Top flow air cleaner

[Verdoorn Racing]

Rules allow us to run a top flow air cleaner. Is there an advantage to running a K&N top flow air cleaner lid with a RC2 filter?

[rubbinsracin]

i think the theory is that it allows more air in, therefore allowing to add more fuel, therefore makeing more power. Our class does not allow them so i dont have any practical experience to give you. but i have heard that oil in the top air flow lids has played some havic on the cars that have run them. but knowing the people that ran them....they probably soaked the thing in 10-30 because more is better lol

[charcoal01]

Asked my motor builder a similar question. The thing about it is, look at the size of your venturies, they are quite a bit smaller than the surface area of your filter, right? The only thing adding a bigger filter is going to do is keep you from losing horsepower if you start to plug up a filter. I don't think adding a top flow is going to show any real gain. Maybe someone who has some chassis dyno experience with one call tell me differently.

[Egoracing]

On a motor with a power adder (Read that as turbo or Blower) you can see some advantage. On a naturally aspirated engine they cause turbulant air flow right at the top of the carburator and hurt the airflow and mixture in the carb. You are MUCH better off with a good air cleaner housing and an Wix filter.

[C10]

We have dyno'ed these top lids on several different combos. In each instance, with proper jetting etc, they LOST HP. We then took the top off and re tested with a K&N regular filter, paper filter, and no filter with just the base of the filter can. The combo that made the most power was the paper filter in the Moroso air cleaner can with the "Bubble top". This combo was 7 hp better then the K&N element properly oiled and almost 14 hp better then the flow top and K&N element. Our mind set after doing the test with some smoke into the air stream is #1 the paper flows better with less restriction, and #2 with the flow top, the air was actually slamming the top of the carb thus creating turbulance and making the carb lose some signal thus decreasing CFM in the process.
The Moroso can with the "bubble" radius in the top and bottom, directs the air towards the carb center but because the can is present, cleans up the "air clutter" giving the engine clean air to use as IT WANTS and not dictated by the slamming. This gave the boosters better signal, made the carb more responsive and the AFR was more consistant across the board. Hope this helps!

[Verdoorn Racing]

Thanks all.

[AmickRacing]

A thought I've always wondered is while screaming down the track (with a regular open style hood scoop style deflector), will it create a venturi effect (similar to blowing across the top of a straw and having the drink spray out).

Even if it doesn't, it seems like they aren't great, but if it does have that effect, then it's bad too. Basically, seems there's nothing really great about them at all for what we use em for.

[R2C Competition Filters]

AmickRacing is correct.

That certainly does occur based on pressure differential at speed. We were never able to produce any benefit during testing.

R2C Racing