C5 MAF Sensor Screen removal
nttp
I am thinking of removing the screen on my 2001 C5 LS1 MAF sensor. I am
installing ram-air and this screen will definitely reduce the flow. I have a
good K&N filter system installed and the unit should not be subject to any
debris.
Has anybody mad this modification, and if so, what is your feedback? Is
there any negative effect?
Thanks,
John
2001 Millennium Yellow C5 Roadster.
reply jsareNOB...@rogers.com
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Gerd Henjes
If you have a way to tune your MAF after you pull the screen and add the K&N
system I'd say go for it.
If you don't you are going to be running lean. The computer will probably
correct for this, but continue to add additional fuel at WOT.
From what I've seen most LS-1's are already rich at WOT, so you will end up
a loser as far as performance is concerned.
Gerd
'97 C-5 Auto. '04 Z-06 with HP Tuning software
"nttp" <jsareNOB...@rogers.com> wrote in message
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Larry Bud
> system I'd say go for it.
>
> If you don't you are going to be running lean. The computer will probably
> correct for this, but continue to add additional fuel at WOT.
>
> From what I've seen most LS-1's are already rich at WOT, so you will end up
> a loser as far as performance is concerned.
How do you come to that conclusion? The more air and gas you pump
into the engine, the better.
Jack Conley
"Larry Bud" <larryb...@yahoo.com> wrote in message
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i agree, by removing the screen on a car that already runs rich, you are
adding more air with the same amount of fuel creating a better mixture and
more power... i don't think the car will go "lean" just not as rich as it
used to be.
jack
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Mike
Screens in front of hot wire sensors really have two jobs.
One is to protect against large objects and critters should the
upstream filter fail or be missing. The other is to smooth out
the airflow so that the hot wire is sensing average airflow.
When the screen comes out, inlet duct turbulence comes into
play and airflow at the hot wire may not represent the average
airflow across the crossection of the MAF for all flow rates (from
partial throttle to WOT.) So, mixture may be lean at some flow
rates and rich at others in comparison to running with the screen
in place.
Regards, "Mike"
-- mikeellison3xxxatzzzyahoo.com --
nttp
"nttp" <jsareNOB...@rogers.com> wrote in message
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Larry Bud
That's an interesting theory that I had not thought about. I wonder
if anyone has ever done any tests to see how the sensed flow rate may
vary compared to the average flow rate with and without the screen.
Larry Bud
That's an interesting theory that I had not thought about. I wonder
Refinish King
Without the screen, you are ingesting a big turbulent mass of air, rather
than a more diffuse straightened air stream. So the heated wire would need
more amperage to measure the more massive and turbulent air passing it,
leading the ECM to think that you are at a higher speed and have the
throttle open wider than the actual TPS voltage is reading. It would set a
code.
As far as tuning a MAF, the only way to do that is by injecting an
artificially higher reference voltage, and I hope you know what you're doing
if you attempt that?
Half a volt can destroy the power transistor and also kill the ECM.
I hope this helps?
Refinish King
PS
The best way to keep the MAF healthy is to: gently clean the heated wire
with CRC electronics cleaner(The smaller can, not the bigger can of
electronics parts cleaner)
"Larry Bud" <larryb...@yahoo.com> wrote in message
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Dad
news:EvKEc.800$Kw6...@fe39.usenetserver.com...
> The screen is definitely there to make the air more diffuse:
>
> Without the screen, you are ingesting a big turbulent mass of air, rather
> than a more diffuse straightened air stream. So the heated wire would need
> more amperage to measure the more massive and turbulent air passing it,
> leading the ECM to think that you are at a higher speed and have the
> throttle open wider than the actual TPS voltage is reading. It would set a
> code.
Removing the screen did not set a code. Not sure there has been an effect
either way.
--
Dad
04 C5 CE Z51
72 Shark Black/Black/4spd
Refinish King
But it does interfere with the correct operation of the heated wire
principal.
Good luck and take the time to clean the wire at least at every oil change.
You might notice your relays, especially the MAF relay burning out more.
Because of the wire running hotter and the excess amperage needed to keep
the wire heated to it's specified temperature.
Again, good luck!
Refinish King
"Dad" <knoc...@fish.net> wrote in message
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Dad
much oil in the K&N air filter that time. Always got 25 plus miles per
gallon and never lost a relay, but then I only had 46,000 on it so anything
could have happened.
--
Dad
04 C5 CE Z51
72 Shark Black/Black/4spd
"Refinish King" <noneofyou...@mindyourbusiness.com> wrote in message
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Vetluver
"nttp" <john_sa...@hotmail.com> wrote in message
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I took off my screens at the recommendation of a book called TPIS Insider
Hints for the L98. That was in 91. I just replaced my original MAF. Removal
of the screens was one of the first things they did to increase air flow to
the engine when they raced Vettes in the "Corvette Challenge Series". Myron
Cottrell did flow bench studies that are sited in the book which prove that
CFM is increased significantly with removal of the screens. Just by
decreasing impedences to flow they increased CFM from 400 range to the 600
range as I recall. A stock L98 may not need that much of an increase, but
you change internals, high flow exhaust, headers etc and start running
toward 6000+ rpm, which the C5 also does, you need that airflow to make HP.
I have a well massaged L98 and have not removed the screens from my new MAF
and I can tell you that there is a huge difference in flow rates to the
motor. It has decreased the trottle response and quickness. 0-60 times are
significantly different. I don't know if they have changed the screens or
the design that much on the C5 but air flow is air flow, the more you have
the more HP you make. I may be simplifying this too much but track times
don't lie.
Do they not have a burnoff circuit to clean the wire on the new ones? I
wasn't aware that they ever need cleaning.
Rob
Refinish King
In every day diagnostics, whether it's a vette or a Camaro with an MAF, when
I have a no start problem. If I find the screen is removed, I usually find
the relay being the culprit.
So your success and I'm sure many other's on the group, has me barking up
the wrong trying to figure the high rate of relay failures. When screens are
removed?
I lurk here a lot, because I do a lot of computer modifications, and I find
the information valuable, and also get a chuckle out of Diode. But again
thank you for your valuable input.
Sincerely,
Refinish King