Oh so true!

 

Thats why its there.

Douglas

 

LOL so all 2002-2004 Z06's have poor performance with FI

How on earth do they ever run right with no screen.

Why did GM take it out for the faster car?

Is that why ECS/Doug ditches the MAF?

I have FI and ran with 100mm, stock, and descreened MAF's and none had issues with turbulance.......
They all ran fine until they were maxxed out; perfect driveability. The only issue I ever saw was a maxxed out unit tripping the HF fail test.....with all of them.

If even one car runs right without the screen on FI, then its not an issue to descreen. Mine runs fine without it.

 

True, it's been debated for even longer than I've had the screen out of my LS1 Z28 LOL...which by the way still runs fine and fast after many miles and many years of daily driving and racing with no screen in it's MAF.

 

You are partially correct, an engineer told me the reason....Its use is not a function of performance. GM doesn't just delete it for faster cars...It is a simple function of the Reynols number of the flow regeim in the intake, nothing else....Depending on the air flow, it may range from laminar to transitional to turbulent. You do not want the air flow at the MAF to be in transitional nor to jump between regimes erratically and uncontrolled. The screen in the C6 is there for low air flows ONLY as they are transitional in this flow range. The screen forces the flow to turbulent allowing the MAF to read the flow correctly.

IT is best to leave it unless you are making changes that change air flow, such as force induction or engine displacement changes....

However....since it affects conditions at essentially idle...removing it will not affect performance at higer than idle rpms....IT is a game to reuce emissions, the fleet GM makes is looked at as a whole with regard to emissions, at idle cars are quite dirty, the screen improves this, but the results are only visible when all cars are looked at together, not inividually....

 

Like anything else in the performance world, adding/removing/leaving the MAF screen is one variable of tuning that should be part of an overall configuration that is right for your specific application. If all your components are perfectly matched and tuned on your car the screen is probably is not needed. In my case I believe it is a way to offset the issue of turbulence at low air speeds due to my air intake design. There is no question it worked!
In the end words like "always" or "never" just do not apply in all cases since each case is specific to the circumstance.

 

Is it true that the LS3 does not have a MAF screen?

 

No screen same style as the LS7

 

Hope your right about the NA 440 making 30hp w/ the LPE 100mm. I am swapping out a 99 C5 78mm on Tues for a 100mm LPE in my LS7 440. We are going to dyno the car before we start, we may also dyno it w/ an 85mm as well as the 100mm. I will be posting the results in the C5 general section Tuesday night...

 

I have never seen a car lose power from it and higher HP cars arent at the magical flow levels you report GM has them at. I dont buy a word of it based on not seeing a single shread of dyno or track proof to support any of the tech info this engineer has told you.

Heresay has just as much value here as it does in court.

FI cars dont run it.

C5 Z06 deleted it at the factory and you may want to take a look at the air cleaner assembly before you quote that GM uses it whern the assembly needs it. No screen and its exactly the same as the base C5 with a screen. This car can pass emissions even with a cam 20 degrees more intake duration than the stock cam so its not even close to needing a screen for that reason. Saying the LS engine is dirty at idel is really misinformed. Its actually one of the cleanest running engines around and my C5 w/forged 348 with a 224/230 cam and ported heads with no screen on the MAF passed emissions for years in NY when they had the sniffer.

I ran my C5's and C6's without them and just about every car I tuned and they span the universe for power levels and thereofre air flow levels....stock to 800hp. I have yet to see a car lose power from it so please produce even one car that did.....any power level.

 

He is on this forum if he wants to chime in.

Post them here too so we can see the lower dyno numbers with the lack of laminar air flow straightening science.

 

Another tuner could have gotten the same result with or without a screen.

 

Heresay, hardly. That is the beauty of science. There really is no debate as the concept of the Reynolds number has been settled science since 1883 when presented by Osborne Reynolds.

The only debate over time has been the types of people tackling fluid mechanics problems. Those that understand, those that do not understand, and those that desire to learn.

The Reynolds number does not care about dynos, tracks, streets or garages. There really is nothing magical about it as you say, its beauty is in its simplicity. It does not matter the car, F1 or Tata....It is a function of velocity, dynamic viscosity, diameter (in this case) and density.

The point where we are talking here is at the MAF, so the air filter has is really just a minor loss in the flow equation. We are also not talking about laminar flows, since the intake does not flow in that regime under operating conditions.

Since fluid flow (air) is conserved in our engine system, to change the need to have the screen or not, you will need to change something in the Reynolds equation. Holding the other variables at STP, to increase HP in our engines, flow of air is increased either by increase in displacement or pushing more air into the engine. Beautiful, isn't it?

Can you remove the screen? Sure....Is the MAF sensing element calibrated to have the screen there? Sure is. What will removing the screen affect? A slight increase in the pressure (decrease in vacuum) of the air reaching the cylinders by removal of the screen as a minor loss; and the calibration of the MAF sensing unit since it was calibrated to have the screen there.

As for the engine being dirty at idle, all engines are dirtiest at idle conditions, that is common knowledge and our vette engines are no different. Anything GM does to make this condition better, when applied across the fleet, makes their environmental emissions, as a whole, better.

 

I have to chime in here, if you change a fact, you change the conclusion. I am not arguing either way about "reynolds" as I am unfamiliar with it, although it seems to make sense. However, here are some facts we can probably agree on, that I know to be true. the MAF screen in question is a restriction on the order of 100 cfm, or more. This was determined by SLP in NJ., as well as other entities . And yes the screened MAF was calibrated with the screen , but if you make the proper adjustment to LTFT's as well as enrichment values, you then have a properly scaled MAF that can flow 100+ more cfm. Weather or not your particular set up can make use of that additional flow is another point. But why port the throttle body, intake manifold and heads and then leave the screen in ? Let the big dog eat ! A restriction is a restriction. Get as much air through the engine as possible, adj the fuel proportionately, make HP ! NASCAR put restrictor plates on the cars, why? TO SLOW THEM DOWN ! Ok I done , sorry,... too much coffee this morning .......

 

I removed the Vararam and reinstalled my OEM intake.





I did not purchase this intake, it came on the car. However, this is the 2nd Vararam product that I've had on a vehicle of mine and the quality of both has been trash. Thanks to screened MAF's and their ability to pick up the slack where Vararam left off

 

What kinda of small particulate got through? That's scary.

 

Probably more than I care to worry about at this point. What's done is done. If the oil filter had been the item of interest then I would have a greater concern....but the car runs fine.

 

Damn, that is worse than mine! My Vararam had sand in it when I took it off though

For what its worth; both tuners I consulted with before supercharging my car recommended me to NOT remove the screen; their reasoning was that the gains are negligible and MAF accuracy is reduced without the screen in place.

 

Sorry you had problems, please don't hijack this thread with your Vararam issues. This thread is about removing your MAF screen for performance reasons or possibly going with a Speed Density Tune for higher HP applications, and up to this point has been pretty informative.

Not being a dick, but I can just see this thread getting de-railed into a my CIA is better than yours e-fight.

 

So you removed your vara-trash and installed boost?