Do you 3800sc swappers have this screen lookiing thing at the end of your TB? Purpose? Maybe to provide a more even air flow in the TB for accurate monitoring?

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" DRIVE IT LIKE YOU LOVE IT"

It is ment to straighten the airflow so the MAF sensor in the TB gets more accurate readings......Mine is a little crushed so I want to leave it out but some 97/98 engines dont like that....not sure if I leave it out or trying to get a replacement....

Thanks for the answer to that --have always wondered --I thought the screen was to keep unwanted debis out of there, as its not brought up often ..

[This message has been edited by 3800superfast (edited 09-10-2006).]

At my job as an Technical Designer I see alot of air systems for power boilers and I can see a need for this screen to give the MAF sensor an even flow for a more accurate reading. I was just wondering if what I know about large ducts and flues applies to automobles and to what degree. I know that when my 97 3800sc is running without a CAI when I put my hand just in front(not blocking but just near the opening) of the TB the engine seems to starve for air. It sounds like the MAF is pretty darn sensitive.

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" DRIVE IT LIKE YOU LOVE IT"

I kept mine in my bonnie. I took it out and it idled like crap, so I put it back in. This was in the Series I SC 94/95.

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'94 Bonneville SSEi - 115k
Law of Mechanical Repair:
After your hands become coated with grease, your nose will begin to itch or you'll have to pee... never fails.

quote Originally posted by Fie Ro: It is ment to straighten the airflow so the MAF sensor in the TB gets more accurate readings......Mine is a little crushed so I want to leave it out but some 97/98 engines dont like that....not sure if I leave it out or trying to get a replacement....

I know my 98 dosent like it gone. With it removed, idles rough - with it in, no issues.

They are essential for accurate MAF sensor inputs. Even tuned without it, the engine still won't run as good and still won't make as much power.

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"You sit here and try to challenge my intellegence" -vega

Hmm, I wonder why?

I pulled the TB screen in my 99 up TB on both my motors, never had an idle issue with either one. If you are running a 97/98 TB, then you need to pull the complete TB off and go to a 99 up TB. The 97/98 TB flow like 35-40% less then the 99 up right off the bat. This is because the 97/98 have the MAF body sticking right thru the center of the TB, blocking alot of incoming air. Never ran my 97/98 TB long enough without the screen to tell how it would idle. I did leave the screen in my 85mm SLP MAF when I upgraded to the LS1 TB though.

quote Originally posted by MstangsBware: Not true--All motors are not the same, so all react differant to differant MODs.

I said MAF. If the car has a MAF sensor, it needs SOMETHING to smooth out the airflow across the MAF shafts. This is done via the honeycomb screen in most applications. So unless you have an inline or vertical banked engine/cylinder, with vertical valve openings (Very common....right...), verticale intake runners, and a verticle throttle plate and MAF sensor, it will make a difference. ANY bend in the intake tract of the engine stroke will cause turbulence and unequal airflow, which all harm the MAF. You need the screen in for optimal ECU performance.

I've never had the screen on my TB since I bought the car (97 L67). I did experience some roughness in the idle, however after replacing my IAC and installing a CAI (PALINDROME!) it smoothed out. I don't know if replacing the screen would add any benefit or not. Just posting my anecdotal.

quote Originally posted by AaronZ34: I said MAF. If the car has a MAF sensor, it needs SOMETHING to smooth out the airflow across the MAF shafts. This is done via the honeycomb screen in most applications. So unless you have an inline or vertical banked engine/cylinder, with vertical valve openings (Very common....right...), verticale intake runners, and a verticle throttle plate and MAF sensor, it will make a difference. ANY bend in the intake tract of the engine stroke will cause turbulence and unequal airflow, which all harm the MAF. You need the screen in for optimal ECU performance.

A aftermarket MAF can be a MOD to a motor if you are adding a bigger TB to it. But besids that, I am saying you cant base one theory on all motors, they are all differant in one way or another. It has been proven over on Club GP all the time with ppl adding MODs to there cars and getting differnt results. I can say mine runs fine without the screen in and have had no issues.

As far as removing it,
Pros: No
Cons: Yes

Leave it in.

[This message has been edited by Jncomutt (edited 05-13-2006).]

quote Originally posted by MstangsBware: A aftermarket MAF can be a MOD to a motor if you are adding a bigger TB to it. But besids that, I am saying you cant base one theory on all motors, they are all differant in one way or another. It has been proven over on Club GP all the time with ppl adding MODs to there cars and getting differnt results. I can say mine runs fine without the screen in and have had no issues.

Yes an aftermarket MAF can be a modification, but not because it is more accurate, but because it minimalizes the inherent flaw of MAF-based systems, which is the restriction in intake airflow. And if you notice, most either come with some sort of air-regulation device, or use the factory honeycomb piece. Furthermore, a larger MAF doesn't have to go with a larger throttle body, in most applications the MAF is more of a restriction than the throttle body itself.

I have been on CGP for a while now, and I laugh at the increasing amounts of blown motors and rising ignorance. Show me an internal combustion engine that does not have ANY intake turbulance, and that is the one that doesn't need or won't benefit from a airflow equalizer. Until you can do that, EVERY engine I've seen has intake turbulence by design, thus airflow is uneven and will cause uneven MAF readings, resulting in poor EFI performance. How do you knwo your's runs fine? How about the classic CGP line, well my KR is only at *Insert number you think matters*

So its concluded that some run better with it in. And I read here that some TBs have different MAF that do not restrict air flow. So is an upgrade in TB recommended?

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" DRIVE IT LIKE YOU LOVE IT"

pulled off the zzp site

FREE MOD: Throttle Body Screen Removal





FREE MOD: Throttle Body Screen Removal
The stock Throttle Body can be restrictive even on a stock engine. The factory installs a screen in the inlet of the Throttle Body to straighten the air as it travels into the MAF sensor. This provides a smoother idle and more consistent fuel delivery. For Maximum performance this screen is disruption in the airflow that can be removed with little or *no adverse effects. On the flow bench we have realized a 10-15% increase in airflow by removing the screen.

Begin by using two sharp objects like screws to pinch the retaining C clip together. Pull towards you for removal. Insert a small object like a screw or flat head screw driver into the edge of the screen and pry it out being careful not to damage it.

* In 97 and 98 GM incorporated the MAF channel into the TB itself. On these cars we have noticed that some of them will idle rough without the screen in the throttle body. If you experience this, simply replace your screen.

I've seen a number of people on the F-body boards
damage their MAF screens trying to pry them out from
the front, which hurts if they need to put them back
in again.

Here's how I did it:
1. Pull off the intake
2. Remove the snap ring as you described. I hooked
it with the end of a paper clip
3. Use a small philips screwdriver to remove the MAF
sensor from the housing
4. Reach inside the throttle body with a finger and
carefully push the screen out
5. Reinstall the MAF sensor and replace the intake

Hope this helps out some people who don't like the
idea of prying at the edge of the thin honeycomb
metal.

-Jeff

quote Originally posted by AaronZ34: Yes an aftermarket MAF can be a modification, but not because it is more accurate, but because it minimalizes the inherent flaw of MAF-based systems, which is the restriction in intake airflow. And if you notice, most either come with some sort of air-regulation device, or use the factory honeycomb piece. Furthermore, a larger MAF doesn't have to go with a larger throttle body, in most applications the MAF is more of a restriction than the throttle body itself. I have been on CGP for a while now, and I laugh at the increasing amounts of blown motors and rising ignorance. Show me an internal combustion engine that does not have ANY intake turbulance, and that is the one that doesn't need or won't benefit from a airflow equalizer. Until you can do that, EVERY engine I've seen has intake turbulence by design, thus airflow is uneven and will cause uneven MAF readings, resulting in poor EFI performance. How do you knwo your's runs fine? How about the classic CGP line, well my KR is only at *Insert number you think matters*

You can keep spouting off all the Technical crap you want to out of your manuels, I could care less about what they say. I can tell you I run a de-screened TB and have no issues what so ever and still dont till this day. I do agree with you on the number of blown motors that you read about over on CGP. Thats from ppl with lack on knowledge and that dont ask questions before adding MODs. Most ppl go with an aftermarket MAF not because its a restiction in the TB but because they tap out the stock MAF or upgrade to a larger TB. And on the question of "How do you know yours runs fine?". I scan with AutoTap everytime I drive my car so I know exactly what my car is doing at all times. And I have 0 KR no matter how hard I push my car, why, because I have suppoting MODs to match what I have done to the motor.

I've also worked on quite a few L67s. But that's besides the point.

On many vehicles it won't make a highly noticable difference in fuel delivery. But it can, especially under certain weather conditions, and it isn't worth the risk for 5 imaginary horsepower.

Flow numbers are bullsh!t, learn that right now. Sure it may flow more, but what good is that when the rest of the engine doesn't? So since you're so good at proving things, we need to know the exact maximum flow of the 3800, boosted or N/A. Because I highly doubt the 6 intake ports on the ehad combined outflow the MAF. And even if they did it's useless becuase you are never pulling with all 6 cylinders, typically 1, maybe 2 at a time. So does the stock MAF outflow 2 cylinders at redline? I guarantee it does.

There is no such thing as a free mod. GM spends millions of dollars a year developing highly advanced fuel injection systems that outperform most aftermarket systems in EVERY category. From the factory your GM will never be out of tune. There is no reason to fu*k with this for the 5hp it might add.

As for the 9s comment, big deal, my Honda ran 10s.

Well I carefully removed my TB screen. When I started the engine up I noticed right away the idle was a little eractic but after a few minutes it settled down. I wasnt able to drive it because it raining again here in Akron. It does seem that the throttle is a little more responsive but then again it could be my imagination.

We will see.

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" DRIVE IT LIKE YOU LOVE IT"

do me a favour and save the screen if youre not going to use it....

quote Originally posted by Fie Ro: do me a favour and save the screen if youre not going to use it....

Ill keep it on hand just in case..

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" DRIVE IT LIKE YOU LOVE IT"

quote Originally posted by Fie Ro: do me a favour and save the screen if youre not going to use it....

If you need one, I have 2 good ones on hand that I pulled from my TBs.

quote Originally posted by MstangsBware: If you need one, I have 2 good ones on hand that I pulled from my TBs.

Thanks I may need one....mine is dented and bent in a few places, looks like its delicate stuff

this is my 98 (GTP) TB and you see the Maf housing is quite a restriction there

Are there any gains at all in smoothing that part (without disturbing Maf in/outlets)?

Wel I have mine out. no problems.

huh.. should there be? stock 98 TB

quote Originally posted by Fie Ro: Thanks I may need one....mine is dented and bent in a few places, looks like its delicate stuff Are there any gains at all in smoothing that part (without disturbing Maf in/outlets)?

If your screen is dented and crushed, then would be a good thng to pull it out or reaplce it if you wanna keep it in. There will be some small gains but to gain the most, upgrade to a 99 up TB and get rid of the 98 Tb you have.