Cadillac

I know this is the most frequently discussed topic on the TBI forum and I am sorry if this has been beaten to death but I want to know: If I put an open element on my 305 TBI, what will I gain? From what I tell the answer is :

**Better Sound when you gas it.
**~5-10 HP.

Does that cover it? This might seem to be the first mod, best-costing-bang-for-buck thing i oughta do to my 305.

Curious,

BronYrAur

iTrader: (1)

Yep, you're pretty much right; it just let's your choked engine breath a little bit easier. Good first mod.

Formula4Speed

the extra air will also let your engine make better high end power

bbtaz97

iTrader: (3)

for a k+n from jegs i tihkn its either one of these

14'' Air Cleaners:
Drop base, race ready low profile air cleaner drops filter 1-1/4'' below carburetor flange. Fits most 4 bbl carburetors.
599-60-1280 Neck:5-1/8''
Element Height: 3'' $89.99


14'' Air Cleaners:
Drop base, race-ready low profile air cleaner drops filter 13/16'' below carburetor flange. Fits most 4bbl carbs.
599-60-1430 Neck: 5-1/8''
Element Height: 3'' $89.99


and you leave that space ring on. The more i think about it i think its the bottom one if you got a stock hood and as long as you dont have a real readical intake but some here will point out witch one for sure.

Cadillac

Yep... thanks for the confirmation. I think I have everything I need to know after reading the Open Element thread and the link so graciously provided by DevilAdvocate:

Step By Step Open Element

Thanks mates!

cali92RS

I know im gonna be flamed, but i had one on for a while, and i never felt a damn thing. I had to put on my stocker for the smog check, and there was no difference. I think there might be a placebo effect that some people feel..."i definitely felt it on the butt dyno"...yeah right
If u have a cowl hood then there would be a difference cuz of the cool air.
Go ahead start the flaming, this has always been debated but i wont believe it till i see some actual numbers instead of the "butt dyno"

Benm109

I don't think anyone will flame you. All cars respond different to mods and sometimes it's hard for people to feel (you know, "butt dyno"). When I completely rebuilt my tired old motor (bored .030 over, 3 angle valve job, Edelbrock TBI intake) and took it for a test drive, I didn't feel a difference. Two weeks after that, I put on a 14" by 3" open element, did the ultimate TBI mods, and installed a Hypertech PROM (I know they suck), and I still didn't feel a difference.

I know I have more HP and TQ now than when I first bought the car but it is hard for me, personally, to feel.

Dewey316

Butt dyno's are very in accurate.

I have done things to my car, and it feels slower, i pick up .5 at the track.

I have done things that feel fast, and have lost a full second.

I would be willing to bet, that if most of you drove my car, it wouldn't feel nearly as fast as some of yours. but I would bet i beat you in a race.

cali92RS

U are making my point. No one has shown any numbers to support the open elemnts claim. People say it just felt faster, and thats what this whole element debate is based on..."cuz it felt faster"

90RS305

Maybe so, but if you think about it, mathmatically it is the better option. If air temps were the same with the stock snorkel and the open element there is no way you could lose performance, cuz you're getting somewhere in the neighborhood of a couple hundred percent better air flow. Now here in Arizona, sure, air under the hood is so bloody hot that it'll slow you down. "FEELS" like more throttle response, and it "FEELS" like it is pulling better at higher RPM's, but it slowed me down at the track. Now take someone who lives in the northern states with a lot cooler ambient air, Numbers suggest that better times are VERY probable. Anywho I'm just saying, don't be so quick to discredit it...

Poncho Villa

Wow, cant' believe there are some people who didn't notice a difference with an open element! Of course, someone just checked out my motor, guy who builds motors, and he says mine has been rebuilt. So a fresh or modded motor will definitely respond better. When I put my open element on, my car was screamin. My friend, who builds motors, went for a hellride with me and totally could tell the difference--not just more induction noise, but higher rpms and more speed, greasy speed! Granted, not nearly as much of a difference as a major mod like heads/cam, NOS, that sort of thing, but a definite improvement--and I don't have cold air induction--yet!

Arizona man has got a point too. I live in So Cal, and on cold nights, the car has a bit more punch, because ambient air temp is lower. As soon as I get some coin for CAI of some kind, I will no longer have to breath manifold cooked underhood air.

And there is at least one pretty trick CAI mod on this site using the stock aircleaner too.

P.S. check out this months Hot Rod magazine, and their third gen Camaro, 305, with Vortec head/cam and 670 cfm TBI that makes 330hp and 378tq at the crank! (Around 270hp at the wheels. Not bad for a 305, and thats before the NOS, Spillner!) Pretty sure they weren't using the stock air cleaner.

S!MON

I have also felt a huge difference. definitely best bang for the buck!

I also made some cold air stuff (cardomain site in the sig) which also works well when it's a little bit colder outside.
greetings

S!MON

Cadillac

This thread is stareting to rock... :rockon:

OK, I think I'm sold on doing this simply because after the sorely needed paint job, funds will be tight until some stocks come in (go NVDA!!!).

Anyway, the whole dang smog check in CA is a bummer and keeping the parts from the original breather so I can pass this test in the future will be important.

I do have a question though. Look at this pic:



When I do the mod, do I just leave manifold vent wide open? Is this even a vent? What exactly is the purpose of this?

Curious,

Z28GEN3

I didnt notice anything new accept the hissing noise, but i installed a small OE on mine, 2x9 is pretty small. I just ordered a larger OE, dont know if ill see a difference rite away but i plan on sealing it to the hood scoop i'm installing, so in the long run something should change in the area of airflow and air temp.

BronYrAur

iTrader: (1)

I was at a local track day and a guy I know with a TBI car with headers, full exhaust, edelbrock intake and some suspension stuff. He was running the stock air cleaner and was running kind of slow. We borrowed someone else's open element setup and tried it on his car and he picked up about .6 improvement. That's a Huge difference between stock and open element if you ask me.

Benm109

Cadillac- You just leave that where it is. All it does is allow the hot air around the exhaust manifold be routed into the engine when the car warms up. Once you get an open element just leave it there and don't worry about it.


BronYrAu0r- Thanks for posting that. Even though it's not HP numbers like someone requested, I think that is proof enough. And, an open element makes since anyway. Your allowing a whole lot more air in the engine, hot or not. That alone is more than worth it, in my opinion.

rx7speed

question though is on the drag strip how many variables are there from one run to the next
driver, launch rpms, stick of the track due to temp and other things, stick of the tires due to heat and such, air temps, air humidity, wind, and all sorts of other things

BronYrAur

iTrader: (1)

That doesn't really play much of a role though here. This was on the same day, probably 10 minutes apart between runs. Same operating temperature approx. Track conditions were the same, he used the same technique to launch and just left it in drive. I'd say that's pretty fair and that all variables were very close.

cali92RS

MMM...
If u look on precision industry's vigilante website they boast up to a .5 sec improvement on e/t's after using on of their converters. I guess we are all barking up the wrong tree. Why spend $800 on a torque convertor when u can spend $80 on a open element air cleaner.
Some people do cam swaps, head swaps or torque converter swaps (granted not all at the same time ) and not not pick up half a second, so u can see where the skeptisism comes from.

BronYrAur

iTrader: (1)

You're looking at this issue the wrong way. Those converters boast that kind of improvement on a healthy running engine. Any stock 305 TBI is not considered a healthy V8 by any stretch of the imagination. By getting rid of the factory air cleaner, you are eliminating a huge restriction in the intake tract. It's forcing our engines to breathe through a straw, the snorkel is tiny and the thermac blocks a huge amount of the already-small tube. With an open element you are allowing the engine to breathe as much as it wants whenever it needs the air. The stock setup is limiting the engine to breathing only a given (in this case small) amount of air even at WOT.

Cams and head swaps are for gaining big power on unrestricted setups. This open element is not really like "upgradeing" persay but it's removing a bottleneck to try to get a healthy engine. Headers and exhaust are the same deal, Check out the manifolds and Y-pipe on our cars. They are TINY, they also cause a giant restriction. Notice that most other cars that have decent factory exhaust will not gain big power from headers whereas TBI cars have seen gains of up to 30hp with just exhaust.

90RS305

Ok, heres a good way to look at it. Try this: With you're mouth closed and one nostil(sp?) plugged, try and breath normally. No prob right? Now start running. Don't work so well, huh? Now do the same thing with your mouth wide open. Works a LOT better! At the same time, you now have the potential to run faster, and more efficiently. The rest of your body can't really get more output unless it's getting more input. Same with our cars. Say you get a higher flow TBI unit. Ain't gonna do a whole lot of good if you don't have more air to flow to it...

Bruce (90RS305)

kdrolt

It's a stove that uses heated air (from around the exhaust manifold) to be digested by the engine. There is supposed to be a hose connecting the stove hole to the underside hole on the air cleaner snorkle. When the engine is cold, the intake air is supposed to be pulled from the tube so that the engine only uses heated air. After the engine warms up, the device in the snorkle is supposed to close-off the flow from the stove/pipe and instead pull cooler (unheated) air straight from the snorkle snout.

The set up is intended to help the engine warm up more quickly, especially in very cold climates.

Cadillac

Seems contrary. Cool air contains more O2 and therefore provides a better explosion/more power. I understand the engine warming explanation but in California I'd call that useless.

I just need to do this. I hope Kragen has the parts.

BronYrAur

iTrader: (1)

Best solution: Headers.

Cadillac

Cost? HP gain?

ShiftyCapone

iTrader: (7)

Cost depends on what you buy. Gains depend on what type you buy along with if you tune the car afterwards.

kdrolt

It has/had nothing to do with improving engine output. It had everything to do with quicker engine warmup, and therefore reducing unburned HC emissions.

That system might be useless in SoCal or Phoenix, but it's probably not useless in International Falls MN. Or the Michigan UP.

I forgot to add that the vacuum line oruting to the top of that snorkle means that when the driver goes to WOT, and the engine intake manifold pressure jumps to atmospheric, then the lack of vacuum causes a flap valve to shut off the heated airflow (from the stove) and allows unheated air to run directly from the snorkle mouth. So that system is designed to allow optimum power gain from denser cold(er) unheated air. That system will also work best when the mouth of the snorkle is ducted (with a suitable flexible hose) away from the engine compartment and closer to the front of the car to get the best cold air feed. The ONLY deficiency in this system is that there is a brief lag time for the valve to work, in addition to the lag of the cold air reaching the engine.

So it's actually a decent engineering design compromise for quicker engine warmup, excellent part throttle vaporization (from using warm engine air), and decent cold air ingestion during WOT. The use of the small-diameter long-throat snorkle also serves as an acoustic resonator to boost the VE during part throttle cruise, as well as to reducing intake noise at WOT.

To the untrained TGO eye, the factory air cleaner looks rather restrictive and low-performance..... but there are engineering reasons behind it. HTH.

Ann.racer92

dude kdrolt, wtf man we are here to get help with our cars and have fun with them, while you obviously know what you're talking about and im not in any way insulting your intelligence but "to the untrained tgo eye" cmon man. i read the post about that supposed 383 with the diff Tbi's and while you are extemely smart in a mathematical sense you're a big pain in the A** to us untrained TGO people.
in the couple of years i have been here ths forum has shown itself to be above and beyond what anyone had hoped for, IIRC there are one or two Tbi 305's in the 11's in part because of this board.
thanks for bringing your smarts to the convo but leave your attitude at the door.

Ann.racer92

my apologies your seemingly superior attitude pissed me off.

BronYrAur

iTrader: (1)

That was pretty harsh, someone asked why something was there (thermac) and he told them the reason for it and explained some other things. I'm sure it was very informative for a lot of people that didn't know that stuff. I've seen maybe 3 posts from you, I've seen many from him. Don't think you can come on the board and start saying stuff like that right off the bat, I think YOU need to leave the attitude at the door.

ShiftyCapone

iTrader: (7)

I didn't sense an attidude from him but I did sence some nice educational material. You should listen to him. He is merely stating how it works since people asked for it. Many people take science lessons as an insult. His was certainly not.

Ann.racer92

i apologized lack of tone of voice for reference can lead to different interperetations.

ShiftyCapone

iTrader: (7)

No harm done. Message boards are a lot like IM. It is hard to tell sarcasm from plain old knowledge sometimes. Fortunatly we have to help.

cali92RS

So if i say:

"Kiss my a$$ "...Its all good? Cool

ShiftyCapone

iTrader: (7)

You know what I mean.

90RS305

xlwhellraiser

iTrader: (1)

Yo, I have just dropped a 14 inch open element, and I took 8ft. 4inch "dryer to vent hook up kit" aluminum fire resistant. I stuck the ends of it right next to the fender where there is a hole between the fender, and battery and smog pump (its coming from both sides, ture dual, ha). Than I secured it to my air cleaner. This has made so much change to my 305 that its more than noticeable. Now I can actually burn tire if I press the gas 3/4 down. (this did not happen at all with stock cleaner). The bird takes a bit longer to warm up, and I can drive longer cooler (in 90degree weather). The acceleration is improved immensly as well.
Now I will hit 220, than go down to 160-170, run there for a while and get up to 180-190. Its just great. I will post pictures as soon as I take them
I would highly recommend an open element, but be carefull that its not rubbing against your coil wires, and if it is make sure you tape em up good, as well as your open element, and get some cardboard between them for security reasons. Trust me.

Good luck

Cadillac

Cripes almighty... how in the heck do I determine what product is right for my 305?

K&N Filters Site

I'm guessing that if "TraviZ" doesn't get back to me about one he might have for sale, I'll have to buy one new.



I guess I need to know if my neck flange is 5-1/8". Also, I suppose I should also shoot for the lowest element height?

~C

90RS305

Cadillac

Dragging this one from the depths...

Open element in from Sacramento (Thanks TJ!). I'm going to try and put it on this weekend (my birthday).

406-IROC

Try switching from the stock air cleaner, and then back to the open element... and observe you're RPM gauge. There is no doubt that you're RPM's increase much faster with the open element.

But, the reason people don't really 'feel' the difference with this being the first mod, is because now you're intake and heads have replaced the air cleaner, and have become the 'new' bottle-neck in it's place.

What good is more air, when the anemic 305 can't even use it to it's advantage?

After port matching the intake, heads, and installing a free flowing exhaust.... the benefit of switching to an open element will become very very prevalent.

Also.... try that little test again of switching back and forth from the stock air cleaner, to the open element... after the above mentioned mods that is.

Avenger007

Open element is good in some ways but it creates other problems, that of hot air intake charging. An open element can cause your engine to suck hot underhood air. While you are getting more air to your motor, you are getting more hot air as well. Check out this page and scroll down to "Cold air / ram air (CA/RA) induction for the 5.0 liter LO3". Hes got info and suggests a ramair system instead. Course you could combine them.

http://www.goingfaster.com/spo/modthel03.html

Poncho Villa

Open air element made a HUGE difference in my car! More power, faster and higher revs, and a burly induction noise. I have a Flowmaster catback, too, though, 3" I think, which probably helped the motor use the extra air.

Hot Rod magazine just did an article on K&N open elements, and proved they make more power. Best combo was an open air element on a stubstack, with an X-Stream filter lid.

As for the intake air being hotter, that may be so, but I still noticed an improvement. Besides, when you are driving, you still get some air circulation under the hood.

I want to get a ram air hood to get colder intake air. Had a duct under the front, blowing cold air up into the engine bay, but it was blowing dirt everywhere so I took it off. Did notice an impovement with the colder air though.

rsscoty

I did notice big difference in my '91 305, everyone keeps asking for data. There was an article on this very subject in Hot Rod I believe where they took an engine and dybo'd it with different air cleaner/ breather setups. I will do a search today and try to find it. Very good read.
Scoty

Cadillac

I want to see that.

jovial86

I got a quick question for you guys. Are you just supposed to leave the vacuum hose plugged with a bolt? That doesnt seem right to me for some reason. I'm going open element on my firebird so I can use a 3-point strut tower brace.

ShiftyCapone

iTrader: (7)

Don't plug the line, although that would work but look ugly. Instead cap off the vacuum port with a vacuum cap that is sold in the "help" section at autozone.

90RS305

Shifty is right. And to aid in curing your confusion, the whole reason you plug that line is to keep the vaccume line working properly, so your computer thinks its still connected. With the stock intake on and the vaccume line routed to its proper location, it is designed to open a valve going from the driver's side header (see: "heater stove") to your intake to allow warmer air into the mix and make cold starts easier. If left unplugged, when trying to start your car the computer would sense there is no vaccume pressure in that line and throw a code. Hope that made sense...
:werd:

Bruce (90RS305)