Hey guys,

Im upgrading my 90' 323 BP SOHC and need some information. I'm currently making an air intake tube out of aluminium to replace the standard rubber one with the resonance chamber. The tube will connect straight from the throttle body to the VAF sensor and this way I can get rid of the ugly resonance chamber as well.

The question is can anyone tell me what the reducer on the standard intake hose is designed to do? Ive been told that it is used to quiten the intake noise but im not sure.

Any help would be most appreciated.
Thanks

 

by removing the Hbox you will also lose about 2-4ft.lbs of torque....

not sure what you mean by the reducer though....the stock air box has a few silencer chambers as well as that long thing just above the radiator. All that comes out when you remove the stock air box.

 

By removing the resonator box is that loss of torque really all that noticeable?

The reducer is on the stock intake tube. As the tube comes off the resonator box the tube looks as though it goes narrower then fattens up again.

 

basically, if you're used to flooring it, something so small is very noticeable on the low end. keep the resonator intact
peace

 

Here's a question. I have heard the reference to the resonance and H-box many times, but don't know what they are. Which is the long thingy attatched to the airbox, and which is the boxy thingamabobber on the flexible intake pipe between throttle body and VAF?

 

the hbox (directly behind the VAF attached to the rubber stock tube, regulates the air pulses into the intake. Which makes for better velocity and a better air/fuel mix.

the long tube above the radiator, is i believe used for 2 things, 1, a silencer to quiet the intake noise and to heat the air, why it heats the air, i have no idea which hurts performance.

but all in all, you'll have more torque (low end) with the stock air box fully intact than with a cone filter. So if you do mainly street driving low end is a good thing. If your foot is nailed to the floor constantly or you drag race, it won't matter much as the gains from an intake tube and cone filter will benefit more on the top end.

I tested my intakes with and without the hobx. I did notice better "out of corner" umph with the hbox. Merely a seat of the pants dyno test, but it did help.

 

Yea i can vouch on the torque part. There was a car show last weekend here and i "borrowed" there dyno for a couple of hours. The stock airbox is better then a cone filter on the low end, the gains on the top end were there but it wasnt much. I would imagine if your autocrossing and or just racing around town/city, its a much better option to stay with the airbox. Before i get called for bs, i couldnt bring my webcam to there dyno since its connected to my puter, i encourage you to do your on test if you boubt me.