legacycentral bbs

you might think about putting the 45 degree box on. I picked up a bunch of car magazines that were free on craigslist and most were from the 90's. There was a Street Power magazine from 97 that had a hop up article on a 90 300zx twin turbo. The part that caught my attention was replacing the stock air box which has the same setup as the airbox on our cars. The inlet to the maf is in a corner with the wall very close and it is hard for the air to travel up and make that tight turn into the maf. They were seeing an 18 horse increase by getting rid of the stock box which is a huge restriction. Why Subaru put the shrouded airbox on the turbo cars and the 45 degree box on na cars beats me. I would think the 45 degree box should be worth at least 10 horses on our cars going by their results. The guy that was doing these kits was Jim Wolf technologies who I have no idea if he is still in business, but when I saw the pictures of the airbox I said that looks really familiar.

Jeff

Pics?

Hi,
THIS ARTICLE has some related info on the restrictions in the intake..... the main restriction is the snorkus.

And HERE'S MINE on my previous '90 Legacy w/the turbo swap.

I've not come up w/a decent coffee-cup mod for my '93 SS...yet.
Td

That article is where I got the idea. I wish they had gone on and tested the airbox. It would have been good to have some cold hard facts, but all you have to do is look at the two and you will see that the 45 degree one is able to flow much more air because the maf entrance is not shrouded by the walls of the box and the air doesn't have to make two 90 degree turns.

Jeff

Josh hosted some pictures of my airbox setup. If you search for 45 degree airbox you should come up with the threads with the pictures. Wish I was better at this computer stuff so I could link it here.

Jeff

Heres Jeffs old post: http://bbs.legacycentral.org/viewtopic. ... city+stack

If I build another turbo Legacy, it will likely get a 45* air box rather than the Apexi Power Intake I have now.

I'd be curious to see what changing to the 45 deg airbox does for the pressure drop. I've thought about the way the airbox is shaped and I question whether Subaru did it intentionally to create an area of low pressure just before the MAF to possibly help the air flow more evenly through the MAF. That may just be a hair brain idea though....

I converted to the 45 degree airbox as well and am running a custom made intake pipe. It's kind of a bitch to remove the airbox/intake pipe, but works well.

http://www.main.experiencetherave.com/s ... install/10
http://www.main.experiencetherave.com/s ... install/13

Josh,
In this pic I circled what looks like an 'extra' hose to the airbox. Or what is it, plz?

Thanks

Yes, that is an extra inlet "feeder" pipe to the bottom side of the airbox. I don't know if it really makes a difference, but I had added it probably around 2002 and decided to leave it there when I changed air boxes.

That is the one downside to this setup in that there isn't enough give in the system to take things apart easily. If I would start at the rubber elbow where it connects to the turbo I think it would be much easier. I always start in the middle and end up fighting things.

Jeff

I'm running a different 45 degree box for under the intake routing. Could probably benefit from widening the hole in the box and fender wall. Mine is hard to remove/install as well.

The one thing I didn't really do is widen the hole that protrudes in the fender. They talk about it in the autospeed article....it's essentially creating a velocity stack to improve air flow.

So...the small hole is GOOD?

You should install one of those electric turbos in the fender and duct it all up. BOOM!

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kimokalihi wrote:So...the small hole is GOOD?

No, but it makes your intake "hose" look bigger

Another thing I did to improve the flow was to use a thin wall tube on the inside of the 90 degree rubber connector on top the turbo. The sleeve is on the inside of the ribs so they can still flex, but now they don't impair the flow of air. There is a lip that keeps the thing in place.

Jeff

Jeff,

That's a really good idea! Do you have any pictures of that?

I don't have any pictures of it. It was easy to measure for the length and od. The lip is at 90 degrees so it is shaped kind of like a top hat and it rests on the edge right before the ribs. I had a metal spinning shop do it for me. My only concern is if the thing digs into the rubber when things are flexing. Everything looked fine the last time I checked.

Jeff

If you have an opportunity to take a picture of it when you're doing some work, I'd love to see it.

I will get you one when I can.

Have you had an opportunity to get a picture of the sleeved 90°?

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No I haven't even been doing anything to the car. Thanks for reminding me about it.

Jeff