I havn't owned my Firebird for very long. I'm running a completely stock 1991 305 TBI. I noticed today when the hood was up , an iritating clicking sound. It's similar to a hockey card being run throught he spokes of a bike at high speed. I took off the aircleaner cover, and the sound is coming from the injection system (sounds like explained, like an electric switch turning on and off several times a second). Is this normal?

 

injections, yes, it is normal. If you look closely at the injectors spraying the fuel, you will notice that the spray is not continuous, but pulses of fuel.

 

Yes, that is perfectly normal. Sounds cool after a while. No other car (that runs right) sounds like that.

 

Thanks guys. I figured that's what was going on. I just wanted to check.

 

Just wait until you get an open element on there. You will hear all kinds of cool noises after that.

 

Shifty, I have a question about those. I bought a K&N to replace my stock filter, but after thinking about it... The single intake inlet/hose looks like it is VERY restricive.

Infact most older 3rd gens have 2 larger inlets instead, right?


Is it possible to buy a custom baseplate/lid for my existing K&N? Or must I buy the whole kit? This is an open element right? I think it's my best choice.

If I can do this.. I guess I could go allt he way and install an Xstream filter lid aswell for more filter surface/airflow. What do you think?

 

The second pic you posted is the dual snorkel found on older HO models. It is very popular and much better than the one you have now. There is some fitment issues with the AC but that can be corrected. Take a look at the sticky at the top and there is some great links to open element stuff. You will see that pretty much everyone goes witgh an open element. Do not even bother modifying your stock intake because it is an odd size and open elements go for 20 bucks. Adding K&N stuff adds to the cost but is worth it. I have an extreem lid but I only have it for looks. It is pointless to have since the stock hood will just come down right on top of it and restrict any air from entering in form the top.

 

Looks good

I already have a K&N filter (same size as stock filter). What I woud like to do is purchase a plate, and lid (like you have/or chrome) to fit the existing filter. Is that possible? Or are the plates/filters different sizes?

 

If you bought the K&N for the stock air cleaner, it'll be too small. You'll need a 14x3 one.

 

You might could find a base to fit your stock K+N filter but don't do it. It is not worth it. Trust us, get the 14X3 Open Element and put a K+N filter on that.

 

How much did you pay for the stock replacement K&N filter?

Steve

 

$71.99 bucks can. + tax.

I hate the idea of buying another & accessories.

I'm just thinking here.. Wouldnt an open element be drawing in a lot of hot air? Especially during intown driving? Wouldn't the HO dual outlet conversion be a good idea? I could probably grab one at a wrecker. I think the open element looks pretty sexy, but spending the extra cash to replace a brand new $75 dollar filter seems a little silly.

You guys are very helpfull. Thanks for the assistance

Maybe you would take a look at two other threads I'm awaiting a reply to.

Tuneup Stuff
Oil Weight Stuff

 

If you have no mods to the engine I would just mod the stock air cleaner. If you cut off the the snorkle just past the heat riser valve, say about three inches past it, then just replace the black flex tubing with a longer peace and you have a much better flowing cold air intake than stock. It won't flow like an open element but should be sufficent for a stock motor, and cheep as well.

Steve

 

Yea that is its only downfall. However for 20 bucks you cannot beat it. However, a lot of hot air is a little better than a little cold air. The dual snorkel would be the best idea and can be found in any junk yard.

 

Dude i think the open element is the cheapest and best easy mod you can do to a tbi car. I thought the same that it would be drawing in more hot air and it wouldnt help anything and boy was i wrong. Go for it i got the summit open element with 3" k+n for 50 bucks.

 

Check out this thread:
https://www.thirdgen.org/techbb2/sho...hreadid=171757
That's the sticky at the top about open elements. That is EVERYTHING you need to know about them. I would highly recommend reading through the whole thing (minus the last few posts, kinda redundant info) as there are a few things you wouldn't think about that could effect your car. HTH!!

Bruce (90RS305)

 

Thanks for the help guys.. I guess I can't get a plate/top for my current K&N then... After paying $72 bucks for just the filter, I'm not lookign to spend the money on a bigger aircleaner + a lid/bottom. Unless there is a relatively cheap base/top that woudl fit my stock filter...

 

If you have access to an old air filter assembly you can make your own open element. Just cut everthing on the outside of the filter off, lid included, then repaint the lid in your favorite color.

Steve

 

How much vacuum or what kpa would a stock lo3 see at wot. I'm just curious as to the difference between stock and open element.

Steve

 

Are you talking manifold vacuum? If so than the same as stock. The intake manifold vacuum won't change until you swap intakes, heads or cam.

 

Vacuum or kpa just depending on which methed you are using to log with,will change anytime you remove a restiction weather it is an air filter, tb, intake. The cam won't have much effect if any at wot nor will the heads.

Steve

 

A cam swap can drastically effect engine vacuum. Thst is why they have vacuum canisters for real lopey cams. As for stock, you are right the vacuum will change when restrictions are moved but the difference is so minimal. The changes you see are with variences with durations and such. Are we confusing each other?

 

Shifty, as I said in my last post, readings taken at WOT. All other areas could and would be affected. As far as on a stock engine, if you can't tell any difference at WOT after making a change in an air filter, tb or intake then you haven't really made an improvement. I know you'll never see "0"ins. in vacuum or 100kpa with out some help by either ram air (N/A), or forced induction which will be more than 100+ kpa. Anyway thats just how I understand it.

Steve

 

I gottcha now and that makes more sense. I thought you meant at idle as well. At WOT you are absolutely correct.