Air cleaner in Stock Class
 

Learning as I go, I had another question - the NHRA rulebook states that an air cleaner, if used, must be OEM automotive or retain OEM configuration. Big-block Chevy Super Sport's came from the factory with an open-element air cleaner. Does this mean I can use one of these on another GM product in Stock Class, or am I stuck with the OEM air cleaner that came on the car? And what about a K&N, which has the OEM configuration? Thanks again for your suggestions!

Re: Air cleaner in Stock Class
 

K&N is fine.

Re: Air cleaner in Stock Class
 

Just not the K&N with the filter top.

Re: Air cleaner in Stock Class
 

Really. we have run filter top on dusty tracks...not legal?

Re: Air cleaner in Stock Class
 

We went through tech at Indy Open in the fall with filter style top and no comments were made ...pretty easy to take off if they don't like it...we leave it off every once in a while doesn't seem to make any difference to speed. ...Thanx Trevor

Re: Air cleaner in Stock Class
 

Thanks for the input! I'm going to try with and without to see if there are any disadvantages to using the high-flow element. I'm hoping it will smooth out the airflow somewhat with the Q-jet.

Re: Air cleaner in Stock Class
 

X2, in D3, they dont like the K&N filter top....

Wade

Re: Air cleaner in Stock Class
 

The K&N Filter top is just hype. It does not offer any HP improvement at all. Just run a Moroso lower and top base with a racing air filter element from Wix and you will see a lot more performance.

http://www.wixfilters.com/filterlookup/racing.asp#air

The K&N Filter top will disrupt the airflow to the carburetor.

Re: Air cleaner in Stock Class
 

X2 on this one. We did back to back dyno test, and actually lost horsepower with the filter top. What a marketing joke.

Re: Air cleaner in Stock Class
 

We have our engine pic in the National Dragster several years ago and got a call from Tech and were told to take that K&N Filter Top off!!! Well, we did.....

Re: Air cleaner in Stock Class
 

There's another thread here about air cleaners with some interesting info about K&Ns and other HP filter systems. Worth a read.

http://classracer.com/classforum/sho...ir+cleaners%21

Re: Air cleaner in Stock Class
 

Thanks for the info - I'll check it out!

Re: Air cleaner in Stock Class
 

So is it legal to just hose clamp a filter on the end of the throttle body?

Re: Air cleaner in Stock Class
 

The K&N filter top, worthless or not for HP, is allowable per NHRA. This was an issue when they first came out. The rationale is you do not need any lid so a K&N lid is acceptable.
I always ran one in D/S with the factory ram-air system. Can't say that it helped but it certainly didn't hurt. And Arizona is somewhat dusty so I always ran a filter.
I just noticed Todd put a link to the old discussion....

Re: Air cleaner in Stock Class
 

I remember this topic in early `03,and the Zane`s mentioned they were asked to remove the K&N top,I never had been asked. Sure enough,in Phoenix that year I was asked to remove it in tech. Still sitting in my storage unit.

Re: Air cleaner in Stock Class
 

What about the definition of an OEM system for fuel injected cars? Can you simply remove the intake plumbing and bolt the filter on throttle body like mopar jeff suggested? Also, what about using common aftermarket "cold-air" style systems who use smooth mandrel built plumbing to replace the disruptive factory rubber tubing prior to the throttle body? Anyone have experience with legality and/or hp benefit of such a setup?

Re: Air cleaner in Stock Class
 

I was told by IHRA that we are allowed to put a filter directly on the throttle body. I would ask them at your next race as I am not sure NHRA's ruling.

Re: Air cleaner in Stock Class
 

I know I race a pretty slow car,but a few years ago,I tried the K&N top during some "testing"

The car lost .03

Re: Air cleaner in Stock Class
 

The effect of the filter +/- is going to depend on your tuneup. It's just like changing fuels: You can't just swap it in the tank and then assume that the new fuel is quicker or slower than the old. You have to tune for whatever you have changed in the system.

I have some Dynatech cone collector inserts that I have to run at one track due to a muffler requirement. First time I put them in the car, it slowed it down .03. Played with them again and it picked it up .05.... but I had the car jetted different.

In *any* case, it's a matter of tuning, and what you want to see. I specifically use my K&N to tune the car to what I want it to run, although I run it 95% of the time just to protect my engine.

IHRA is ok with the filtertop, and even the Quicktime air bell, but the "stub stacks" are a no-no.

Re: Air cleaner in Stock Class
 

I have tested back to back with and without a air cleaner, my car slowed .03. I agree, some testing with jet change would probably pick it up.

I also use a air cleaner base from an old LTD Ford that has been trimmed to fit the engine, that is worth .03 doing nothing put putting it on the car. No element just the base.
The reason for using it, because of the nice radius into the carb.

Re: Air cleaner in Stock Class
 

Has anyone tested and run the R2C filter?
What were your results?

http://www.r2cperformance.com/14.html

Stock/Super Stock Prototype Filter
 

Here are photos of the offset media, Stock/Super Stock filter prototype shown in 5" height. This is synthetic fiber media that does not require oiling. Normal track maintenance is simple using 40-60 PSI compressed air directed from the inside surfaces outward and it's ready to go, race after race. The filters are washable using mild, biodegradable detergents. Efficiency is improved as well. The 4" filter is tested at 1200 SCFM.

Regards,
Ed