Open Air Cleaner Install on 305 TBI
 

This subject has been brought up before, whether or not there are any benefits to changing out the factory air cleaner. I just finished installing the new air cleaner on my 91 RS. The TBI unit is basically a glorified computer controlled, fuel injected carburetor, without the conventional carb. attributes, so tricking it out the "old school" way is easy to do. I needed a new cleaner element anyway, so I decided to go all the way. I did notice a slight boost in performance off the line, but it's more noticeable when dropping it down into passing gear. Not only does the new one look a lot better (I like going for good looks as well as functionality), but you also get a nice throaty "carburetor" sound from under the hood. Sucking in hotter under-hood air might be a little concern, so I left the factory air inlet horn in place to bring in fresh air while cruising. I already had put in a 180 stat, and am also going to make my cooling fan turn on sooner. All in all, I feel the good definitely outweighs the bad with this modification, and I'm pleased with the results.

Attachment 42562


Attachment 42563
Here you can see the factory spacer ring that the stock air cleaner base sets on.


Attachment 42564
Just by simply removing the spacer, you can see how much it opens up air-flow access to
the TBI.


Attachment 42565
Here is the old air cleaner base in it's stock position. It really makes no sense to me to put a spacer ring on
the TBI unit, and then need to use a drastic drop-down base to compensate for the spacer to allow for hood
clearance. Basically, it's jacked up one way, and dropped back down another way. The incoming air has to go
through a restrictive horn, then up and over the raised center portion of the base, over that raised flange,
and past the two large injector pods to make it's way down the TBI's throat.


Attachment 42566
Here is the new "flat style" air cleaner base with the spacer ring removed. You can see how
the flow of air has a much easier and straighter path. And there is still plenty of clearance
between the bottom of the air cleaner base and the throttle linkage and distributor.


Attachment 42567
Close-up shot of the stock base.


Attachment 42568
Close-up shot of the new base...HUGE difference!

RE: Installed a Free Flow Open Air Cleaner 305 TBI
 

nice work... didn't know you had a 3rd gen, next step a 3" K&N and fiberglass cowl hood.

RE: Installed a Free Flow Open Air Cleaner 305 TBI
 

You got it! I wanted to see if this works first before investing in a K&N filter (the filter assembly came with a paper element). And yeah, the '91 is my "normal" everyday car. The 69 is for fun, dry weather driving.

RE: Installed a Free Flow Open Air Cleaner 305 TBI
 

I may try that on my blazer...looks like a little fun.

RE: Installed a Free Flow Open Air Cleaner 305 TBI
 

looks great. i'll have to give that a try.

RE: Installed a Free Flow Open Air Cleaner 305 TBI
 

I did the same thing by installing an open element intake and I think it was the best thing to do. I like the more throaty noise plus the sucking noise is also cool. And as a bonus mine is only 10" so it cleared up some space in there for me to work. I hated having to take my damned intake pan off everytime I wanted to do something.

http://img.photobucket.com/albums/v3...h_DSCF2362.jpg

When you take the spacer off, the breather tube that comes from the valve cover to the back of the spacer ring, can that be left to open air or should I plug it? This is on a 95 Silverado, about to do the ULTIMATE TBI mod. Thanks

No you don't want to plug it, that side needs to vent. I replaced the tube in the valve cover with a push-in breather.

Ah okay, yeah that makes sense, thanks I'll get myself a edelbrock chrome breather from advanced, it will go well with my chrome edelbrock air cleaner that I have on there ^.^ I know most people like to retro fit their throttle bodies to fit the single style center hole, I actually drilled 2 holes to maintain the original two hole air cleaner look,

http://s59.photobucket.com/albums/g2...100_2325-1.jpg

There's a picture of mine. I bought the black/red bow tie and closed it up just using a nut and bolt. When I drop the spacer ring I'll put up a picture since I'll be using a taller element to compensate for the space lost by the spacer ring. Thanks for the swift reply by the way!

Forgive me for reviving a month-old thread, but I'm thinking I might like to do this with my 1991 RS and I have a question. I'm really new to anything dealing with engines, so please bear with me.

I noticed in the stock setup that there is a piece of flexible tubing coming from the exhaust manifold to the air intake path, and there's (I think) a valve to control weather exhaust is being recirculated or not. It's somewhat visible in your forth picture. Did you just cap it off and disconnect the valve? Any adverse effects of doing that? I'd go see for myself, but I'm at school and I left the Camaro at home for the winter.