Air filter or not

guscorty · 16-11-2014, 08:20 AM

Hi Everyone,
Sorry for the long winded intro. My car is running a carby only. No turbo, injection or gas. I've been told by not running an air filter you can run up to 2 tenths quicker. The car runs mid 12's and is not a big horsepower car.At the last meeting, I got their late and in the rush to go into qualifying i took off the air filter and left the rubber ring on the carby. (If they had idiot of the day award I would have won hands down). In the burnout, the carby sucked the ring in and jammed the butter flies open and couldn't stop the engine revving. Lucky this didn't happen when I was going over the line. The next run, when I was waiting to stage, the car in front pulled a massive burn out and after that run when I got back to the pits, I was pulling smalls balls of rubber off the front of my bonnet. I only wonder how many balls of rubber went into the bonnet scoop and sucked down the carby. The car has a K & N filter. The question is, for a car like mine, is there really a difference in running no filter and even if there is is it worthwhile?
Cheers Guys.

JG33RD · 16-11-2014, 08:54 AM

I'd run the filter, I do with mine. I'd rather have the piece of mind that I'm keeping the junk out than picking up 2/tenths, which I doubt. I had my car on a chassis dyno to see if my fuel pump was keeping up, we did a comparison with and without filter, K&N extreme top, there was only 1HP difference.

rednose · 16-11-2014, 10:28 AM

I highly doubt there would be 2/10ths in it, maybe on a 16 sec car but surely not on a mid 12 second car.

For peace of mind keep the filter on, a good "CLEAN" filter should not affect performance.

u2canb12 · 16-11-2014, 10:33 AM

2 tenths would be a nice pickup if were true, there was only 4hp difference between filter on and filter off when I dynoed on Zoron's chassis dyno so for piece of mind I leave mine on.

jcxr · 24-11-2014, 03:52 PM

My car actually slowed down without the air filter. Yes, also a mid 12 car.

guscorty · 25-11-2014, 01:41 PM

Thanks for the replies everyone. I think definately run the filter. When I was at that last meetting another fellow who was running a car similar to mine said the same as JG33RD, that when he had his car on the dyno there was no difference in hp with or without the filter, using the K & N, and even with a cheapy filter he only lost 5hp.
Thanks again.

347xt · 25-11-2014, 07:52 PM

My car seem to go quicker with the air filter on then off try it and see what it dose

**gregaust** · 25-11-2014, 10:50 PM

A good filter you will lose nothing. I have seen some Dyno testing gain power with filter on as mentioned above. K+N have a calculator to work out filter size required which works as a good guide. Of course the best K+N if it's too small is no good.

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