rev faster and the car ran perfect.It also fit tight in the box.I checked the filter and the box after I drove the car for a hour and it was fine.No check engine light.So what can be the worst thing that can happen if I leave it it? I have the complete K&N Air Charger on my C6 Z06 and it is a big difference in performance. Thanks
VIPER GTSR 91
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I like this reply plus the K&N is reusable after cleaning. A lot of owners spend 1500.00 for just a 12 hp exhaust gain. Can that be felt in a 600 hp motor? Probably not, but its the addition of many upgrades combined that can be noticed.
VIPER GTSR 91
Enthusiast
This is not the reply I was waiting for. Its the one on here about the Mazda filter being "a loose fit" and my asking which one then do you sell as K&N does not list one for the 08-09 Viper?
Here are my observations. The K&N filter has fitted perfectly on the 08-09 models we have tried it on. It's washable and reusable and does flow about 20% better than the OEM filter (tested). Dodge used these filters on the Gen 2 ACR's and they were rated at 10 hp more than the on-ACR models.
No CEL lights at all.
In our testing with the new models we have always seen the highest numbers with this filter, we may be splitting hairs but it does make a differance. In regards to the smooth tubes, we need to test these. On the early models they made 3-5hp with better air filters.
My 2 cents,
No CEL lights at all.
In our testing with the new models we have always seen the highest numbers with this filter, we may be splitting hairs but it does make a differance. In regards to the smooth tubes, we need to test these. On the early models they made 3-5hp with better air filters.
My 2 cents,
FLL-B/W-GTS
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Thank You Dan for your answer.You answered my question.Keeping the K&N on the Viper.
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