modifying the air box

[devon527]

I just tried it, unless I get creative, it won't stay down. And the lid won't let the lock nut keep it down because the threads don't come through. Lol

[JPT]

You may have to get creative. I haven't tried this on a Festiva, so I don't know how well this will work. If you're going to do this, check two things. Hood clearance and, most important, Make sure the lid seals tight to the air filter.

[TominMO]

^ True on the VAF, but you're still dealing with a 50mm throttle body (about 3 square inches) minus the area the throttle blade takes up. The hole that's left when that duct is removed is about the same size in area.

Then again, extra holes can't hurt.

I was sold on drilling airbox holes when this turned out to be a huge improvement for my 91 Subaru Loyale. It had no pep at all above 4500 until I did this, then it ran very strongly to redline. Since the motor is sucking the air in, it may still be that airflow is faster with the extra holes, despite the throttle body size; in other words, the tiny hole letting air into the airbox itself is more of a restriction than the throttle body. And of course there will be variation in performance difference between different makes/models of cars, depending on how efficient the basic designs are.

[sketchman]

You may have to get creative. I haven't tried this on a Festiva, so I don't know how well this will work. If you're going to do this, check two things. Hood clearance and, most important, Make sure the lid seals tight to the air filter.

Been a while since I saw the carbed setup. Is there a "cone" shape in the lid that dips into the carb inlet a bit or something?

[sketchman]

^ True on the VAF, but you're still dealing with a 50mm throttle body (about 3 square inches) minus the area the throttle blade takes up. The hole that's left when that duct is removed is about the same size in area..

Keep in mind the inlet of the throttle body is quite a bit larger than the narrowest point at the butterfly. Then take away the throttle shaft silhouette. The narrowest point is about 44mm wide without taking anything away. Tiny. Just mic'ed one sitting beside me.

I've modified a manual trans neon throttle body to work with mine that gives me 49mm IIRC. The auto trans neon one will give you 52mm. It involves welding though and was a pain IMO to do. Probably better options out there. I just have them lying around.

[sc72]

Goodmorning All, i followed the suggestions for modifying the air box, pulled the 90 elbow and swiss cheesed the bottom of the box, went for a drive south of town through the hills, it did well going up hill without having to get a run at it so i'm happy. Now for the upside down air cleaner lid, yes we did this and it gave the Q jet a very unique growl. Thanks for the help.