I was reading a thread in the General Discussions forums and came upon this interesting post.

So I went home and took a peak at this myself and much to my suprise it looks as if the intake is almost closed when the hood is shut. How in the world is enough air even getting into that air scoup? I'm actually thinking about cutting the inner part of the hood myself to form a nice air channel, but I don't think it's going to look so hot. Perhaps my brother might take on this project at his body shop and make it nice and clean for me. I like to keep things as close to stock as possible.

For testing purposes I just removed the lower elbow that goes into that closed box under the battery tray. I know I'm sucking in warm air, but at lease I'm actualy sucking in some air!!! Took it for a spin to see what the dyno butt says and now I'm headed directly to an auto supply house to find a hose to route another intake path from this connection. Cold air would be the best choice, I'm thinking someplace under or around the battery tray, even just around the drivers side headlight area might be a good idea.

I guess this is part of what some refer to as OSCAI? I'll try to make mine look good if thats the case. I can't believe Nissan designed the intake and hood to basically cut off the intake air passage when the hood is closed. A minor change in the stamping tool could have formed a nice channel for a better air passage making the stock intake breath a bit better.

My thanks again to all you fellow org members for all the info I've found on this site.

 

Yes, that is OSCAI.

Also, if you look into the main scoop, there is a divider that blocks off a lot of the open area. I'm thinking of cutting out that divider somehow.

 

I thought about that as well, but look closely and you'll see if you do cut that piece out, you will have a bit of an opening on the under side of the scoup too. Not that that's a bad thing, but the way they molded that piece, the divider is actually a hollow piece.

 

Before you do any cutting, take into considertion that the people at Nissan aren't that dumb. Air does enter into that scoop somehow and also through other places throughout the front of the car....enough cool air to circualte throughout the engine bay to bring intake temepratures down without any modifications at motion. *See stickie in General Discussions about intake temperatures.

However, when in motion, modifying the stock scoop may reduce intake temperatures quicker, but not significant enough to realize a nominal power gain.

 

I totally agree with you on the fact that air does get into the intake, but at a restrictive level especially at WOT. Using that branch off just after the scoup as another source for air, cool air if routed correctly, could only bring a bit more free flowing air to the stock intake system. Especially at WOT conditions.

The stickie post about intake temperatures is excellent!

 

Thanks!

 

i havent had a chance to look at this yet , as i just read this, but is there a way to reposition the front of the scoop so that its not being pressed by the hood? i have no idea about how much cutting you are talking about but it might be a good idea..
thanks for the heads up NJmax

 

Yes that really is good research. Your tests proved proved that the HAI is barely warmer than the CAI, and I feel as though this minimal gap does not contribute to either's power. I guess the CAI's only advantage is that if has access to more air, which is what the OSCAI takes care of. After all, that is how Ben got his 15.2 second run.
-Cyrus

 

UPDATE:

I removed the lower "Air Box" or baffle chamber (under the battery tray). There is an elbow that comes off the upper scoup intake, just in front of the radiator fans. That elbow goes into a sealed air box. Makes no sense at all, maybe for noise reduction?

After I removed that sealed air box under the battery, I ran an intake pipe just over into the dead air space under the battery. I felt around under there, there is a slit in the inner fender which appears to be open to the front of the car - Cool Air Source! I'm now sucking air right from that area down low under the battery as well as from the scoup up top. I think I've got better air flow into my stock intake system, the car feels like it downshifts quicker and harder while I'm crusing around town. On the highway it seems like it pulls at lower RPM's a bit more. As far as overall pickup at WOT, I think it breaths just a bit better.