rrounds

First, My car is 100% stock(well I do run a big oil filter) .
I just got done with a test to see if there was a difference in vacuum before the air filter with the air box lid off or on. I put this on my car yesterday
http://s188.photobucket.com/albums/z...onda%20Intake/
and had 8" of vacuum after a WOT run to the top of third gear(8k miles on the filter).
So today I reset the vacuum gauge and did the same third gear run and still had 8" of vacuum, then all I did was take the air box lid off and did the third gear run and it showed no vacuum. Put the lid on and had 8" of vacuum again, reset it on the side of the freeway and took the lid off-no vacuum. So I did this four times and every time with the lid on I had 8" of vacuum and with the lid off it showed no vacuum.
I just don't think the inlet on the stock air box is big enough for a stock engine at WOT. 8" is not a lot but if you add to that a filter that is not flowing very good and you could rob yourself of some top end HP.

Anyway, I just thought I'd share what I found out today with my little test,
ROD

cdelena

The biggest issue with the stock air box is the fact it draws warm air over the radiator so a cheap fix it to insulate the top of the radiator. Removing the top of the box helps it draw more warm air so it is not a positive change. BTW the larger oil filters have a tendency to loosen so using one without a safety wire is a risk.

rrounds

Over 40k miles and the oil filter has not moved. I do mark the filter so when I fill up I also check the oil level and take a look at the filter, it hasn't moved.

ROD

s2000ellier

http://en.wikipedia.org/wiki/Wikipedia:Citation_needed

rrounds

You can insulate the air box and put a cooling plate on the car and the air box would still restrict the airflow.

ROD

speedjunky01

Where are you reading vac from?

If after the TB something is wrong with the way you have the gauge connected

There is no way on gods green earth you will gain 8" of vac from an intake

Use a obd scanner to get a more accurate reading on pressure, I will bet its 0" or slightly positive pressure while at WOT

rrounds

Didn't read the first post did you? It has pic's.

ROD

Saki GT

So what you've shown is that with the lid on, the airbox is creating a stronger negative pressure zone, thus more aggressively pulling more cold air in from the intake horn. You haven't measured air flow or volume changes so you can't say there is a restriction, right? Plus, you don't know how much airflow is needed/optimal, right?

Without the airbox lid there is no neg pressure zone pulling cold air into the box, so that means more air comes in from places other than the cold air that comes in ahead of the radiator - aka the rest of the engine bay.

I think what you've shown is how Honda engineered the intake box to have a level of neg pressure to suck in cold air, but not that the intake is restricted. Remember pos/neg air pressure zones are important for directing air.

Saki GT

This is not correct.

SgtB

That's interesting.

Saki: A restriction is a restriction. The box could pull nothing but cold air from the outside and still maintain 0 vac if the inlet is large enough. I'm going to dig up my vac tester and see what I pull with my V2. FWIW I never really noticed a performance boost. Honestly I just like the sound, and the empty engine bay.