Quick background. I bought my 1997 C5 with a completely stock intake system on it. Removed it shortly after buying the car and installed a vararam that came with a descreened maf. Car ran ok but there were a few issues after the vararam that required tuning to correct, nothing big.

Fast forward a year. I recently had a custom comp cam 228/232 112+4, PRC Stg 1 243 heads, ls6 intake, slowhawk ported tb, 180 deg hypertech thermostat, Z06 Ti's, LG Street's and O/R pipes, underdrive pulley, LS7 lifters, OZ700 Textrailia, etc installed by CT Corvette. Steve did an excellent job and I have no complaints about the build.

Car was difficult to tune myself so I brought it to Slowhawk who did a good job but mentioned that the car wasn't responding to the tunes like he thought it should, plus the HP was down from where it should have been. Car put down 412/394 SAE thru my MN6 and 3.42's. It still had some surging at low rpm and occasional quirks but was very drivable, though sometimes a PITA with the OZ700 Textrailia. I tried cleaning the MAF and air filter but no real improvements.

Fast forward another couple months to today....I finally got around to swapping my OEM SCREENED maf into the car with the Vararam. HOLY CRAP!!!! Easily 80% of the drivability, idle, WOT, surging, etc are GONE...I mean GONE...I can lug it at 1000rpm in a parking lot and still rip all the way up to 6500+ rpm smoothly as can be. Highway economy is showing ~32mpg on the DIC while cruising ~75mph.

For anyone who is thinking of descreening, DON'T! I know the LS6's supposedly have a factory descreened MAF, and its very possible that I just had a bad MAF...but regardless I can confirm the 228/232 112+4 is a GREAT cam for street driving as long as the rest of your engine controls are functioning properly.

 

I agree 1000%.

 

Billdog350: Was the de-screened MAF, a factory, OEM / GM, LSI MAF, or an after market brand?

 

The key point folks need to realize is the LS6 setup has different frequency table weighting than an LS1 setup. You need to reprogram to take "advantage" of a de-screened MAF.

 

I took the screen out on my '01 Z06 before tuning... no issues to speak of.

 

My car runs perfect without the screen also. Even before the H/C with no tuning it ran fine.

 

Sounds like a tuning issue to me.. if the MAF were bad, the tuner should have seen that in the logs.

 

Glad you discovered the issue with your situation Something to consider when troubleshooting for sure!

Descreened here no problems when I was running around with a stock tune.

Dabbling with EFI Live now and have rescaled my MAF after doing the VE tune and its still working great descreened (despite my tuning LOL).

 

Exactly.

I don't know if there is any major performance advantage either way (screened / unscreened), but the MAF table does need to be properly calibrated regardless or the car won't run well.

Billdog, glad you got your issues fixed - I was heavily considering a grind similar to yours prior to going with the Patriot 226 cam; sounds like it is a winner as well!

Brent

 

Something else is going on here, descreening is really minor.

 

Removed the screen - no problems.

Had it tuned - no problems.

The screen straightens the air flow into the MAF and is necessary on side entry set ups like the trucks to smooth turbulance in the air flow. The corvette has a straight entry and the screen is not necessary. "The simple modification that should be performed to every MAF sensor is the gentle removal of the inside screen." How to Build High-Performance Chevy LS1/LS6 V-8s Will Handzel copyright 2004.

The only reason its there is production parts commonality and cost savings. The price premium of the Z06 justifiesa "screenless" MAF, other models get the screened version. There are a lot of common parts among Gen III LSx engines that if changed could improve performance.