Improving factory intake
Thread Starter
Joined: Jun 2005
Posts: 287
Likes: 3
From: Orange Park, FL
Improving factory intake
Pretty straight forward. I want to maximize the stock intake.
First pic is the rain gutter down spout extension I got at Home Depot. I first saw this thing about three years ago and immediately knew I want to try this. Now I have stock car to try it out.
Second pic it the piece trimmed up and ready to go.
Third is the duct outlet.
Fourth, the inlet. Its not secured in the shot, so it looks wonky.
Last is the area oh the hood that needs to be trimmed back and boxed in. I believe this area and the horrific turn into the air flow meter are the biggest bottlenecks of the intake (pre manifold.) Im going to attack the hood tomorrow.
As for the lower half of the air box, I know what needs to be done. I just have to get the parts together.
First pic is the rain gutter down spout extension I got at Home Depot. I first saw this thing about three years ago and immediately knew I want to try this. Now I have stock car to try it out.
Second pic it the piece trimmed up and ready to go.
Third is the duct outlet.
Fourth, the inlet. Its not secured in the shot, so it looks wonky.
Last is the area oh the hood that needs to be trimmed back and boxed in. I believe this area and the horrific turn into the air flow meter are the biggest bottlenecks of the intake (pre manifold.) Im going to attack the hood tomorrow.
As for the lower half of the air box, I know what needs to be done. I just have to get the parts together.
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Nice work, however I doubt it's much of an improvement. 
In stock form, there are plastic panels which are installed between the bumper support and rad support. They direct air from around the relay area, which is fed directly from the bumper opening, up to the intake duct.

In stock form, there are plastic panels which are installed between the bumper support and rad support. They direct air from around the relay area, which is fed directly from the bumper opening, up to the intake duct.
Pretty straightforward...
What is the flow capacity and IAT of the stock system?
Without that data how will you know if your work indeed "maximized" anything?
At best, your mod might lower temp, which is a good thing of course but can you prove it?
What is the flow capacity and IAT of the stock system?
Without that data how will you know if your work indeed "maximized" anything?
At best, your mod might lower temp, which is a good thing of course but can you prove it?
Nice work, however I doubt it's much of an improvement. 
In stock form, there are plastic panels which are installed between the bumper support and rad support. They direct air from around the relay area, which is fed directly from the bumper opening, up to the intake duct.

In stock form, there are plastic panels which are installed between the bumper support and rad support. They direct air from around the relay area, which is fed directly from the bumper opening, up to the intake duct.
it's ironic that most days when i pop an FC hood now that i can see the ground all around in front of the engine.
the stock splitter system moves alot of air but it isn't directed very well, but pulled into the snorkel. this may work better as a sort of ram air duct but the question is, will the small diameter pipe move enough air to help performance.
Last edited by RotaryEvolution; Sep 15, 2013 at 12:50 PM.
I don't think it will help any. The pipe is too small and there are a lot of sharp bends. However, he may get a 1-2 hp increase if he redesigns the air box without baffles. Anyway, the installation looks nice.
i agree, the simplest fix would be tying into the RF brake duct and coming straight up into a CAI box where the factory intake is. but not everyone likes chopping holes in their car, but this always made the most sense as a true CAI mod.
Most track cars have the intake behind hollowed-out FTP and turn signal holes, or ducted next to the radiator inlet similar to the pics in this thread but with a larger duct. While I guess it would be OK on a drag car or a dyno queen, you generally would not want to reduce the brake ducting.
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I would get one of those fiberglass headlight covers with the vent and make a top to the air filter box connect to vent area... or cut a hole in the hood where the snorkel is (i have seen an fiberglass insert for this)... or just leave the oem air intake setup.
Last edited by tuscanidream; Sep 15, 2013 at 04:59 PM.
Thread Starter
Joined: Jun 2005
Posts: 287
Likes: 3
From: Orange Park, FL
Quickie update.
Took out the new duct and reinstalled the stock radiator panel.
Built a manometer and took it out for some data acquisition.
I was pleasantly surprised to find at 7500 rpms in 3rd gear/full throttle, it is only pulling 15inches of water. The tap in point was on the intake pipe at the smaller nipple next to the BAC nipple.
Back to work.
Took out the new duct and reinstalled the stock radiator panel.
Built a manometer and took it out for some data acquisition.
I was pleasantly surprised to find at 7500 rpms in 3rd gear/full throttle, it is only pulling 15inches of water. The tap in point was on the intake pipe at the smaller nipple next to the BAC nipple.
Back to work.
I bought JohnV;s CAI off his ProSolo race car. It was custom fabricated and he had data logging info to prove that it increased air flow into the engine.
https://www.rx7club.com/2nd-generati.../#post10601567
https://www.rx7club.com/2nd-generati.../#post10601567
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