I removed the intake tube's that go through the radiator support this weekend to see what I could come up with to open up the bottle neck of the system. The very ends of the tube's are oval shape and rounded out = about 1&3/4 inches, but into the tube about an inch or so they reduce down even smaller. I then removed the fittings that the tube's connect to on each side of the radiator and stuck a 2&1/2 ID hose through the openings with the tube's back on to see how far they would slide up on them and marked them to cut with tape. I decided that wouldn't work very well because of the taper, you can see what I'm talking about in one of the pic's. I went to town and picked up 2 small piece's of exhaust pipe, one 2&1/8 OD and one 2&1/4 OD. I sawed a + in the end of both pipe's and bent them inward to make a taper on them, I also hammered down & filed any sharp edge's. I used a heat gun to heat the end of the tube to insert the 2&1/8 OD pipe, once it was stretched out I stepped up to the 2&1/4 OD pipe, inserted it and let it cool. Once the tube's were put back on the air boxes I cut off the tops off the piece's that the intake tube's originally connected to and reinstalled them, then inserted 5 inch long piece's of the 2&1/2 hose's on each side for the intake tube's to fit into. The piece's that the tube's connect to have little flap's in the lower portion of them that open when air hits them, what they are for, I have no idea. So now there is no bottle neck, the end's of the intake tube's are now 2&1/4 inch ID. I have 5 or 6 picture's but I can not get them to load and I can not use a hosting site from here at work. So if anybody would like to try to post the pic's, PM me and I can e-mail them with the pic's in an attachment to post them.

 

After doing this was there any noticable difference?

 

I've only drove it once since I done it. I made a couple runs on my G-Tech and it didn't really show much difference, but it was only 38 degrees outside and I really didn't get out of the hole very good. It did a lot of spinning even with the TC on, I bet the posi marks on the road were 25 to 30 foot long. G-Tech was showing 12.3 & 12.4 in the 115's in the 1/4. Anybody have any idea what the little flap's are for in the piece's on each side of the radiator support that the intake tube's connect to?

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I would assume the flaps would be used to deter critters from getting in there if the car isn't running?

Maybe water somehow? I'd have to see them in person to see how they work...

Nice write-up.

SQ

 

I just found it odd, they appear to open as wind would hit them. One other thing I found a little odd was that the right side intake tube was just a little bit bigger around than the left.

 

I ripped all of that out the tubes are fine just sitting behind the grille. I could not figure out what they were for either, but I assume they are better out then in you are getting more air to the engine. I have a question thought this might be a good thread to run it by. I will try to be detailed so you can understand what I am saying. I thought about doing the same thing you did only when i heat up the end of the tube to widen it, put a piece of 3-4 inch PVC ring inside. Reason being that way i can clamp off of it. It will be really ridged and stiff. After you have melted it and put the larger ring in there buy a piece of three inch aluminum pipe run it off the end behind the grill and attach a filter. In other words on your last picture run a 90 degree three inch piece of aluminum and put a filter on the end and connect it to the end of the tube. Remove both box filters and repeat for both sides. It will almost be like a dual needswings intake only using our stock air boxes. If anyone can get the visual let me know lol and tell me what they think I might try it.

 

I know what you are saying and I was considering doing the same thing to keep the 'stock' look.

The stock air boxes are like a heater on those filters...all they do is heat up the air.

I would also consider plumbing a hose inside the stock filter box that directs air once it is inside the box. Basically, run a tube through the stock air box. This will prevent any turbulence inside the odd shaped box, and it will also allow you to fill the stock airbox with dry ice or some type of insulation to keep the tube inside of it from getting so hot.

It may be difficult to do with the stock boxes without ruining them...but just a thought. I haven't gotten far enough to look at it yet.

SQ

 

The main problem there is that from the bottom side of the OEM filter out to the ends of the tube's it is not a sealed system. I had thought about something like that.

 

Where are the leaks?

I was thinking a front mount panel filter setup of some kind away from all of the heat would help as well, but that would require more fabrication (similar to an LS1 vette or FBody).

SQ

 

I think they are sealed There is only one clip that leaks air in on the bottom of the SL boxes its a clip in the back that needs to be sealed other then that I think they are.

 

If you remove the collar that joins the tubes to the filter boxes, you will see that they are anything but sealed. There is some odd German engineering goin' on there, lots of 1/8 inch-ish holes molded in them.

 

Nice write up!

 

Wow, another custom job by another good member. Nice job! The more I read posts like this, the more I want to start tackling my stock baby. Soon, really soon.....