Custom Airbox advice

Hi, Im thinking about making an cold air box but would like peoples opinion on it. I have recently tried an induction kit and an stock air box. Correct me I am wrong I found the the induction sounds louder and I notice that from 4000rpm to xxxxrmp seems quicker then stock.

So I'm thinking of making a airbox with the same air feed from the bonnet end and then replace the one under the head lamp with a bigger air feed but won't be using a panel filter but induction kit and bigger airbox. Open for suggestion

So I guess in short I want to use the stock airbox idea but make it fit induction filter and make the cold air feed under the headlamp bigger

Have a look at Jevansio's thread on this very thing. You could do a similar thing with a custom box, have a ported feed coming in from under the headlight panel.

Have a look at Jevansio's thread on this very thing. You could do a similar thing with a custom box, have a ported feed coming in from under the headlight panel.

beat me to it....

Thank you. Another thing I would like to know is stock better or a good Induction filter? Because I thought off another idea which was just keep stock but make the cold air feed bigger.

Stock will run colder. The cone filters will allow more airflow. The question is whether the increased airflow with increased intake temperatures is better or worse than the more restricted airflow with lower intake temperatures.

It's a trade off bud. In order to have the absolute best of both worlds you want to design something similar to what Jay did. Using the stock box would be fairly straight forward. A little bit of DIY would have it as a square box that could accept a cone filter. Cut a hole in the bottom of the box and cut a hole in the bottom panel of the bay, have a tube/pipe running between the box and said hole (The same as Jays).

Job done.

K&N's website has a good section which gives approx filter surface area for given HP levels. My filter was around 500hp for an N/A (turbos add 80%) so was approx 900hp. I thought my filter would be waaayyyy more than enough, but at a smidge over 700hp there's a little room for error, but it's not like it's double over specced or anything.

IMHO I would only run the stock airbox on stock - BPU cars, once single I'd want an appropriately sized (most likely cone shaped as they are the only ones with the surface area to match the in most case doubled BHP) filter either mounted outside the bay, or boxed from engine bay heat

Okay to get more air flowing a cone would be better, the stock air box will be colder. I've read your thread on the air box jevansio its very interesting and figures to prove what works, great thread.

So if I approach my way which is very similar to yours, I keep the cone make an identical stock air box with little adjustment: Make cold air feed bigger. It will look like a normal stock air filter with all the feeds but under it is actually a cone. That way i can get more air flow plus its going to be cold.

Another question is that does the size of the cold air box matter?

I can tell you that, on stock turbos and airbox, Soarers perform better with the airbox and a stock panel filter. An Australian forum spent alot of time comparing airboxes and cone filters using dyno and manometers

I have no reason to believe that the Supra airbox/filter, with its cold air ram feed will perform worse than a cone filter.

I would use the stock airbox, it is not restrictive, is sealed from the engine bay heat, has 2 cool air feeds and uses a filter with a larger surface area than most cone filters used in induction kits.

I would use the stock airbox, it is not restrictive, is sealed from the engine bay heat, has 2 cool air feeds and uses a filter with a larger surface area than most cone filters used in induction kits.

If i replace the cold feed under the headlamp with a bigger one, that should still be gaining more air flow right? afterwards making sure its sealed from the heat. That could improve the stock airbox right?

Do a search on Google for 'Soarer BFI mod'

Do a search on Google for 'Soarer BFI mod'

http://planetsoarer.com/BFI3/bfi3.htm Its seems interesting guess on that page is what i might go for.

http://planetsoarer.com/BFI3/bfi3.htm Its seems interesting guess on that page is what i might go for.

I'm not convinced by that, yes there was a rise in power after the modification which doesn't surprise me, but a car sat on a dyno with the bonnet up and a huge fan blowing air across front is very different to a car driving in traffic with high under bonnet air temps.

I'm not convinced by that, yes there was a rise in power after the modification which doesn't surprise me, but a car sat on a dyno with the bonnet up and a huge fan blowing air across front is very different to a car driving in traffic with high under bonnet air temps.

But who is searching for bhp when sat in traffic?

But who is searching for bhp when sat in traffic?

Not sat in traffic but following traffic then you get an opening to overtake or the road opens up and you hit the go pedal.

Equally though, who is searching for BHP when driving their car with the bonnet up?